| 0/0 |
2026/08/12 11:59 |
flow |
repro-c |
57m
Results: map[EquivalenceAnalysis:The reproducer successfully triggered the exact bug. The crash report shows the same WARNING in irqentry_exit originating from hrtimer_test_and_clear_rearm_deferred_tif as the original bug description. The call traces match perfectly. OtherCrashReports:<nil> ReproC:#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <sched.h>
#include <string.h>
#include <errno.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_SET 2
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
#endif
#ifndef SYS_rseq
#define SYS_rseq 334
#endif
struct my_rseq_slice_ctrl {
union {
uint32_t all;
struct {
uint8_t request;
uint8_t granted;
uint16_t __reserved;
};
};
};
struct my_rseq {
uint32_t cpu_id_start;
uint32_t cpu_id;
uint64_t rseq_cs;
uint32_t flags;
uint32_t node_id;
uint32_t mm_cid;
struct my_rseq_slice_ctrl slice_ctrl;
uint8_t __reserved;
char end[];
} __attribute__((aligned(64)));
int thread_fn(void *arg) {
struct my_rseq *rseq_area = NULL;
if (posix_memalign((void **)&rseq_area, 64, sizeof(struct my_rseq)) != 0) {
printf("[-] posix_memalign failed: %s\n", strerror(errno));
exit(1);
}
memset(rseq_area, 0, sizeof(struct my_rseq));
/* Register our custom RSEQ area */
int ret = syscall(SYS_rseq, rseq_area, sizeof(struct my_rseq), 0, 0x53053053);
if (ret != 0) {
printf("[-] rseq syscall failed: %s\n", strerror(errno));
exit(1);
}
/* Enable the RSEQ time slice extension feature */
if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0) != 0) {
printf("[-] prctl PR_RSEQ_SLICE_EXTENSION failed: %s\n", strerror(errno));
exit(1);
}
/*
* Spin in user space requesting a slice extension.
* A timer interrupt will eventually hit, set _TIF_NEED_RESCHED,
* and trigger the lockdep warning on return to user space.
*/
while (1) {
rseq_area->slice_ctrl.request = 1;
/* Prevent compiler from optimizing out the store */
asm volatile("" ::: "memory");
}
return 0;
}
int main() {
cpu_set_t set;
CPU_ZERO(&set);
CPU_SET(0, &set);
if (sched_setaffinity(0, sizeof(set), &set) != 0) {
printf("[-] sched_setaffinity failed: %s\n", strerror(errno));
exit(1);
}
printf("[+] sched_setaffinity successful.\n");
for (int i = 0; i < 2; i++) {
char *stack = malloc(1024 * 1024);
if (!stack) {
printf("[-] malloc failed: %s\n", strerror(errno));
exit(1);
}
void *stack_top = (void *)(((uintptr_t)stack + 1024 * 1024) & ~0xF);
pid_t pid = clone(thread_fn, stack_top,
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD, NULL);
if (pid == -1) {
printf("[-] clone failed: %s\n", strerror(errno));
exit(1);
}
}
printf("[+] Created 2 spinning threads on CPU 0.\n");
/* Wait enough time for the scheduler tick to hit the spinning threads */
sleep(5);
printf("[+] Done.\n");
return 0;
}
Reproduced:true ReproducedBugTitle:WARNING in irqentry_exit ReproducedCrashReport:------------[ cut here ]------------
__lockdep_enabled && this_cpu_read(hardirqs_enabled)
WARNING: include/linux/hrtimer_rearm.h:17 at hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_loop kernel/entry/common.c:54 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at exit_to_user_mode_loop kernel/entry/common.c:101 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit+0x484/0x8f0 kernel/entry/common.c:165, CPU#0: syz-executor381/5899
Modules linked in:
CPU: 0 UID: 0 PID: 5899 Comm: syz-executor381 Not tainted syzkaller #1 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline]
RIP: 0010:hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline]
RIP: 0010:rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline]
RIP: 0010:__exit_to_user_mode_loop kernel/entry/common.c:54 [inline]
RIP: 0010:exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
RIP: 0010:__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
RIP: 0010:irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
RIP: 0010:irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
RIP: 0010:irqentry_exit+0x484/0x8f0 kernel/entry/common.c:165
Code: 00 00 00 00 00 0f 01 ca c6 83 59 16 00 00 00 0f 1f 44 00 00 48 83 3c 24 00 0f 85 46 01 00 00 e8 02 e5 fc f5 e9 d4 fe ff ff 90 <0f> 0b 90 e9 74 ff ff ff 48 89 df e8 9c e4 fc f5 41 89 c7 89 44 24
RSP: 0000:ffffc90003c9fef0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: ffff88810d470000 RCX: 0000000000000046
RDX: 0000000000000000 RSI: ffffffff8e167570 RDI: ffffffff8c321580
RBP: 00000000ffffe000 R08: ffffffff90608537 R09: 1ffffffff20c10a6
R10: dffffc0000000000 R11: fffffbfff20c10a7 R12: ffff88810d471648
R13: 0000000000001010 R14: ffffc90003c9ff48 R15: 0000000000001388
FS: 000055558794e400(0000) GS:ffff8881a50f5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1060ef0fe8 CR3: 00000001fcd34000 CR4: 0000000000352ef0
Call Trace:
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0033:0x7f1060f019ab
Code: 00 00 e8 f8 2e 00 00 45 31 c0 31 c9 31 c0 ba 01 00 00 00 be 02 00 00 00 bf 4f 00 00 00 e8 7d de 01 00 85 c0 75 0a c6 43 1c 01 <c6> 43 1c 01 eb f6 e8 0a 29 00 00 8b 38 e8 33 55 01 00 48 8d 3d 74
RSP: 002b:00007f1060ef0ff0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00005555879507c0 RCX: 00007f1060f1f82a
RDX: 0000000000000001 RSI: 0000000000000002 RDI: 000000000000004f
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe9234cc68
R13: 0000000000000002 R14: 00007f1060fa2cc0 R15: 0000000000000002
</TASK>
]
|
| 1/1 |
2026/08/12 11:59 |
action |
kernel-checkouter |
0m
Results: map[KernelSrc:/app/workdir/cache/src/c45b8d2d54442f1c99f033bbcbb42035c84d8267]
|
| 2/1 |
2026/08/12 11:59 |
action |
kernel-builder |
26m
Results: map[KernelObj:/app/workdir/cache/build/4294aa5a624a5018d74b040887a789c459a1e124]
|
| 3/1 |
2026/08/12 12:26 |
action |
codesearch-prepare |
11m
Results: map[Index:codesearch-index]
|
| 4/1 |
2026/08/12 12:38 |
agent |
initial-researcher |
4m
Model:
Instruction: 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.
Prompt: Bug Description: WARNING in irqentry_exit
------------[ cut here ]------------
__lockdep_enabled && this_cpu_read(hardirqs_enabled)
WARNING: ./include/linux/hrtimer_rearm.h:17 at hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_loop kernel/entry/common.c:54 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at exit_to_user_mode_loop kernel/entry/common.c:101 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit+0x718/0xa00 kernel/entry/common.c:165, CPU#0: syz.2.3762/30761
Modules linked in:
CPU: 0 UID: 0 PID: 30761 Comm: syz.2.3762 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:hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline]
RIP: 0010:hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline]
RIP: 0010:rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline]
RIP: 0010:__exit_to_user_mode_loop kernel/entry/common.c:54 [inline]
RIP: 0010:exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
RIP: 0010:__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
RIP: 0010:irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
RIP: 0010:irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
RIP: 0010:irqentry_exit+0x718/0xa00 kernel/entry/common.c:165
Code: 00 00 00 80 e8 c9 ee 58 f6 fb 83 3d 95 d1 69 05 00 74 1a 65 8b 05 d8 2a ab 08 85 c0 75 0f 65 8b 05 29 26 ab 08 85 c0 74 04 90 <0f> 0b 90 41 f7 c5 00 10 00 00 0f 84 74 fc ff ff f0 41 80 64 24 01
RSP: 0000:ffffc9000414ff00 EFLAGS: 00010202
RAX: 0000000000000001 RBX: ffffc9000414ff48 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8e1a8f2e RDI: ffffffff8c400a80
RBP: ffffc9000414ff38 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888022f39f00
R13: 0000000000000010 R14: 000001efbbd43bba R15: 0000000000000000
FS: 00007f3e64dd56c0(0000) GS:ffff888123de1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ddddff8 CR3: 0000000034bd6000 CR4: 00000000003526f0
Call Trace:
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0033:0x7f3e66b9e019
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:00007f3e64dd50e8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f3e66e26098 RCX: 00007f3e66b9e019
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3e66e26098
RBP: 00007f3e66e26090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3e66e26128 R14: 00007ffe410c4bf0 R15: 00007ffe410c4cd8
</TASK>
Reply: ### Bug Analysis
The bug is a logic error in the exit-to-user-mode path regarding the RSEQ (Restartable Sequences) time slice extension feature.
When returning to user space, the kernel checks for pending work in `__exit_to_user_mode_loop()`. If rescheduling is needed (`_TIF_NEED_RESCHED`), it attempts to grant an RSEQ slice extension by calling `rseq_grant_slice_extension()`. Crucially, just before this check, `local_irq_enable()` is called, meaning `rseq_grant_slice_extension()` executes with **interrupts enabled**.
If the slice extension is granted, `rseq_grant_slice_extension()` calls `hrtimer_rearm_deferred_tif()`, which in turn calls `hrtimer_test_and_clear_rearm_deferred_tif()`. This function contains a `lockdep_assert_irqs_disabled()` check. Because interrupts were explicitly enabled in the loop above, this assertion fails, triggering the reported `WARNING`.
### Reproduction Strategy
To trigger this bug, we need to force `rseq_grant_slice_extension()` to successfully grant a slice extension while returning from a timer interrupt. The conditions for this are:
1. The thread must have a registered RSEQ area large enough to support v2 features (size $\ge$ 33 bytes).
2. The RSEQ slice extension must be enabled for the thread via `prctl(PR_RSEQ_SLICE_EXTENSION)`.
3. The user-space `rseq.slice_ctrl.request` flag must be set to `1`.
4. A timer interrupt must hit the thread while it is executing in user space, setting `_TIF_NEED_RESCHED` without setting other pending work flags (like signals).
We can achieve this by creating a raw thread using `clone()` (to bypass glibc's default RSEQ registration), registering a properly aligned 64-byte RSEQ structure, enabling the slice extension, and spinning in an infinite loop that continuously sets the `request` flag. When the scheduler tick interrupts the loop, the bug will trigger on the return to user space.
### Minimal Reproducer
```c
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <sched.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_SET 2
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
#endif
struct my_rseq_slice_ctrl {
union {
uint32_t all;
struct {
uint8_t request;
uint8_t granted;
uint16_t __reserved;
};
};
};
/*
* RSEQ area must be large enough (>= 33 bytes) to support slice_ctrl
* and aligned to the allocation alignment (64 bytes).
*/
struct my_rseq {
uint32_t cpu_id_start;
uint32_t cpu_id;
uint64_t rseq_cs;
uint32_t flags;
uint32_t node_id;
uint32_t mm_cid;
struct my_rseq_slice_ctrl slice_ctrl;
uint8_t __reserved;
char end[];
} __attribute__((aligned(64)));
struct my_rseq rseq_area;
int thread_fn(void *arg) {
/* Register our custom RSEQ area */
int ret = syscall(SYS_rseq, &rseq_area, sizeof(rseq_area), 0, 0x53053053);
if (ret != 0) {
perror("rseq");
return 1;
}
/* Enable the RSEQ time slice extension feature */
if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0) != 0) {
perror("prctl");
return 1;
}
/*
* Spin in user space requesting a slice extension.
* A timer interrupt will eventually hit, set _TIF_NEED_RESCHED,
* and trigger the lockdep warning on return to user space.
*/
while (1) {
rseq_area.slice_ctrl.request = 1;
}
return 0;
}
int main() {
char *stack = malloc(1024 * 1024);
if (!stack) {
perror("malloc");
return 1;
}
/*
* Use clone with CLONE_VM to ensure the new thread does not inherit
* any existing glibc RSEQ registrations.
*/
pid_t pid = clone(thread_fn, stack + 1024 * 1024,
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD, NULL);
if (pid == -1) {
perror("clone");
return 1;
}
/* Wait for the thread to trigger the bug */
sleep(2);
return 0;
}
```
|
| 5/2 |
2026/08/12 12:38 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 4642
output: 38
thoughts: 109
Thoughts: **Bug Report Analysis: High-Resolution Timer Rearm Warning**
So, I've just encountered a bug report that's flagged a `WARNING` originating from `irqentry_exit`. This warning specifically points to `include/linux/hrtimer_rearm.h:17`, and more precisely, the function `hrtimer_test_and_clear_rearm_deferred_tif` within that file. It's occurring on CPU #0 and seems to be associated with a syzbot test instance (`syz.2.3762/30761`).
My immediate next step, given this information, is to dive directly into the source code at the indicated location: `include/linux/hrtimer_rearm.h:17`. I need to understand the context of this `WARNING` and how `hrtimer_test_and_clear_rearm_deferred_tif` is being invoked and what conditions might be leading to this warning. This will likely involve tracing the call stack and examining the state of the high-resolution timer rearm flags.
|
| 6/2 |
2026/08/12 12:38 |
tool |
read-file |
0m
Args: map[File:include/linux/hrtimer_rearm.h FirstLine:1 LineCount:100]
Results: map[Contents: 1: // SPDX-License-Identifier: GPL-2.0
2: #ifndef _LINUX_HRTIMER_REARM_H
3: #define _LINUX_HRTIMER_REARM_H
4:
5: #ifdef CONFIG_HRTIMER_REARM_DEFERRED
6: #include <linux/thread_info.h>
7:
8: void __hrtimer_rearm_deferred(void);
9:
10: /*
11: * This is purely CPU local, so check the TIF bit first to avoid the overhead of
12: * the atomic test_and_clear_bit() operation for the common case where the bit
13: * is not set.
14: */
15: static __always_inline bool hrtimer_test_and_clear_rearm_deferred_tif(unsigned long tif_work)
16: {
17: lockdep_assert_irqs_disabled();
18:
19: if (unlikely(tif_work & _TIF_HRTIMER_REARM)) {
20: clear_thread_flag(TIF_HRTIMER_REARM);
21: return true;
22: }
23: return false;
24: }
25:
26: #define TIF_REARM_MASK (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY | _TIF_HRTIMER_REARM)
27:
28: /* Invoked from the exit to user before invoking exit_to_user_mode_loop() */
29: static __always_inline bool
30: hrtimer_rearm_deferred_user_irq(unsigned long *tif_work, const unsigned long tif_mask)
31: {
32: /* Help the compiler to optimize the function out for syscall returns */
33: if (!(tif_mask & _TIF_HRTIMER_REARM))
34: return false;
35: /*
36: * Rearm the timer if none of the resched flags is set before going into
37: * the loop which re-enables interrupts.
38: */
39: if (unlikely((*tif_work & TIF_REARM_MASK) == _TIF_HRTIMER_REARM)) {
40: clear_thread_flag(TIF_HRTIMER_REARM);
41: __hrtimer_rearm_deferred();
42: /* Don't go into the loop if HRTIMER_REARM was the only flag */
43: *tif_work &= ~TIF_HRTIMER_REARM;
44: return !*tif_work;
45: }
46: return false;
47: }
48:
49: /* Invoked from the time slice extension decision function */
50: static __always_inline void hrtimer_rearm_deferred_tif(unsigned long tif_work)
51: {
52: if (hrtimer_test_and_clear_rearm_deferred_tif(tif_work))
53: __hrtimer_rearm_deferred();
54: }
55:
56: /*
57: * This is to be called on all irqentry_exit() paths that will enable
58: * interrupts.
59: */
60: static __always_inline void hrtimer_rearm_deferred(void)
61: {
62: hrtimer_rearm_deferred_tif(read_thread_flags());
63: }
64:
65: /*
66: * Invoked from the scheduler on entry to __schedule() so it can defer
67: * rearming after the load balancing callbacks which might change hrtick.
68: */
69: static __always_inline bool hrtimer_test_and_clear_rearm_deferred(void)
70: {
71: return hrtimer_test_and_clear_rearm_deferred_tif(read_thread_flags());
72: }
73:
74: #else /* CONFIG_HRTIMER_REARM_DEFERRED */
75: static __always_inline void __hrtimer_rearm_deferred(void) { }
76: static __always_inline void hrtimer_rearm_deferred(void) { }
77: static __always_inline void hrtimer_rearm_deferred_tif(unsigned long tif_work) { }
78: static __always_inline bool
79: hrtimer_rearm_deferred_user_irq(unsigned long *tif_work, const unsigned long tif_mask) { return false; }
80: static __always_inline bool hrtimer_test_and_clear_rearm_deferred(void) { return false; }
81: #endif /* !CONFIG_HRTIMER_REARM_DEFERRED */
82:
83: #endif
]
|
| 7/2 |
2026/08/12 12:38 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 6103
output: 35
thoughts: 404
Thoughts: **My Investigation into a `lockdep_assert_irqs_disabled()` Warning**
Alright, so I've just encountered a `lockdep_assert_irqs_disabled()` warning. This immediately tells me something is wrong with interrupt context management; specifically, an assertion is failing because interrupts are *not* disabled when they are expected to be. The specific location pointed out by the warning is `include/linux/hrtimer_rearm.h:17`.
Looking at the call trace provided, I can see a clear path leading to this assertion failure. The highest function in the trace, the one directly triggering the assert, is `hrtimer_test_and_clear_rearm_deferred_tif` at the exact line mentioned. This function is then called by `hrtimer_rearm_deferred_tif` and subsequently by `rseq_grant_slice_extension`.
The path continues deeper, involving functions like `__exit_to_user_mode_loop` and `exit_to_user_mode_loop` in `kernel/entry/common.c`, and then through a series of `irqentry_exit_to_user_mode_prepare` and finally `irqentry_exit`. This chain of calls suggests that the problem is occurring during a transition from kernel mode back to user mode, specifically within the interrupt entry/exit handling.
My immediate next step, as an expert in this domain, would be to dive into the source code at `kernel/entry/common.c:54` and `include/linux/rseq_entry.h:236`. I want to understand the precise logic within `rseq_grant_slice_extension` and the surrounding code in `__exit_to_user_mode_loop` that leads to the call to `hrtimer_test_and_clear_rearm_deferred_tif` in a state where interrupts are not disabled. This will likely involve scrutinizing how deferred timer rearming is handled during the context switch back to user space, and where the interrupt disabling state might be incorrectly managed or lost.
|
| 8/2 |
2026/08/12 12:38 |
tool |
read-file |
0m
Args: map[File:kernel/entry/common.c FirstLine:40 LineCount:100]
Results: map[Contents: 40: #define TIF_SLICE_EXT_DENY (EXIT_TO_USER_MODE_WORK & ~TIF_SLICE_EXT_SCHED)
41:
42: static __always_inline unsigned long __exit_to_user_mode_loop(struct pt_regs *regs,
43: unsigned long ti_work)
44: {
45: /*
46: * Before returning to user space ensure that all pending work
47: * items have been completed.
48: */
49: while (ti_work & EXIT_TO_USER_MODE_WORK_LOOP) {
50:
51: local_irq_enable();
52:
53: if (ti_work & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)) {
54: if (!rseq_grant_slice_extension(ti_work, TIF_SLICE_EXT_DENY))
55: schedule();
56: }
57:
58: if (ti_work & _TIF_UPROBE)
59: uprobe_notify_resume(regs);
60:
61: if (ti_work & _TIF_PATCH_PENDING)
62: klp_update_patch_state(current);
63:
64: if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) {
65: futex_fixup_robust_unlock(regs);
66: arch_do_signal_or_restart(regs);
67: }
68:
69: if (ti_work & _TIF_NOTIFY_RESUME)
70: resume_user_mode_work(regs);
71:
72: /* Architecture specific TIF work */
73: arch_exit_to_user_mode_work(regs, ti_work);
74:
75: /*
76: * Disable interrupts and reevaluate the work flags as they
77: * might have changed while interrupts and preemption was
78: * enabled above.
79: */
80: local_irq_disable();
81:
82: /* Check if any of the above work has queued a deferred wakeup */
83: tick_nohz_user_enter_prepare();
84:
85: ti_work = read_thread_flags();
86: }
87:
88: /* Return the latest work state for arch_exit_to_user_mode() */
89: return ti_work;
90: }
91:
92: /**
93: * exit_to_user_mode_loop - do any pending work before leaving to user space
94: * @regs: Pointer to pt_regs on entry stack
95: * @ti_work: TIF work flags as read by the caller
96: */
97: __always_inline unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
98: unsigned long ti_work)
99: {
100: for (;;) {
101: ti_work = __exit_to_user_mode_loop(regs, ti_work);
102:
103: if (likely(!rseq_exit_to_user_mode_restart(regs, ti_work)))
104: return ti_work;
105: ti_work = read_thread_flags();
106: }
107: }
108:
109: noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs)
110: {
111: if (user_mode(regs)) {
112: irqentry_state_t ret = {
113: .exit_rcu = false,
114: };
115:
116: irqentry_enter_from_user_mode(regs);
117: return ret;
118: }
119:
120: return irqentry_enter_from_kernel_mode(regs);
121: }
122:
123: /**
124: * arch_irqentry_exit_need_resched - Architecture specific need resched function
125: *
126: * Invoked from raw_irqentry_exit_cond_resched() to check if resched is needed.
127: * Defaults return true.
128: *
129: * The main purpose is to permit arch to avoid preemption of a task from an IRQ.
130: */
131: static inline bool arch_irqentry_exit_need_resched(void);
132:
133: #ifndef arch_irqentry_exit_need_resched
134: static inline bool arch_irqentry_exit_need_resched(void) { return true; }
135: #endif
136:
137: void raw_irqentry_exit_cond_resched(void)
138: {
139: if (!preempt_count()) {
]
|
| 9/2 |
2026/08/12 12:38 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 7980
output: 39
thoughts: 217
Thoughts: **My Thought Process Unraveling a Kernel Conundrum**
My current focus is on the `__exit_to_user_mode_loop` function within the kernel. I'm scrutinizing its behavior, particularly when the `EXIT_TO_USER_MODE_WORK_LOOP` flag is set. The core of my observation lies within the `while` loop, where `local_irq_enable()` is called unconditionally. Immediately following this, there's a check for reschedule requests, both standard (`_TIF_NEED_RESCHED`) and lazy (`_TIF_NEED_RESCHED_LAZY`).
The critical junction appears when these reschedule flags are set. In such a scenario, the code attempts to invoke `rseq_grant_slice_extension`. My investigation into `rseq_grant_slice_extension` reveals that it, in turn, calls `hrtimer_rearm_deferred_tif`, which then calls `hrtimer_test_and_clear_rearm_deferred_tif`. The very last step in this chain, and the one that immediately raises a red flag for me, is `lockdep_assert_irqs_disabled()`.
Herein lies the paradox that has captured my attention: `local_irq_enable()` has just been executed, making it explicit that interrupts are *enabled*. Yet, deep within the execution path triggered by the reschedule flags, `lockdep` is asserting that interrupts *must be disabled*. This is a direct contradiction. To resolve this, I'm now directing my attention to `include/linux/rseq_entry.h`, specifically line 236, to meticulously examine the logic and conditions that lead to this apparent assertion violation. My goal is to understand how this sequence of events can occur and what the implications are for interrupt handling and the overall stability of this kernel path.
|
| 10/2 |
2026/08/12 12:38 |
tool |
read-file |
0m
Args: map[File:include/linux/rseq_entry.h FirstLine:200 LineCount:100]
Results: map[Contents: 200: * #1 is not any different from a regular remote reschedule as it
201: * sets the previously not set bit and then raises the IPI which
202: * folds it into the preempt counter
203: *
204: * #2 is obviously incorrect from a scheduler POV, but it's not
205: * differently incorrect than the code below clearing the
206: * reschedule request with the safety net of the timer.
207: *
208: * The important part is that the clearing is protected against the
209: * scheduler IPI and also against any other interrupt which might
210: * end up waking up a task and setting the bits in the middle of
211: * the operation:
212: *
213: * clear_tsk()
214: * ---> Interrupt
215: * wakeup_on_this_cpu()
216: * set_tsk()
217: * set_preempt()
218: * clear_preempt()
219: *
220: * which would be inconsistent state.
221: */
222: scoped_guard(irq) {
223: clear_tsk_need_resched(curr);
224: clear_preempt_need_resched();
225: }
226: return true;
227:
228: efault:
229: force_sig(SIGSEGV);
230: return false;
231: }
232:
233: static __always_inline bool rseq_grant_slice_extension(unsigned long ti_work, unsigned long mask)
234: {
235: if (unlikely(__rseq_grant_slice_extension(ti_work & mask))) {
236: hrtimer_rearm_deferred_tif(ti_work);
237: return true;
238: }
239: return false;
240: }
241:
242: #else /* CONFIG_RSEQ_SLICE_EXTENSION */
243: static __always_inline bool rseq_slice_extension_enabled(void) { return false; }
244: static __always_inline bool rseq_arm_slice_extension_timer(void) { return false; }
245: static __always_inline void rseq_slice_clear_grant(struct task_struct *t) { }
246: static __always_inline bool rseq_grant_slice_extension(unsigned long ti_work, unsigned long mask) { return false; }
247: #define rseq_slice_clear_user(rseq, efault) do { } while (0)
248: #endif /* !CONFIG_RSEQ_SLICE_EXTENSION */
249:
250: bool rseq_debug_update_user_cs(struct task_struct *t, struct pt_regs *regs, unsigned long csaddr);
251:
252: static __always_inline void rseq_note_user_irq_entry(void)
253: {
254: if (IS_ENABLED(CONFIG_GENERIC_IRQ_ENTRY))
255: current->rseq.event.user_irq = true;
256: }
257:
258: /*
259: * Check whether there is a valid critical section and whether the
260: * instruction pointer in @regs is inside the critical section.
261: *
262: * - If the critical section is invalid, terminate the task.
263: *
264: * - If valid and the instruction pointer is inside, set it to the abort IP.
265: *
266: * - If valid and the instruction pointer is outside, clear the critical
267: * section address.
268: *
269: * Returns true, if the section was valid and either fixup or clear was
270: * done, false otherwise.
271: *
272: * In the failure case task::rseq_event::fatal is set when a invalid
273: * section was found. It's clear when the failure was an unresolved page
274: * fault.
275: *
276: * If inlined into the exit to user path with interrupts disabled, the
277: * caller has to protect against page faults with pagefault_disable().
278: *
279: * In preemptible task context this would be counterproductive as the page
280: * faults could not be fully resolved. As a consequence unresolved page
281: * faults in task context are fatal too.
282: */
283:
284: #ifdef RSEQ_BUILD_SLOW_PATH
285: /*
286: * The debug version is put out of line, but kept here so the code stays
287: * together.
288: *
289: * @csaddr has already been checked by the caller to be in user space
290: */
291: bool rseq_debug_update_user_cs(struct task_struct *t, struct pt_regs *regs,
292: unsigned long csaddr)
293: {
294: struct rseq_cs __user *ucs = (struct rseq_cs __user *)(unsigned long)csaddr;
295: u64 start_ip, abort_ip, offset, cs_end, head, tasksize = TASK_SIZE;
296: unsigned long ip = instruction_pointer(regs);
297: u64 __user *uc_head = (u64 __user *) ucs;
298: u32 usig, __user *uc_sig;
299:
]
|
| 11/2 |
2026/08/12 12:38 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 9839
output: 39
thoughts: 99
Thoughts: **My Thought Process Regarding Interrupts and `rseq_grant_slice_extension`**
My initial thought upon observing the call to `rseq_grant_slice_extension` within `__exit_to_user_mode_loop` was to note that interrupts were enabled at that juncture. This immediately raised a flag in my mind because I know that `hrtimer_rearm_deferred_tif` has a strict requirement for interrupts to be disabled. My reasoning for this is rooted in the fact that `hrtimer_rearm_deferred_tif` internally invokes `hrtimer_test_and_clear_rearm_deferred_tif`, and this latter function includes a `lockdep_assert_irqs_disabled()` assertion. This assertion is a critical safeguard, meaning that if interrupts are not disabled when `hrtimer_test_and_clear_rearm_deferred_tif` is called, the system will panic, as it's a clear violation of the expected state. Therefore, the apparent mismatch between the interrupt state during the `rseq_grant_slice_extension` call and the requirements of `hrtimer_rearm_deferred_tif` demands further investigation. My next step, logically, would be to delve into the implementation of `__rseq_grant_slice_extension` itself to understand how it interacts with or modifies the interrupt state, or if there's a mechanism I'm overlooking that reconciles this apparent conflict.
|
| 12/2 |
2026/08/12 12:38 |
tool |
read-file |
0m
Args: map[File:include/linux/rseq_entry.h FirstLine:100 LineCount:100]
Results: map[Contents: 100:
101: if (likely(!current->rseq.slice.state.granted))
102: return false;
103:
104: return __rseq_arm_slice_extension_timer();
105: }
106:
107: static __always_inline void rseq_slice_clear_grant(struct task_struct *t)
108: {
109: if (IS_ENABLED(CONFIG_RSEQ_STATS) && t->rseq.slice.state.granted)
110: rseq_stat_inc(rseq_stats.s_revoked);
111: t->rseq.slice.state.granted = false;
112: }
113:
114: /*
115: * Open coded, so it can be invoked within a user access region.
116: *
117: * This clears the user space state of the time slice extensions field only when
118: * the task has registered the optimized RSEQ_ABI V2. Some legacy registrations,
119: * e.g. TCMalloc, have conflicting non-ABI fields in struct RSEQ, which would be
120: * overwritten by an unconditional write.
121: */
122: #define rseq_slice_clear_user(rseq, efault) \
123: do { \
124: if (rseq_slice_extension_enabled()) \
125: unsafe_put_user(0U, &rseq->slice_ctrl.all, efault); \
126: } while (0)
127:
128: static __always_inline bool __rseq_grant_slice_extension(bool work_pending)
129: {
130: struct task_struct *curr = current;
131: struct rseq_slice_ctrl usr_ctrl;
132: union rseq_slice_state state;
133: struct rseq __user *rseq;
134:
135: if (!rseq_slice_extension_enabled())
136: return false;
137:
138: /* If not enabled or not a return from interrupt, nothing to do. */
139: state = curr->rseq.slice.state;
140: state.enabled &= curr->rseq.event.user_irq;
141: if (likely(!state.state))
142: return false;
143:
144: rseq = curr->rseq.usrptr;
145: scoped_user_rw_access(rseq, efault) {
146:
147: /*
148: * Quick check conditions where a grant is not possible or
149: * needs to be revoked.
150: *
151: * 1) Any TIF bit which needs to do extra work aside of
152: * rescheduling prevents a grant.
153: *
154: * 2) A previous rescheduling request resulted in a slice
155: * extension grant.
156: */
157: if (unlikely(work_pending || state.granted)) {
158: /* Clear user control unconditionally. No point for checking */
159: unsafe_put_user(0U, &rseq->slice_ctrl.all, efault);
160: rseq_slice_clear_grant(curr);
161: return false;
162: }
163:
164: unsafe_get_user(usr_ctrl.all, &rseq->slice_ctrl.all, efault);
165: if (likely(!(usr_ctrl.request)))
166: return false;
167:
168: /* Grant the slice extention */
169: usr_ctrl.request = 0;
170: usr_ctrl.granted = 1;
171: unsafe_put_user(usr_ctrl.all, &rseq->slice_ctrl.all, efault);
172: }
173:
174: rseq_stat_inc(rseq_stats.s_granted);
175:
176: curr->rseq.slice.state.granted = true;
177: /* Store expiry time for arming the timer on the way out */
178: curr->rseq.slice.expires = data_race(rseq_slice_ext_nsecs) + ktime_get_mono_fast_ns();
179: /*
180: * This is racy against a remote CPU setting TIF_NEED_RESCHED in
181: * several ways:
182: *
183: * 1)
184: * CPU0 CPU1
185: * clear_tsk()
186: * set_tsk()
187: * clear_preempt()
188: * Raise scheduler IPI on CPU0
189: * --> IPI
190: * fold_need_resched() -> Folds correctly
191: * 2)
192: * CPU0 CPU1
193: * set_tsk()
194: * clear_tsk()
195: * clear_preempt()
196: * Raise scheduler IPI on CPU0
197: * --> IPI
198: * fold_need_resched() <- NOOP as TIF_NEED_RESCHED is false
199: *
]
|
| 13/2 |
2026/08/12 12:38 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 11527
output: 38
thoughts: 247
Thoughts: **The Perplexing Path of `__rseq_grant_slice_extension`**
My current focus is on understanding the execution flow around `__rseq_grant_slice_extension`, specifically concerning its return value and subsequent calls. I've noted that `__rseq_grant_slice_extension` returns `true` precisely when it successfully grants a slice extension. Following this, it invokes `hrtimer_rearm_deferred_tif` with the `ti_work` parameter.
This immediately raises a red flag for me because I know, or at least strongly suspect based on common patterns, that `hrtimer_rearm_deferred_tif` mandates that interrupts be disabled prior to its invocation.
Now, I'm examining the `__exit_to_user_mode_loop` function, and within its `while` loop, I see this snippet:
```c
while (ti_work & EXIT_TO_USER_MODE_WORK_LOOP) {
local_irq_enable(); // <-- Here's the crucial part!
if (ti_work & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)) {
if (!rseq_grant_slice_extension(ti_work, TIF_SLICE_EXT_DENY))
schedule();
}
}
```
As you can see, `local_irq_enable()` is called *before* the check for `_TIF_NEED_RESCHED` or `_TIF_NEED_RESCHED_LAZY` and, consequently, before `rseq_grant_slice_extension` is potentially called. This means `rseq_grant_slice_extension` is being invoked with interrupts *enabled*.
This directly conflicts with my understanding of the requirements of `hrtimer_rearm_deferred_tif`, which is called *from within* `rseq_grant_slice_extension` and expects interrupts to be disabled.
My next step is to delve deeper into the implementation of `hrtimer_rearm_deferred_tif` itself to confirm this dependency and pinpoint the exact nature of the potential race condition or incorrect assumption in this execution path.
|
| 14/2 |
2026/08/12 12:38 |
tool |
read-file |
0m
Args: map[File:include/linux/hrtimer_rearm.h FirstLine:40 LineCount:20]
Results: map[Contents: 40: clear_thread_flag(TIF_HRTIMER_REARM);
41: __hrtimer_rearm_deferred();
42: /* Don't go into the loop if HRTIMER_REARM was the only flag */
43: *tif_work &= ~TIF_HRTIMER_REARM;
44: return !*tif_work;
45: }
46: return false;
47: }
48:
49: /* Invoked from the time slice extension decision function */
50: static __always_inline void hrtimer_rearm_deferred_tif(unsigned long tif_work)
51: {
52: if (hrtimer_test_and_clear_rearm_deferred_tif(tif_work))
53: __hrtimer_rearm_deferred();
54: }
55:
56: /*
57: * This is to be called on all irqentry_exit() paths that will enable
58: * interrupts.
59: */
]
|
| 15/2 |
2026/08/12 12:38 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 12089
output: 42
thoughts: 265
Thoughts: **My Thought Process Unraveling a Potential Bug**
Right, so I've been digging into this and it seems I've hit upon a bug related to deferred timer rearming. Specifically, `hrtimer_rearm_deferred_tif` calls into `hrtimer_test_and_clear_rearm_deferred_tif`, and within that, there's a `lockdep_assert_irqs_disabled()`. This is a strong indicator that interrupts *should* be disabled at this point.
The core of the problem, as I see it, is that `rseq_grant_slice_extension` is being invoked with interrupts *enabled*, while `hrtimer_rearm_deferred_tif`, which it subsequently calls, absolutely requires them to be disabled. This is a clear mismatch and a potential source of issues.
Now, the crucial question is how to actually *reproduce* this scenario. To trigger the bug, I need `rseq_grant_slice_extension` to return `true`. Delving deeper into `__rseq_grant_slice_extension`, I've identified the conditions necessary for it to return `true`:
1. `rseq_slice_extension_enabled()` must evaluate to `true`.
2. `curr->rseq.slice.state.enabled` needs to be `true`.
3. `curr->rseq.event.user_irq` must also be `true`.
4. `work_pending` has to be `false`. I've clarified that `work_pending` corresponds to `ti_work & TIF_SLICE_EXT_DENY`.
5. `state.granted` must be `false`.
6. Finally, `usr_ctrl.request` needs to be `true`.
My next step is to meticulously examine `rseq_slice_extension_enabled()` to understand how that condition can be met, as it's the gateway to the rest of the chain leading to the potential interrupt handling issue.
|
| 16/2 |
2026/08/12 12:38 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:include/linux/rseq_entry.h Name:rseq_slice_extension_enabled]
Results: map[SourceCode: 88: static __always_inline bool rseq_slice_extension_enabled(void)
89: {
90: return static_branch_likely(&rseq_slice_extension_key);
91: }
SourceFile:include/linux/rseq_entry.h]
|
| 17/2 |
2026/08/12 12:38 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 12468
output: 55
thoughts: 18
Thoughts: **Tracing the Origins of `rseq_slice_extension_key`**
My primary objective right now is to pinpoint exactly where the `rseq_slice_extension_key` is activated within the codebase. I need to understand its lifecycle and the conditions under which it comes into play, which will likely involve a comprehensive search across relevant modules and functions. I anticipate this will require navigating through various layers of the system, from high-level configuration to more granular implementation details. My expectation is that by identifying its enablement points, I'll gain crucial insights into its purpose and its interaction with other system components, ultimately allowing me to better analyze or debug its behavior.
|
| 18/2 |
2026/08/12 12:38 |
tool |
codesearch-find-references |
0m
Args: map[ContextFile:include/linux/rseq_entry.h IncludeSnippetLines:5 Name:rseq_slice_extension_key SourceTreePrefix:]
Results: map[References:<nil> TruncatedOutput:false]
|
| 19/2 |
2026/08/12 12:38 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 12540
output: 28
thoughts: 16
Thoughts: **My Thought Process for `rseq_slice_extension_key`**
Alright, so I'm mulling over this problem, and my mind just pinged. A specific term, `rseq_slice_extension_key`, just popped into my head. It feels like a crucial piece of the puzzle, or at least a very strong lead. My immediate instinct is to dive deep into this. I need to understand exactly what this `rseq_slice_extension_key` refers to. Is it a specific data structure? A configuration setting? A concept within a particular framework or protocol I'm working with? I suspect it's tied to how sequences or regions are being handled, possibly with some kind of extension mechanism. The "slice" part suggests partitioning or a subset, and the "extension" implies adding functionality or data beyond the standard. The "key" itself points towards an identifier, a way to access or reference this extended slice. My next step, without a doubt, is a thorough search for this term. I need to find its definition, its usage, and its context within the system or domain I'm currently focused on. This is likely a critical keyword for unlocking the current challenge.
|
| 20/2 |
2026/08/12 12:38 |
tool |
grepper |
0m
Args: map[Expression:rseq_slice_extension_key PathPrefix:]
Results: map[Output:include/linux/rseq_entry.h=77=DECLARE_STATIC_KEY_MAYBE(CONFIG_RSEQ_DEBUG_DEFAULT_ENABLE, rseq_debug_enabled);
--
include/linux/rseq_entry.h-85-#ifdef CONFIG_RSEQ_SLICE_EXTENSION
include/linux/rseq_entry.h:86:DECLARE_STATIC_KEY_TRUE(rseq_slice_extension_key);
include/linux/rseq_entry.h-87-
include/linux/rseq_entry.h=88=static __always_inline bool rseq_slice_extension_enabled(void)
include/linux/rseq_entry.h-89-{
include/linux/rseq_entry.h:90: return static_branch_likely(&rseq_slice_extension_key);
include/linux/rseq_entry.h-91-}
--
kernel/rseq.c=573=static DEFINE_PER_CPU(struct slice_timer, slice_timer);
kernel/rseq.c:574:DEFINE_STATIC_KEY_TRUE(rseq_slice_extension_key);
kernel/rseq.c-575-
--
kernel/rseq.c=863=static int __init rseq_slice_cmdline(char *str)
--
kernel/rseq.c-870- if (!on)
kernel/rseq.c:871: static_branch_disable(&rseq_slice_extension_key);
kernel/rseq.c-872- return 1;
]
|
| 21/2 |
2026/08/12 12:38 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 12955
output: 28
thoughts: 36
Thoughts: **My Thought Process on RSEQ Slice Extension**
So, my first inclination here is to understand the fundamental trigger for this "RSEQ slice extension" functionality. The documentation clearly states it's enabled by default *if* `CONFIG_RSEQ_SLICE_EXTENSION` is set. That's the primary gate.
Therefore, my immediate next step, as I process this information, is to verify the state of this specific configuration. I need to confirm whether this default is actually active in the current context. The most direct way to do that, based on the provided snippet, is to inspect the `curr->rseq.slice.state.enabled` flag. This boolean value will definitively tell me if the slice extension is currently live and operational according to the configuration. It's a straightforward check to confirm the execution path we're dealing with.
|
| 22/2 |
2026/08/12 12:38 |
tool |
grepper |
0m
Args: map[Expression:rseq.*slice.*state.*enabled PathPrefix:]
Results: map[Output:kernel/rseq.c=415=static long rseq_register(struct rseq __user * rseq, u32 rseq_len, int flags, u32 sig)
--
kernel/rseq.c-474-#ifdef CONFIG_RSEQ_SLICE_EXTENSION
kernel/rseq.c:475: current->rseq.slice.state.enabled = !!(rseqfl & RSEQ_CS_FLAG_SLICE_EXT_ENABLED);
kernel/rseq.c-476-#endif
--
kernel/rseq.c=746=int rseq_slice_extension_prctl(unsigned long arg2, unsigned long arg3)
--
kernel/rseq.c-751- return -EINVAL;
kernel/rseq.c:752: return current->rseq.slice.state.enabled ? PR_RSEQ_SLICE_EXT_ENABLE : 0;
kernel/rseq.c-753-
--
kernel/rseq.c-767- /* No change? */
kernel/rseq.c:768: if (enable == !!current->rseq.slice.state.enabled)
kernel/rseq.c-769- return 0;
--
kernel/rseq.c-773-
kernel/rseq.c:774: if (current->rseq.slice.state.enabled)
kernel/rseq.c-775- valid |= RSEQ_CS_FLAG_SLICE_EXT_ENABLED;
--
kernel/rseq.c-787-
kernel/rseq.c:788: current->rseq.slice.state.enabled = enable;
kernel/rseq.c-789- return 0;
]
|
| 23/2 |
2026/08/12 12:38 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 13435
output: 28
thoughts: 97
Thoughts: **My Thought Process Regarding RSEQ Slice Extensions**
So, my initial thought is about how to get these RSEQ slice extensions up and running. I'm recalling that it can be done in two ways: either by directly registering RSEQ with the `RSEQ_CS_FLAG_SLICE_EXT_ENABLED` flag, or by leveraging the `prctl` system call.
However, I'm pausing to refine my understanding of the `prctl` approach. I seem to remember it involves a specific command related to slice extensions. I'm thinking it's `prctl(PR_RSEQ_SLICE_EXT_ENABLE)`, but then a small doubt creeps in. Was it quite that direct? Or was there a more general command that then took the specific extension enable as an argument?
Ah, yes, I'm jogging my memory now. It's actually `prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLIC_EXT_ENABLE)`. The `PR_RSEQ_SLICE_EXTENSION` command seems to be the overarching mechanism for dealing with slice extensions, and then `PR_RSEQ_SLICE_EXT_ENABLE` is the specific instruction to, well, enable them.
To solidify this, I'm making a mental note to go and confirm this by looking at the definitive source: the `include/uapi/linux/prctl.h` header file. That's where the kernel's user-API definitions reside, and it will definitively tell me the exact constants and structure for this `prctl` operation. That's the most reliable way to ensure I'm using the correct interface.
|
| 24/2 |
2026/08/12 12:38 |
tool |
grepper |
0m
Args: map[Expression:PR_RSEQ_SLICE_EXTENSION PathPrefix:]
Results: map[Output:Documentation/userspace-api/rseq.rst=134=The thread has to enable the functionality via prctl(2)::
Documentation/userspace-api/rseq.rst-135-
Documentation/userspace-api/rseq.rst:136: prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET,
Documentation/userspace-api/rseq.rst-137- PR_RSEQ_SLICE_EXT_ENABLE, 0, 0);
--
Documentation/userspace-api/rseq.rst=150=The state can be also queried via prctl(2)::
Documentation/userspace-api/rseq.rst-151-
Documentation/userspace-api/rseq.rst:152: prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET, 0, 0, 0);
Documentation/userspace-api/rseq.rst-153-
--
include/uapi/linux/prctl.h=134=struct prctl_mm_map {
--
include/uapi/linux/prctl.h-389-/* RSEQ time slice extensions */
include/uapi/linux/prctl.h:390:#define PR_RSEQ_SLICE_EXTENSION 79
include/uapi/linux/prctl.h:391:# define PR_RSEQ_SLICE_EXTENSION_GET 1
include/uapi/linux/prctl.h:392:# define PR_RSEQ_SLICE_EXTENSION_SET 2
include/uapi/linux/prctl.h-393-/*
--
kernel/rseq.c=746=int rseq_slice_extension_prctl(unsigned long arg2, unsigned long arg3)
--
kernel/rseq.c-748- switch (arg2) {
kernel/rseq.c:749: case PR_RSEQ_SLICE_EXTENSION_GET:
kernel/rseq.c-750- if (arg3)
--
kernel/rseq.c-753-
kernel/rseq.c:754: case PR_RSEQ_SLICE_EXTENSION_SET: {
kernel/rseq.c-755- u32 rflags, valid = RSEQ_CS_FLAG_SLICE_EXT_AVAILABLE;
--
kernel/sys.c=2534=SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
--
kernel/sys.c-2886- break;
kernel/sys.c:2887: case PR_RSEQ_SLICE_EXTENSION:
kernel/sys.c-2888- if (arg4 || arg5)
--
tools/perf/trace/beauty/include/uapi/linux/prctl.h=134=struct prctl_mm_map {
--
tools/perf/trace/beauty/include/uapi/linux/prctl.h-389-/* RSEQ time slice extensions */
tools/perf/trace/beauty/include/uapi/linux/prctl.h:390:#define PR_RSEQ_SLICE_EXTENSION 79
tools/perf/trace/beauty/include/uapi/linux/prctl.h:391:# define PR_RSEQ_SLICE_EXTENSION_GET 1
tools/perf/trace/beauty/include/uapi/linux/prctl.h:392:# define PR_RSEQ_SLICE_EXTENSION_SET 2
tools/perf/trace/beauty/include/uapi/linux/prctl.h-393-/*
--
tools/testing/selftests/rseq/slice_test.c-27-
tools/testing/selftests/rseq/slice_test.c:28:#ifndef PR_RSEQ_SLICE_EXTENSION
tools/testing/selftests/rseq/slice_test.c:29:# define PR_RSEQ_SLICE_EXTENSION 79
tools/testing/selftests/rseq/slice_test.c:30:# define PR_RSEQ_SLICE_EXTENSION_GET 1
tools/testing/selftests/rseq/slice_test.c:31:# define PR_RSEQ_SLICE_EXTENSION_SET 2
tools/testing/selftests/rseq/slice_test.c-32-# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
--
tools/testing/selftests/rseq/slice_test.c=123=FIXTURE_SETUP(slice_ext)
--
tools/testing/selftests/rseq/slice_test.c-129-
tools/testing/selftests/rseq/slice_test.c:130: if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET,
tools/testing/selftests/rseq/slice_test.c-131- PR_RSEQ_SLICE_EXT_ENABLE, 0, 0))
]
|
| 25/2 |
2026/08/12 12:38 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 14779
output: 38
thoughts: 141
Thoughts: **My Thought Process on RSEQ Slice Extension**
Alright, so I've been mulling over this whole RSEQ slice extension business, and it seems like there are a few key steps I need to take to get it working.
First off, I absolutely need to get `rseq` registered. That's the foundational piece, without which none of this will even get off the ground.
Once `rseq` is out of the way, the next critical action is to issue the `prctl` call. Specifically, I've got to use `prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0);`. This seems to be the explicit command to enable the slice extension mechanism.
Following that, I'm thinking I'll need to set `usr_ctrl.request = 1`. This feels like the signal to the system that I'm ready and waiting for this extension to be granted or utilized.
Now, here's where things get a bit more nuanced. I initially thought about triggering an interrupt that would set `TIF_NEED_RESCHED` or `TIF_NEED_RESCHED_LAZY`. However, a quick re-evaluation of `__rseq_grant_slice_extension` made me pause. I noticed it checks `work_pending`. This suggests that simply forcing a reschedule flag might not be the direct trigger. I need to revisit `__rseq_grant_slice_extension` with this `work_pending` check in mind. My focus should be on understanding how `work_pending` is influenced and how that relates to the slice extension being granted. This is the piece I need to dig into more thoroughly to ensure the logic flows correctly.
|
| 26/2 |
2026/08/12 12:38 |
tool |
read-file |
0m
Args: map[File:include/linux/rseq_entry.h FirstLine:128 LineCount:50]
Results: map[Contents: 128: static __always_inline bool __rseq_grant_slice_extension(bool work_pending)
129: {
130: struct task_struct *curr = current;
131: struct rseq_slice_ctrl usr_ctrl;
132: union rseq_slice_state state;
133: struct rseq __user *rseq;
134:
135: if (!rseq_slice_extension_enabled())
136: return false;
137:
138: /* If not enabled or not a return from interrupt, nothing to do. */
139: state = curr->rseq.slice.state;
140: state.enabled &= curr->rseq.event.user_irq;
141: if (likely(!state.state))
142: return false;
143:
144: rseq = curr->rseq.usrptr;
145: scoped_user_rw_access(rseq, efault) {
146:
147: /*
148: * Quick check conditions where a grant is not possible or
149: * needs to be revoked.
150: *
151: * 1) Any TIF bit which needs to do extra work aside of
152: * rescheduling prevents a grant.
153: *
154: * 2) A previous rescheduling request resulted in a slice
155: * extension grant.
156: */
157: if (unlikely(work_pending || state.granted)) {
158: /* Clear user control unconditionally. No point for checking */
159: unsafe_put_user(0U, &rseq->slice_ctrl.all, efault);
160: rseq_slice_clear_grant(curr);
161: return false;
162: }
163:
164: unsafe_get_user(usr_ctrl.all, &rseq->slice_ctrl.all, efault);
165: if (likely(!(usr_ctrl.request)))
166: return false;
167:
168: /* Grant the slice extention */
169: usr_ctrl.request = 0;
170: usr_ctrl.granted = 1;
171: unsafe_put_user(usr_ctrl.all, &rseq->slice_ctrl.all, efault);
172: }
173:
174: rseq_stat_inc(rseq_stats.s_granted);
175:
176: curr->rseq.slice.state.granted = true;
177: /* Store expiry time for arming the timer on the way out */
]
|
| 27/2 |
2026/08/12 12:38 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 15715
output: 58
thoughts: 301
Thoughts: **My Thought Process Regarding Scheduler and RSEQ Interaction**
Alright, let's break down this snippet and what it implies about the scheduler's interaction with the RSEQ (Restartable Sequences) mechanism. I'm seeing something here that seems a bit counter-intuitive at first glance, and I want to trace the logic carefully.
The core of my concern revolves around how `work_pending` is being evaluated within the `__exit_to_user_mode_loop`. It's being passed `ti_work & TIF_SLICE_EXT_DENY`. This immediately flags my attention because `TIF_SLICE_EXT_DENY` is defined as `(EXIT_TO_USER_MODE_WORK & ~TIF_SLICE_EXT_SCHED)`. This means that `work_pending` will evaluate to true if *any* bit within `EXIT_TO_USER_MODE_WORK` is set, *except* for `TIF_SLICE_EXT_SCHED`.
Now, looking at the `if` condition inside the loop: `if (ti_work & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY))`. This condition is designed to trigger a `schedule()` call if either of the reschedule flags are set.
My problem is this: If `work_pending` is set as described above (meaning *any* exit-to-user mode work is pending, not specifically reschedule work), and then we proceed to check for `_TIF_NEED_RESCHED` or `_TIF_NEED_RESCHED_LAZY`, it seems like we're not being specific enough. I want to ensure that we *only* proceed to the `schedule()` call if the *specific* condition for rescheduling is met. The current logic, as I see it, allows a `schedule()` to occur if `work_pending` is true (due to other pending flags like `_TIF_SIGPENDING`, `_TIF_NOTIFY_RESUME`, etc.) *and* the reschedule flags are *also* set. This feels like it could lead to unnecessary context switches or rescheduling when the primary intent might be to handle other pending user-mode work.
The subsequent check, `curr->rseq.event.user_irq` being true, is also critical. I know that `rseq_note_user_irq_entry()` sets this flag. This function is likely called to signal that the system has entered user mode and RSEQ is aware of it. However, my immediate question is: *when* exactly is `rseq_note_user_irq_entry()` invoked? Understanding its call sites is key to determining the exact conditions under which this reschedule logic will engage. I need to be sure that the `user_irq` flag is only set in situations that genuinely warrant the scheduler's intervention in this specific context, and that it aligns with the intended behavior of `TIF_SLICE_EXT_DENY`. My goal is to confirm that the scheduler is only invoked when specifically requested by the reschedule flags, and not as a side-effect of other pending work within the `__exit_to_user_mode_loop`.
|
| 28/2 |
2026/08/12 12:39 |
tool |
codesearch-find-references |
0m
Args: map[ContextFile:include/linux/rseq_entry.h IncludeSnippetLines:5 Name:rseq_note_user_irq_entry SourceTreePrefix:]
Results: map[References:[map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:irqentry_enter_from_user_mode SourceFile:include/linux/irq-entry-common.h SourceLine:294 SourceSnippet: 289: * The function establishes state (lockdep, RCU (context tracking), tracing)
290: */
291: static __always_inline void irqentry_enter_from_user_mode(struct pt_regs *regs)
292: {
293: enter_from_user_mode(regs);
294: rseq_note_user_irq_entry();
295: }
]] TruncatedOutput:false]
|
| 29/2 |
2026/08/12 12:39 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 16232
output: 42
thoughts: 339
Thoughts: **The Path to Triggering a `lockdep` Warning via rseq Slice Extension**
My current line of thinking is focused on how to reliably trigger a specific `lockdep` warning related to the `rseq` (restartable sequences) mechanism and its slice extension feature. I've been tracing the execution flow, and here's my breakdown of the thought process and the steps involved:
Initially, I understood that any interrupt originating from user mode would set a `user_irq` flag to true. This then leads to a call to the `__exit_to_user_mode_loop` function. My investigation revealed a critical condition within this loop: if the `_TIF_NEED_RESCHED` flag is set, the `rseq_grant_slice_extension` function is invoked. This is the core of the problem I'm trying to expose.
To make `rseq_grant_slice_extension` execute, I identified four key prerequisites:
1. First, I need to ensure that `rseq` is properly registered within the system.
2. Next, the slice extension capability needs to be explicitly enabled for the relevant `rseq` structure using the `prctl` system call.
3. Then, I must set the `rseq->slice_ctrl.request` field to `1`. This signals the intent to request a slice extension.
4. Finally, the system must be in a state where it's running an infinite loop in user space. This provides a stable environment to wait for the trigger.
The trigger itself, as I've identified, is a timer interrupt. When this timer interrupt occurs, it will cause the system to return to user space, subsequently calling `__exit_to_user_mode_loop`. Because the timer interrupt is what sets `_TIF_NEED_RESCHED`, this will then lead to the problematic call to `rseq_grant_slice_extension` and, consequently, the bug I'm looking to hit.
However, my analysis didn't stop there. I then dug deeper into the call chain initiated by `rseq_grant_slice_extension`. I realized that this function, in turn, calls `__rseq_grant_slice_extension`. If `__rseq_grant_slice_extension` returns true (which is what I'm aiming for), it proceeds to call `hrtimer_rearm_deferred_tif`. This is where the `lockdep` assertion comes into play.
Specifically, `hrtimer_rearm_deferred_tif` calls `hrtimer_test_and_clear_rearm_deferred_tif`. Within this function, there's a crucial `lockdep_assert_irqs_disabled()` assertion. My concern is that this assertion will fail because `local_irq_enable()` was called *just before* `rseq_grant_slice_extension` within the `__exit_to_user_mode_loop` function. This means interrupts will be enabled at the point where `lockdep` expects them to be disabled, leading to the warning I'm trying to trigger.
To solidify this understanding, I've made a mental note to go back and meticulously verify the exact definitions of the `rseq_slice_ctrl` and `rseq` structures to ensure I haven't missed any subtle details that might alter this execution path.
|
| 30/2 |
2026/08/12 12:39 |
tool |
codesearch-struct-layout |
0m
Args: map[ContextFile:include/uapi/linux/rseq.h FieldOffset:<nil> Name:rseq]
Results: map[Fields:[map[Name:cpu_id_start OffsetBits:0 SizeBits:32] map[Name:cpu_id OffsetBits:32 SizeBits:32] map[Name:rseq_cs OffsetBits:64 SizeBits:64] map[Name:flags OffsetBits:128 SizeBits:32] map[Name:node_id OffsetBits:160 SizeBits:32] map[Name:mm_cid OffsetBits:192 SizeBits:32] map[Name:slice_ctrl OffsetBits:224 SizeBits:32] map[Name:__reserved OffsetBits:256 SizeBits:8] map[Name:end OffsetBits:264 SizeBits:0]]]
|
| 31/2 |
2026/08/12 12:39 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 16720
output: 46
thoughts: 35
Thoughts: **My Thought Process on `slice_ctrl` and `rseq_slice_ctrl`**
Ah, I've just realized something important: the `slice_ctrl` field is positioned at an offset of 28 bytes, which translates to 224 bits. This specific detail immediately triggers a need for verification. My next step, therefore, is to dive into the definition of the `rseq_slice_ctrl` union to confirm how this offset and bit positioning are being utilized within its structure. I need to ensure my understanding aligns with the actual implementation.
|
| 32/2 |
2026/08/12 12:39 |
tool |
codesearch-struct-layout |
0m
Args: map[ContextFile:include/uapi/linux/rseq.h FieldOffset:<nil> Name:rseq_slice_ctrl]
Results: map[Fields:[map[Name: OffsetBits:0 SizeBits:32]]]
|
| 33/2 |
2026/08/12 12:39 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 16807
output: 39
thoughts: 34
Thoughts: **My Thought Process:**
Okay, so I'm looking at this piece of code, and I've just noticed something that's caught my attention: there's an anonymous struct nested *inside* `rseq_slice_ctrl`. That's a bit unusual, or at least it's a detail that I want to understand more deeply. My immediate instinct is to go straight to the source. I need to consult the definitive documentation for this. Therefore, my next step is to open up and thoroughly read the header file `include/uapi/linux/rseq.h`. I'm expecting to find the definition of `rseq_slice_ctrl` there, and crucially, to see how this anonymous struct is declared and what its purpose is within the `rseq` (restartable sequences) mechanism. My goal is to fully grasp the structure's layout, its members, and how it contributes to the overall functionality of restartable sequences, especially in terms of control.
|
| 34/2 |
2026/08/12 12:39 |
tool |
read-file |
0m
Args: map[File:include/uapi/linux/rseq.h FirstLine:140 LineCount:50]
Results: map[Contents: 140: * instruction sequence block, as well as when the kernel detects that
141: * it is preempting or delivering a signal outside of the range
142: * targeted by the rseq_cs. Also needs to be set to NULL by user-space
143: * before reclaiming memory that contains the targeted struct rseq_cs.
144: *
145: * Read and set by the kernel. Set by user-space with single-copy
146: * atomicity semantics. This field should only be updated by the
147: * thread which registered this data structure. Aligned on 64-bit.
148: *
149: * 32-bit architectures should update the low order bits of the
150: * rseq_cs field, leaving the high order bits initialized to 0.
151: */
152: __u64 rseq_cs;
153:
154: /*
155: * Restartable sequences flags field.
156: *
157: * This field was initially intended to allow event masking for
158: * single-stepping through rseq critical sections with debuggers.
159: * The kernel does not support this anymore and the relevant bits
160: * are checked for being always false:
161: * - RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT
162: * - RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL
163: * - RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE
164: *
165: * It is now used for feature status advertisement by the kernel.
166: * See: enum rseq_cs_flags_bit for further information.
167: */
168: __u32 flags;
169:
170: /*
171: * Restartable sequences node_id field. Updated by the kernel. Read by
172: * user-space with single-copy atomicity semantics. This field should
173: * only be read by the thread which registered this data structure.
174: * Aligned on 32-bit. Contains the current NUMA node ID.
175: */
176: __u32 node_id;
177:
178: /*
179: * Restartable sequences mm_cid field. Updated by the kernel. Read by
180: * user-space with single-copy atomicity semantics. This field should
181: * only be read by the thread which registered this data structure.
182: * Aligned on 32-bit. Contains the current thread's concurrency ID
183: * (allocated uniquely within a memory map).
184: */
185: __u32 mm_cid;
186:
187: /*
188: * Time slice extension control structure. CPU local updates from
189: * kernel and user space.
]
|
| 35/2 |
2026/08/12 12:39 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 17696
output: 39
thoughts: 6
Thoughts: **My Deep Dive into the Nuances of the Subject**
Alright, the initial read is complete. My mind is now sifting through the information presented. I'm trying to establish a foundational understanding of the core concepts, looking for the central arguments and any immediately apparent anomalies or points of contention. It's like laying out the pieces of a puzzle, getting a feel for their shapes and colors, even if I don't yet see the full picture.
I'm specifically focusing on identifying the author's primary thesis or objective. What are they trying to convey, prove, or explore? I'm also mentally cataloging the key evidence or reasoning they employ to support their claims. Are these logical deductions, empirical data, established theories, or perhaps something more novel? As an expert, I'm naturally inclined to evaluate the *quality* of this support – is it robust, well-cited, and does it hold up to scrutiny?
Simultaneously, I'm beginning to anticipate potential implications. Where does this information lead? What are the downstream effects of these ideas? I'm looking for connections to broader fields, existing research, or even practical applications within my own domain. This is where the "expert" lens really kicks in – I'm not just absorbing; I'm contextualizing and analyzing from a position of established knowledge.
I'm also making a mental note of areas that feel underdeveloped or where I have immediate questions. Is there a gap in the explanation? Is a particular assumption not fully justified? These are the seeds of deeper inquiry, the points where my intellectual curiosity is piqued and where I'll likely want to direct further reading or analysis. It's a process of building a mental framework, and I'm actively seeking out both the solid beams and the potential weak points.
In short, my thought process is one of active, critical engagement. I'm not just passively receiving information; I'm dissecting it, evaluating it, and beginning to integrate it with my existing understanding. The goal is to move beyond a surface-level comprehension to a nuanced, insightful grasp of the subject matter. And right now, all signs point to the need for a deeper exploration.
|
| 36/2 |
2026/08/12 12:39 |
tool |
read-file |
0m
Args: map[File:include/uapi/linux/rseq.h FirstLine:190 LineCount:50]
Results: map[Contents: 190: */
191: struct rseq_slice_ctrl slice_ctrl;
192:
193: /*
194: * Before rseq became extensible, its original size was 32 bytes even
195: * though the active rseq area was only 20 bytes.
196: * Exposing a 32 bytes feature size would make life needlessly painful
197: * for userspace. Therefore, add a reserved byte after byte 32
198: * to bump the rseq feature size from 32 to 33.
199: * The next field to be added to the rseq area will be larger
200: * than one byte, and will replace this reserved byte.
201: */
202: __u8 __reserved;
203:
204: /*
205: * Flexible array member at end of structure, after last feature field.
206: */
207: char end[];
208: } __attribute__((aligned(32)));
209:
210: #endif /* _UAPI_LINUX_RSEQ_H */
]
|
| 37/2 |
2026/08/12 12:39 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 18054
output: 41
thoughts: 12
Thoughts: **My Thought Process Regarding `rseq_slice_ctrl`**
Okay, so I'm trying to get a handle on this `rseq_slice_ctrl` thing. My immediate, and most pressing, question is: where is this entity actually defined? I need to know its origin, its context. Is it a global variable? A struct? A function pointer? Perhaps it's a macro that expands to something else entirely? Without knowing its definition, I can't effectively reason about its behavior, its scope, or how it's intended to be used. This is the foundational piece of information I need to move forward with any deeper analysis or understanding of the system I'm working with.
|
| 38/2 |
2026/08/12 12:39 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:include/uapi/linux/rseq.h Name:rseq_slice_ctrl]
Results: map[SourceCode: 68: /**
69: * rseq_slice_ctrl - Time slice extension control structure
70: * @all: Compound value
71: * @request: Request for a time slice extension
72: * @granted: Granted time slice extension
73: *
74: * @request is set by user space and can be cleared by user space or kernel
75: * space. @granted is set and cleared by the kernel and must only be read
76: * by user space.
77: */
78: struct rseq_slice_ctrl {
79: union {
80: __u32 all;
81: struct {
82: __u8 request;
83: __u8 granted;
84: __u16 __reserved;
85: };
86: };
87: };
SourceFile:include/uapi/linux/rseq.h]
|
| 39/2 |
2026/08/12 12:39 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 18366
output: 43
thoughts: 768
Thoughts: **Understanding the `rseq` Slice Control Mechanism**
My initial thought process was to directly manipulate the `rseq` structure to enable a specific functionality related to slice control. I identified that the `request` field within `slice_ctrl` is located at offset 0 relative to `slice_ctrl`, and `slice_ctrl` itself resides at offset 28 within the `rseq` structure. Therefore, I reasoned that setting `rseq.slice_ctrl.request = 1` should be the direct way to achieve what I intended.
To validate this, I proceeded to construct a reproducer program. The core idea was to register the `rseq` structure, enable the slice extension using `prctl`, and then set the `request` field within a tight loop, simulating continuous operation.
However, as I was writing the reproducer, a subtle point about the `rseq` structure's size and alignment came to my mind. I realized that simply passing `sizeof(my_rseq)` to the `sys_rseq` system call might not be entirely accurate, especially concerning the `slice_ctrl` offset. I needed to verify the exact layout and size of the `struct rseq`.
Consulting the `include/uapi/linux/rseq.h` header file, I examined the definition of `struct rseq`:
```c
struct rseq {
__u32 cpu_id_start;
__u32 cpu_id;
__u64 rseq_cs;
__u32 flags;
__u32 node_id;
__u32 mm_cid;
struct rseq_slice_ctrl slice_ctrl; // This is at offset 28
__u8 __reserved;
char end[];
} __attribute__((aligned(32)));
```
My analysis of the structure's members revealed that `slice_ctrl` is indeed at offset 28. The total size up to `slice_ctrl` is 28 bytes. Including `slice_ctrl` (which is 4 bytes), the size becomes 32 bytes. The presence of `__reserved` (1 byte) pushes the explicit size to 33 bytes.
The `__attribute__((aligned(32)))` directive complicates things further. While it doesn't change the *minimum* size, it ensures the structure's size is a multiple of 32 bytes. Therefore, 33 bytes rounded up to the nearest multiple of 32 would result in a 64-byte allocation for `my_rseq`.
This led to a critical question: what is the correct value to pass as `rseq_len` to `sys_rseq`? The documentation and common practice suggest it should be the size of the registered area. Typically, `sizeof(struct rseq)` is used, but given the alignment and potential for padding, I questioned whether this was universally correct for the context of slice extensions.
To resolve this ambiguity and ensure my reproducer was robust, I decided to consult existing test cases. Specifically, I planned to examine `tools/testing/selftests/rseq/slice_test.c` to observe how the `rseq` structure is registered and handled in a verified context, paying close attention to how the length and offsets are managed, particularly when dealing with slice extensions. This would provide empirical evidence and guide the correct implementation of my reproducer and my understanding of the `rseq` slice control mechanism.
|
| 40/2 |
2026/08/12 12:39 |
tool |
read-file |
0m
Args: map[File:tools/testing/selftests/rseq/slice_test.c FirstLine:1 LineCount:100]
Results: map[Contents: 1: // SPDX-License-Identifier: LGPL-2.1
2: #define _GNU_SOURCE
3: #include <assert.h>
4: #include <pthread.h>
5: #include <sched.h>
6: #include <signal.h>
7: #include <stdbool.h>
8: #include <stdio.h>
9: #include <string.h>
10: #include <syscall.h>
11: #include <unistd.h>
12:
13: #include <linux/prctl.h>
14: #include <sys/prctl.h>
15: #include <sys/time.h>
16:
17: #include "rseq.h"
18:
19: #include "../kselftest_harness.h"
20:
21: #ifndef __NR_rseq_slice_yield
22: # define __NR_rseq_slice_yield 471
23: #endif
24:
25: #define BITS_PER_INT 32
26: #define BITS_PER_BYTE 8
27:
28: #ifndef PR_RSEQ_SLICE_EXTENSION
29: # define PR_RSEQ_SLICE_EXTENSION 79
30: # define PR_RSEQ_SLICE_EXTENSION_GET 1
31: # define PR_RSEQ_SLICE_EXTENSION_SET 2
32: # define PR_RSEQ_SLICE_EXT_ENABLE 0x01
33: #endif
34:
35: #ifndef RSEQ_SLICE_EXT_REQUEST_BIT
36: # define RSEQ_SLICE_EXT_REQUEST_BIT 0
37: # define RSEQ_SLICE_EXT_GRANTED_BIT 1
38: #endif
39:
40: #ifndef asm_inline
41: # define asm_inline asm __inline
42: #endif
43:
44: #define NSEC_PER_SEC 1000000000L
45: #define NSEC_PER_USEC 1000L
46:
47: struct noise_params {
48: int64_t noise_nsecs;
49: int64_t sleep_nsecs;
50: int64_t run;
51: };
52:
53: FIXTURE(slice_ext)
54: {
55: pthread_t noise_thread;
56: struct noise_params noise_params;
57: };
58:
59: FIXTURE_VARIANT(slice_ext)
60: {
61: int64_t total_nsecs;
62: int64_t slice_nsecs;
63: int64_t noise_nsecs;
64: int64_t sleep_nsecs;
65: bool no_yield;
66: };
67:
68: FIXTURE_VARIANT_ADD(slice_ext, n2_2_50)
69: {
70: .total_nsecs = 5LL * NSEC_PER_SEC,
71: .slice_nsecs = 2LL * NSEC_PER_USEC,
72: .noise_nsecs = 2LL * NSEC_PER_USEC,
73: .sleep_nsecs = 50LL * NSEC_PER_USEC,
74: };
75:
76: FIXTURE_VARIANT_ADD(slice_ext, n50_2_50)
77: {
78: .total_nsecs = 5LL * NSEC_PER_SEC,
79: .slice_nsecs = 50LL * NSEC_PER_USEC,
80: .noise_nsecs = 2LL * NSEC_PER_USEC,
81: .sleep_nsecs = 50LL * NSEC_PER_USEC,
82: };
83:
84: FIXTURE_VARIANT_ADD(slice_ext, n2_2_50_no_yield)
85: {
86: .total_nsecs = 5LL * NSEC_PER_SEC,
87: .slice_nsecs = 2LL * NSEC_PER_USEC,
88: .noise_nsecs = 2LL * NSEC_PER_USEC,
89: .sleep_nsecs = 50LL * NSEC_PER_USEC,
90: .no_yield = true,
91: };
92:
93:
94: static inline bool elapsed(struct timespec *start, struct timespec *now,
95: int64_t span)
96: {
97: int64_t delta = now->tv_sec - start->tv_sec;
98:
99: delta *= NSEC_PER_SEC;
100: delta += now->tv_nsec - start->tv_nsec;
]
|
| 41/2 |
2026/08/12 12:39 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 20616
output: 45
thoughts: 17
Thoughts: **My Thought Process on `slice_test.c` and rseq Initialization**
Alright, so I'm diving into `slice_test.c` here, and my primary objective is to understand how it orchestrates the setup of rseq. This isn't about the surface-level API calls, but rather the underlying mechanics, the sequence of events and configurations that bring rseq into a functional state for testing purposes. I expect to find the core initialization routines, the allocation of necessary resources, and how it ensures that rseq is properly integrated into the test environment before any actual testing begins. I'm looking for the foundational pieces that make the subsequent tests possible, the establishment of the rseq context and its associated data structures. Essentially, I want to trace the lineage of rseq's birth within this specific test file.
|
| 42/2 |
2026/08/12 12:39 |
tool |
read-file |
0m
Args: map[File:tools/testing/selftests/rseq/slice_test.c FirstLine:100 LineCount:100]
Results: map[Contents: 100: delta += now->tv_nsec - start->tv_nsec;
101: return delta >= span;
102: }
103:
104: static void *noise_thread(void *arg)
105: {
106: struct noise_params *p = arg;
107:
108: while (RSEQ_READ_ONCE(p->run)) {
109: struct timespec ts_start, ts_now;
110:
111: clock_gettime(CLOCK_MONOTONIC, &ts_start);
112: do {
113: clock_gettime(CLOCK_MONOTONIC, &ts_now);
114: } while (!elapsed(&ts_start, &ts_now, p->noise_nsecs));
115:
116: ts_start.tv_sec = 0;
117: ts_start.tv_nsec = p->sleep_nsecs;
118: clock_nanosleep(CLOCK_MONOTONIC, 0, &ts_start, NULL);
119: }
120: return NULL;
121: }
122:
123: FIXTURE_SETUP(slice_ext)
124: {
125: cpu_set_t affinity;
126:
127: if (__rseq_register_current_thread(true, false))
128: SKIP(return, "RSEQ not supported\n");
129:
130: if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET,
131: PR_RSEQ_SLICE_EXT_ENABLE, 0, 0))
132: SKIP(return, "Time slice extension not supported\n");
133:
134: ASSERT_EQ(sched_getaffinity(0, sizeof(affinity), &affinity), 0);
135:
136: /* Pin it on a single CPU. Avoid CPU 0 */
137: for (int i = 1; i < CPU_SETSIZE; i++) {
138: if (!CPU_ISSET(i, &affinity))
139: continue;
140:
141: CPU_ZERO(&affinity);
142: CPU_SET(i, &affinity);
143: ASSERT_EQ(sched_setaffinity(0, sizeof(affinity), &affinity), 0);
144: break;
145: }
146:
147: self->noise_params.noise_nsecs = variant->noise_nsecs;
148: self->noise_params.sleep_nsecs = variant->sleep_nsecs;
149: self->noise_params.run = 1;
150:
151: ASSERT_EQ(pthread_create(&self->noise_thread, NULL, noise_thread, &self->noise_params), 0);
152: }
153:
154: FIXTURE_TEARDOWN(slice_ext)
155: {
156: self->noise_params.run = 0;
157: pthread_join(self->noise_thread, NULL);
158: }
159:
160: TEST_F(slice_ext, slice_test)
161: {
162: unsigned long success = 0, yielded = 0, scheduled = 0, raced = 0;
163: unsigned long total = 0, aborted = 0;
164: struct rseq_abi *rs = rseq_get_abi();
165: struct timespec ts_start, ts_now;
166:
167: ASSERT_NE(rs, NULL);
168:
169: clock_gettime(CLOCK_MONOTONIC, &ts_start);
170: do {
171: struct timespec ts_cs;
172: bool req = false;
173:
174: clock_gettime(CLOCK_MONOTONIC, &ts_cs);
175:
176: total++;
177: RSEQ_WRITE_ONCE(rs->slice_ctrl.request, 1);
178: do {
179: clock_gettime(CLOCK_MONOTONIC, &ts_now);
180: } while (!elapsed(&ts_cs, &ts_now, variant->slice_nsecs));
181:
182: /*
183: * request can be cleared unconditionally, but for making
184: * the stats work this is actually checking it first
185: */
186: if (RSEQ_READ_ONCE(rs->slice_ctrl.request)) {
187: RSEQ_WRITE_ONCE(rs->slice_ctrl.request, 0);
188: /* Race between check and clear! */
189: req = true;
190: success++;
191: }
192:
193: if (RSEQ_READ_ONCE(rs->slice_ctrl.granted)) {
194: /* The above raced against a late grant */
195: if (req)
196: success--;
197: if (variant->no_yield) {
198: syscall(__NR_getpid);
199: aborted++;
]
|
| 43/2 |
2026/08/12 12:39 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 22192
output: 34
thoughts: 146
Thoughts: **My Thought Process Regarding rseq System Call Implementation**
Ah, I've encountered this `__rseq_register_current_thread(true, false)` call, and it immediately makes me think about the underlying system call. My immediate inclination is that I can simplify this by directly invoking the `rseq` system call myself. I'm considering two primary ways to do this: `syscall(SYS_rseq, &my_rseq, 32, 0, 0)` or perhaps `syscall(SYS_rseq, &my_rseq, 32, 0, 0x53053053)`.
Before I commit to a specific approach, though, I need to ensure I'm using the system call correctly. My mind immediately goes to its signature. I recall (or would quickly look up) that the `sys_rseq` system call expects the following arguments: `int rseq(struct rseq *rseq, u32 rseq_len, int flags, u32 sig);`. This is crucial. I need to map my intended arguments to these parameters precisely.
To confirm my understanding and to verify the exact behavior and expected argument values, especially concerning the `flags` and `sig` parameters, my next step is to dive into the kernel source. Specifically, I'll be looking at `kernel/rseq.c` to examine the implementation of `sys_rseq`. This will allow me to understand any nuances, default behaviors, or specific required values for the flags and signature that might not be immediately obvious from the man page or general documentation. This detailed inspection of the kernel code is the bedrock of ensuring a robust and correct implementation.
|
| 44/2 |
2026/08/12 12:39 |
tool |
read-file |
0m
Args: map[File:kernel/rseq.c FirstLine:400 LineCount:50]
Results: map[Contents: 400: unsafe_put_user(0, &rseq->cpu_id_start, efault);
401: unsafe_put_user(RSEQ_CPU_ID_UNINITIALIZED, &rseq->cpu_id, efault);
402: unsafe_put_user(0, &rseq->node_id, efault);
403: unsafe_put_user(0, &rseq->mm_cid, efault);
404: }
405: return true;
406:
407: efault:
408: force_sig(SIGSEGV);
409: return false;
410: }
411:
412: /* The original rseq structure size (including padding) is 32 bytes. */
413: #define ORIG_RSEQ_SIZE 32
414:
415: static long rseq_register(struct rseq __user * rseq, u32 rseq_len, int flags, u32 sig)
416: {
417: u32 rseqfl = 0;
418: u8 version = 1;
419:
420: if (!access_ok(rseq, rseq_len))
421: return -EFAULT;
422:
423: /*
424: * Architectures, which use the generic IRQ entry code (at least) enable
425: * registrations with a size greater than the original v1 fixed sized
426: * @rseq_len, which has been validated already to utilize the optimized
427: * v2 ABI mode which also enables extended RSEQ features beyond MMCID.
428: */
429: if (IS_ENABLED(CONFIG_GENERIC_IRQ_ENTRY) && rseq_len > ORIG_RSEQ_SIZE)
430: version = 2;
431:
432: if (IS_ENABLED(CONFIG_RSEQ_SLICE_EXTENSION) && version > 1) {
433: if (rseq_slice_extension_enabled()) {
434: rseqfl |= RSEQ_CS_FLAG_SLICE_EXT_AVAILABLE;
435: if (flags & RSEQ_FLAG_SLICE_EXT_DEFAULT_ON)
436: rseqfl |= RSEQ_CS_FLAG_SLICE_EXT_ENABLED;
437: }
438: }
439:
440: scoped_user_write_access(rseq, efault) {
441: /*
442: * If the rseq_cs pointer is non-NULL on registration, clear it to
443: * avoid a potential segfault on return to user-space. The proper thing
444: * to do would have been to fail the registration but this would break
445: * older libcs that reuse the rseq area for new threads without
446: * clearing the fields. Don't bother reading it, just reset it.
447: */
448: unsafe_put_user(0UL, &rseq->rseq_cs, efault);
449: unsafe_put_user(rseqfl, &rseq->flags, efault);
]
|
| 45/2 |
2026/08/12 12:39 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 23242
output: 39
thoughts: 194
Thoughts: **Understanding `rseq` Version 2 Requirements**
Okay, so I've been digging into the `rseq` system call, specifically how to enable version 2. My current understanding is that to get version 2, the `rseq_len` parameter needs to be greater than `ORIG_RSEQ_SIZE`, which I know is a constant set at 32.
So, the logical next step is to determine what `rseq_len` *should* be. Based on the requirement, it needs to be larger than 32. This immediately brings `sizeof(struct rseq)` to mind. I'm thinking it should be around the size of the `struct rseq` itself. My initial recollection is that this size might be 33 or potentially 64 bytes, depending on certain factors.
To confirm, I need to be absolutely sure about `ORIG_RSEQ_SIZE`. Yes, I've verified it's indeed 32.
This leads me to believe that a `syscall(SYS_rseq, &my_rseq, sizeof(my_rseq), 0, 0)` call *will* work for enabling version 2, provided that `sizeof(my_rseq)` is indeed greater than 32.
Now, I'm just re-evaluating that `sizeof(struct rseq)`. My mental model is that it *would* be 32 bytes if the `__reserved` field wasn't present. However, it *is* present, which pushes the size to 33 bytes. And given typical memory alignment practices, that 33 bytes would likely be rounded up to 64 bytes.
To be completely certain, I need to go and look at the definitive source: `include/uapi/linux/rseq.h` to check the actual `sizeof(struct rseq)` definition. That will be my final confirmation.
|
| 46/2 |
2026/08/12 12:39 |
tool |
read-file |
0m
Args: map[File:include/uapi/linux/rseq.h FirstLine:190 LineCount:20]
Results: map[Contents: 190: */
191: struct rseq_slice_ctrl slice_ctrl;
192:
193: /*
194: * Before rseq became extensible, its original size was 32 bytes even
195: * though the active rseq area was only 20 bytes.
196: * Exposing a 32 bytes feature size would make life needlessly painful
197: * for userspace. Therefore, add a reserved byte after byte 32
198: * to bump the rseq feature size from 32 to 33.
199: * The next field to be added to the rseq area will be larger
200: * than one byte, and will replace this reserved byte.
201: */
202: __u8 __reserved;
203:
204: /*
205: * Flexible array member at end of structure, after last feature field.
206: */
207: char end[];
208: } __attribute__((aligned(32)));
209:
]
|
| 47/2 |
2026/08/12 12:39 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 23766
output: 34
thoughts: 28
Thoughts: **My Thought Process**
Right, so the first thing that strikes me is the size of the `struct rseq` in memory. It's 64 bytes. That's a pretty concrete value, and it immediately makes me think about how it's being used, particularly in relation to system calls.
My next thought goes straight to the `sys_rseq` system call. I'm looking at its definition, and the very first thing it does, the initial check it performs, is on `rseq_len`. This tells me that the length of the `rseq` structure is a critical piece of information for the system call to function correctly. It's not just a passive data structure; its size and how that size is communicated are fundamental to the `sys_rseq` operation. It suggests that `rseq_len` is likely used to validate the buffer being passed or to determine how much data within that buffer is relevant.
|
| 48/2 |
2026/08/12 12:39 |
tool |
read-file |
0m
Args: map[File:kernel/rseq.c FirstLine:450 LineCount:50]
Results: map[Contents: 450: /* Initialize IDs in user space */
451: unsafe_put_user(RSEQ_CPU_ID_UNINITIALIZED, &rseq->cpu_id_start, efault);
452: unsafe_put_user(RSEQ_CPU_ID_UNINITIALIZED, &rseq->cpu_id, efault);
453: unsafe_put_user(0U, &rseq->node_id, efault);
454: unsafe_put_user(0U, &rseq->mm_cid, efault);
455:
456: /*
457: * All fields past mm_cid are only valid for non-legacy v2
458: * registrations.
459: */
460: if (version > 1) {
461: if (IS_ENABLED(CONFIG_RSEQ_SLICE_EXTENSION))
462: unsafe_put_user(0U, &rseq->slice_ctrl.all, efault);
463: }
464: }
465:
466: /*
467: * Activate the registration by setting the rseq area address, length
468: * and signature in the task struct.
469: */
470: current->rseq.usrptr = rseq;
471: current->rseq.len = rseq_len;
472: current->rseq.sig = sig;
473:
474: #ifdef CONFIG_RSEQ_SLICE_EXTENSION
475: current->rseq.slice.state.enabled = !!(rseqfl & RSEQ_CS_FLAG_SLICE_EXT_ENABLED);
476: #endif
477:
478: /*
479: * Ensure the cpu_id_start and cpu_id fields are updated before
480: * returning to user-space.
481: */
482: current->rseq.event.has_rseq = version;
483: rseq_force_update();
484: return 0;
485:
486: efault:
487: return -EFAULT;
488: }
489:
490: static long rseq_unregister(struct rseq __user * rseq, u32 rseq_len, int flags, u32 sig)
491: {
492: if (flags & ~RSEQ_FLAG_UNREGISTER)
493: return -EINVAL;
494: if (current->rseq.usrptr != rseq || !current->rseq.usrptr)
495: return -EINVAL;
496: if (rseq_len != current->rseq.len)
497: return -EINVAL;
498: if (current->rseq.sig != sig)
499: return -EPERM;
]
|
| 49/2 |
2026/08/12 12:39 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 24618
output: 34
thoughts: 28
Thoughts: **A Moment of Realization**
My mind is racing, and then it hits me. I was digging into the `sys_rseq` system call, trying to understand its inner workings, and something just clicked. At the very outset of the `sys_rseq` function's implementation, there's a critical check. Yes, that's it – it's validating the `rseq_len` parameter. This is a fundamental piece of the puzzle I'm trying to solve, and recognizing this initial safeguard feels like a significant breakthrough.
|
| 50/2 |
2026/08/12 12:39 |
tool |
read-file |
0m
Args: map[File:kernel/rseq.c FirstLine:500 LineCount:50]
Results: map[Contents: 500: if (!rseq_reset_ids())
501: return -EFAULT;
502: rseq_reset(current);
503: return 0;
504: }
505:
506: static long rseq_reregister(struct rseq __user * rseq, u32 rseq_len, u32 sig)
507: {
508: /*
509: * If rseq is already registered, check whether the provided address
510: * differs from the prior one.
511: */
512: if (current->rseq.usrptr != rseq || rseq_len != current->rseq.len)
513: return -EINVAL;
514: if (current->rseq.sig != sig)
515: return -EPERM;
516: /* Already registered. */
517: return -EBUSY;
518: }
519:
520: static bool rseq_length_valid(struct rseq __user *rseq, unsigned int rseq_len)
521: {
522: /*
523: * Ensure the provided rseq is properly aligned, as communicated to
524: * user-space through the ELF auxiliary vector AT_RSEQ_ALIGN. If
525: * rseq_len is the original rseq size, the required alignment is the
526: * original struct rseq alignment.
527: *
528: * In order to be valid, rseq_len is either the original rseq size, or
529: * large enough to contain all supported fields, as communicated to
530: * user-space through the ELF auxiliary vector AT_RSEQ_FEATURE_SIZE.
531: */
532: if (rseq_len < ORIG_RSEQ_SIZE)
533: return false;
534:
535: if (rseq_len == ORIG_RSEQ_SIZE)
536: return IS_ALIGNED((unsigned long)rseq, ORIG_RSEQ_SIZE);
537:
538: return IS_ALIGNED((unsigned long)rseq, rseq_alloc_align()) &&
539: rseq_len >= offsetof(struct rseq, end);
540: }
541:
542: #define RSEQ_FLAGS_SUPPORTED (RSEQ_FLAG_SLICE_EXT_DEFAULT_ON)
543:
544: /*
545: * sys_rseq - Register or unregister restartable sequences for the caller thread.
546: */
547: SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len, int, flags, u32, sig)
548: {
549: if (flags & RSEQ_FLAG_UNREGISTER)
]
|
| 51/2 |
2026/08/12 12:39 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 25479
output: 36
thoughts: 93
Thoughts: **My Thought Process**
Ah, I've just realized a crucial constraint on `rseq_len`. It absolutely *must* be greater than or equal to the offset of the `end` field within the `struct rseq`. I know from memory or a quick check that `offsetof(struct rseq, end)` is precisely 33. This implies that a valid `rseq_len` can, in fact, be as large as `sizeof(struct rseq)`, which I recall is 64. But that's not the only consideration; the `rseq` structure itself needs to adhere to a specific alignment requirement, dictated by `rseq_alloc_align()`. So, my next step is to delve into the definition of `rseq_alloc_align()` to fully understand this alignment constraint.
|
| 52/2 |
2026/08/12 12:40 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:kernel/rseq.c Name:rseq_alloc_align]
Results: map[SourceCode: 163: /*
164: * Value returned by getauxval(AT_RSEQ_ALIGN) and expected by rseq
165: * registration. This is the active rseq area size rounded up to next
166: * power of 2, which guarantees that the rseq structure will always be
167: * aligned on the nearest power of two large enough to contain it, even
168: * as it grows.
169: */
170: static inline unsigned int rseq_alloc_align(void)
171: {
172: return 1U << get_count_order(offsetof(struct rseq, end));
173: }
SourceFile:include/linux/rseq.h]
|
| 53/2 |
2026/08/12 12:40 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 25803
output: 43
thoughts: 872
Thoughts: **My Thought Process on Refining the rseq Setup**
I was working through how to correctly set up a `rseq` region, specifically aiming to incorporate the slice extension. My initial thought process centered around understanding the alignment and size requirements dictated by the `rseq` structure itself.
I recalled that the `end` member of the `struct rseq` is located at an offset of 33 bytes. I then applied a `get_count_order` function to this offset, which resulted in a value of 6. This immediately told me that the required alignment for `rseq` is `1U << 6`, which equals 64 bytes. Consequently, I deduced that any `rseq` region, including the one I intend to use, must be at least 33 bytes in size (`rseq_len >= 33`).
With this understanding, I realized I could use `__attribute__((aligned(64)))` for my custom `rseq` structure, which I've named `my_rseq`. Since my structure is designed to be 64 bytes, passing `sizeof(my_rseq)` (which is 64) as the `rseq_len` parameter to the `rseq` syscall should be perfectly valid.
Next, I turned my attention to refining the reproducer code. I started by defining a `my_rseq_slice_ctrl` structure, as the standard `rseq` structure might not inherently include the `slice_ctrl` field. This new structure is designed to hold the `request` and `granted` fields for slice control.
Then, I defined my `my_rseq` structure, incorporating the `slice_ctrl` field and ensuring it's properly aligned using `__attribute__((aligned(64)))`. This structure also includes the necessary fields like `cpu_id_start`, `cpu_id`, `rseq_cs`, `flags`, `node_id`, and `mm_cid`, followed by the `slice_ctrl` and a `__reserved` field, ending with a flexible array member `end[]`.
The critical part that followed was managing existing `rseq` registrations, particularly those potentially made by glibc. I initially pondered whether I could reuse glibc's `rseq` if it was large enough and supported the slice extension. However, I quickly realized that glibc might not have registered it with the slice extension enabled.
My first inclination was to unregister any existing `rseq` registration, perhaps by using the `RSEQ_FLAG_UNREGISTER` flag with a known signature like `0x53053053`. I considered directly calling the `rseq` syscall with `__builtin_thread_pointer()` plus some offset.
However, I then refined my thinking. I recognized that attempting to unregister a glibc-registered `rseq` might be complex, especially if I don't have the exact signature or if glibc's internal mechanisms are involved. A more robust approach would be to either:
1. **Perform the operation in a raw `clone` context**: This would bypass glibc's initialization entirely.
2. **Handle potential registration conflicts**: I considered calling the `rseq` syscall with my desired structure and size, and if it failed with `EBUSY`, it might indicate an existing registration. However, I dismissed this as a viable solution because glibc's `rseq` might not be large enough for my slice extension needs.
Finally, I recalled seeing a more direct approach in existing code, specifically in `slice_test.c`, where `__rseq_register_current_thread` handles the registration process. This led me to believe that the complexities of unregistering glibc's `rseq` might be implicitly handled or bypassed by a proper registration flow, and I should focus on correctly setting up *my* `rseq` region.
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| 54/2 |
2026/08/12 12:40 |
tool |
read-file |
0m
Args: map[File:tools/testing/selftests/rseq/rseq.c FirstLine:100 LineCount:50]
Results: map[Contents: 100: }
101:
102: bool rseq_available(void)
103: {
104: int rc;
105:
106: rc = sys_rseq(NULL, 0, 0, 0);
107: if (rc != -1)
108: abort();
109: switch (errno) {
110: case ENOSYS:
111: return false;
112: case EINVAL:
113: return true;
114: default:
115: abort();
116: }
117: }
118:
119: /*
120: * Return the feature size supported by the kernel.
121: *
122: * Depending on the value returned by getauxval(AT_RSEQ_FEATURE_SIZE):
123: *
124: * 0: Return ORIG_RSEQ_FEATURE_SIZE (20)
125: * > 0: Return the value from getauxval(AT_RSEQ_FEATURE_SIZE).
126: *
127: * It should never return a value below ORIG_RSEQ_FEATURE_SIZE.
128: */
129: static unsigned int get_rseq_kernel_feature_size(void)
130: {
131: unsigned long auxv_rseq_feature_size, auxv_rseq_align;
132:
133: auxv_rseq_align = getauxval(AT_RSEQ_ALIGN);
134: assert(!auxv_rseq_align || auxv_rseq_align <= RSEQ_THREAD_AREA_ALLOC_SIZE);
135:
136: auxv_rseq_feature_size = getauxval(AT_RSEQ_FEATURE_SIZE);
137: assert(!auxv_rseq_feature_size || auxv_rseq_feature_size <= RSEQ_THREAD_AREA_ALLOC_SIZE);
138: if (auxv_rseq_feature_size)
139: return auxv_rseq_feature_size;
140: else
141: return ORIG_RSEQ_FEATURE_SIZE;
142: }
143:
144: int __rseq_register_current_thread(bool nolibc, bool legacy)
145: {
146: unsigned int size;
147: int rc;
148:
149: if (!rseq_ownership) {
]
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2026/08/12 12:40 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 27433
output: 43
thoughts: 25
Thoughts: **My Investigation into glibc's rseq Unregistration Mechanism**
Right, so I'm trying to get a handle on how glibc's rseq (register-based system calls) mechanism is actually *unregistered* from the current thread. My immediate focus is on the function `__rseq_register_current_thread`. I want to understand the internal workings of this function and specifically how it achieves the unregistration of rseq. This is a pretty low-level detail, and understanding it will give me a clearer picture of the thread lifecycle and resource management within glibc, especially concerning these optimized system call pathways. My goal here is to trace the execution flow within `__rseq_register_current_thread` when it's invoked for the purpose of tearing down the rseq setup for a given thread.
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| 56/2 |
2026/08/12 12:40 |
tool |
read-file |
0m
Args: map[File:tools/testing/selftests/rseq/rseq.c FirstLine:150 LineCount:50]
Results: map[Contents: 150: /* Treat libc's ownership as a successful registration. */
151: return nolibc ? -EBUSY : 0;
152: }
153:
154: /* The minimal allocation size is 32, which is the legacy allocation size */
155: size = get_rseq_kernel_feature_size();
156: if (legacy || size < ORIG_RSEQ_ALLOC_SIZE)
157: rseq_alloc_size = ORIG_RSEQ_ALLOC_SIZE;
158: else
159: rseq_alloc_size = size;
160:
161: rc = sys_rseq(&__rseq.abi, rseq_alloc_size, 0, RSEQ_SIG);
162: if (rc) {
163: /*
164: * After at least one thread has registered successfully
165: * (rseq_size > 0), the registration of other threads should
166: * never fail.
167: */
168: if (RSEQ_READ_ONCE(rseq_size) > 0) {
169: /* Incoherent success/failure within process. */
170: abort();
171: }
172: return -1;
173: }
174: assert(rseq_current_cpu_raw() >= 0);
175:
176: /*
177: * The first thread to register sets the rseq_size to mimic the libc
178: * behavior.
179: */
180: if (RSEQ_READ_ONCE(rseq_size) == 0)
181: RSEQ_WRITE_ONCE(rseq_size, size);
182:
183: return 0;
184: }
185:
186: int rseq_unregister_current_thread(void)
187: {
188: int rc;
189:
190: if (!rseq_ownership) {
191: /* Treat libc's ownership as a successful unregistration. */
192: return 0;
193: }
194: rc = sys_rseq(&__rseq.abi, rseq_alloc_size, RSEQ_ABI_FLAG_UNREGISTER, RSEQ_SIG);
195: if (rc)
196: return -1;
197: return 0;
198: }
199:
]
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2026/08/12 12:40 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 28212
output: 24
thoughts: 5795
Thoughts: **My Thoughts on RSEQ and a Kernel Bug**
It seems glibc, starting with version 2.35, automatically registers the `rseq` (runtime signaling) mechanism. This is interesting because if glibc can register it, it implies we should be able to unregister it. I started looking into how that might be done, perhaps by directly invoking the `rseq` syscall.
Initially, I considered using weak symbols like `__rseq_size` and `__rseq_offset` to locate glibc's registration and then unregister it. However, I realized this approach would fail if I were compiling statically or without glibc, as these symbols might not be present.
My thoughts then shifted towards creating a thread in a way that bypasses glibc's usual setup. I considered using `clone` with `CLONE_VM` but *without* `CLONE_THREAD`, or even a raw `syscall(SYS_clone)`. My initial understanding was that `clone` without `CLONE_THREAD` creates a new process. If a new process is created, glibc's `_start` routine would run, which *would* register `rseq`. However, I then recalled that we could still unregister it.
This led me to explore `clone` more deeply. The idea was to create a new process and then unregister `rseq` there.
As I delved into the specifics of `rseq`, I came across the `PR_RSEQ_SLICE_EXTENSION` functionality and a structure `my_rseq` that would be involved. The core idea was to potentially register our own `rseq` area. I thought about using `syscall(SYS_rseq, &rseq_area, sizeof(rseq_area), 0, 0x53053053)` and checking for `EBUSY`. If it was busy, I considered using `prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0)`.
A key question arose: if glibc registered `rseq`, did it include the `slice_ctrl`? I discovered that if glibc's `__rseq_size` was 33 or greater, then `slice_ctrl` would be available. This suggested I might be able to *use* glibc's own `rseq` registration for my purposes, specifically by enabling the slice extension. I drafted some code exploring this, checking for the presence and size of glibc's `rseq` and then attempting to enable the slice extension.
However, I recognized a potential weakness: what if glibc was older and didn't register `rseq` at all, or registered it with a size less than 33? In that scenario, my logic to use glibc's `rseq` wouldn't work, and I'd need to register my own. This led me to refine the code to handle both cases: attempting to leverage glibc's `rseq` if available and suitable, and falling back to registering my own if not.
Then, a new concern surfaced: `__builtin_thread_pointer()` is GCC-specific and might not be universally available across all architectures. I started thinking about how to unregister glibc's `rseq` without relying on it. The thought was that if `syscall(SYS_rseq, ...)` returned `EBUSY`, I could proceed with `prctl`, but this raised another problem: if it returned `EBUSY`, I wouldn't know the location of glibc's `rseq` area to set the `request = 1` flag.
This brought me back to the `clone` syscall. I reasoned that if I used `syscall(SYS_clone, ...)` directly to create a *raw thread*, glibc wouldn't be involved in its initialization, and therefore, it wouldn't register `rseq` for that new thread. This seemed like a cleaner way to ensure a fresh `rseq` state. I explored using `clone` with a new stack and noted that without `CLONE_THREAD`, it would be a new process.
My thinking then clarified: the `clone` *wrapper* in glibc is minimal and doesn't register `rseq`. It's `pthread_create` that handles `rseq` registration. Therefore, using `syscall(SYS_clone)` directly to create a thread would indeed bypass glibc's `rseq` registration. This seemed like the most robust way to get a thread without `rseq` being registered by glibc. I even considered that a global `rseq_area` would be fine since I'd only have one thread using it.
This line of thought culminated in the realization that a direct `clone` syscall provides a thread where `syscall(SYS_rseq, ...)` should succeed without issues.
However, this exploration of `rseq` and thread creation indirectly led me to a specific kernel bug. I was investigating a `lockdep_assert_irqs_disabled()` warning occurring in `hrtimer_test_and_clear_rearm_deferred_tif`. This function is called from `hrtimer_rearm_deferred_tif`, which in turn is invoked by `rseq_grant_slice_extension`. The problematic part is that `rseq_grant_slice_extension` is called after `local_irq_enable()`, but `hrtimer_rearm_deferred_tif` expects interrupts to be disabled.
I dug into the kernel code for `__rseq_grant_slice_extension` and discovered that it uses a `scoped_guard(irq)` block, which *disables* and then *enables* interrupts before returning. Crucially, when `__rseq_grant_slice_extension` returns `true`, it means interrupts are *enabled*. This is precisely what causes the `lockdep` assertion to fail in `hrtimer_test_and_clear_rearm_deferred_tif`.
To trigger this bug, I identified the necessary conditions:
1. The `rseq_slice_extension_enabled()` kernel configuration must be set.
2. The slice extension must be enabled in user space via `prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0)`.
3. A user interrupt needs to occur to set `curr->rseq.event.user_irq` to true.
4. There must be no other pending reschedule work flags set.
5. The `granted` flag in the `rseq` state must be false.
6. User space must set the `request` flag in the `rseq_slice_ctrl`.
7. A timer interrupt must happen while the thread is in user space, setting `_TIF_NEED_RESCHED`.
With these conditions in mind, I started crafting a reproducer program. My strategy was to create a raw thread using `clone` directly, ensuring that glibc wouldn't register `rseq` for it. This way, `syscall(SYS_rseq, ...)` would succeed. Then, I'd enable the slice extension and enter a loop where I repeatedly set the `request` flag. The idea was that an interrupt occurring during this loop would trigger the bug.
I also briefly considered using `fork()` and then `syscall(SYS_rseq, ...)` in the child, but I wasn't entirely sure how glibc's `fork` wrapper or the kernel's handling of `fork` would affect `rseq` registration in the child process. I decided the direct `clone` approach was more certain to provide a clean slate.
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| 58/2 |
2026/08/12 12:41 |
tool |
grepper |
0m
Args: map[Expression:rseq.*fork PathPrefix:]
Results: map[Output:include/linux/rseq.h=140=static inline void rseq_execve(struct task_struct *t)
--
include/linux/rseq.h-154- */
include/linux/rseq.h:155:static inline void rseq_fork(struct task_struct *t, u64 clone_flags)
include/linux/rseq.h-156-{
--
include/linux/rseq.h=182=static inline void rseq_virt_userspace_exit(void) { }
include/linux/rseq.h:183:static inline void rseq_fork(struct task_struct *t, u64 clone_flags) { }
include/linux/rseq.h-184-static inline void rseq_execve(struct task_struct *t) { }
--
kernel/fork.c=1994=__latent_entropy struct task_struct *copy_process(
--
kernel/fork.c-2460-
kernel/fork.c:2461: rseq_fork(p, clone_flags);
kernel/fork.c-2462-
]
|
| 59/2 |
2026/08/12 12:41 |
llm |
initial-researcher |
0m
Model:
Tokens:
input: 34304
output: 36
thoughts: 10
Thoughts: **My Thought Process Regarding `rseq_fork`**
Alright, so my immediate inclination here is to delve into the specifics of `rseq_fork`. I want to understand its operational mechanics, its purpose within the broader system, and how it's intended to function in practice. I'm considering its potential implications for concurrency, resource management, and overall system performance. What are the underlying assumptions it makes about the environment it operates in? What are the trade-offs involved in its design? I need to get a clear picture of its role and any potential challenges or benefits it might introduce. Essentially, I'm looking for a thorough understanding of its implementation details and its strategic place in the architecture.
|
| 60/2 |
2026/08/12 12:41 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:include/linux/rseq.h Name:rseq_fork]
Results: map[SourceCode: 145: /*
146: * If parent process has a registered restartable sequences area, the
147: * child inherits. Unregister rseq for a clone with CLONE_VM set.
148: *
149: * On fork, keep the IDs (CPU, MMCID) of the parent, which avoids a fault
150: * on the COW page on exit to user space, when the child stays on the same
151: * CPU as the parent. That's obviously not guaranteed, but in overcommit
152: * scenarios it is more likely and optimizes for the fork/exec case without
153: * taking the fault.
154: */
155: static inline void rseq_fork(struct task_struct *t, u64 clone_flags)
156: {
157: if (clone_flags & CLONE_VM)
158: rseq_reset(t);
159: else
160: t->rseq = current->rseq;
161: }
SourceFile:include/linux/rseq.h]
|
| 61/2 |
2026/08/12 12:41 |
llm |
initial-researcher |
1m
Model:
Tokens:
input: 34643
output: 1288
thoughts: 7166
Thoughts: **My Thought Process on Reproducing the `lockdep_assert_irqs_disabled()` Warning in the Linux Kernel**
I've been investigating a rather peculiar kernel warning, `lockdep_assert_irqs_disabled()`, that appears during the execution of specific sequences involving `rseq` (registerable syscall extension) and timer interrupts. My goal here is to not just understand *why* this happens, but to construct a minimal, self-contained reproducer that reliably triggers it, which I can then use to demonstrate the underlying issue to others.
My initial analysis points to a race condition or a logic flaw in how the kernel handles the transition back to user-space from an interrupt context, particularly when `rseq` slice extensions are involved. The warning itself tells me that a function (`hrtimer_test_and_clear_rearm_deferred_tif`) that expects interrupts to be disabled is being called while they are, in fact, enabled. This is a classic `lockdep` violation.
The call trace provided in the bug report is invaluable:
```
RIP: 0010:hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline]
RIP: 0010:hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline]
RIP: 0010:rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline]
RIP: 0010:__exit_to_user_mode_loop kernel/entry/common.c:54 [inline]
```
This trace clearly shows the path: an interrupt triggers `__exit_to_user_mode_loop`, which then potentially calls `rseq_grant_slice_extension`, which in turn calls `hrtimer_rearm_deferred_tif`. The key is to understand what enables `rseq_grant_slice_extension` and what causes interrupts to be enabled at the wrong time.
The `__exit_to_user_mode_loop` function is where the kernel prepares to return to user space. Crucially, it has a section where it explicitly *enables* interrupts:
```c
while (ti_work & EXIT_TO_USER_MODE_WORK_LOOP) {
local_irq_enable(); // <-- Here!
if (ti_work & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)) {
if (!rseq_grant_slice_extension(ti_work, TIF_SLICE_EXT_DENY))
schedule();
}
// ...
}
```
So, the problem arises if `rseq_grant_slice_extension` is called *after* `local_irq_enable()`. This function is designed to grant slice extensions requested by user space. For this to happen, we need a user-space thread that:
1. Has `rseq` registered.
2. Has the slice extension feature enabled.
3. Is actively requesting a slice extension.
4. Experiences an interrupt (like a timer tick) while in this state.
This leads me to consider how `rseq` behaves with `fork` and `clone`. The documentation and my understanding of `fork` (where `CLONE_VM` is *not* set) indicate that the child process inherits the parent's `rseq` registration. However, the `rseq` user pointer (`t->rseq.usrptr`) is copy-on-write (COW). If the parent registered `rseq` via glibc, the child will initially have it. If we want to register our *own* `rseq`, we'd typically need to unregister the inherited one, or use a `clone` variant that clears it.
This is where `clone` with `CLONE_VM` becomes critical. The kernel's `rseq_fork` function explicitly calls `rseq_reset(t)` when `CLONE_VM` is set. This means `clone` with `CLONE_VM` effectively *clears* any existing `rseq` registration, providing a clean slate for our custom registration. This is exactly what `pthread_create` does internally. So, `clone(CLONE_VM)` is the ideal starting point.
To make this a thread rather than a separate process (which simplifies memory management and resource sharing in this context), I'll use `CLONE_THREAD`. Additionally, since `CLONE_THREAD` requires `CLONE_SIGHAND`, and `CLONE_SIGHAND` requires `CLONE_VM`, the flags naturally expand. To ensure a clean environment for file descriptors and other process-specific data, I'll include `CLONE_FS` and `CLONE_FILES` as well. Therefore, the target `clone` flags become `CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD`.
Now, let's define our `rseq` structure. The bug report and kernel source suggest that for features like slice extensions, a certain structure and alignment are expected. I'll define `struct my_rseq` mirroring the kernel's `struct rseq`, ensuring it's aligned to 64 bytes (`__attribute__((aligned(64)))`) as required by the kernel for `rseq` regions. The fields `cpu_id_start`, `cpu_id`, `rseq_cs`, `flags`, `node_id`, `mm_cid`, and `slice_ctrl` are necessary. The total size of the defined fields is 33 bytes, and with the 64-byte alignment, `sizeof(rseq_area)` will be 64 bytes, which is the expected minimum and correctly aligned size for enabling `rseq` v2 features.
The reproducer's logic in the new thread (`thread_fn`) will be:
1. **Register `rseq`**: Call `syscall(SYS_rseq, &rseq_area, sizeof(rseq_area), 0, sig)` to register our `rseq_area`. The `sizeof(rseq_area)` must be at least 33 and aligned to 64.
2. **Enable Slice Extension**: Use `prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0)` to enable the slice extension feature for this thread.
3. **Request Slice Extension**: Enter an infinite loop where `rseq_area.slice_ctrl.request` is constantly set to `1`. This signals to the kernel that we want a slice extension.
The `main` function will:
1. Allocate a stack for the new thread.
2. Call `clone` with the determined flags to create the thread.
3. Sleep for a short duration (e.g., 2 seconds) to allow the thread to run and for timer interrupts to occur.
The crucial part is that the timer interrupt (scheduler tick) will eventually fire. This will set `_TIF_NEED_RESCHED`. When the kernel prepares to return to user space, `__exit_to_user_mode_loop` will be invoked. It will see `_TIF_NEED_RESCHED`, enable interrupts (`local_irq_enable()`), and then call `rseq_grant_slice_extension`.
The `rseq_grant_slice_extension` function (and its internal helper `__rseq_grant_slice_extension`) checks if `rseq_slice_extension_enabled()` and if the user requested it (`usr_ctrl.request == 1`). Assuming `CONFIG_RSEQ_SLICE_EXTENSION` is enabled in the kernel (which it is, given the stack trace), and our thread is continuously setting `request = 1`, the slice extension will be granted. The function then sets `curr->rseq.slice.state.granted = true` and, importantly, calls `hrtimer_rearm_deferred_tif`. Because interrupts were enabled just before this in `__exit_to_user_mode_loop`, the `hrtimer_test_and_clear_rearm_deferred_tif` will indeed trigger the `lockdep_assert_irqs_disabled()` warning.
Therefore, the complete reproducer involves setting up the `rseq` structure, creating a thread with `clone(CLONE_VM | ...)` that registers and enables `rseq` slice extensions, and then enters a tight loop requesting them, ensuring that when the inevitable timer interrupt occurs, the kernel's logic for returning to user space and handling `rseq` slice extensions triggers the `lockdep` violation.
This thought process leads directly to the following C code, which I believe is a solid reproducer.
```c
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <sched.h>
#include <signal.h>
#include <string.h> // For memset, though not strictly necessary here
// Define RSEQ slice extension constants if not present
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_SET 2
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
#endif
// User-space representation of the rseq slice control structure
struct my_rseq_slice_ctrl {
union {
uint32_t all;
struct {
uint8_t request;
uint8_t granted;
uint16_t __reserved;
};
};
};
// User-space representation of the rseq structure, aligned as expected by the kernel
struct my_rseq {
uint32_t cpu_id_start;
uint32_t cpu_id;
uint64_t rseq_cs;
uint32_t flags;
uint32_t node_id;
uint32_t mm_cid;
struct my_rseq_slice_ctrl slice_ctrl;
uint8_t __reserved;
char end[]; // Flexible array member
} __attribute__((aligned(64)));
// Global rseq area to be registered by the new thread
struct my_rseq rseq_area;
// The function executed by the new thread
int thread_fn(void *arg) {
// Register our rseq structure with the kernel.
// sizeof(rseq_area) is 64 bytes due to alignment, which is >= 33.
// The flags and sig parameters can be arbitrary for registration.
int ret = syscall(SYS_rseq, &rseq_area, sizeof(rseq_area), 0, 0x53053053);
if (ret != 0) {
perror("syscall(SYS_rseq) failed");
return 1;
}
// Enable the rseq slice extension feature for this thread.
if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0) != 0) {
perror("prctl(PR_RSEQ_SLICE_EXTENSION) failed");
return 1;
}
// Enter an infinite loop, continuously requesting a slice extension.
// This ensures that when an interrupt occurs and the thread returns to
// user-space, rseq_grant_slice_extension will be called with a pending request.
while (1) {
rseq_area.slice_ctrl.request = 1;
// A small yield or pause might make the race slightly more reliable
// in some very specific scenarios, but for the core issue, this busy-loop is sufficient.
// usleep(1);
}
return 0; // Should not be reached
}
int main() {
// Allocate a stack for the new thread. 1MB should be plenty.
char *stack = malloc(1024 * 1024);
if (!stack) {
perror("malloc");
return 1;
}
// Zero out the stack is good practice, though not strictly required for this reproducer.
// memset(stack, 0, 1024 * 1024);
// Create a new thread using clone.
// CLONE_VM is crucial as it resets rseq, allowing our custom registration.
// CLONE_THREAD, CLONE_FS, CLONE_FILES, CLONE_SIGHAND are used to create
// a proper thread within the same process context.
pid_t pid = clone(thread_fn, stack + 1024 * 1024, CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD, NULL);
if (pid == -1) {
perror("clone");
free(stack);
return 1;
}
// Let the child thread run for a few seconds.
// During this time, timer interrupts will occur, and eventually,
// the condition for the lockdep warning will be met.
sleep(2);
printf("Main thread exiting. If the kernel had lockdep enabled, the warning should have appeared.\n");
// In a real scenario, you might want to signal the thread to exit cleanly.
// For this reproducer, letting the process exit is sufficient.
free(stack);
return 0;
}
```
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loop |
|
14m
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iteration |
0 |
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action |
If |
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Args:
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| 65/3 |
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action |
merge-strategy |
0m
Results: map[CurrentReproStrategy:### Bug Analysis
The bug is a logic error in the exit-to-user-mode path regarding the RSEQ (Restartable Sequences) time slice extension feature.
When returning to user space, the kernel checks for pending work in `__exit_to_user_mode_loop()`. If rescheduling is needed (`_TIF_NEED_RESCHED`), it attempts to grant an RSEQ slice extension by calling `rseq_grant_slice_extension()`. Crucially, just before this check, `local_irq_enable()` is called, meaning `rseq_grant_slice_extension()` executes with **interrupts enabled**.
If the slice extension is granted, `rseq_grant_slice_extension()` calls `hrtimer_rearm_deferred_tif()`, which in turn calls `hrtimer_test_and_clear_rearm_deferred_tif()`. This function contains a `lockdep_assert_irqs_disabled()` check. Because interrupts were explicitly enabled in the loop above, this assertion fails, triggering the reported `WARNING`.
### Reproduction Strategy
To trigger this bug, we need to force `rseq_grant_slice_extension()` to successfully grant a slice extension while returning from a timer interrupt. The conditions for this are:
1. The thread must have a registered RSEQ area large enough to support v2 features (size $\ge$ 33 bytes).
2. The RSEQ slice extension must be enabled for the thread via `prctl(PR_RSEQ_SLICE_EXTENSION)`.
3. The user-space `rseq.slice_ctrl.request` flag must be set to `1`.
4. A timer interrupt must hit the thread while it is executing in user space, setting `_TIF_NEED_RESCHED` without setting other pending work flags (like signals).
We can achieve this by creating a raw thread using `clone()` (to bypass glibc's default RSEQ registration), registering a properly aligned 64-byte RSEQ structure, enabling the slice extension, and spinning in an infinite loop that continuously sets the `request` flag. When the scheduler tick interrupts the loop, the bug will trigger on the return to user space.
### Minimal Reproducer
```c
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <sched.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_SET 2
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
#endif
struct my_rseq_slice_ctrl {
union {
uint32_t all;
struct {
uint8_t request;
uint8_t granted;
uint16_t __reserved;
};
};
};
/*
* RSEQ area must be large enough (>= 33 bytes) to support slice_ctrl
* and aligned to the allocation alignment (64 bytes).
*/
struct my_rseq {
uint32_t cpu_id_start;
uint32_t cpu_id;
uint64_t rseq_cs;
uint32_t flags;
uint32_t node_id;
uint32_t mm_cid;
struct my_rseq_slice_ctrl slice_ctrl;
uint8_t __reserved;
char end[];
} __attribute__((aligned(64)));
struct my_rseq rseq_area;
int thread_fn(void *arg) {
/* Register our custom RSEQ area */
int ret = syscall(SYS_rseq, &rseq_area, sizeof(rseq_area), 0, 0x53053053);
if (ret != 0) {
perror("rseq");
return 1;
}
/* Enable the RSEQ time slice extension feature */
if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0) != 0) {
perror("prctl");
return 1;
}
/*
* Spin in user space requesting a slice extension.
* A timer interrupt will eventually hit, set _TIF_NEED_RESCHED,
* and trigger the lockdep warning on return to user space.
*/
while (1) {
rseq_area.slice_ctrl.request = 1;
}
return 0;
}
int main() {
char *stack = malloc(1024 * 1024);
if (!stack) {
perror("malloc");
return 1;
}
/*
* Use clone with CLONE_VM to ensure the new thread does not inherit
* any existing glibc RSEQ registrations.
*/
pid_t pid = clone(thread_fn, stack + 1024 * 1024,
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD, NULL);
if (pid == -1) {
perror("clone");
return 1;
}
/* Wait for the thread to trigger the bug */
sleep(2);
return 0;
}
```]
|
| 66/3 |
2026/08/12 12:42 |
agent |
repro-generator |
0m
Model:
Results: map[IsProbe:true RawCandidateReproC:#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_GET 1
#endif
int main() {
int ret;
// Check if rseq syscall is available
ret = syscall(SYS_rseq, NULL, 0, 0, 0);
if (ret < 0 && errno == ENOSYS) {
printf("[-] rseq syscall not supported: %s\n", strerror(errno));
exit(1);
}
printf("[+] rseq syscall is available.\n");
// Check if PR_RSEQ_SLICE_EXTENSION is supported
ret = prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET, 0, 0, 0);
if (ret < 0 && errno == EINVAL) {
printf("[-] PR_RSEQ_SLICE_EXTENSION not supported: %s\n", strerror(errno));
exit(1);
}
printf("[+] PR_RSEQ_SLICE_EXTENSION is supported.\n");
return 0;
}
]
Instruction: 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.
Prompt: Bug Description: WARNING in irqentry_exit
------------[ cut here ]------------
__lockdep_enabled && this_cpu_read(hardirqs_enabled)
WARNING: ./include/linux/hrtimer_rearm.h:17 at hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_loop kernel/entry/common.c:54 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at exit_to_user_mode_loop kernel/entry/common.c:101 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit+0x718/0xa00 kernel/entry/common.c:165, CPU#0: syz.2.3762/30761
Modules linked in:
CPU: 0 UID: 0 PID: 30761 Comm: syz.2.3762 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:hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline]
RIP: 0010:hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline]
RIP: 0010:rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline]
RIP: 0010:__exit_to_user_mode_loop kernel/entry/common.c:54 [inline]
RIP: 0010:exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
RIP: 0010:__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
RIP: 0010:irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
RIP: 0010:irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
RIP: 0010:irqentry_exit+0x718/0xa00 kernel/entry/common.c:165
Code: 00 00 00 80 e8 c9 ee 58 f6 fb 83 3d 95 d1 69 05 00 74 1a 65 8b 05 d8 2a ab 08 85 c0 75 0f 65 8b 05 29 26 ab 08 85 c0 74 04 90 <0f> 0b 90 41 f7 c5 00 10 00 00 0f 84 74 fc ff ff f0 41 80 64 24 01
RSP: 0000:ffffc9000414ff00 EFLAGS: 00010202
RAX: 0000000000000001 RBX: ffffc9000414ff48 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8e1a8f2e RDI: ffffffff8c400a80
RBP: ffffc9000414ff38 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888022f39f00
R13: 0000000000000010 R14: 000001efbbd43bba R15: 0000000000000000
FS: 00007f3e64dd56c0(0000) GS:ffff888123de1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ddddff8 CR3: 0000000034bd6000 CR4: 00000000003526f0
Call Trace:
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0033:0x7f3e66b9e019
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:00007f3e64dd50e8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f3e66e26098 RCX: 00007f3e66b9e019
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3e66e26098
RBP: 00007f3e66e26090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3e66e26128 R14: 00007ffe410c4bf0 R15: 00007ffe410c4cd8
</TASK>
Strategy: ### Bug Analysis
The bug is a logic error in the exit-to-user-mode path regarding the RSEQ (Restartable Sequences) time slice extension feature.
When returning to user space, the kernel checks for pending work in `__exit_to_user_mode_loop()`. If rescheduling is needed (`_TIF_NEED_RESCHED`), it attempts to grant an RSEQ slice extension by calling `rseq_grant_slice_extension()`. Crucially, just before this check, `local_irq_enable()` is called, meaning `rseq_grant_slice_extension()` executes with **interrupts enabled**.
If the slice extension is granted, `rseq_grant_slice_extension()` calls `hrtimer_rearm_deferred_tif()`, which in turn calls `hrtimer_test_and_clear_rearm_deferred_tif()`. This function contains a `lockdep_assert_irqs_disabled()` check. Because interrupts were explicitly enabled in the loop above, this assertion fails, triggering the reported `WARNING`.
### Reproduction Strategy
To trigger this bug, we need to force `rseq_grant_slice_extension()` to successfully grant a slice extension while returning from a timer interrupt. The conditions for this are:
1. The thread must have a registered RSEQ area large enough to support v2 features (size $\ge$ 33 bytes).
2. The RSEQ slice extension must be enabled for the thread via `prctl(PR_RSEQ_SLICE_EXTENSION)`.
3. The user-space `rseq.slice_ctrl.request` flag must be set to `1`.
4. A timer interrupt must hit the thread while it is executing in user space, setting `_TIF_NEED_RESCHED` without setting other pending work flags (like signals).
We can achieve this by creating a raw thread using `clone()` (to bypass glibc's default RSEQ registration), registering a properly aligned 64-byte RSEQ structure, enabling the slice extension, and spinning in an infinite loop that continuously sets the `request` flag. When the scheduler tick interrupts the loop, the bug will trigger on the return to user space.
### Minimal Reproducer
```c
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <sched.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_SET 2
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
#endif
struct my_rseq_slice_ctrl {
union {
uint32_t all;
struct {
uint8_t request;
uint8_t granted;
uint16_t __reserved;
};
};
};
/*
* RSEQ area must be large enough (>= 33 bytes) to support slice_ctrl
* and aligned to the allocation alignment (64 bytes).
*/
struct my_rseq {
uint32_t cpu_id_start;
uint32_t cpu_id;
uint64_t rseq_cs;
uint32_t flags;
uint32_t node_id;
uint32_t mm_cid;
struct my_rseq_slice_ctrl slice_ctrl;
uint8_t __reserved;
char end[];
} __attribute__((aligned(64)));
struct my_rseq rseq_area;
int thread_fn(void *arg) {
/* Register our custom RSEQ area */
int ret = syscall(SYS_rseq, &rseq_area, sizeof(rseq_area), 0, 0x53053053);
if (ret != 0) {
perror("rseq");
return 1;
}
/* Enable the RSEQ time slice extension feature */
if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0) != 0) {
perror("prctl");
return 1;
}
/*
* Spin in user space requesting a slice extension.
* A timer interrupt will eventually hit, set _TIF_NEED_RESCHED,
* and trigger the lockdep warning on return to user space.
*/
while (1) {
rseq_area.slice_ctrl.request = 1;
}
return 0;
}
int main() {
char *stack = malloc(1024 * 1024);
if (!stack) {
perror("malloc");
return 1;
}
/*
* Use clone with CLONE_VM to ensure the new thread does not inherit
* any existing glibc RSEQ registrations.
*/
pid_t pid = clone(thread_fn, stack + 1024 * 1024,
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD, NULL);
if (pid == -1) {
perror("clone");
return 1;
}
/* Wait for the thread to trigger the bug */
sleep(2);
return 0;
}
```
|
| 67/4 |
2026/08/12 12:42 |
llm |
repro-generator |
0m
Model:
Tokens:
input: 6486
output: 22
thoughts: 1934
Thoughts: **My Thought Process for Creating the rseq Capability Probe**
My immediate goal is to generate a minimal, standalone C program. This program's purpose is strictly defined: to verify that the test environment has the necessary kernel capabilities and privileges to proceed. It's not about triggering the actual bug yet, but about confirming the foundation.
The bug I'm eventually aiming to reproduce involves a `WARNING` in `irqentry_exit` related to `hrtimer_test_and_clear_rearm_deferred_tif` and `rseq_grant_slice_extension`. The root cause, as I understand it, is calling `rseq_grant_slice_extension` with interrupts *enabled*, when it internally expects them to be *disabled* due to calls like `hrtimer_rearm_deferred_tif`.
But before I even think about reproducing that specific interaction, the prompt is adamant: I *must* start with a "probe" program. This is a strict, non-negotiable requirement. The probe's sole function is to check for subsystem availability and privileges. Examples given include checking `/dev/vhci` or loading a dummy BPF program. The key is to *not* attempt complex logic or trigger the bug, no matter how simple it seems. I need to wait until I have confirmation that the environment is ready, indicated by a `CapabilitiesVerified` flag (though I'm just focusing on building the probe for now).
Therefore, my probe program needs to focus on the prerequisites for the bug. The bug involves `rseq` and specifically the `PR_RSEQ_SLICE_EXTENSION` capability. So, my probe should check for two things:
1. **Is `SYS_rseq` supported?** This is the fundamental system call for rseq.
2. **Is `PR_RSEQ_SLICE_EXTENSION` supported?** This is the specific feature that seems to be at the heart of the bug. If this isn't supported, the bug can't be triggered anyway.
Let's start sketching out the probe.
First, I'll need standard headers: `stdio.h`, `stdlib.h`, `unistd.h`, `sys/syscall.h` (for `SYS_rseq`), `sys/prctl.h` (for `prctl`), `stdint.h`, `errno.h`, and `string.h`.
I know that `PR_RSEQ_SLICE_EXTENSION` might not be defined in standard headers, so I'll need to define it myself, along with its associated constants like `PR_RSEQ_SLICE_EXTENSION_SET` and `PR_RSEQ_SLICE_EXT_ENABLE`. Looking at common definitions, `PR_RSEQ_SLICE_EXTENSION` is typically 79, and `PR_RSEQ_SLICE_EXTENSION_SET` is 2. I'll also need `PR_RSEQ_SLICE_EXTENSION_GET` (which is 1) to check its status.
For checking `SYS_rseq`, the simplest way is to call the `syscall` directly. If the kernel doesn't support it, `syscall(SYS_rseq, ...)` should return `ENOSYS`. I can pass `NULL` for the rseq area and zero for its size and flags for this initial check, as I'm not trying to *register* rseq here, just see if the syscall itself exists.
```c
ret = syscall(SYS_rseq, NULL, 0, 0, 0);
if (ret < 0 && errno == ENOSYS) {
printf("[-] rseq syscall not supported: %s\n", strerror(errno));
exit(1);
}
printf("[+] rseq syscall is available.\n");
```
Next, for `PR_RSEQ_SLICE_EXTENSION`. The prompt implies checking if a specific operation *works*. A common way to check for capability support with `prctl` is to attempt a "get" operation. If the capability is *not* supported by the kernel, `prctl` with that operation is expected to return `EINVAL`. So, I'll try `prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET, 0, 0, 0)`.
```c
ret = prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET, 0, 0, 0);
if (ret < 0 && errno == EINVAL) {
printf("[-] PR_RSEQ_SLICE_EXTENSION not supported: %s\n", strerror(errno));
exit(1);
}
printf("[+] PR_RSEQ_SLICE_EXTENSION is supported.\n");
```
I considered if I needed to register `rseq` first before checking `PR_RSEQ_SLICE_EXTENSION`. However, the prompt emphasizes simplicity for the probe. The `PR_RSEQ_SLICE_EXTENSION_GET` operation should, in theory, just query the kernel's support for the feature itself, without necessarily requiring a fully registered rseq area. If the kernel simply doesn't *recognize* the `PR_RSEQ_SLICE_EXTENSION` `prctl` option, it should return `EINVAL`, which is exactly what I want to detect. If glibc has already registered rseq, this might complicate a *set* operation, but for a *get* operation on the capability itself, it should be fine.
I'll add the `#define _GNU_SOURCE` at the top as `prctl` and `syscall` can sometimes require it for certain extended functionalities.
So, the combined program looks like this:
```c
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
#include <sched.h> // Might not be strictly needed for this probe, but good to have for rseq related work
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_GET 1
# define PR_RSEQ_SLICE_EXTENSION_SET 2
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
#endif
int main() {
int ret;
// 1. Check if rseq syscall is available
// Call with dummy arguments. If unsupported, errno will be ENOSYS.
ret = syscall(SYS_rseq, NULL, 0, 0, 0);
if (ret < 0 && errno == ENOSYS) {
fprintf(stderr, "[-] rseq syscall not supported: %s\n", strerror(errno));
exit(1);
}
printf("[+] rseq syscall is available.\n");
// 2. Check if PR_RSEQ_SLICE_EXTENSION is supported
// Attempting a GET operation. If the prctl option itself is not recognized
// by the kernel, it should return EINVAL.
ret = prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET, 0, 0, 0);
if (ret < 0 && errno == EINVAL) {
fprintf(stderr, "[-] PR_RSEQ_SLICE_EXTENSION not supported: %s\n", strerror(errno));
exit(1);
}
printf("[+] PR_RSEQ_SLICE_EXTENSION is supported.\n");
printf("[+] Environment capabilities verified.\n");
return 0;
}
```
I've changed `printf` to `fprintf(stderr, ...)` for error messages, as that's standard practice. This probe now directly addresses the two critical capabilities required for the subsequent bug reproduction. If this program succeeds, I'll have the green light to move on to the next phase, which would involve attempting to trigger the actual bug.
|
| 68/4 |
2026/08/12 12:43 |
tool |
grepper |
0m
Args: map[Expression:PR_RSEQ_SLICE_EXTENSION]
Results: map[Output:Documentation/userspace-api/rseq.rst=134=The thread has to enable the functionality via prctl(2)::
Documentation/userspace-api/rseq.rst-135-
Documentation/userspace-api/rseq.rst:136: prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET,
Documentation/userspace-api/rseq.rst-137- PR_RSEQ_SLICE_EXT_ENABLE, 0, 0);
--
Documentation/userspace-api/rseq.rst=150=The state can be also queried via prctl(2)::
Documentation/userspace-api/rseq.rst-151-
Documentation/userspace-api/rseq.rst:152: prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET, 0, 0, 0);
Documentation/userspace-api/rseq.rst-153-
--
include/uapi/linux/prctl.h=134=struct prctl_mm_map {
--
include/uapi/linux/prctl.h-389-/* RSEQ time slice extensions */
include/uapi/linux/prctl.h:390:#define PR_RSEQ_SLICE_EXTENSION 79
include/uapi/linux/prctl.h:391:# define PR_RSEQ_SLICE_EXTENSION_GET 1
include/uapi/linux/prctl.h:392:# define PR_RSEQ_SLICE_EXTENSION_SET 2
include/uapi/linux/prctl.h-393-/*
--
kernel/rseq.c=746=int rseq_slice_extension_prctl(unsigned long arg2, unsigned long arg3)
--
kernel/rseq.c-748- switch (arg2) {
kernel/rseq.c:749: case PR_RSEQ_SLICE_EXTENSION_GET:
kernel/rseq.c-750- if (arg3)
--
kernel/rseq.c-753-
kernel/rseq.c:754: case PR_RSEQ_SLICE_EXTENSION_SET: {
kernel/rseq.c-755- u32 rflags, valid = RSEQ_CS_FLAG_SLICE_EXT_AVAILABLE;
--
kernel/sys.c=2534=SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
--
kernel/sys.c-2886- break;
kernel/sys.c:2887: case PR_RSEQ_SLICE_EXTENSION:
kernel/sys.c-2888- if (arg4 || arg5)
--
tools/perf/trace/beauty/include/uapi/linux/prctl.h=134=struct prctl_mm_map {
--
tools/perf/trace/beauty/include/uapi/linux/prctl.h-389-/* RSEQ time slice extensions */
tools/perf/trace/beauty/include/uapi/linux/prctl.h:390:#define PR_RSEQ_SLICE_EXTENSION 79
tools/perf/trace/beauty/include/uapi/linux/prctl.h:391:# define PR_RSEQ_SLICE_EXTENSION_GET 1
tools/perf/trace/beauty/include/uapi/linux/prctl.h:392:# define PR_RSEQ_SLICE_EXTENSION_SET 2
tools/perf/trace/beauty/include/uapi/linux/prctl.h-393-/*
--
tools/testing/selftests/rseq/slice_test.c-27-
tools/testing/selftests/rseq/slice_test.c:28:#ifndef PR_RSEQ_SLICE_EXTENSION
tools/testing/selftests/rseq/slice_test.c:29:# define PR_RSEQ_SLICE_EXTENSION 79
tools/testing/selftests/rseq/slice_test.c:30:# define PR_RSEQ_SLICE_EXTENSION_GET 1
tools/testing/selftests/rseq/slice_test.c:31:# define PR_RSEQ_SLICE_EXTENSION_SET 2
tools/testing/selftests/rseq/slice_test.c-32-# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
--
tools/testing/selftests/rseq/slice_test.c=123=FIXTURE_SETUP(slice_ext)
--
tools/testing/selftests/rseq/slice_test.c-129-
tools/testing/selftests/rseq/slice_test.c:130: if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET,
tools/testing/selftests/rseq/slice_test.c-131- PR_RSEQ_SLICE_EXT_ENABLE, 0, 0))
]
|
| 69/4 |
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llm |
repro-generator |
0m
Model:
Tokens:
input: 9665
output: 39
thoughts: 39
Thoughts: **My Thought Process**
Alright, so the first thing that hits me is the confirmation: `PR_RSEQ_SLICE_EXTENSION` is definitely supported. That's a good starting point.
Now, my immediate next step is to dive into the implementation details. Where would this be managed? Given it's a `PR_` (prctl) related capability, the `kernel/rseq.c` file is the most logical place to look. Specifically, I'm going to be hunting for the function that handles or registers this particular `rseq` slice extension. My hypothesis is that there'll be a function named something like `rseq_slice_extension_prctl` within that file. That's where the kernel will be setting things up or checking for its presence.
|
| 70/4 |
2026/08/12 12:43 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:kernel/rseq.c Name:rseq_slice_extension_prctl]
Results: map[SourceCode: 746: int rseq_slice_extension_prctl(unsigned long arg2, unsigned long arg3)
747: {
748: switch (arg2) {
749: case PR_RSEQ_SLICE_EXTENSION_GET:
750: if (arg3)
751: return -EINVAL;
752: return current->rseq.slice.state.enabled ? PR_RSEQ_SLICE_EXT_ENABLE : 0;
753:
754: case PR_RSEQ_SLICE_EXTENSION_SET: {
755: u32 rflags, valid = RSEQ_CS_FLAG_SLICE_EXT_AVAILABLE;
756: bool enable = !!(arg3 & PR_RSEQ_SLICE_EXT_ENABLE);
757:
758: if (arg3 & ~PR_RSEQ_SLICE_EXT_ENABLE)
759: return -EINVAL;
760: if (!rseq_slice_extension_enabled())
761: return -ENOTSUPP;
762: if (!current->rseq.usrptr)
763: return -ENXIO;
764: if (!rseq_v2(current))
765: return -ENOTSUPP;
766:
767: /* No change? */
768: if (enable == !!current->rseq.slice.state.enabled)
769: return 0;
770:
771: if (get_user(rflags, ¤t->rseq.usrptr->flags))
772: goto die;
773:
774: if (current->rseq.slice.state.enabled)
775: valid |= RSEQ_CS_FLAG_SLICE_EXT_ENABLED;
776:
777: if ((rflags & valid) != valid)
778: goto die;
779:
780: rflags &= ~RSEQ_CS_FLAG_SLICE_EXT_ENABLED;
781: rflags |= RSEQ_CS_FLAG_SLICE_EXT_AVAILABLE;
782: if (enable)
783: rflags |= RSEQ_CS_FLAG_SLICE_EXT_ENABLED;
784:
785: if (put_user(rflags, ¤t->rseq.usrptr->flags))
786: goto die;
787:
788: current->rseq.slice.state.enabled = enable;
789: return 0;
790: }
791: default:
792: return -EINVAL;
793: }
794: die:
795: force_sig(SIGSEGV);
796: return -EFAULT;
797: }
SourceFile:kernel/rseq.c]
|
| 71/4 |
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llm |
repro-generator |
0m
Model:
Tokens:
input: 10525
output: 369
thoughts: 702
Thoughts: **My Thought Process on Enabling and Detecting rseq Slice Extension**
My immediate goal is to ascertain the support for the `PR_RSEQ_SLICE_EXTENSION` feature, specifically using the `GET` operation. I know that the `prctl` system call, when invoked with `PR_RSEQ_SLICE_EXTENSION` and the `PR_RSEQ_SLICE_EXTENSION_GET` subcommand, will return the current state of the slice extension. Crucially, I recall that if the third argument (`arg3`, which in this context is intended to be a pointer or value related to the extension's state) is non-zero, it signals an invalid argument and returns `-EINVAL`. However, when I'm just trying to *query* the support, `arg3` should be 0.
The key insight here is how `prctl` behaves when the `PR_RSEQ_SLICE_EXTENSION` capability itself isn't recognized by the kernel. In such a scenario, `prctl` will return `-EINVAL`. This is my primary indicator that the feature is *not* supported at all.
However, my initial thought was slightly incomplete. I need to refine my understanding of the success conditions for the `GET` operation. If `prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET, 0, 0, 0)` returns `0` or `PR_RSEQ_SLICE_EXT_ENABLE`, it signifies that the feature *is* supported and is either disabled or enabled, respectively. So, any return value other than `-EINVAL` (and not `-ENOSYS` for the underlying `rseq` syscall, which I'll check separately) indicates support.
With this clarified understanding, I'm ready to draft a probe program. The program needs to first verify the fundamental availability of the `rseq` syscall itself. I'll use `syscall(SYS_rseq, NULL, 0, 0, 0)` for this; a return value less than 0 with `errno` set to `ENOSYS` will tell me `rseq` isn't even present.
Next, I'll proceed to check for `PR_RSEQ_SLICE_EXTENSION` support. I'll call `prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET, 0, 0, 0)`. If this call returns `-EINVAL`, I'll interpret it as the extension *not* being supported and exit. Otherwise, if it returns successfully (0 or `PR_RSEQ_SLICE_EXT_ENABLE`), I'll know the extension is supported.
I then paused to think about edge cases and the behavior within the kernel's `rseq_slice_extension_prctl` function. I recalled that for a `SET` operation, the function might return `-ENOTSUPP` if `rseq` isn't enabled or if `rseq_v2` isn't active. However, for the `GET` operation, the behavior is simpler: it just returns the `enabled` state of the slice extension, which defaults to 0 if `rseq` hasn't even been registered for the current thread. This confirms that for `GET`, a non-`-EINVAL` return from `prctl` is indeed the correct indicator of support.
Finally, I considered any other prerequisites. The bug I'm investigating relies on thread creation via `clone`, which is a ubiquitous syscall. The other critical prerequisite is that `rseq` must be registered. My probe program directly addresses the support for the `PR_RSEQ_SLICE_EXTENSION` feature, which is the primary concern, and I've also ensured the underlying `rseq` syscall is present. With this, I'm confident in the probe program I've written and am ready to submit it.
|
| 72/4 |
2026/08/12 12:43 |
tool |
set-results |
0m
Args: map[IsProbe:true RawCandidateReproC:#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_GET 1
#endif
int main() {
int ret;
// Check if rseq syscall is available
ret = syscall(SYS_rseq, NULL, 0, 0, 0);
if (ret < 0 && errno == ENOSYS) {
printf("[-] rseq syscall not supported: %s\n", strerror(errno));
exit(1);
}
printf("[+] rseq syscall is available.\n");
// Check if PR_RSEQ_SLICE_EXTENSION is supported
ret = prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET, 0, 0, 0);
if (ret < 0 && errno == EINVAL) {
printf("[-] PR_RSEQ_SLICE_EXTENSION not supported: %s\n", strerror(errno));
exit(1);
}
printf("[+] PR_RSEQ_SLICE_EXTENSION is supported.\n");
return 0;
}
]
Results: map[IsProbe:true RawCandidateReproC:#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_GET 1
#endif
int main() {
int ret;
// Check if rseq syscall is available
ret = syscall(SYS_rseq, NULL, 0, 0, 0);
if (ret < 0 && errno == ENOSYS) {
printf("[-] rseq syscall not supported: %s\n", strerror(errno));
exit(1);
}
printf("[+] rseq syscall is available.\n");
// Check if PR_RSEQ_SLICE_EXTENSION is supported
ret = prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET, 0, 0, 0);
if (ret < 0 && errno == EINVAL) {
printf("[-] PR_RSEQ_SLICE_EXTENSION not supported: %s\n", strerror(errno));
exit(1);
}
printf("[+] PR_RSEQ_SLICE_EXTENSION is supported.\n");
return 0;
}
]
|
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loop |
|
0m
|
| 74/4 |
2026/08/12 12:43 |
iteration |
0 |
0m
|
| 75/5 |
2026/08/12 12:43 |
action |
merge-repro-c |
0m
Results: map[CurrentCandidateReproC:#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_GET 1
#endif
int main() {
int ret;
// Check if rseq syscall is available
ret = syscall(SYS_rseq, NULL, 0, 0, 0);
if (ret < 0 && errno == ENOSYS) {
printf("[-] rseq syscall not supported: %s\n", strerror(errno));
exit(1);
}
printf("[+] rseq syscall is available.\n");
// Check if PR_RSEQ_SLICE_EXTENSION is supported
ret = prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET, 0, 0, 0);
if (ret < 0 && errno == EINVAL) {
printf("[-] PR_RSEQ_SLICE_EXTENSION not supported: %s\n", strerror(errno));
exit(1);
}
printf("[+] PR_RSEQ_SLICE_EXTENSION is supported.\n");
return 0;
}
]
|
| 76/5 |
2026/08/12 12:43 |
action |
compile-c-prog |
0m
Results: map[CompilerError: FormattedReproC:#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_GET 1
#endif
int main() {
int ret;
// Check if rseq syscall is available
ret = syscall(SYS_rseq, NULL, 0, 0, 0);
if (ret < 0 && errno == ENOSYS) {
printf("[-] rseq syscall not supported: %s\n", strerror(errno));
exit(1);
}
printf("[+] rseq syscall is available.\n");
// Check if PR_RSEQ_SLICE_EXTENSION is supported
ret = prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET, 0, 0, 0);
if (ret < 0 && errno == EINVAL) {
printf("[-] PR_RSEQ_SLICE_EXTENSION not supported: %s\n", strerror(errno));
exit(1);
}
printf("[+] PR_RSEQ_SLICE_EXTENSION is supported.\n");
return 0;
}
]
|
| 77/5 |
2026/08/12 12:43 |
action |
If |
0m
Args:
|
| 78/3 |
2026/08/12 12:43 |
action |
run-c-repro |
3m
Results: map[CandidateBugTitle: CandidateCrashReport: CandidateReproduced:false ConsoleOutput:[ 70.466886][ T33] kauditd_printk_skb: 10 callbacks suppressed
[ 70.466896][ T33] audit: type=1400 audit(1786538677.299:201): avc: denied { transition } for pid=5825 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
[ 70.476104][ T33] audit: type=1400 audit(1786538677.309:202): avc: denied { noatsecure } for pid=5825 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 70.482209][ T33] audit: type=1400 audit(1786538677.309:203): avc: denied { rlimitinh } for pid=5825 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 70.488126][ T33] audit: type=1400 audit(1786538677.309:204): avc: denied { siginh } for pid=5825 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 71.739853][ T1371] ieee802154 phy0 wpan0: encryption failed: -22
[ 71.743018][ T1371] ieee802154 phy1 wpan1: encryption failed: -22
Warning: Permanently added '[localhost]:36363' (ED25519) to the list of known hosts.
[+] rseq syscall is available.
[+] PR_RSEQ_SLICE_EXTENSION is supported.
[ 73.457239][ T33] audit: type=1400 audit(1786538680.289:205): avc: denied { write } for pid=5840 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
[ 73.499419][ T33] audit: type=1400 audit(1786538680.339:206): avc: denied { write } for pid=5843 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
[ 73.752397][ T33] audit: type=1400 audit(1786538680.589:207): avc: denied { write } for pid=5846 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
[ 73.788589][ T33] audit: type=1400 audit(1786538680.629:208): avc: denied { write } for pid=5849 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
[ 74.596251][ T33] audit: type=1400 audit(1786538681.429:209): avc: denied { write } for pid=5852 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
[ 74.641121][ T33] audit: type=1400 audit(1786538681.479:210): avc: denied { write } for pid=5855 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
[ 75.666333][ T33] kauditd_printk_skb: 4 callbacks suppressed
[ 75.666343][ T33] audit: type=1400 audit(1786538682.499:215): avc: denied { write } for pid=5870 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
[ 75.717470][ T33] audit: type=1400 audit(1786538682.549:216): avc: denied { write } for pid=5873 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
[ 76.815889][ T33] audit: type=1400 audit(1786538683.649:217): avc: denied { write } for pid=5876 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
[ 76.873163][ T33] audit: type=1400 audit(1786538683.709:218): avc: denied { write } for pid=5879 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
[ 76.947606][ T33] audit: type=1400 audit(1786538683.779:219): avc: denied { write } for pid=5882 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
[ 76.997100][ T33] audit: type=1400 audit(1786538683.829:220): 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
[ 81.981575][ T10] cfg80211: failed to load regulatory.db
OtherCrashReports:<nil> StraceOutput:/strace -e \!wait4,clock_nanosleep,nanosleep -s 100 -x -f /syz-executor3053671555
<...>
[ 68.637825][ T33] kauditd_printk_skb: 10 callbacks suppressed
[ 68.637835][ T33] audit: type=1400 audit(1786538766.449:201): avc: denied { transition } for pid=5821 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
[ 68.646753][ T33] audit: type=1400 audit(1786538766.449:202): avc: denied { noatsecure } for pid=5821 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 68.652724][ T33] audit: type=1400 audit(1786538766.449:203): avc: denied { rlimitinh } for pid=5821 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 68.662491][ T33] audit: type=1400 audit(1786538766.449:204): avc: denied { siginh } for pid=5821 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 71.487292][ T33] audit: type=1400 audit(1786538769.299:205): avc: denied { write } for pid=5829 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
[ 71.535947][ T33] audit: type=1400 audit(1786538769.349:206): avc: denied { write } for pid=5832 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
[ 71.670940][ T1376] ieee802154 phy0 wpan0: encryption failed: -22
[ 71.678784][ T1376] ieee802154 phy1 wpan1: encryption failed: -22
[ 72.098945][ T33] audit: type=1400 audit(1786538769.919:207): avc: denied { write } for pid=5835 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
[ 72.136468][ T33] audit: type=1400 audit(1786538769.949:208): avc: denied { write } for pid=5838 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
[ 72.566112][ T33] audit: type=1400 audit(1786538770.379:209): avc: denied { write } for pid=5841 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
[ 72.605186][ T33] audit: type=1400 audit(1786538770.419:210): avc: denied { write } for pid=5844 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
[ 74.211125][ T33] kauditd_printk_skb: 4 callbacks suppressed
[ 74.211134][ T33] audit: type=1400 audit(1786538772.029:215): avc: denied { write } for pid=5863 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
[ 74.262784][ T33] audit: type=1400 audit(1786538772.079:216): avc: denied { write } for pid=5866 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
[ 74.415407][ T33] audit: type=1400 audit(1786538772.229:217): avc: denied { write } for pid=5869 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
[ 74.462921][ T33] audit: type=1400 audit(1786538772.279:218): avc: denied { write } for pid=5872 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
[ 75.046027][ T33] audit: type=1400 audit(1786538772.859:219): 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
[ 75.093642][ T33] audit: type=1400 audit(1786538772.909:220): 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
Warning: Permanently added '[localhost]:3199' (ED25519) to the list of known hosts.
execve("/syz-executor3053671555", ["/syz-executor3053671555"], 0x7ffdd234add0 /* 11 vars */) = 0
brk(NULL) = 0x555569281000
brk(0x555569281d80) = 0x555569281d80
arch_prctl(ARCH_SET_FS, 0x555569281400) = 0
set_tid_address(0x5555692816d0) = 5890
set_robust_list(0x5555692816e0, 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-executor3053671555", 4096) = 23
getrandom("\x6c\xe1\x41\xc2\x60\x53\xf0\x35", 8, GRND_NONBLOCK) = 8
brk(NULL) = 0x555569281d80
brk(0x5555692a2d80) = 0x5555692a2d80
brk(0x5555692a3000) = 0x5555692a3000
mprotect(0x7f4b16ab9000, 20480, PROT_READ) = 0
rseq(NULL, 0, 0, 0) = -1 EINVAL (Invalid argument)
fstat(1, {st_mode=S_IFIFO|0600, st_size=0, ...}) = 0
prctl(PR_RSEQ_SLICE_EXTENSION, 0x1, 0, 0, 0) = 0
write(1, "[+] rseq syscall is available.\n[+] PR_RSEQ_SLICE_EXTENSION is supported.\n", 73) = 73
exit_group(0) = ?
[+] rseq syscall is available.
[+] PR_RSEQ_SLICE_EXTENSION is supported.
+++ exited with 0 +++
[ 81.919216][ T10] cfg80211: failed to load regulatory.db
TestError:]
|
| 79/3 |
2026/08/12 12:46 |
action |
truncate-log |
0m
Results: map[TruncatedConsoleOutput:[ 70.466886][ T33] kauditd_printk_skb: 10 callbacks suppressed
[ 70.466896][ T33] audit: type=1400 audit(1786538677.299:201): avc: denied { transition } for pid=5825 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
[ 70.476104][ T33] audit: type=1400 audit(1786538677.309:202): avc: denied { noatsecure } for pid=5825 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 70.482209][ T33] audit: type=1400 audit(1786538677.309:203): avc: denied { rlimitinh } for pid=5825 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 70.488126][ T33] audit: type=1400 audit(1786538677.309:204): avc: denied { siginh } for pid=5825 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 71.739853][ T1371] ieee802154 phy0 wpan0: encryption failed: -22
[ 71.743018][ T1371] ieee802154 phy1 wpan1: encryption failed: -22
Warning: Permanently added '[localhost]:36363' (ED25519) to the list of known hosts.
[+] rseq syscall is available.
[+] PR_RSEQ_SLICE_EXTENSION is supported.
[ 73.457239][ T33] audit: type=1400 audit(1786538680.289:205): avc: denied { write } for pid=5840 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
[ 73.499419][ T33] audit: type=1400 audit(1786538680.339:206): avc: denied { write } for pid=5843 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
[ 73.752397][ T33] audit: type=1400 audit(1786538680.589:207): avc: denied { write } for pid=5846 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
[ 73.788589][ T33] audit: type=1400 audit(1786538680.629:208): avc: denied { write } for pid=5849 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
[ 74.596251][ T33] audit: type=1400 audit(1786538681.429:209): avc: denied { write } for pid=5852 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
[ 74.641121][ T33] audit: type=1400 audit(1786538681.479:210): avc: denied { write } for pid=5855 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
[ 75.666333][ T33] kauditd_printk_skb: 4 callbacks suppressed
[ 75.666343][ T33] audit: type=1400 audit(1786538682.499:215): avc: denied { write } for pid=5870 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
[ 75.717470][ T33] audit: type=1400 audit(1786538682.549:216): avc: denied { write } for pid=5873 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
[ 76.815889][ T33] audit: type=1400 audit(1786538683.649:217): avc: denied { write } for pid=5876 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
[ 76.873163][ T33] audit: type=1400 audit(1786538683.709:218): avc: denied { write } for pid=5879 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
[ 76.947606][ T33] audit: type=1400 audit(1786538683.779:219): avc: denied { write } for pid=5882 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
[ 76.997100][ T33] audit: type=1400 audit(1786538683.829:220): 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
[ 81.981575][ T10] cfg80211: failed to load regulatory.db
TruncatedCrashReport: TruncatedStraceOutput:/strace -e \!wait4,clock_nanosleep,nanosleep -s 100 -x -f /syz-executor3053671555
<...>
[ 68.637825][ T33] kauditd_printk_skb: 10 callbacks suppressed
[ 68.637835][ T33] audit: type=1400 audit(1786538766.449:201): avc: denied { transition } for pid=5821 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
[ 68.646753][ T33] audit: type=1400 audit(1786538766.449:202): avc: denied { noatsecure } for pid=5821 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 68.652724][ T33] audit: type=1400 audit(1786538766.449:203): avc: denied { rlimitinh } for pid=5821 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 68.662491][ T33] audit: type=1400 audit(1786538766.449:204): avc: denied { siginh } for pid=5821 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 71.487292][ T33] audit: type=1400 audit(1786538769.299:205): avc: denied { write } for pid=5829 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
[ 71.535947][ T33] audit: type=1400 audit(1786538769.349:206): avc: denied { write } for pid=5832 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
[ 71.670940][ T1376] ieee802154 phy0 wpan0: encryption failed: -22
[ 71.678784][ T1376] ieee802154 phy1 wpan1: encryption failed: -22
[ 72.098945][ T33] audit: type=1400 audit(1786538769.919:207): avc: denied { write } for pid=5835 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
[ 72.136468][ T33] audit: type=1400 audit(1786538769.949:208): avc: denied { write } for pid=5838 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
[ 72.566112][ T33] audit: type=1400 audit(1786538770.379:209): avc: denied { write } for pid=5841 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
[ 72.605186][ T33] audit: type=1400 audit(1786538770.419:210): avc: denied { write } for pid=5844 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
[ 74.211125][ T33] kauditd_printk_skb: 4 callbacks suppressed
[ 74.211134][ T33] audit: type=1400 audit(1786538772.029:215): avc: denied { write } for pid=5863 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
[ 74.262784][ T33] audit: type=1400 audit(1786538772.079:216): avc: denied { write } for pid=5866 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
[ 74.415407][ T33] audit: type=1400 audit(1786538772.229:217): avc: denied { write } for pid=5869 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
[ 74.462921][ T33] audit: type=1400 audit(1786538772.279:218): avc: denied { write } for pid=5872 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
[ 75.046027][ T33] audit: type=1400 audit(1786538772.859:219): 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
[ 75.093642][ T33] audit: type=1400 audit(1786538772.909:220): 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
Warning: Permanently added '[localhost]:3199' (ED25519) to the list of known hosts.
execve("/syz-executor3053671555", ["/syz-executor3053671555"], 0x7ffdd234add0 /* 11 vars */) = 0
brk(NULL) = 0x555569281000
brk(0x555569281d80) = 0x555569281d80
arch_prctl(ARCH_SET_FS, 0x555569281400) = 0
set_tid_address(0x5555692816d0) = 5890
set_robust_list(0x5555692816e0, 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-executor3053671555", 4096) = 23
getrandom("\x6c\xe1\x41\xc2\x60\x53\xf0\x35", 8, GRND_NONBLOCK) = 8
brk(NULL) = 0x555569281d80
brk(0x5555692a2d80) = 0x5555692a2d80
brk(0x5555692a3000) = 0x5555692a3000
mprotect(0x7f4b16ab9000, 20480, PROT_READ) = 0
rseq(NULL, 0, 0, 0) = -1 EINVAL (Invalid argument)
fstat(1, {st_mode=S_IFIFO|0600, st_size=0, ...}) = 0
prctl(PR_RSEQ_SLICE_EXTENSION, 0x1, 0, 0, 0) = 0
write(1, "[+] rseq syscall is available.\n[+] PR_RSEQ_SLICE_EXTENSION is supported.\n", 73) = 73
exit_group(0) = ?
[+] rseq syscall is available.
[+] PR_RSEQ_SLICE_EXTENSION is supported.
+++ exited with 0 +++
[ 81.919216][ T10] cfg80211: failed to load regulatory.db
]
|
| 80/3 |
2026/08/12 12:46 |
agent |
repro-oracle |
0m
Model:
Results: map[Feedback:The environment probe executed successfully. The `rseq` syscall and `PR_RSEQ_SLICE_EXTENSION` prctl are both supported and available in the environment. You can now proceed to generate the full reproducer in the next iteration. ProbePassed:true TerminalError: TitleMatches:false]
Instruction: 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.
Prompt: Bug Description: WARNING in irqentry_exit
------------[ cut here ]------------
__lockdep_enabled && this_cpu_read(hardirqs_enabled)
WARNING: ./include/linux/hrtimer_rearm.h:17 at hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_loop kernel/entry/common.c:54 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at exit_to_user_mode_loop kernel/entry/common.c:101 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit+0x718/0xa00 kernel/entry/common.c:165, CPU#0: syz.2.3762/30761
Modules linked in:
CPU: 0 UID: 0 PID: 30761 Comm: syz.2.3762 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:hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline]
RIP: 0010:hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline]
RIP: 0010:rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline]
RIP: 0010:__exit_to_user_mode_loop kernel/entry/common.c:54 [inline]
RIP: 0010:exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
RIP: 0010:__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
RIP: 0010:irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
RIP: 0010:irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
RIP: 0010:irqentry_exit+0x718/0xa00 kernel/entry/common.c:165
Code: 00 00 00 80 e8 c9 ee 58 f6 fb 83 3d 95 d1 69 05 00 74 1a 65 8b 05 d8 2a ab 08 85 c0 75 0f 65 8b 05 29 26 ab 08 85 c0 74 04 90 <0f> 0b 90 41 f7 c5 00 10 00 00 0f 84 74 fc ff ff f0 41 80 64 24 01
RSP: 0000:ffffc9000414ff00 EFLAGS: 00010202
RAX: 0000000000000001 RBX: ffffc9000414ff48 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8e1a8f2e RDI: ffffffff8c400a80
RBP: ffffc9000414ff38 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888022f39f00
R13: 0000000000000010 R14: 000001efbbd43bba R15: 0000000000000000
FS: 00007f3e64dd56c0(0000) GS:ffff888123de1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ddddff8 CR3: 0000000034bd6000 CR4: 00000000003526f0
Call Trace:
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0033:0x7f3e66b9e019
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:00007f3e64dd50e8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f3e66e26098 RCX: 00007f3e66b9e019
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3e66e26098
RBP: 00007f3e66e26090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3e66e26128 R14: 00007ffe410c4bf0 R15: 00007ffe410c4cd8
</TASK>
IsProbe: true
Reproduced: false
Console Output: [ 70.466886][ T33] kauditd_printk_skb: 10 callbacks suppressed
[ 70.466896][ T33] audit: type=1400 audit(1786538677.299:201): avc: denied { transition } for pid=5825 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
[ 70.476104][ T33] audit: type=1400 audit(1786538677.309:202): avc: denied { noatsecure } for pid=5825 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 70.482209][ T33] audit: type=1400 audit(1786538677.309:203): avc: denied { rlimitinh } for pid=5825 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 70.488126][ T33] audit: type=1400 audit(1786538677.309:204): avc: denied { siginh } for pid=5825 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 71.739853][ T1371] ieee802154 phy0 wpan0: encryption failed: -22
[ 71.743018][ T1371] ieee802154 phy1 wpan1: encryption failed: -22
Warning: Permanently added '[localhost]:36363' (ED25519) to the list of known hosts.
[+] rseq syscall is available.
[+] PR_RSEQ_SLICE_EXTENSION is supported.
[ 73.457239][ T33] audit: type=1400 audit(1786538680.289:205): avc: denied { write } for pid=5840 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
[ 73.499419][ T33] audit: type=1400 audit(1786538680.339:206): avc: denied { write } for pid=5843 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
[ 73.752397][ T33] audit: type=1400 audit(1786538680.589:207): avc: denied { write } for pid=5846 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
[ 73.788589][ T33] audit: type=1400 audit(1786538680.629:208): avc: denied { write } for pid=5849 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
[ 74.596251][ T33] audit: type=1400 audit(1786538681.429:209): avc: denied { write } for pid=5852 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
[ 74.641121][ T33] audit: type=1400 audit(1786538681.479:210): avc: denied { write } for pid=5855 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
[ 75.666333][ T33] kauditd_printk_skb: 4 callbacks suppressed
[ 75.666343][ T33] audit: type=1400 audit(1786538682.499:215): avc: denied { write } for pid=5870 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
[ 75.717470][ T33] audit: type=1400 audit(1786538682.549:216): avc: denied { write } for pid=5873 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
[ 76.815889][ T33] audit: type=1400 audit(1786538683.649:217): avc: denied { write } for pid=5876 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
[ 76.873163][ T33] audit: type=1400 audit(1786538683.709:218): avc: denied { write } for pid=5879 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
[ 76.947606][ T33] audit: type=1400 audit(1786538683.779:219): avc: denied { write } for pid=5882 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
[ 76.997100][ T33] audit: type=1400 audit(1786538683.829:220): 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
[ 81.981575][ T10] cfg80211: failed to load regulatory.db
Strace Output: /strace -e \!wait4,clock_nanosleep,nanosleep -s 100 -x -f /syz-executor3053671555
<...>
[ 68.637825][ T33] kauditd_printk_skb: 10 callbacks suppressed
[ 68.637835][ T33] audit: type=1400 audit(1786538766.449:201): avc: denied { transition } for pid=5821 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
[ 68.646753][ T33] audit: type=1400 audit(1786538766.449:202): avc: denied { noatsecure } for pid=5821 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 68.652724][ T33] audit: type=1400 audit(1786538766.449:203): avc: denied { rlimitinh } for pid=5821 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 68.662491][ T33] audit: type=1400 audit(1786538766.449:204): avc: denied { siginh } for pid=5821 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 71.487292][ T33] audit: type=1400 audit(1786538769.299:205): avc: denied { write } for pid=5829 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
[ 71.535947][ T33] audit: type=1400 audit(1786538769.349:206): avc: denied { write } for pid=5832 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
[ 71.670940][ T1376] ieee802154 phy0 wpan0: encryption failed: -22
[ 71.678784][ T1376] ieee802154 phy1 wpan1: encryption failed: -22
[ 72.098945][ T33] audit: type=1400 audit(1786538769.919:207): avc: denied { write } for pid=5835 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
[ 72.136468][ T33] audit: type=1400 audit(1786538769.949:208): avc: denied { write } for pid=5838 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
[ 72.566112][ T33] audit: type=1400 audit(1786538770.379:209): avc: denied { write } for pid=5841 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
[ 72.605186][ T33] audit: type=1400 audit(1786538770.419:210): avc: denied { write } for pid=5844 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
[ 74.211125][ T33] kauditd_printk_skb: 4 callbacks suppressed
[ 74.211134][ T33] audit: type=1400 audit(1786538772.029:215): avc: denied { write } for pid=5863 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
[ 74.262784][ T33] audit: type=1400 audit(1786538772.079:216): avc: denied { write } for pid=5866 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
[ 74.415407][ T33] audit: type=1400 audit(1786538772.229:217): avc: denied { write } for pid=5869 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
[ 74.462921][ T33] audit: type=1400 audit(1786538772.279:218): avc: denied { write } for pid=5872 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
[ 75.046027][ T33] audit: type=1400 audit(1786538772.859:219): 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
[ 75.093642][ T33] audit: type=1400 audit(1786538772.909:220): 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
Warning: Permanently added '[localhost]:3199' (ED25519) to the list of known hosts.
execve("/syz-executor3053671555", ["/syz-executor3053671555"], 0x7ffdd234add0 /* 11 vars */) = 0
brk(NULL) = 0x555569281000
brk(0x555569281d80) = 0x555569281d80
arch_prctl(ARCH_SET_FS, 0x555569281400) = 0
set_tid_address(0x5555692816d0) = 5890
set_robust_list(0x5555692816e0, 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-executor3053671555", 4096) = 23
getrandom("\x6c\xe1\x41\xc2\x60\x53\xf0\x35", 8, GRND_NONBLOCK) = 8
brk(NULL) = 0x555569281d80
brk(0x5555692a2d80) = 0x5555692a2d80
brk(0x5555692a3000) = 0x5555692a3000
mprotect(0x7f4b16ab9000, 20480, PROT_READ) = 0
rseq(NULL, 0, 0, 0) = -1 EINVAL (Invalid argument)
fstat(1, {st_mode=S_IFIFO|0600, st_size=0, ...}) = 0
prctl(PR_RSEQ_SLICE_EXTENSION, 0x1, 0, 0, 0) = 0
write(1, "[+] rseq syscall is available.\n[+] PR_RSEQ_SLICE_EXTENSION is supported.\n", 73) = 73
exit_group(0) = ?
[+] rseq syscall is available.
[+] PR_RSEQ_SLICE_EXTENSION is supported.
+++ exited with 0 +++
[ 81.919216][ T10] cfg80211: failed to load regulatory.db
Crash Report:
|
| 81/4 |
2026/08/12 12:46 |
llm |
repro-oracle |
0m
Model:
Tokens:
input: 10282
output: 80
thoughts: 373
Thoughts: **Analysis of Probe Execution and Findings**
My analysis of the executed program and its output confirms a successful environment probe. I noted the presence of a WARNING message during the `irqentry_exit` phase, specifically concerning `hrtimer_rearm_deferred_tif` and `rseq_grant_slice_extension`. However, it's crucial to contextualize this within the overall execution. The program itself was a straightforward environment probe, designed to ascertain the availability and support for certain system features.
Examining the console output, I observed clear affirmations: "[+] rseq syscall is available." and "[+] PR_RSEQ_SLICE_EXTENSION is supported." This directly tells me that the core functionalities I was testing are indeed present and operational.
Diving into the strace output, I saw the `rseq` syscall being invoked with specific parameters, including `cpu_id_start=0` and `flags=0`, which returned successfully (0). Following that, the `prctl` call for `PR_RSEQ_SLICE_EXTENSION` was also executed with parameters `0x1, 0, 0, 0` and returned successfully (0). The subsequent `write` call to stdout produced the exact messages I saw in the console output, confirming the accurate reporting of these capabilities. The program then gracefully exited.
Given this, the probe has unambiguously passed. I will therefore set `ProbePassed` to true. I am also pleased to report that there were no terminal errors, and the condition "Title matches" (implying a crash or unexpected termination) is false. Based on these findings, I will provide the following feedback: "The environment probe executed successfully. The `rseq` syscall and `PR_RSEQ_SLICE_EXTENSION` prctl are both supported and available in the environment. You can now proceed to generate the full reproducer in the next iteration." This succinctly summarizes the positive outcome and guides the next step.
|
| 82/4 |
2026/08/12 12:46 |
tool |
set-results |
0m
Args: map[Feedback:The environment probe executed successfully. The `rseq` syscall and `PR_RSEQ_SLICE_EXTENSION` prctl are both supported and available in the environment. You can now proceed to generate the full reproducer in the next iteration. ProbePassed:true TerminalError: TitleMatches:false]
Results: map[Feedback:The environment probe executed successfully. The `rseq` syscall and `PR_RSEQ_SLICE_EXTENSION` prctl are both supported and available in the environment. You can now proceed to generate the full reproducer in the next iteration. ProbePassed:true TerminalError: TitleMatches:false]
|
| 83/3 |
2026/08/12 12:46 |
action |
loop-controller |
0m
Results: map[CapabilitiesVerified:true ContinueSignal:continue EquivalenceAnalysis: OracleFeedback:The environment probe executed successfully. The `rseq` syscall and `PR_RSEQ_SLICE_EXTENSION` prctl are both supported and available in the environment. You can now proceed to generate the full reproducer in the next iteration. ReproC: Reproduced:false ReproducedBugTitle: ReproducedCrashReport:]
|
| 84/2 |
2026/08/12 12:46 |
iteration |
1 |
10m
|
| 85/3 |
2026/08/12 12:46 |
action |
If |
2m
Args: map[OracleFeedback:The environment probe executed successfully. The `rseq` syscall and `PR_RSEQ_SLICE_EXTENSION` prctl are both supported and available in the environment. You can now proceed to generate the full reproducer in the next iteration.]
|
| 86/4 |
2026/08/12 12:46 |
agent |
strategy-refiner |
2m
Model:
Instruction: 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.
Prompt: Bug Description: WARNING in irqentry_exit
------------[ cut here ]------------
__lockdep_enabled && this_cpu_read(hardirqs_enabled)
WARNING: ./include/linux/hrtimer_rearm.h:17 at hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_loop kernel/entry/common.c:54 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at exit_to_user_mode_loop kernel/entry/common.c:101 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit+0x718/0xa00 kernel/entry/common.c:165, CPU#0: syz.2.3762/30761
Modules linked in:
CPU: 0 UID: 0 PID: 30761 Comm: syz.2.3762 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:hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline]
RIP: 0010:hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline]
RIP: 0010:rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline]
RIP: 0010:__exit_to_user_mode_loop kernel/entry/common.c:54 [inline]
RIP: 0010:exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
RIP: 0010:__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
RIP: 0010:irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
RIP: 0010:irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
RIP: 0010:irqentry_exit+0x718/0xa00 kernel/entry/common.c:165
Code: 00 00 00 80 e8 c9 ee 58 f6 fb 83 3d 95 d1 69 05 00 74 1a 65 8b 05 d8 2a ab 08 85 c0 75 0f 65 8b 05 29 26 ab 08 85 c0 74 04 90 <0f> 0b 90 41 f7 c5 00 10 00 00 0f 84 74 fc ff ff f0 41 80 64 24 01
RSP: 0000:ffffc9000414ff00 EFLAGS: 00010202
RAX: 0000000000000001 RBX: ffffc9000414ff48 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8e1a8f2e RDI: ffffffff8c400a80
RBP: ffffc9000414ff38 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888022f39f00
R13: 0000000000000010 R14: 000001efbbd43bba R15: 0000000000000000
FS: 00007f3e64dd56c0(0000) GS:ffff888123de1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ddddff8 CR3: 0000000034bd6000 CR4: 00000000003526f0
Call Trace:
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0033:0x7f3e66b9e019
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:00007f3e64dd50e8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f3e66e26098 RCX: 00007f3e66b9e019
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3e66e26098
RBP: 00007f3e66e26090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3e66e26128 R14: 00007ffe410c4bf0 R15: 00007ffe410c4cd8
</TASK>
Current Strategy: ### Bug Analysis
The bug is a logic error in the exit-to-user-mode path regarding the RSEQ (Restartable Sequences) time slice extension feature.
When returning to user space, the kernel checks for pending work in `__exit_to_user_mode_loop()`. If rescheduling is needed (`_TIF_NEED_RESCHED`), it attempts to grant an RSEQ slice extension by calling `rseq_grant_slice_extension()`. Crucially, just before this check, `local_irq_enable()` is called, meaning `rseq_grant_slice_extension()` executes with **interrupts enabled**.
If the slice extension is granted, `rseq_grant_slice_extension()` calls `hrtimer_rearm_deferred_tif()`, which in turn calls `hrtimer_test_and_clear_rearm_deferred_tif()`. This function contains a `lockdep_assert_irqs_disabled()` check. Because interrupts were explicitly enabled in the loop above, this assertion fails, triggering the reported `WARNING`.
### Reproduction Strategy
To trigger this bug, we need to force `rseq_grant_slice_extension()` to successfully grant a slice extension while returning from a timer interrupt. The conditions for this are:
1. The thread must have a registered RSEQ area large enough to support v2 features (size $\ge$ 33 bytes).
2. The RSEQ slice extension must be enabled for the thread via `prctl(PR_RSEQ_SLICE_EXTENSION)`.
3. The user-space `rseq.slice_ctrl.request` flag must be set to `1`.
4. A timer interrupt must hit the thread while it is executing in user space, setting `_TIF_NEED_RESCHED` without setting other pending work flags (like signals).
We can achieve this by creating a raw thread using `clone()` (to bypass glibc's default RSEQ registration), registering a properly aligned 64-byte RSEQ structure, enabling the slice extension, and spinning in an infinite loop that continuously sets the `request` flag. When the scheduler tick interrupts the loop, the bug will trigger on the return to user space.
### Minimal Reproducer
```c
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <sched.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_SET 2
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
#endif
struct my_rseq_slice_ctrl {
union {
uint32_t all;
struct {
uint8_t request;
uint8_t granted;
uint16_t __reserved;
};
};
};
/*
* RSEQ area must be large enough (>= 33 bytes) to support slice_ctrl
* and aligned to the allocation alignment (64 bytes).
*/
struct my_rseq {
uint32_t cpu_id_start;
uint32_t cpu_id;
uint64_t rseq_cs;
uint32_t flags;
uint32_t node_id;
uint32_t mm_cid;
struct my_rseq_slice_ctrl slice_ctrl;
uint8_t __reserved;
char end[];
} __attribute__((aligned(64)));
struct my_rseq rseq_area;
int thread_fn(void *arg) {
/* Register our custom RSEQ area */
int ret = syscall(SYS_rseq, &rseq_area, sizeof(rseq_area), 0, 0x53053053);
if (ret != 0) {
perror("rseq");
return 1;
}
/* Enable the RSEQ time slice extension feature */
if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0) != 0) {
perror("prctl");
return 1;
}
/*
* Spin in user space requesting a slice extension.
* A timer interrupt will eventually hit, set _TIF_NEED_RESCHED,
* and trigger the lockdep warning on return to user space.
*/
while (1) {
rseq_area.slice_ctrl.request = 1;
}
return 0;
}
int main() {
char *stack = malloc(1024 * 1024);
if (!stack) {
perror("malloc");
return 1;
}
/*
* Use clone with CLONE_VM to ensure the new thread does not inherit
* any existing glibc RSEQ registrations.
*/
pid_t pid = clone(thread_fn, stack + 1024 * 1024,
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD, NULL);
if (pid == -1) {
perror("clone");
return 1;
}
/* Wait for the thread to trigger the bug */
sleep(2);
return 0;
}
```
Feedback: The environment probe executed successfully. The `rseq` syscall and `PR_RSEQ_SLICE_EXTENSION` prctl are both supported and available in the environment. You can now proceed to generate the full reproducer in the next iteration.
Reply: An analysis of the bug and the kernel source code confirms that the `WARNING in irqentry_exit` is a lockdep warning triggered when `rseq_grant_slice_extension()` calls `hrtimer_rearm_deferred_tif()` with interrupts enabled. This happens because `__exit_to_user_mode_loop()` explicitly enables interrupts before checking for RSEQ slice extensions.
To trigger this bug, we need to satisfy the conditions for `rseq_grant_slice_extension()` to successfully grant a slice extension:
1. The thread must have a registered RSEQ area large enough to support the `slice_ctrl` field (size $\ge$ 33 bytes).
2. The RSEQ slice extension must be enabled for the thread via `prctl(PR_RSEQ_SLICE_EXTENSION)`.
3. The user-space `rseq.slice_ctrl.request` flag must be set to `1`.
4. A timer interrupt must hit the thread while it is executing in user space, setting `_TIF_NEED_RESCHED` without setting other pending work flags.
We can achieve this by creating a raw thread using `clone()` (to bypass glibc's default RSEQ registration, which might not be large enough or might conflict), registering a properly aligned 64-byte RSEQ structure, enabling the slice extension, and spinning in an infinite loop that continuously sets the `request` flag. When the scheduler tick interrupts the loop, the bug will trigger on the return to user space.
Here is the complete C reproducer:
```c
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <sched.h>
#include <string.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_SET 2
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
#endif
#ifndef SYS_rseq
#define SYS_rseq 334
#endif
struct my_rseq_slice_ctrl {
union {
uint32_t all;
struct {
uint8_t request;
uint8_t granted;
uint16_t __reserved;
};
};
};
/*
* RSEQ area must be large enough (>= 33 bytes) to support slice_ctrl
* and aligned to the allocation alignment (64 bytes).
*/
struct my_rseq {
uint32_t cpu_id_start;
uint32_t cpu_id;
uint64_t rseq_cs;
uint32_t flags;
uint32_t node_id;
uint32_t mm_cid;
struct my_rseq_slice_ctrl slice_ctrl;
uint8_t __reserved;
char end[];
} __attribute__((aligned(64)));
int thread_fn(void *arg) {
struct my_rseq rseq_area __attribute__((aligned(64)));
memset(&rseq_area, 0, sizeof(rseq_area));
/* Register our custom RSEQ area */
int ret = syscall(SYS_rseq, &rseq_area, sizeof(rseq_area), 0, 0x53053053);
if (ret != 0) {
return 1;
}
/* Enable the RSEQ time slice extension feature */
if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0) != 0) {
return 1;
}
/*
* Spin in user space requesting a slice extension.
* A timer interrupt will eventually hit, set _TIF_NEED_RESCHED,
* and trigger the lockdep warning on return to user space.
*/
while (1) {
rseq_area.slice_ctrl.request = 1;
/* Prevent compiler from optimizing out the store */
asm volatile("" ::: "memory");
}
return 0;
}
int main() {
char *stack = malloc(1024 * 1024);
if (!stack) {
return 1;
}
/*
* Use raw clone to ensure the new thread does not inherit
* any existing glibc RSEQ registrations.
*/
pid_t pid = clone(thread_fn, stack + 1024 * 1024,
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD, NULL);
if (pid == -1) {
return 1;
}
/* Wait enough time for the scheduler tick to hit the spinning thread */
sleep(5);
return 0;
}
```
|
| 87/5 |
2026/08/12 12:46 |
llm |
strategy-refiner |
0m
Model:
Tokens:
input: 5975
output: 20
thoughts: 221
Thoughts: **My Thought Process on Reproducing the `irqentry_exit` Warning**
Okay, so the primary objective here is to create a C reproducer for this specific bug: the `WARNING in irqentry_exit` that occurs at `hrtimer_test_and_clear_rearm_deferred_tif`. My understanding is that the root cause lies within `rseq_grant_slice_extension` calling `hrtimer_rearm_deferred_tif` while interrupts are still enabled. This, naturally, trips the lockdep mechanism and generates the warning we're trying to trigger deterministically.
I'm looking back at the previous reproducer strategy, and it seems like it was on the right track. The feedback I received was quite encouraging: "The environment probe executed successfully. The `rseq` syscall and `PR_RSEQ_SLICE_EXTENSION` prctl are both supported and available in the environment. You can now proceed to generate the full reproducer in the next iteration." This tells me that the groundwork is laid, and the kernel features required for the exploit are present and detectable.
Now, here's where I pause and think. The feedback implies that the *next iteration* is for the *full reproducer*. However, I recall that the previous strategy *did* provide a minimal reproducer, or at least what I considered to be one. My current task, as I see it, is simply to present that C code. It feels like I'm being asked to finalize something that's already mostly done, which is good, but I need to ensure I'm not missing a nuance.
Before I just dump the C code, I want to be absolutely sure about the underlying mechanics. Specifically, I need to double-check the `rseq` struct layout and the constants associated with `PR_RSEQ_SLICE_EXTENSION`. This is critical for ensuring the reproducer accurately manipulates the relevant kernel structures. To confirm the `rseq` struct layout – its sizes and offsets – I'll make a mental note (or perhaps a quick actual note) to use `codesearch-struct-layout`. This tool is invaluable for guaranteeing that my C code aligns perfectly with the kernel's internal representation of the `rseq` data structure. Accuracy here is paramount to triggering the bug reliably.
|
| 88/5 |
2026/08/12 12:46 |
tool |
codesearch-struct-layout |
0m
Args:
Results: map[Fields:[map[Name:cpu_id_start OffsetBits:0 SizeBits:32] map[Name:cpu_id OffsetBits:32 SizeBits:32] map[Name:rseq_cs OffsetBits:64 SizeBits:64] map[Name:flags OffsetBits:128 SizeBits:32] map[Name:node_id OffsetBits:160 SizeBits:32] map[Name:mm_cid OffsetBits:192 SizeBits:32] map[Name:slice_ctrl OffsetBits:224 SizeBits:32] map[Name:__reserved OffsetBits:256 SizeBits:8] map[Name:end OffsetBits:264 SizeBits:0]]]
|
| 89/5 |
2026/08/12 12:46 |
llm |
strategy-refiner |
0m
Model:
Tokens:
input: 6329
output: 22
thoughts: 329
Thoughts: **Confirmation of `rseq` Struct and Slice Control Alignment**
My primary focus has been on verifying the structure of the `rseq` struct, specifically how the `slice_ctrl` field is positioned and sized, in relation to previous implementations. I've carefully examined the provided layout, noting the offsets for each member: `cpu_id_start` at 0, `cpu_id` at 32, `rseq_cs` at 64, `flags` at 128, `node_id` at 160, `mm_cid` at 192, and `slice_ctrl` at 224. The `__reserved` field starts at 256, and the struct effectively ends at 264.
My analysis confirms that the offset for `slice_ctrl` is indeed 224 bits, which translates to 28 bytes from the start of the struct. Furthermore, I've confirmed that the size of `slice_ctrl` is 32 bits, or 4 bytes. This aligns perfectly with the `my_rseq_slice_ctrl` struct I was working with in the previous strategy, which contains a `uint32_t` union encapsulating `request`, `granted`, and `__reserved` fields. The overall structure of `my_rseq`, as defined with its various `uint32_t` and `uint64_t` members followed by `my_rseq_slice_ctrl` and then a `__reserved` byte and a flexible array member `end`, also matches the expected layout precisely, including the `__attribute__((aligned(64)))` directive.
With this structural confirmation in hand, my next logical step is to investigate the `PR_RSEQ_SLICE_EXTENSION` constants, as they will dictate the behavior and interpretation of the `slice_ctrl` field.
|
| 90/5 |
2026/08/12 12:46 |
tool |
grepper |
0m
Args: map[Expression:PR_RSEQ_SLICE_EXTENSION]
Results: map[Output:Documentation/userspace-api/rseq.rst=134=The thread has to enable the functionality via prctl(2)::
Documentation/userspace-api/rseq.rst-135-
Documentation/userspace-api/rseq.rst:136: prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET,
Documentation/userspace-api/rseq.rst-137- PR_RSEQ_SLICE_EXT_ENABLE, 0, 0);
--
Documentation/userspace-api/rseq.rst=150=The state can be also queried via prctl(2)::
Documentation/userspace-api/rseq.rst-151-
Documentation/userspace-api/rseq.rst:152: prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET, 0, 0, 0);
Documentation/userspace-api/rseq.rst-153-
--
include/uapi/linux/prctl.h=134=struct prctl_mm_map {
--
include/uapi/linux/prctl.h-389-/* RSEQ time slice extensions */
include/uapi/linux/prctl.h:390:#define PR_RSEQ_SLICE_EXTENSION 79
include/uapi/linux/prctl.h:391:# define PR_RSEQ_SLICE_EXTENSION_GET 1
include/uapi/linux/prctl.h:392:# define PR_RSEQ_SLICE_EXTENSION_SET 2
include/uapi/linux/prctl.h-393-/*
--
kernel/rseq.c=746=int rseq_slice_extension_prctl(unsigned long arg2, unsigned long arg3)
--
kernel/rseq.c-748- switch (arg2) {
kernel/rseq.c:749: case PR_RSEQ_SLICE_EXTENSION_GET:
kernel/rseq.c-750- if (arg3)
--
kernel/rseq.c-753-
kernel/rseq.c:754: case PR_RSEQ_SLICE_EXTENSION_SET: {
kernel/rseq.c-755- u32 rflags, valid = RSEQ_CS_FLAG_SLICE_EXT_AVAILABLE;
--
kernel/sys.c=2534=SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
--
kernel/sys.c-2886- break;
kernel/sys.c:2887: case PR_RSEQ_SLICE_EXTENSION:
kernel/sys.c-2888- if (arg4 || arg5)
--
tools/perf/trace/beauty/include/uapi/linux/prctl.h=134=struct prctl_mm_map {
--
tools/perf/trace/beauty/include/uapi/linux/prctl.h-389-/* RSEQ time slice extensions */
tools/perf/trace/beauty/include/uapi/linux/prctl.h:390:#define PR_RSEQ_SLICE_EXTENSION 79
tools/perf/trace/beauty/include/uapi/linux/prctl.h:391:# define PR_RSEQ_SLICE_EXTENSION_GET 1
tools/perf/trace/beauty/include/uapi/linux/prctl.h:392:# define PR_RSEQ_SLICE_EXTENSION_SET 2
tools/perf/trace/beauty/include/uapi/linux/prctl.h-393-/*
--
tools/testing/selftests/rseq/slice_test.c-27-
tools/testing/selftests/rseq/slice_test.c:28:#ifndef PR_RSEQ_SLICE_EXTENSION
tools/testing/selftests/rseq/slice_test.c:29:# define PR_RSEQ_SLICE_EXTENSION 79
tools/testing/selftests/rseq/slice_test.c:30:# define PR_RSEQ_SLICE_EXTENSION_GET 1
tools/testing/selftests/rseq/slice_test.c:31:# define PR_RSEQ_SLICE_EXTENSION_SET 2
tools/testing/selftests/rseq/slice_test.c-32-# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
--
tools/testing/selftests/rseq/slice_test.c=123=FIXTURE_SETUP(slice_ext)
--
tools/testing/selftests/rseq/slice_test.c-129-
tools/testing/selftests/rseq/slice_test.c:130: if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET,
tools/testing/selftests/rseq/slice_test.c-131- PR_RSEQ_SLICE_EXT_ENABLE, 0, 0))
]
|
| 91/5 |
2026/08/12 12:46 |
llm |
strategy-refiner |
0m
Model:
Tokens:
input: 7903
output: 34
thoughts: 322
Thoughts: **My Thought Process Regarding the rseq Slice Extension Bug**
Okay, so I'm looking at these constants here: `PR_RSEQ_SLICE_EXTENSION`, `PR_RSEQ_SLICE_EXTENSION_GET`, `PR_RSEQ_SLICE_EXTENSION_SET`, and `PR_RSEQ_SLICE_EXT_ENABLE`. They seem straightforward enough.
Now, the bug report points to a specific line in `hrtimer_rearm.h` – line 17, within the `hrtimer_test_and_clear_rearm_deferred_tif` function. The reproducer, it says, just needs to spin in userspace with `request = 1`. That seems like a good starting point.
I'm also considering the `rseq` struct itself. I know it's 33 bytes, which translates to 264 bits plus 8 bits. The `SYS_rseq` syscall takes a `size` argument.
Here's where a potential issue arises: `sizeof(rseq_area)` is 64 bytes, and this is due to the `__attribute__((aligned(64)))`. The crucial part is that the `SYS_rseq` syscall is *supposed* to expect the *exact* size of the registered area. If I pass `sizeof(rseq_area)`, which is 64 bytes, the kernel might reject it if it's expecting something different. I need to dive into the `SYS_rseq` implementation to see precisely what size it's expecting. That's the next logical step to verify if this is the root cause.
|
| 92/5 |
2026/08/12 12:46 |
tool |
codesearch-definition-source |
0m
Error:
Args: map[ContextFile:kernel/rseq.c Name:sys_rseq]
Results: map[SourceCode: SourceFile:]
|
| 93/5 |
2026/08/12 12:46 |
llm |
strategy-refiner |
0m
Model:
Tokens:
input: 8264
output: 23
thoughts: 19
Thoughts: **My Thought Process for Locating `sys_rseq`**
Alright, so I need to get my hands on the `sys_rseq` system call implementation. My immediate instinct is to dive into the kernel source code, and the most logical place to start looking for system call implementations is within the `kernel` directory. Given that "rseq" sounds like a specific subsystem or feature, I'd hypothesize that it might have its own dedicated file. Therefore, my first port of call, or rather, my first `grep` or `find` command, would be targeting `kernel/rseq.c`. This file name is a strong candidate for housing the definition and logic of `sys_rseq` due to the direct naming convention and its placement within the core kernel source tree.
|
| 94/5 |
2026/08/12 12:46 |
tool |
grepper |
0m
Args: map[Expression:SYSCALL_DEFINE4\(rseq]
Results: map[Output:kernel/rseq.c=520=static bool rseq_length_valid(struct rseq __user *rseq, unsigned int rseq_len)
--
kernel/rseq.c-546- */
kernel/rseq.c:547:SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len, int, flags, u32, sig)
kernel/rseq.c-548-{
]
|
| 95/5 |
2026/08/12 12:46 |
llm |
strategy-refiner |
0m
Model:
Tokens:
input: 8420
output: 36
thoughts: 12
Thoughts: **My Thought Process**
Right, first things first, I need to verify the integrity of the sequence lengths. My immediate impulse is to check the `rseq_length_valid` flag. This is a crucial sanity check, as any discrepancies here could cascade into downstream analysis, potentially leading to erroneous conclusions. I'm assuming this flag, when set, indicates that the lengths derived from the sequence data have passed a predefined set of validation criteria, ensuring their reliability for subsequent operations. If this check fails, it signals a fundamental issue with the input data or the processing that generated these lengths, and I'll need to investigate the source of that validation failure before proceeding further.
|
| 96/5 |
2026/08/12 12:47 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:kernel/rseq.c Name:rseq_length_valid]
Results: map[SourceCode: 520: static bool rseq_length_valid(struct rseq __user *rseq, unsigned int rseq_len)
521: {
522: /*
523: * Ensure the provided rseq is properly aligned, as communicated to
524: * user-space through the ELF auxiliary vector AT_RSEQ_ALIGN. If
525: * rseq_len is the original rseq size, the required alignment is the
526: * original struct rseq alignment.
527: *
528: * In order to be valid, rseq_len is either the original rseq size, or
529: * large enough to contain all supported fields, as communicated to
530: * user-space through the ELF auxiliary vector AT_RSEQ_FEATURE_SIZE.
531: */
532: if (rseq_len < ORIG_RSEQ_SIZE)
533: return false;
534:
535: if (rseq_len == ORIG_RSEQ_SIZE)
536: return IS_ALIGNED((unsigned long)rseq, ORIG_RSEQ_SIZE);
537:
538: return IS_ALIGNED((unsigned long)rseq, rseq_alloc_align()) &&
539: rseq_len >= offsetof(struct rseq, end);
540: }
SourceFile:kernel/rseq.c]
|
| 97/5 |
2026/08/12 12:47 |
llm |
strategy-refiner |
0m
Model:
Tokens:
input: 8842
output: 36
thoughts: 63
Thoughts: **My Thought Process Regarding RSEQ Structure Allocation and Alignment**
Okay, let's break down my thinking here. I'm looking at this `offsetof(struct rseq, end)` value, which I've determined to be 33 bytes. This is a critical piece of information for me because it tells me the minimum size required to accommodate the `rseq` structure itself, specifically up to its `end` member. Consequently, any `rseq_len` value I consider *must* be at least 33 bytes to avoid potential buffer overflows or memory corruption when accessing the `end` field.
Given that, passing `sizeof(rseq_area)` which is 64 bytes, to a function expecting a length or size argument related to `rseq` seems perfectly acceptable. 64 bytes is comfortably larger than the 33-byte minimum I've identified, so there's no immediate concern about truncation or missing data related to the core `rseq` structure.
However, this is where my internal alarm bells start to ring, and I pause. My immediate follow-up question is: "Wait, `rseq_alloc_align()` is what?" This implies I'm not just concerned with the raw size of the `rseq` structure, but also with its *alignment requirements*. The `offsetof` only tells me about the contiguous memory layout, but memory access and performance can be significantly impacted by alignment. If `rseq_alloc_align()` dictates a stricter alignment than what `sizeof(rseq_area)` might provide by default (or if it dictates an alignment that's a multiple of 64, or some other specific requirement), then simply passing a size of 64 might not be sufficient. I need to know what that alignment value is, because I might need to allocate memory that is not only large enough but also aligned *precisely* according to what `rseq_alloc_align()` specifies. This is crucial for ensuring correct operation and avoiding potential performance penalties or even outright crashes on certain architectures due to misaligned memory accesses.
|
| 98/5 |
2026/08/12 12:47 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:kernel/rseq.c Name:rseq_alloc_align]
Results: map[SourceCode: 163: /*
164: * Value returned by getauxval(AT_RSEQ_ALIGN) and expected by rseq
165: * registration. This is the active rseq area size rounded up to next
166: * power of 2, which guarantees that the rseq structure will always be
167: * aligned on the nearest power of two large enough to contain it, even
168: * as it grows.
169: */
170: static inline unsigned int rseq_alloc_align(void)
171: {
172: return 1U << get_count_order(offsetof(struct rseq, end));
173: }
SourceFile:include/linux/rseq.h]
|
| 99/5 |
2026/08/12 12:47 |
llm |
strategy-refiner |
0m
Model:
Tokens:
input: 9136
output: 42
thoughts: 3817
Thoughts: **My Thoughts on the RSEQ Slice Extension Bug**
Okay, let me walk through my thought process here. I'm trying to understand and reproduce a lockdep warning related to the RSEQ slice extension, specifically concerning deferred timer rearming.
First, I need to get the RSEQ area set up correctly. I know `offsetof(struct rseq, end)` is 33. The `get_count_order` of 33 gives me 6, which means `1U << 6` is 64. This tells me that the required alignment for the RSEQ structure, as determined by `rseq_alloc_align()`, is 64 bytes. My `struct my_rseq` is indeed declared with `__attribute__((aligned(64)))`, so `IS_ALIGNED((unsigned long)rseq, 64)` will evaluate to true. This means the alignment requirement for my RSEQ structure is met.
Now, about the `rseq_area` itself. Initially, I considered using a global `struct my_rseq rseq_area;`. My first thought was, "If I use `clone` with `CLONE_VM`, the new thread shares the same address space. If I register `rseq_area` for the new thread, it should be fine since only one thread is using it." But then I realized, "Wait, what if the main thread also uses it?" The main thread *doesn't* register it, at least not explicitly by my code.
Then I remembered that glibc might pre-register its own RSEQ area for the main thread. So, if I use `clone` with `CLONE_VM`, does glibc automatically register RSEQ for the new thread? No, because I'm using the raw `clone` syscall, not `pthread_create`. What about glibc's `clone` wrapper, though? Does it do something special? No, if I'm using the raw `syscall(SYS_clone, ...)` or even `clone(...)`, it *might* be okay.
To be on the safe side, I thought about allocating `rseq_area` on the heap or stack of the new thread, or just sticking with a global variable. But then I had another thought: "If glibc *did* register RSEQ for the main thread, and I use `clone` with `CLONE_VM`, the new thread gets a different thread ID. The kernel tracks RSEQ per thread. So, registering a *new* RSEQ area for the new thread should be perfectly fine."
Let's re-examine the `clone` call in the strategy:
```c
pid_t pid = clone(thread_fn, stack + 1024 * 1024,
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD, NULL);
```
Wait, `clone` here is the glibc function, not the raw syscall. Is it safe to use it like this? Yes, it's standard. But, I recalled that `CLONE_THREAD` requires `CLONE_SIGHAND`, and `CLONE_SIGHAND` requires `CLONE_VM`. So, the combination `CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD` is indeed correct.
Then I considered an alternative: "What if I just use `pthread_create` and unregister the glibc RSEQ area first?" I could try `syscall(SYS_rseq, glibc_rseq_area, glibc_rseq_size, RSEQ_FLAG_UNREGISTER, 0x53053053);`. But the problem is, I don't know the exact signature glibc used for its registration.
Actually, I realized, I can just use `syscall(SYS_rseq, &rseq_area, sizeof(rseq_area), 0, 0x53053053);` within the new thread. If glibc has already registered an RSEQ area for this new thread, `SYS_rseq` should fail with `EBUSY` or `EINVAL`. But, if I use raw `clone` syscall, glibc doesn't know about the new thread, so it won't register RSEQ for it. And what about the `clone` *function* itself – could it register RSEQ? Usually, it doesn't. `pthread_create` is the one that registers RSEQ.
To be absolutely sure, I decided using `syscall(SYS_clone, ...)` or `syscall(SYS_clone3, ...)` would be the most robust. However, I concluded that the `clone` function itself is generally fine.
So, I refined the reproducer. The structure `my_rseq` needs to be aligned to 64 bytes. Initially, I used a global `rseq_area`. Then I thought, "If I run this reproducer multiple times, or if syzkaller runs it in a loop, `rseq_area` is a global. If multiple threads try to register the *same* `rseq_area`, `SYS_rseq` might succeed for the first, but could fail for others, or they might overwrite each other's `slice_ctrl`." Since I'm only creating one thread per process in this specific scenario, it's fine.
But to be absolutely safe, I considered allocating `rseq_area` on the thread's stack or heap. I drafted this version:
```c
int thread_fn(void *arg) {
struct my_rseq *rseq_area = memalign(64, sizeof(struct my_rseq));
// ...
int ret = syscall(SYS_rseq, rseq_area, sizeof(*rseq_area), 0, 0x53053053);
// ...
}
```
This requires `<malloc.h>` or `posix_memalign`. Or, I could use `__attribute__((aligned(64)))` on a local variable directly.
```c
int thread_fn(void *arg) {
struct my_rseq rseq_area __attribute__((aligned(64)));
memset(&rseq_area, 0, sizeof(rseq_area));
// ...
```
Yes, a local variable is perfectly fine and thread-safe. The kernel doesn't care where it is in user space, as long as it's properly aligned. And since the thread spins infinitely, the stack memory won't be freed.
I then double-checked the size calculation for `rseq_area`. The fields add up to 33 bytes before alignment. With `__attribute__((aligned(64)))`, the `sizeof(rseq_area)` becomes 64 bytes. This is correct because the `end` field implies a variable-length part, and the `__attribute__((aligned(64)))` ensures the entire structure, including its potential variable-length tail, respects the alignment.
I also made sure `SYS_rseq` is defined, including a fallback `#define` just in case.
Finally, I reviewed the kernel's `rseq_length_valid` logic. If the passed length is 64 (not the original `ORIG_RSEQ_SIZE` of 32), it checks if `rseq` is aligned to 64 and `rseq_len` is at least 33. Since my structure is aligned to 64 and I'm passing 64 as the length (which is greater than 33), the validation should pass.
So, the refined reproducer using a local `rseq_area` seems robust. The `clone` call with `CLONE_THREAD` implies the main thread's exit will also terminate the new thread, hence the `sleep(5)` to keep the process alive long enough for the bug to manifest.
The core of the lockdep warning appears to stem from `rseq_grant_slice_extension` calling `hrtimer_rearm_deferred_tif` while interrupts might be enabled, whereas the latter expects them disabled. My code aims to trigger that specific path.
|
| 100/5 |
2026/08/12 12:47 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:include/linux/rseq_entry.h Name:rseq_grant_slice_extension]
Results: map[SourceCode: 233: static __always_inline bool rseq_grant_slice_extension(unsigned long ti_work, unsigned long mask)
234: {
235: if (unlikely(__rseq_grant_slice_extension(ti_work & mask))) {
236: hrtimer_rearm_deferred_tif(ti_work);
237: return true;
238: }
239: return false;
240: }
SourceFile:include/linux/rseq_entry.h]
|
| 101/5 |
2026/08/12 12:47 |
llm |
strategy-refiner |
0m
Model:
Tokens:
input: 13133
output: 43
thoughts: 19
Thoughts: **My Thought Process on `__rseq_grant_slice_extension`**
Alright, so the system's nudging me towards this particular function: `__rseq_grant_slice_extension`. My immediate impulse is to dive into its definition and understand its operational semantics. I need to see exactly what it's doing under the hood, what its inputs are, what its outputs are, and most importantly, what its side effects are. This is crucial for me to grasp its role within the broader execution context and to identify any potential implications for performance, resource management, or overall system stability. I'm particularly interested in how it interacts with other components and whether it introduces any bottlenecks or dependencies that I need to be aware of as an expert in this domain.
|
| 102/5 |
2026/08/12 12:47 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:include/linux/rseq_entry.h Name:__rseq_grant_slice_extension]
Results: map[SourceCode: 128: static __always_inline bool __rseq_grant_slice_extension(bool work_pending)
129: {
130: struct task_struct *curr = current;
131: struct rseq_slice_ctrl usr_ctrl;
132: union rseq_slice_state state;
133: struct rseq __user *rseq;
134:
135: if (!rseq_slice_extension_enabled())
136: return false;
137:
138: /* If not enabled or not a return from interrupt, nothing to do. */
139: state = curr->rseq.slice.state;
140: state.enabled &= curr->rseq.event.user_irq;
141: if (likely(!state.state))
142: return false;
143:
144: rseq = curr->rseq.usrptr;
145: scoped_user_rw_access(rseq, efault) {
146:
147: /*
148: * Quick check conditions where a grant is not possible or
149: * needs to be revoked.
150: *
151: * 1) Any TIF bit which needs to do extra work aside of
152: * rescheduling prevents a grant.
153: *
154: * 2) A previous rescheduling request resulted in a slice
155: * extension grant.
156: */
157: if (unlikely(work_pending || state.granted)) {
158: /* Clear user control unconditionally. No point for checking */
159: unsafe_put_user(0U, &rseq->slice_ctrl.all, efault);
160: rseq_slice_clear_grant(curr);
161: return false;
162: }
163:
164: unsafe_get_user(usr_ctrl.all, &rseq->slice_ctrl.all, efault);
165: if (likely(!(usr_ctrl.request)))
166: return false;
167:
168: /* Grant the slice extention */
169: usr_ctrl.request = 0;
170: usr_ctrl.granted = 1;
171: unsafe_put_user(usr_ctrl.all, &rseq->slice_ctrl.all, efault);
172: }
173:
174: rseq_stat_inc(rseq_stats.s_granted);
175:
176: curr->rseq.slice.state.granted = true;
177: /* Store expiry time for arming the timer on the way out */
178: curr->rseq.slice.expires = data_race(rseq_slice_ext_nsecs) + ktime_get_mono_fast_ns();
179: /*
180: * This is racy against a remote CPU setting TIF_NEED_RESCHED in
181: * several ways:
182: *
183: * 1)
184: * CPU0 CPU1
185: * clear_tsk()
186: * set_tsk()
187: * clear_preempt()
188: * Raise scheduler IPI on CPU0
189: * --> IPI
190: * fold_need_resched() -> Folds correctly
191: * 2)
192: * CPU0 CPU1
193: * set_tsk()
194: * clear_tsk()
195: * clear_preempt()
196: * Raise scheduler IPI on CPU0
197: * --> IPI
198: * fold_need_resched() <- NOOP as TIF_NEED_RESCHED is false
199: *
200: * #1 is not any different from a regular remote reschedule as it
201: * sets the previously not set bit and then raises the IPI which
202: * folds it into the preempt counter
203: *
204: * #2 is obviously incorrect from a scheduler POV, but it's not
205: * differently incorrect than the code below clearing the
206: * reschedule request with the safety net of the timer.
207: *
208: * The important part is that the clearing is protected against the
209: * scheduler IPI and also against any other interrupt which might
210: * end up waking up a task and setting the bits in the middle of
211: * the operation:
212: *
213: * clear_tsk()
214: * ---> Interrupt
215: * wakeup_on_this_cpu()
216: * set_tsk()
217: * set_preempt()
218: * clear_preempt()
219: *
220: * which would be inconsistent state.
221: */
222: scoped_guard(irq) {
223: clear_tsk_need_resched(curr);
224: clear_preempt_need_resched();
225: }
226: return true;
227:
228: efault:
229: force_sig(SIGSEGV);
230: return false;
231: }
SourceFile:include/linux/rseq_entry.h]
|
| 103/5 |
2026/08/12 12:47 |
llm |
strategy-refiner |
0m
Model:
Tokens:
input: 14753
output: 21
thoughts: 2075
Thoughts: **My Thoughts on the rseq Slice Extension Bug**
I've been digging into the `rseq_grant_slice_extension` function, trying to understand precisely when it returns `true`. My analysis shows it requires several conditions to be met simultaneously:
1. The `rseq_slice_extension_enabled()` feature must be active.
2. The current thread's `rseq.slice.state.enabled` flag must be set.
3. The `rseq.event.user_irq` flag must be true, indicating an interrupt originating from user mode.
4. Crucially, no other pending work flags (like `SIGPENDING`) should be set, meaning `work_pending` is false. Only `TIF_NEED_RESCHED` should be the relevant flag.
5. The `state.granted` flag within the rseq slice must be false.
6. The `usr_ctrl.request` flag must be true.
Now, when `__rseq_grant_slice_extension` *does* return `true`, it then proceeds to call `hrtimer_rearm_deferred_tif(ti_work)`. This is where things get interesting, and I've identified a potential bug.
I noticed that `__rseq_grant_slice_extension` itself clears the `TIF_NEED_RESCHED` flag internally, within a `scoped_guard(irq)` block. This guard is designed to disable interrupts, perform its critical section, and then re-enable interrupts.
The problem arises because `rseq_grant_slice_extension` is called from `__exit_to_user_mode_loop`, specifically after `local_irq_enable_exit_to_user(ti_work)` has just enabled interrupts. Following this, `rseq_grant_slice_extension` is invoked, which in turn calls `__rseq_grant_slice_extension`.
Inside `__rseq_grant_slice_extension`, the `scoped_guard(irq)` disables interrupts, clears `TIF_NEED_RESCHED`, and then *re-enables interrupts*. This means that when `__rseq_grant_slice_extension` returns `true`, the interrupts are already back to an enabled state.
Subsequently, `rseq_grant_slice_extension` calls `hrtimer_rearm_deferred_tif(ti_work)`. The issue here is that `hrtimer_rearm_deferred_tif` internally calls `hrtimer_test_and_clear_rearm_deferred_tif`, which contains a `lockdep_assert_irqs_disabled()` assertion. Because the interrupts were already re-enabled by the `scoped_guard(irq)` before `hrtimer_rearm_deferred_tif` was called, this assertion will fail, exposing a bug.
To reliably trigger this, I've outlined the necessary conditions:
1. `rseq_slice_extension_enabled()` must be true. This can be achieved via `prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0)`.
2. `curr->rseq.event.user_irq` needs to be true. This happens when returning to user space after a user-mode interrupt.
3. `work_pending` must be false, meaning `ti_work & _TIF_WORK_MASK` is zero (excluding `_TIF_NEED_RESCHED`).
4. `usr_ctrl.request` must be true. This needs to be actively set within a loop.
This leads me to believe my reproducer logic is sound. The remaining challenge is how to generate a user-mode interrupt that also sets `TIF_NEED_RESCHED`. A scheduler tick (timer interrupt) is the perfect candidate for this. If I simply spin in a `while (1)` loop within user space, the scheduler tick will eventually occur, set `TIF_NEED_RESCHED`, and then transition back to user mode. Since the operation is happening from user space, `curr->rseq.event.user_irq` will be set correctly.
I've refined the reproducer code to reflect this, carefully considering the use of `clone` and the rseq registration signature to ensure a clean test environment. I've also noted the need to potentially unregister any pre-existing rseq areas if glibc happens to register one, using `syscall(SYS_rseq, NULL, 0, RSEQ_FLAG_UNREGISTER, 0x53053053)`. I need to confirm the exact value of `RSEQ_FLAG_UNREGISTER`.
|
| 104/5 |
2026/08/12 12:48 |
tool |
grepper |
0m
Args: map[Expression:RSEQ_FLAG_UNREGISTER]
Results: map[Output:include/uapi/linux/rseq.h=21=enum rseq_flags {
include/uapi/linux/rseq.h:22: RSEQ_FLAG_UNREGISTER = (1 << 0),
include/uapi/linux/rseq.h-23- RSEQ_FLAG_SLICE_EXT_DEFAULT_ON = (1 << 1),
--
kernel/rseq.c=490=static long rseq_unregister(struct rseq __user * rseq, u32 rseq_len, int flags, u32 sig)
kernel/rseq.c-491-{
kernel/rseq.c:492: if (flags & ~RSEQ_FLAG_UNREGISTER)
kernel/rseq.c-493- return -EINVAL;
--
kernel/rseq.c=547=SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len, int, flags, u32, sig)
kernel/rseq.c-548-{
kernel/rseq.c:549: if (flags & RSEQ_FLAG_UNREGISTER)
kernel/rseq.c-550- return rseq_unregister(rseq, rseq_len, flags, sig);
]
|
| 105/5 |
2026/08/12 12:48 |
llm |
strategy-refiner |
0m
Model:
Tokens:
input: 17162
output: 34
thoughts: 98
Thoughts: **My Thought Process Regarding RSEQ Unregistration**
Okay, so I'm looking at this `RSEQ_FLAG_UNREGISTER` constant. The way I understand it, it's defined as `1 << 0`, which simply evaluates to `1`. This means that when I need to perform an unregistration operation, I'll likely be using a system call and passing `1` as one of the flags.
Based on that, I can see myself constructing a `syscall` for `SYS_rseq`. The initial thought is to call it like this: `syscall(SYS_rseq, NULL, 0, 1, 0x53053053);`. The `NULL` and `0` would represent the pointer to the `rseq` data and its length, respectively. The `1` is where `RSEQ_FLAG_UNREGISTER` comes into play, signaling the unregistration intent. The final argument, `0x53053053`, is likely some kind of magic value or version identifier for the `rseq` operation itself.
However, a crucial question immediately pops into my head: does `rseq_unregister`, or rather the mechanism behind the `SYS_rseq` call when the unregister flag is set, actually *require* the `rseq` pointer and `rseq_len` arguments to perfectly match what was originally registered? I mean, if I'm unregistering, I might not necessarily have access to the original `rseq` structure or its exact length anymore. This feels like a potential pitfall.
To resolve this uncertainty, my next logical step is to delve into the documentation or source code for `rseq_unregister` (or the `SYS_rseq` system call's behavior when the unregister flag is active). I need to verify the exact semantics of these arguments in the context of unregistration to ensure I'm not making a faulty assumption that could lead to errors or unexpected behavior.
|
| 106/5 |
2026/08/12 12:48 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:kernel/rseq.c Name:rseq_unregister]
Results: map[SourceCode: 490: static long rseq_unregister(struct rseq __user * rseq, u32 rseq_len, int flags, u32 sig)
491: {
492: if (flags & ~RSEQ_FLAG_UNREGISTER)
493: return -EINVAL;
494: if (current->rseq.usrptr != rseq || !current->rseq.usrptr)
495: return -EINVAL;
496: if (rseq_len != current->rseq.len)
497: return -EINVAL;
498: if (current->rseq.sig != sig)
499: return -EPERM;
500: if (!rseq_reset_ids())
501: return -EFAULT;
502: rseq_reset(current);
503: return 0;
504: }
SourceFile:kernel/rseq.c]
|
| 107/5 |
2026/08/12 12:48 |
llm |
strategy-refiner |
0m
Model:
Tokens:
input: 17548
output: 1196
thoughts: 3662
Thoughts: **My Thoughts on Reproducing the rseq Slice Extension Bug**
I've been wrestling with how to correctly set up a scenario to trigger a potential issue with the `rseq` slice extension, specifically around its registration and unregistration. My primary goal is to create a user-space thread that self-registers for `rseq` and then attempts to leverage the slice extension, ensuring that glibc's own `rseq` mechanisms don't interfere.
My initial thought was about `rseq_unregister`. It's clear that this function requires the exact `rseq` area address and length to be passed in, matching what's currently registered. This immediately struck me as a problem for unregistering glibc's internal `rseq` area. Without knowing its precise details, I can't reliably remove it.
This led me to consider how new threads are typically created. If I use glibc's `clone` function, does it automatically register `rseq` for the newly spawned thread? My understanding is that `clone` is generally a low-level wrapper around the `clone` syscall. Unlike `pthread_create`, it doesn't involve glibc's thread initialization code. Therefore, a thread created with `clone` would likely start executing its entry point function (`thread_fn` in my case) without any `rseq` area already registered by glibc. This means a subsequent `syscall(SYS_rseq, ...)` from my `thread_fn` should succeed. To be absolutely certain about the raw syscall behavior, I could opt for `syscall(SYS_clone, ...)`, but that would introduce architecture-specific details, which I'd prefer to avoid. So, using `clone` from `<sched.h>` seems like the most straightforward and portable approach for this specific goal.
Then, I considered the alternative: `pthread_create`. If I used `pthread_create`, glibc *would* register `rseq`. The problem here is that glibc's `rseq` area might not be large enough for my needs (e.g., it might be 32 bytes when I require 64). Even if it were large enough, I wouldn't be sure if it includes the necessary `slice_ctrl` field. Therefore, the approach of using `clone` and explicitly registering my own `rseq` area seems much more controlled and reliable for demonstrating the slice extension behavior.
With this strategy in mind, I began constructing the reproducer code.
I defined the necessary structures: `my_rseq_slice_ctrl` and `my_rseq`, ensuring they match the expected kernel layouts and are aligned to 64 bytes, as is typical for `rseq` areas.
In `thread_fn`, the core logic unfolds:
1. I declare `rseq_area` on the stack, also aligned to 64 bytes.
2. I zero it out using `memset`.
3. I then call `syscall(SYS_rseq, &rseq_area, sizeof(rseq_area), 0, 0x53053053)`. The `0x53053053` is a magic number used by `rseq` to identify the thread. If this registration fails, it's a strong indicator that glibc might have already registered something, which contradicts my assumption about `clone`.
4. Next, I enable the slice extension feature using `prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0)`. If this fails, it means the feature isn't supported or something is wrong with the `prctl` call.
5. Finally, I enter an infinite loop: `while (1) { rseq_area.slice_ctrl.request = 1; ... }`. The intention here is to repeatedly set the `request` flag. The idea is that on a timer interrupt (or another event that causes the kernel to check `rseq`), the kernel will see `request = 1`, grant the extension, and clear `request` and `granted`. My loop will then immediately set `request = 1` again, setting up a rapid cycle of requests.
A crucial detail emerged here: the compiler might optimize away the `rseq_area.slice_ctrl.request = 1;` assignment if it perceives it as a dead store within an infinite loop. To prevent this, I added `asm volatile("" ::: "memory");` after the assignment. This serves as a memory barrier, telling the compiler that memory might have been modified and preventing it from optimizing away the write.
In `main`, the setup is relatively simple:
1. I allocate a large stack for the new thread using `malloc`.
2. I use `clone` to create the new thread, passing `thread_fn` as the entry point and the allocated stack. The flags `CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD` are selected as a minimal set for creating a thread that shares resources with its parent but has its own stack and execution context. I noted that `CLONE_THREAD` implies `CLONE_SIGHAND`, which in turn requires `CLONE_VM`. The other flags (`FS`, `FILES`) are common for `pthread_create` and seemed appropriate here.
3. I then `sleep(5)` to give the scheduler enough time to let the spinning thread execute and trigger the necessary kernel checks for the `rseq` slice extension.
I did some further checks:
* **Stack Alignment:** `malloc` guarantees alignment to at least 16 bytes. While `clone` technically prefers alignment to the architecture's stack alignment (often 16 bytes on x86-64), `stack + 1024 * 1024` should be sufficiently aligned.
* **`clone` Flags:** The selected `clone` flags are standard for thread creation and don't seem to be missing anything critical in this context. The `CLONE_THREAD` flag means that signals are handled differently, and the exit signal is ignored, which is fine for this reproducer.
* **`rseq_area` Scope:** Declaring `rseq_area` on the stack of `thread_fn` is perfectly acceptable. Since `thread_fn` never returns, its stack frame persists for the lifetime of the thread, and the memory allocated for `rseq_area` remains valid.
* **`slice_ctrl` Structure:** I verified that my `struct my_rseq_slice_ctrl` perfectly matches the kernel's expected layout, especially the `union` containing `all` and the `struct` with `request`, `granted`, and `__reserved`. This ensures the byte-level interpretation by the kernel is correct.
* **`request` vs. `granted` Logic:** I reviewed the kernel's `__rseq_grant_slice_extension` logic. It correctly checks if `state.granted` is already true. If it is, it clears the user-visible `slice_ctrl.all` and returns `false`. Importantly, it also clears the internal `state.granted` flag. When the thread resumes after scheduling (which happens after `schedule()` is called due to the `false` return), `state.granted` will be `false` again. This allows the user-space loop to set `request = 1` and the kernel to grant the extension again on the next timer interrupt. This repeated granting is precisely what's needed to trigger the bug. If `state.granted` is false, the kernel grants the extension, sets `state.granted` to true, and crucially, clears `slice_ctrl.all` to 0. My loop then immediately sets `request = 1`, ensuring the cycle continues.
Overall, the reproducer seems robust. It leverages `clone` to bypass glibc's `rseq` setup, explicitly registers a custom `rseq` area, enables the slice extension, and then enters a tight loop designed to repeatedly trigger the extension grant mechanism. The inclusion of `asm volatile("" ::: "memory");` addresses potential compiler optimizations, and the alignment and flag considerations seem appropriate. The logic for how the `request` and `granted` flags interact in the kernel suggests that the desired rapid cycling of extension grants should occur.
|
| 108/3 |
2026/08/12 12:48 |
action |
merge-strategy |
0m
Results: map[CurrentReproStrategy:An analysis of the bug and the kernel source code confirms that the `WARNING in irqentry_exit` is a lockdep warning triggered when `rseq_grant_slice_extension()` calls `hrtimer_rearm_deferred_tif()` with interrupts enabled. This happens because `__exit_to_user_mode_loop()` explicitly enables interrupts before checking for RSEQ slice extensions.
To trigger this bug, we need to satisfy the conditions for `rseq_grant_slice_extension()` to successfully grant a slice extension:
1. The thread must have a registered RSEQ area large enough to support the `slice_ctrl` field (size $\ge$ 33 bytes).
2. The RSEQ slice extension must be enabled for the thread via `prctl(PR_RSEQ_SLICE_EXTENSION)`.
3. The user-space `rseq.slice_ctrl.request` flag must be set to `1`.
4. A timer interrupt must hit the thread while it is executing in user space, setting `_TIF_NEED_RESCHED` without setting other pending work flags.
We can achieve this by creating a raw thread using `clone()` (to bypass glibc's default RSEQ registration, which might not be large enough or might conflict), registering a properly aligned 64-byte RSEQ structure, enabling the slice extension, and spinning in an infinite loop that continuously sets the `request` flag. When the scheduler tick interrupts the loop, the bug will trigger on the return to user space.
Here is the complete C reproducer:
```c
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <sched.h>
#include <string.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_SET 2
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
#endif
#ifndef SYS_rseq
#define SYS_rseq 334
#endif
struct my_rseq_slice_ctrl {
union {
uint32_t all;
struct {
uint8_t request;
uint8_t granted;
uint16_t __reserved;
};
};
};
/*
* RSEQ area must be large enough (>= 33 bytes) to support slice_ctrl
* and aligned to the allocation alignment (64 bytes).
*/
struct my_rseq {
uint32_t cpu_id_start;
uint32_t cpu_id;
uint64_t rseq_cs;
uint32_t flags;
uint32_t node_id;
uint32_t mm_cid;
struct my_rseq_slice_ctrl slice_ctrl;
uint8_t __reserved;
char end[];
} __attribute__((aligned(64)));
int thread_fn(void *arg) {
struct my_rseq rseq_area __attribute__((aligned(64)));
memset(&rseq_area, 0, sizeof(rseq_area));
/* Register our custom RSEQ area */
int ret = syscall(SYS_rseq, &rseq_area, sizeof(rseq_area), 0, 0x53053053);
if (ret != 0) {
return 1;
}
/* Enable the RSEQ time slice extension feature */
if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0) != 0) {
return 1;
}
/*
* Spin in user space requesting a slice extension.
* A timer interrupt will eventually hit, set _TIF_NEED_RESCHED,
* and trigger the lockdep warning on return to user space.
*/
while (1) {
rseq_area.slice_ctrl.request = 1;
/* Prevent compiler from optimizing out the store */
asm volatile("" ::: "memory");
}
return 0;
}
int main() {
char *stack = malloc(1024 * 1024);
if (!stack) {
return 1;
}
/*
* Use raw clone to ensure the new thread does not inherit
* any existing glibc RSEQ registrations.
*/
pid_t pid = clone(thread_fn, stack + 1024 * 1024,
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD, NULL);
if (pid == -1) {
return 1;
}
/* Wait enough time for the scheduler tick to hit the spinning thread */
sleep(5);
return 0;
}
```]
|
| 109/3 |
2026/08/12 12:48 |
agent |
repro-generator |
5m
Model:
Results: map[IsProbe:false RawCandidateReproC:#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <sched.h>
#include <string.h>
#include <errno.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_SET 2
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
#endif
#ifndef SYS_rseq
#define SYS_rseq 334
#endif
struct my_rseq_slice_ctrl {
union {
uint32_t all;
struct {
uint8_t request;
uint8_t granted;
uint16_t __reserved;
};
};
};
struct my_rseq {
uint32_t cpu_id_start;
uint32_t cpu_id;
uint64_t rseq_cs;
uint32_t flags;
uint32_t node_id;
uint32_t mm_cid;
struct my_rseq_slice_ctrl slice_ctrl;
uint8_t __reserved;
char end[];
} __attribute__((aligned(64)));
int thread_fn(void *arg) {
struct my_rseq *rseq_area = NULL;
if (posix_memalign((void **)&rseq_area, 64, sizeof(struct my_rseq)) != 0) {
printf("[-] posix_memalign failed: %s\n", strerror(errno));
exit(1);
}
memset(rseq_area, 0, sizeof(struct my_rseq));
/* Register our custom RSEQ area */
int ret = syscall(SYS_rseq, rseq_area, sizeof(struct my_rseq), 0, 0x53053053);
if (ret != 0) {
printf("[-] rseq syscall failed: %s\n", strerror(errno));
exit(1);
}
/* Enable the RSEQ time slice extension feature */
if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0) != 0) {
printf("[-] prctl PR_RSEQ_SLICE_EXTENSION failed: %s\n", strerror(errno));
exit(1);
}
/*
* Spin in user space requesting a slice extension.
* A timer interrupt will eventually hit, set _TIF_NEED_RESCHED,
* and trigger the lockdep warning on return to user space.
*/
while (1) {
rseq_area->slice_ctrl.request = 1;
/* Prevent compiler from optimizing out the store */
asm volatile("" ::: "memory");
}
return 0;
}
int main() {
cpu_set_t set;
CPU_ZERO(&set);
CPU_SET(0, &set);
if (sched_setaffinity(0, sizeof(set), &set) != 0) {
printf("[-] sched_setaffinity failed: %s\n", strerror(errno));
exit(1);
}
printf("[+] sched_setaffinity successful.\n");
for (int i = 0; i < 2; i++) {
char *stack = malloc(1024 * 1024);
if (!stack) {
printf("[-] malloc failed: %s\n", strerror(errno));
exit(1);
}
void *stack_top = (void *)(((uintptr_t)stack + 1024 * 1024) & ~0xF);
pid_t pid = clone(thread_fn, stack_top,
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD, NULL);
if (pid == -1) {
printf("[-] clone failed: %s\n", strerror(errno));
exit(1);
}
}
printf("[+] Created 2 spinning threads on CPU 0.\n");
/* Wait enough time for the scheduler tick to hit the spinning threads */
sleep(5);
printf("[+] Done.\n");
return 0;
}
]
Instruction: 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.
Prompt: Bug Description: WARNING in irqentry_exit
------------[ cut here ]------------
__lockdep_enabled && this_cpu_read(hardirqs_enabled)
WARNING: ./include/linux/hrtimer_rearm.h:17 at hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_loop kernel/entry/common.c:54 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at exit_to_user_mode_loop kernel/entry/common.c:101 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit+0x718/0xa00 kernel/entry/common.c:165, CPU#0: syz.2.3762/30761
Modules linked in:
CPU: 0 UID: 0 PID: 30761 Comm: syz.2.3762 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:hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline]
RIP: 0010:hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline]
RIP: 0010:rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline]
RIP: 0010:__exit_to_user_mode_loop kernel/entry/common.c:54 [inline]
RIP: 0010:exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
RIP: 0010:__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
RIP: 0010:irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
RIP: 0010:irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
RIP: 0010:irqentry_exit+0x718/0xa00 kernel/entry/common.c:165
Code: 00 00 00 80 e8 c9 ee 58 f6 fb 83 3d 95 d1 69 05 00 74 1a 65 8b 05 d8 2a ab 08 85 c0 75 0f 65 8b 05 29 26 ab 08 85 c0 74 04 90 <0f> 0b 90 41 f7 c5 00 10 00 00 0f 84 74 fc ff ff f0 41 80 64 24 01
RSP: 0000:ffffc9000414ff00 EFLAGS: 00010202
RAX: 0000000000000001 RBX: ffffc9000414ff48 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8e1a8f2e RDI: ffffffff8c400a80
RBP: ffffc9000414ff38 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888022f39f00
R13: 0000000000000010 R14: 000001efbbd43bba R15: 0000000000000000
FS: 00007f3e64dd56c0(0000) GS:ffff888123de1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ddddff8 CR3: 0000000034bd6000 CR4: 00000000003526f0
Call Trace:
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0033:0x7f3e66b9e019
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:00007f3e64dd50e8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f3e66e26098 RCX: 00007f3e66b9e019
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3e66e26098
RBP: 00007f3e66e26090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3e66e26128 R14: 00007ffe410c4bf0 R15: 00007ffe410c4cd8
</TASK>
Strategy: An analysis of the bug and the kernel source code confirms that the `WARNING in irqentry_exit` is a lockdep warning triggered when `rseq_grant_slice_extension()` calls `hrtimer_rearm_deferred_tif()` with interrupts enabled. This happens because `__exit_to_user_mode_loop()` explicitly enables interrupts before checking for RSEQ slice extensions.
To trigger this bug, we need to satisfy the conditions for `rseq_grant_slice_extension()` to successfully grant a slice extension:
1. The thread must have a registered RSEQ area large enough to support the `slice_ctrl` field (size $\ge$ 33 bytes).
2. The RSEQ slice extension must be enabled for the thread via `prctl(PR_RSEQ_SLICE_EXTENSION)`.
3. The user-space `rseq.slice_ctrl.request` flag must be set to `1`.
4. A timer interrupt must hit the thread while it is executing in user space, setting `_TIF_NEED_RESCHED` without setting other pending work flags.
We can achieve this by creating a raw thread using `clone()` (to bypass glibc's default RSEQ registration, which might not be large enough or might conflict), registering a properly aligned 64-byte RSEQ structure, enabling the slice extension, and spinning in an infinite loop that continuously sets the `request` flag. When the scheduler tick interrupts the loop, the bug will trigger on the return to user space.
Here is the complete C reproducer:
```c
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <sched.h>
#include <string.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_SET 2
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
#endif
#ifndef SYS_rseq
#define SYS_rseq 334
#endif
struct my_rseq_slice_ctrl {
union {
uint32_t all;
struct {
uint8_t request;
uint8_t granted;
uint16_t __reserved;
};
};
};
/*
* RSEQ area must be large enough (>= 33 bytes) to support slice_ctrl
* and aligned to the allocation alignment (64 bytes).
*/
struct my_rseq {
uint32_t cpu_id_start;
uint32_t cpu_id;
uint64_t rseq_cs;
uint32_t flags;
uint32_t node_id;
uint32_t mm_cid;
struct my_rseq_slice_ctrl slice_ctrl;
uint8_t __reserved;
char end[];
} __attribute__((aligned(64)));
int thread_fn(void *arg) {
struct my_rseq rseq_area __attribute__((aligned(64)));
memset(&rseq_area, 0, sizeof(rseq_area));
/* Register our custom RSEQ area */
int ret = syscall(SYS_rseq, &rseq_area, sizeof(rseq_area), 0, 0x53053053);
if (ret != 0) {
return 1;
}
/* Enable the RSEQ time slice extension feature */
if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0) != 0) {
return 1;
}
/*
* Spin in user space requesting a slice extension.
* A timer interrupt will eventually hit, set _TIF_NEED_RESCHED,
* and trigger the lockdep warning on return to user space.
*/
while (1) {
rseq_area.slice_ctrl.request = 1;
/* Prevent compiler from optimizing out the store */
asm volatile("" ::: "memory");
}
return 0;
}
int main() {
char *stack = malloc(1024 * 1024);
if (!stack) {
return 1;
}
/*
* Use raw clone to ensure the new thread does not inherit
* any existing glibc RSEQ registrations.
*/
pid_t pid = clone(thread_fn, stack + 1024 * 1024,
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD, NULL);
if (pid == -1) {
return 1;
}
/* Wait enough time for the scheduler tick to hit the spinning thread */
sleep(5);
return 0;
}
```
Previous Reproducer Attempt:
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_GET 1
#endif
int main() {
int ret;
// Check if rseq syscall is available
ret = syscall(SYS_rseq, NULL, 0, 0, 0);
if (ret < 0 && errno == ENOSYS) {
printf("[-] rseq syscall not supported: %s\n", strerror(errno));
exit(1);
}
printf("[+] rseq syscall is available.\n");
// Check if PR_RSEQ_SLICE_EXTENSION is supported
ret = prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET, 0, 0, 0);
if (ret < 0 && errno == EINVAL) {
printf("[-] PR_RSEQ_SLICE_EXTENSION not supported: %s\n", strerror(errno));
exit(1);
}
printf("[+] PR_RSEQ_SLICE_EXTENSION is supported.\n");
return 0;
}
Execution Results & Debugging Feedback:
The environment probe executed successfully. The `rseq` syscall and `PR_RSEQ_SLICE_EXTENSION` prctl are both supported and available in the environment. You can now proceed to generate the full reproducer in the next iteration.
|
| 110/4 |
2026/08/12 12:48 |
llm |
repro-generator |
0m
Model:
Tokens:
input: 6757
output: 28
thoughts: 2976
Thoughts: **My Thoughts on Generating a Reproducer for the `irqentry_exit` Warning**
My primary objective here is to craft a concrete, runnable piece of code that reliably triggers the `WARNING in irqentry_exit` bug. The bug, as indicated by the kernel messages, appears to be related to the interaction between `hrtimer`, `rseq`, and deferred work flags when an interrupt occurs while the system is transitioning out of user mode.
The bug report points to several key areas in the kernel code:
* `./include/linux/hrtimer_rearm.h:17`
* `./include/linux/hrtimer_rearm.h:52`
* `./include/linux/rseq_entry.h:236`
* `kernel/entry/common.c:54`
This suggests a complex interplay involving high-resolution timers, the RSEQ (Restartable Sequences) mechanism, and the system's entry/exit points from user space, specifically concerning deferred tasks.
The strategy provided gives me a clear path forward:
1. **RSEQ Area Size:** The thread needs a registered RSEQ area. Crucially, this area must be large enough to accommodate the `slice_ctrl` field, which implies a minimum size of 33 bytes. This is a structural requirement from the RSEQ API itself.
2. **RSEQ Slice Extension Enablement:** The `PR_RSEQ_SLICE_EXTENSION` feature must be explicitly enabled for the thread using `prctl(PR_RSEQ_SLICE_EXTENSION)`. This tells the kernel that this thread intends to use slice extension capabilities.
3. **User-space `request` Flag:** Within the RSEQ structure, the `rseq.slice_ctrl.request` flag must be set to `1`. This is the user-space signal to the kernel that a slice extension is being *requested*.
4. **The Triggering Event:** The core of the bug appears to be an interrupt (likely a timer interrupt, given the `hrtimer` references) that occurs *precisely* when the thread is in user space and has `_TIF_NEED_RESCHED` set, *but no other pending work flags* are set. This specific state is likely what leads to the lockdep warning during the `irqentry_exit` path.
Looking at the initial C reproducer provided, I see a good starting point. It attempts to set up the RSEQ area, enable the slice extension, and then enter a tight loop to constantly set the `request` flag. The `clone` call is used correctly to create a new thread without inheriting RSEQ state, which is important for isolation.
However, I immediately identify a few areas for improvement to make it a *full* reproducer candidate, focusing on robustness and clarity:
* **Error Checking:** The original reproducer lacks explicit error checking for `syscall`, `prctl`, `malloc`, and `clone`. As an expert, I know that robust code must validate the return values of system calls and library functions. I need to add checks and print informative error messages using `strerror(errno)`.
* **Memory Allocation and Alignment:** The original code places `rseq_area` on the stack of `thread_fn`. While `clone` allocates a stack, the alignment requirements for RSEQ structures (and potentially the stack itself) can be tricky. The kernel's RSEQ mechanism expects specific alignments for its internal structures to function correctly. A stack-allocated variable might not satisfy these alignment guarantees depending on the compiler and architecture. The RSEQ documentation or related kernel code would specify this. The prompt mentions `rseq` requires 32-byte alignment, and the `__attribute__((aligned(64)))` in the structure definition suggests 64-byte alignment is desired for the overall structure. To avoid potential stack alignment issues, dynamically allocating the RSEQ area using `aligned_alloc` with the required alignment (64 bytes seems a safe bet given the attribute) is a more reliable approach. This also allows me to pass the allocated pointer directly to `thread_fn`.
* **Clarity of `sizeof(struct my_rseq)`:** The calculation of the size of `struct my_rseq` needs careful consideration. Even though the sum of its members is 33 bytes, the `__attribute__((aligned(64)))` will ensure the *allocation* is 64 bytes. This is crucial because the `rseq` syscall requires a length that's sufficient for the kernel to interpret the structure, and it must also respect the alignment. The kernel likely has a minimum size requirement and also expects the provided length to be consistent with the actual allocated size.
* **Passing the RSEQ Area:** If `rseq_area` is dynamically allocated, I need to pass its pointer to `thread_fn` as an argument.
* **Preventing Optimization:** The `asm volatile("" ::: "memory");` is correctly used to prevent the compiler from optimizing away the store to `rseq_area->slice_ctrl.request`, ensuring the loop actually writes to memory.
With these points in mind, I'll refine the reproducer. I will:
1. Include `<errno.h>` for `errno` and `strerror`.
2. Use `aligned_alloc(64, sizeof(struct my_rseq))` for the RSEQ area.
3. Pass the allocated `rseq_area` pointer to `thread_fn`.
4. Add `printf` statements to indicate progress and successful execution of key steps.
5. Add robust error checking for all system calls and memory allocations.
My refined reproducer will aim to be a self-contained, easily compilable, and executable demonstration of the conditions leading to the `irqentry_exit` warning. The goal is to make it as straightforward as possible for someone reviewing the code to understand *how* the bug is being triggered.
|
| 111/4 |
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tool |
codesearch-definition-source |
0m
Error:
Args: map[ContextFile: Name:sys_rseq]
Results: map[SourceCode: SourceFile:]
|
| 112/4 |
2026/08/12 12:49 |
llm |
repro-generator |
0m
Model:
Tokens:
input: 9766
output: 23
thoughts: 51
Thoughts: **My Thought Process on `rseq` System Call Definition**
Right, so I've encountered this `SYSCALL_DEFINE4(rseq, ...)`. My immediate thought is to pinpoint the underlying kernel function responsible for handling this system call. Given the `SYSCALL_DEFINE` macro, I know this is directly mapping to a kernel entry point. The `4` in `SYSCALL_DEFINE4` tells me it takes four arguments. The name `rseq` strongly suggests it's related to the `rseq` system call itself. Therefore, my primary hypothesis is that the kernel function is either named `sys_rseq` or `do_rseq`. To confirm this and to see its implementation, the most efficient next step for me, as an expert in this domain, is to perform a targeted search within the kernel source code. I'd use `grep` with the exact macro definition, `SYSCALL_DEFINE4(rseq`, to quickly locate where this system call is registered and to then navigate to its associated handler function. This direct approach is crucial for understanding the system call's behavior and its parameters.
|
| 113/4 |
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tool |
grepper |
0m
Args: map[Expression:SYSCALL_DEFINE4\(rseq]
Results: map[Output:kernel/rseq.c=520=static bool rseq_length_valid(struct rseq __user *rseq, unsigned int rseq_len)
--
kernel/rseq.c-546- */
kernel/rseq.c:547:SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len, int, flags, u32, sig)
kernel/rseq.c-548-{
]
|
| 114/4 |
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llm |
repro-generator |
0m
Model:
Tokens:
input: 9954
output: 34
thoughts: 19
Thoughts: **My Thought Process**
Right, so I'm diving into the code, specifically the `kernel/rseq.c` file, and my attention is drawn to the vicinity of line 547. I'm trying to understand the mechanics and implications of what's happening at this particular juncture within the rseq (restartable sequences) mechanism. My goal here is to fully grasp the inner workings of this code segment, to anticipate its behavior under various conditions, and to identify any potential subtleties or edge cases that might be relevant to my expert understanding of the system. This is about getting to the heart of the matter, not just a superficial glance.
|
| 115/4 |
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tool |
read-file |
0m
Args: map[File:kernel/rseq.c FirstLine:520 LineCount:50]
Results: map[Contents: 520: static bool rseq_length_valid(struct rseq __user *rseq, unsigned int rseq_len)
521: {
522: /*
523: * Ensure the provided rseq is properly aligned, as communicated to
524: * user-space through the ELF auxiliary vector AT_RSEQ_ALIGN. If
525: * rseq_len is the original rseq size, the required alignment is the
526: * original struct rseq alignment.
527: *
528: * In order to be valid, rseq_len is either the original rseq size, or
529: * large enough to contain all supported fields, as communicated to
530: * user-space through the ELF auxiliary vector AT_RSEQ_FEATURE_SIZE.
531: */
532: if (rseq_len < ORIG_RSEQ_SIZE)
533: return false;
534:
535: if (rseq_len == ORIG_RSEQ_SIZE)
536: return IS_ALIGNED((unsigned long)rseq, ORIG_RSEQ_SIZE);
537:
538: return IS_ALIGNED((unsigned long)rseq, rseq_alloc_align()) &&
539: rseq_len >= offsetof(struct rseq, end);
540: }
541:
542: #define RSEQ_FLAGS_SUPPORTED (RSEQ_FLAG_SLICE_EXT_DEFAULT_ON)
543:
544: /*
545: * sys_rseq - Register or unregister restartable sequences for the caller thread.
546: */
547: SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len, int, flags, u32, sig)
548: {
549: if (flags & RSEQ_FLAG_UNREGISTER)
550: return rseq_unregister(rseq, rseq_len, flags, sig);
551:
552: if (unlikely(flags & ~RSEQ_FLAGS_SUPPORTED))
553: return -EINVAL;
554:
555: if (current->rseq.usrptr)
556: return rseq_reregister(rseq, rseq_len, sig);
557:
558: if (!rseq_length_valid(rseq, rseq_len))
559: return -EINVAL;
560:
561: return rseq_register(rseq, rseq_len, flags, sig);
562: }
563:
564: #ifdef CONFIG_RSEQ_SLICE_EXTENSION
565: struct slice_timer {
566: struct hrtimer timer;
567: void *cookie;
568: };
569:
]
|
| 116/4 |
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llm |
repro-generator |
0m
Model:
Tokens:
input: 10803
output: 20
thoughts: 59
Thoughts: **My Thought Process Regarding `rseq_len`**
My initial contemplation centers on the possible values or conditions governing `rseq_len`. I've arrived at two primary hypotheses: either `rseq_len` is strictly defined as `ORIG_RSEQ_SIZE`, which I know to be 32, or it must satisfy the condition where its value is greater than or equal to the offset of the `end` member within the `struct rseq`. To resolve this, my immediate next step is to investigate the precise byte offset of `struct rseq.end` within the structure itself.
|
| 117/4 |
2026/08/12 12:49 |
tool |
codesearch-struct-layout |
0m
Args:
Results: map[Fields:[map[Name:cpu_id_start OffsetBits:0 SizeBits:32] map[Name:cpu_id OffsetBits:32 SizeBits:32] map[Name:rseq_cs OffsetBits:64 SizeBits:64] map[Name:flags OffsetBits:128 SizeBits:32] map[Name:node_id OffsetBits:160 SizeBits:32] map[Name:mm_cid OffsetBits:192 SizeBits:32] map[Name:slice_ctrl OffsetBits:224 SizeBits:32] map[Name:__reserved OffsetBits:256 SizeBits:8] map[Name:end OffsetBits:264 SizeBits:0]]]
|
| 118/4 |
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llm |
repro-generator |
0m
Model:
Tokens:
input: 10995
output: 36
thoughts: 62
Thoughts: **My Thought Process Regarding `rseq` Structure Offsets and Allocation Alignment**
My initial thought process began with a concrete observation: `offsetof(struct rseq, end)` evaluates to 33 bytes. This is a fundamental piece of information about the internal layout of the `rseq` structure.
Immediately following this, I drew a direct inference: if a value labeled `rseq_len` were to be exactly 33 bytes, then this would signify a "valid" length, at least in terms of its relationship to the `end` field. This suggests a potential check or condition where `rseq_len` is compared against this offset.
However, my internal reasoning didn't stop there. I recognized the importance of context and potential dependencies. My thought shifted to how this offset might be utilized in conjunction with memory allocation. This led me to consider the function `rseq_alloc_align()`. My internal question then became: "What does `rseq_alloc_align()` actually return, and how does that relate to the 33-byte offset I just observed?" This is a crucial step because it implies that the validity check might not be a simple direct comparison to 33, but rather an interaction with an alignment value derived from a specific allocation function. I'm now thinking about how the allocated size or alignment requirements might influence the determination of a valid `rseq_len`.
|
| 119/4 |
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tool |
codesearch-definition-source |
0m
Args: map[ContextFile:kernel/rseq.c Name:rseq_alloc_align]
Results: map[SourceCode: 163: /*
164: * Value returned by getauxval(AT_RSEQ_ALIGN) and expected by rseq
165: * registration. This is the active rseq area size rounded up to next
166: * power of 2, which guarantees that the rseq structure will always be
167: * aligned on the nearest power of two large enough to contain it, even
168: * as it grows.
169: */
170: static inline unsigned int rseq_alloc_align(void)
171: {
172: return 1U << get_count_order(offsetof(struct rseq, end));
173: }
SourceFile:include/linux/rseq.h]
|
| 120/4 |
2026/08/12 12:49 |
llm |
repro-generator |
0m
Model:
Tokens:
input: 11288
output: 26
thoughts: 236
Thoughts: **My Thought Process Regarding `rseq` Alignment and Length**
My immediate thought process was to verify the necessary alignment and minimum length for the `rseq` structure to ensure its correct and safe operation. I started by recalling or looking up the `get_count_order(33)` value, which I know to be 6. This immediately tells me that `1U << 6` is 64. Therefore, the alignment requirement for `rseq_alloc_align()` is 64 bytes. This establishes that the `rseq` structure *must* be aligned to a 64-byte boundary.
Concurrently, I considered the minimum `rseq_len`. Based on the previous calculation, it needs to be greater than or equal to 33.
Then, I connected this to my own implementation. I realized that `sizeof(struct my_rseq)` in my code is indeed 64, explicitly due to the `__attribute__((aligned(64)))` I've applied. This means that `rseq_len`, which will be the size of my structure, is 64. This value, 64, satisfies the condition of being greater than or equal to 33.
Therefore, my current setup – where `rseq_len` is 64 and `rseq` is aligned to 64 bytes – perfectly meets both the calculated alignment and length requirements.
To be absolutely certain and to cross-reference, my next step was to confirm the nature of the `slice_ctrl` struct. I questioned whether this structure, in the context of the kernel, might be a `struct rseq_slice_ctrl` or something similar. My plan was to then explicitly check the definition of `struct rseq` within `include/uapi/linux/rseq.h` to validate my understanding and ensure no discrepancies exist.
|
| 121/4 |
2026/08/12 12:49 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile: Name:rseq]
Results: map[SourceCode: 89: /*
90: * The original size and alignment of the allocation for struct rseq is
91: * 32 bytes.
92: *
93: * The allocation size needs to be greater or equal to
94: * max(getauxval(AT_RSEQ_FEATURE_SIZE), 32), and the allocation needs to
95: * be aligned on max(getauxval(AT_RSEQ_ALIGN), 32).
96: *
97: * As an alternative, userspace is allowed to use both the original size
98: * and alignment of 32 bytes for backward compatibility.
99: *
100: * A single active struct rseq registration per thread is allowed.
101: */
102: struct rseq {
103: /*
104: * Restartable sequences cpu_id_start field. Updated by the
105: * kernel. Read by user-space with single-copy atomicity
106: * semantics. This field should only be read by the thread which
107: * registered this data structure. Aligned on 32-bit. Always
108: * contains a value in the range of possible CPUs, although the
109: * value may not be the actual current CPU (e.g. if rseq is not
110: * initialized). This CPU number value should always be compared
111: * against the value of the cpu_id field before performing a rseq
112: * commit or returning a value read from a data structure indexed
113: * using the cpu_id_start value.
114: */
115: __u32 cpu_id_start;
116: /*
117: * Restartable sequences cpu_id field. Updated by the kernel.
118: * Read by user-space with single-copy atomicity semantics. This
119: * field should only be read by the thread which registered this
120: * data structure. Aligned on 32-bit. Values
121: * RSEQ_CPU_ID_UNINITIALIZED and RSEQ_CPU_ID_REGISTRATION_FAILED
122: * have a special semantic: the former means "rseq uninitialized",
123: * and latter means "rseq initialization failed". This value is
124: * meant to be read within rseq critical sections and compared
125: * with the cpu_id_start value previously read, before performing
126: * the commit instruction, or read and compared with the
127: * cpu_id_start value before returning a value loaded from a data
128: * structure indexed using the cpu_id_start value.
129: */
130: __u32 cpu_id;
131: /*
132: * Restartable sequences rseq_cs field.
133: *
134: * Contains NULL when no critical section is active for the current
135: * thread, or holds a pointer to the currently active struct rseq_cs.
136: *
137: * Updated by user-space, which sets the address of the currently
138: * active rseq_cs at the beginning of assembly instruction sequence
139: * block, and set to NULL by the kernel when it restarts an assembly
140: * instruction sequence block, as well as when the kernel detects that
141: * it is preempting or delivering a signal outside of the range
142: * targeted by the rseq_cs. Also needs to be set to NULL by user-space
143: * before reclaiming memory that contains the targeted struct rseq_cs.
144: *
145: * Read and set by the kernel. Set by user-space with single-copy
146: * atomicity semantics. This field should only be updated by the
147: * thread which registered this data structure. Aligned on 64-bit.
148: *
149: * 32-bit architectures should update the low order bits of the
150: * rseq_cs field, leaving the high order bits initialized to 0.
151: */
152: __u64 rseq_cs;
153:
154: /*
155: * Restartable sequences flags field.
156: *
157: * This field was initially intended to allow event masking for
158: * single-stepping through rseq critical sections with debuggers.
159: * The kernel does not support this anymore and the relevant bits
160: * are checked for being always false:
161: * - RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT
162: * - RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL
163: * - RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE
164: *
165: * It is now used for feature status advertisement by the kernel.
166: * See: enum rseq_cs_flags_bit for further information.
167: */
168: __u32 flags;
169:
170: /*
171: * Restartable sequences node_id field. Updated by the kernel. Read by
172: * user-space with single-copy atomicity semantics. This field should
173: * only be read by the thread which registered this data structure.
174: * Aligned on 32-bit. Contains the current NUMA node ID.
175: */
176: __u32 node_id;
177:
178: /*
179: * Restartable sequences mm_cid field. Updated by the kernel. Read by
180: * user-space with single-copy atomicity semantics. This field should
181: * only be read by the thread which registered this data structure.
182: * Aligned on 32-bit. Contains the current thread's concurrency ID
183: * (allocated uniquely within a memory map).
184: */
185: __u32 mm_cid;
186:
187: /*
188: * Time slice extension control structure. CPU local updates from
189: * kernel and user space.
190: */
191: struct rseq_slice_ctrl slice_ctrl;
192:
193: /*
194: * Before rseq became extensible, its original size was 32 bytes even
195: * though the active rseq area was only 20 bytes.
196: * Exposing a 32 bytes feature size would make life needlessly painful
197: * for userspace. Therefore, add a reserved byte after byte 32
198: * to bump the rseq feature size from 32 to 33.
199: * The next field to be added to the rseq area will be larger
200: * than one byte, and will replace this reserved byte.
201: */
202: __u8 __reserved;
203:
204: /*
205: * Flexible array member at end of structure, after last feature field.
206: */
207: char end[];
208: } __attribute__((aligned(32)));
SourceFile:include/uapi/linux/rseq.h]
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output: 30
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Thoughts: **My Thought Process on `struct rseq_slice_ctrl`**
Right, so my initial thought, upon encountering this piece of code or documentation, was to pinpoint the exact identity of this specific structure. I immediately thought, "Ah, so *this* is what it's called." My next immediate step, as any seasoned professional would, was to dive straight into examining `struct rseq_slice_ctrl`. There's no beating around the bush; I need to understand its definition, its members, and its purpose. This is the foundational step to grasping its role within the larger system.
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tool |
codesearch-definition-source |
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Args: map[ContextFile: Name:rseq_slice_ctrl]
Results: map[SourceCode: 68: /**
69: * rseq_slice_ctrl - Time slice extension control structure
70: * @all: Compound value
71: * @request: Request for a time slice extension
72: * @granted: Granted time slice extension
73: *
74: * @request is set by user space and can be cleared by user space or kernel
75: * space. @granted is set and cleared by the kernel and must only be read
76: * by user space.
77: */
78: struct rseq_slice_ctrl {
79: union {
80: __u32 all;
81: struct {
82: __u8 request;
83: __u8 granted;
84: __u16 __reserved;
85: };
86: };
87: };
SourceFile:include/uapi/linux/rseq.h]
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output: 32
thoughts: 283
Thoughts: **My RSEQ Structure Alignment and Kernel Validation**
Right, I've just realized that my custom `struct my_rseq_slice_ctrl` appears to be identical to the kernel's `struct rseq_slice_ctrl`. Similarly, my `struct my_rseq` seems to be a direct, bit-for-bit match with the kernel's `struct rseq`. This is a good starting point, but it's sparked a crucial question in my mind regarding alignment and kernel validation.
I know the kernel expects `rseq_len` to be at least 33 bytes. However, my `struct my_rseq`, due to the `__attribute__((aligned(64)))` directive, has a size of 64 bytes. My immediate thought is: will the kernel accept an `rseq_len` of 64 bytes, given this alignment?
I've been poring over the `rseq_length_valid` function in the kernel source, and I see the logic:
```c
if (rseq_len == ORIG_RSEQ_SIZE)
return IS_ALIGNED((unsigned long)rseq, ORIG_RSEQ_SIZE);
return IS_ALIGNED((unsigned long)rseq, rseq_alloc_align()) &&
rseq_len >= offsetof(struct rseq, end);
```
Looking at this, my `rseq_len` of 64 bytes is indeed greater than or equal to the required minimum of 33. Furthermore, `rseq_alloc_align()` returns 64, and my `rseq` structure is aligned to 64 bytes. Therefore, based on this validation logic, an `rseq_len` of 64 is perfectly valid. This is a significant relief, as it means my alignment choices are compatible with the kernel's requirements.
Now, my focus shifts to where the bug is actually manifesting. I suspect the issue arises when `rseq_grant_slice_extension` is invoked. That's where I need to direct my attention next.
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tool |
codesearch-definition-source |
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Args: map[ContextFile: Name:rseq_grant_slice_extension]
Results: map[SourceCode: 233: static __always_inline bool rseq_grant_slice_extension(unsigned long ti_work, unsigned long mask)
234: {
235: if (unlikely(__rseq_grant_slice_extension(ti_work & mask))) {
236: hrtimer_rearm_deferred_tif(ti_work);
237: return true;
238: }
239: return false;
240: }
SourceFile:include/linux/rseq_entry.h]
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output: 33
thoughts: 16
Thoughts: **My Thought Process Regarding `__rseq_grant_slice_extension`**
Ah, I've just noticed the invocation of `__rseq_grant_slice_extension`. My initial reaction is one of keen observation, recognizing this as a significant point in the execution flow. It signals a specific operation related to resource management, likely involving the granting of access or rights to a segment of data or memory, termed a "slice." The `extension` part suggests that this isn't a straightforward grant, but rather an augmentation or expansion of existing permissions, or perhaps the establishment of a new slice based on a prior configuration. I'm immediately curious about the context in which this function is being called. What is the precise nature of the slice being extended? What are the implications of this grant on subsequent operations? Is this a proactive measure to ensure future resource availability, or a reactive response to a demand? My expert mind is already formulating hypotheses about its role in the overall system architecture, perhaps in areas like memory allocation, inter-process communication, or even security contexts where granular control over data segments is paramount. I'm looking for patterns and dependencies, trying to place this specific function call within the broader operational logic.
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tool |
codesearch-definition-source |
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Args: map[ContextFile: Name:__rseq_grant_slice_extension]
Results: map[SourceCode: 128: static __always_inline bool __rseq_grant_slice_extension(bool work_pending)
129: {
130: struct task_struct *curr = current;
131: struct rseq_slice_ctrl usr_ctrl;
132: union rseq_slice_state state;
133: struct rseq __user *rseq;
134:
135: if (!rseq_slice_extension_enabled())
136: return false;
137:
138: /* If not enabled or not a return from interrupt, nothing to do. */
139: state = curr->rseq.slice.state;
140: state.enabled &= curr->rseq.event.user_irq;
141: if (likely(!state.state))
142: return false;
143:
144: rseq = curr->rseq.usrptr;
145: scoped_user_rw_access(rseq, efault) {
146:
147: /*
148: * Quick check conditions where a grant is not possible or
149: * needs to be revoked.
150: *
151: * 1) Any TIF bit which needs to do extra work aside of
152: * rescheduling prevents a grant.
153: *
154: * 2) A previous rescheduling request resulted in a slice
155: * extension grant.
156: */
157: if (unlikely(work_pending || state.granted)) {
158: /* Clear user control unconditionally. No point for checking */
159: unsafe_put_user(0U, &rseq->slice_ctrl.all, efault);
160: rseq_slice_clear_grant(curr);
161: return false;
162: }
163:
164: unsafe_get_user(usr_ctrl.all, &rseq->slice_ctrl.all, efault);
165: if (likely(!(usr_ctrl.request)))
166: return false;
167:
168: /* Grant the slice extention */
169: usr_ctrl.request = 0;
170: usr_ctrl.granted = 1;
171: unsafe_put_user(usr_ctrl.all, &rseq->slice_ctrl.all, efault);
172: }
173:
174: rseq_stat_inc(rseq_stats.s_granted);
175:
176: curr->rseq.slice.state.granted = true;
177: /* Store expiry time for arming the timer on the way out */
178: curr->rseq.slice.expires = data_race(rseq_slice_ext_nsecs) + ktime_get_mono_fast_ns();
179: /*
180: * This is racy against a remote CPU setting TIF_NEED_RESCHED in
181: * several ways:
182: *
183: * 1)
184: * CPU0 CPU1
185: * clear_tsk()
186: * set_tsk()
187: * clear_preempt()
188: * Raise scheduler IPI on CPU0
189: * --> IPI
190: * fold_need_resched() -> Folds correctly
191: * 2)
192: * CPU0 CPU1
193: * set_tsk()
194: * clear_tsk()
195: * clear_preempt()
196: * Raise scheduler IPI on CPU0
197: * --> IPI
198: * fold_need_resched() <- NOOP as TIF_NEED_RESCHED is false
199: *
200: * #1 is not any different from a regular remote reschedule as it
201: * sets the previously not set bit and then raises the IPI which
202: * folds it into the preempt counter
203: *
204: * #2 is obviously incorrect from a scheduler POV, but it's not
205: * differently incorrect than the code below clearing the
206: * reschedule request with the safety net of the timer.
207: *
208: * The important part is that the clearing is protected against the
209: * scheduler IPI and also against any other interrupt which might
210: * end up waking up a task and setting the bits in the middle of
211: * the operation:
212: *
213: * clear_tsk()
214: * ---> Interrupt
215: * wakeup_on_this_cpu()
216: * set_tsk()
217: * set_preempt()
218: * clear_preempt()
219: *
220: * which would be inconsistent state.
221: */
222: scoped_guard(irq) {
223: clear_tsk_need_resched(curr);
224: clear_preempt_need_resched();
225: }
226: return true;
227:
228: efault:
229: force_sig(SIGSEGV);
230: return false;
231: }
SourceFile:include/linux/rseq_entry.h]
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Thoughts: **My Thought Process Regarding `__rseq_grant_slice_extension` and User-Space Interrupts**
Okay, I'm digging into the `__rseq_grant_slice_extension` function, and I've spotted a critical condition: `state.enabled &= curr->rseq.event.user_irq;`. This immediately tells me that the `state.enabled` flag is being *ANDed* with `curr->rseq.event.user_irq`. For `state.enabled` to remain true (or at least, for the outcome of this operation to be non-zero, indicating enablement), `curr->rseq.event.user_irq` *must* be set.
Now, what does `curr->rseq.event.user_irq` signify? My understanding is that this flag is specifically set when an interrupt occurs *while the system is in user space*. So, the immediate implication is that to trigger this particular path or condition within `__rseq_grant_slice_extension`, I absolutely need an interrupt to occur while my process is executing in user mode. This isn't just any interrupt; it's one that's recognized as originating from user space.
But that's not the only hurdle. The `__rseq_grant_slice_extension` function also depends on another condition: `work_pending` must be false. This is a clear prerequisite.
And what exactly constitutes `work_pending`? I see it's defined as `ti_work & mask`. This implies a bitmask operation where `ti_work` represents some form of pending work (likely related to tasklet or similar mechanisms), and `mask` is used to filter or select specific types of work. For `work_pending` to be false, the result of this bitwise AND must be zero. In other words, none of the bits in `ti_work` that correspond to the bits set in `mask` can be set.
My attention then shifts to where these conditions are evaluated, specifically looking at `__exit_to_user_mode_loop`. This is where the transition back to user mode typically happens, and it's a logical place to find the checks that ensure these conditions are met before proceeding with something that might involve granting a slice extension based on user-space interrupts. So, within `__exit_to_user_mode_loop`, I'd expect to see the logic that first verifies `work_pending` is indeed false, and then, if that holds true, it would allow the system to proceed to a state where a user-space interrupt could then be properly detected and acted upon by `__rseq_grant_slice_extension`.
In essence, my mental model is: we need to be in user space, an interrupt needs to fire *while* we're in user space, and crucially, there must be no other pending work that would prevent this specific extension from being granted.
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tool |
codesearch-definition-source |
0m
Args: map[ContextFile: Name:__exit_to_user_mode_loop]
Results: map[SourceCode: 42: static __always_inline unsigned long __exit_to_user_mode_loop(struct pt_regs *regs,
43: unsigned long ti_work)
44: {
45: /*
46: * Before returning to user space ensure that all pending work
47: * items have been completed.
48: */
49: while (ti_work & EXIT_TO_USER_MODE_WORK_LOOP) {
50:
51: local_irq_enable();
52:
53: if (ti_work & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)) {
54: if (!rseq_grant_slice_extension(ti_work, TIF_SLICE_EXT_DENY))
55: schedule();
56: }
57:
58: if (ti_work & _TIF_UPROBE)
59: uprobe_notify_resume(regs);
60:
61: if (ti_work & _TIF_PATCH_PENDING)
62: klp_update_patch_state(current);
63:
64: if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) {
65: futex_fixup_robust_unlock(regs);
66: arch_do_signal_or_restart(regs);
67: }
68:
69: if (ti_work & _TIF_NOTIFY_RESUME)
70: resume_user_mode_work(regs);
71:
72: /* Architecture specific TIF work */
73: arch_exit_to_user_mode_work(regs, ti_work);
74:
75: /*
76: * Disable interrupts and reevaluate the work flags as they
77: * might have changed while interrupts and preemption was
78: * enabled above.
79: */
80: local_irq_disable();
81:
82: /* Check if any of the above work has queued a deferred wakeup */
83: tick_nohz_user_enter_prepare();
84:
85: ti_work = read_thread_flags();
86: }
87:
88: /* Return the latest work state for arch_exit_to_user_mode() */
89: return ti_work;
90: }
SourceFile:kernel/entry/common.c]
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Thoughts: **My Thought Process Regarding `__exit_to_user_mode_loop` and Interrupt Handling**
It's becoming clear to me that there's a potential interrupt handling issue brewing when `__exit_to_user_mode_loop` is invoked. My investigation shows that, indeed, `__exit_to_user_loop` explicitly calls `local_irq_enable()` *before* it proceeds to call `rseq_grant_slice_extension`. This is a critical observation because the subsequent execution path hinges on the return value of `rseq_grant_slice_extension`.
My concern deepens when `rseq_grant_slice_extension` returns `true`. In that scenario, it triggers a call to `hrtimer_rearm_deferred_tif(ti_work)`. Now, here's the crux of the matter: `hrtimer_rearm_deferred_tif` contains a `lockdep_assert_irqs_disabled()` assertion.
This sequence of events—enabling interrupts, then potentially executing code that *expects* interrupts to be disabled—raises a significant red flag for me. It suggests a window where interrupts might be enabled when they shouldn't be, potentially leading to race conditions or incorrect state management within the kernel's timer and interrupt handling mechanisms. I need to carefully analyze the implications of this interrupt enabling and disabling dance.
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tool |
codesearch-definition-source |
0m
Args: map[ContextFile: Name:hrtimer_rearm_deferred_tif]
Results: map[SourceCode: 49: /* Invoked from the time slice extension decision function */
50: static __always_inline void hrtimer_rearm_deferred_tif(unsigned long tif_work)
51: {
52: if (hrtimer_test_and_clear_rearm_deferred_tif(tif_work))
53: __hrtimer_rearm_deferred();
54: }
SourceFile:include/linux/hrtimer_rearm.h]
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Thoughts: **My Internal Monologue on `hrtimer_test_and_clear_rearm_deferred_tif`**
Okay, let's dive into this `hrtimer_test_and_clear_rearm_deferred_tif` function. I'm approaching this as a seasoned practitioner, so I'm not just looking at the surface-level operations, but the underlying intent and the implications for system behavior.
My immediate thought upon seeing this function name is that it's a very specific test case, likely within the kernel's testing framework for high-resolution timers. The "test_and_clear" part signals an atomic operation – we're checking a flag and, if it's set, clearing it in one fell swoop. This is crucial for avoiding race conditions, a common pitfall in concurrent systems.
The "rearm_deferred_tif" part is where the real meat of the test lies. "Rearm" implies that a timer, once it expires, might be rescheduled. "Deferred" suggests that this rescheduling isn't happening immediately upon expiration, but rather at some later, potentially different, point in time. And "tif" most likely stands for "timer interrupt flag," a common mechanism in timer implementations to signal that a timer event has occurred or needs to be processed.
So, putting it together, I'm thinking this test is designed to verify a specific behavior around high-resolution timers where a timer, after expiring, doesn't immediately rearm itself. Instead, there's a mechanism for *deferring* that rearming operation, and this test is checking the state of the "timer interrupt flag" in that context.
My hypothesis is that this function will likely:
1. **Check the state of the `deferred_tif` flag:** It needs to see if this deferral flag is set. This is the "test" part of the name.
2. **Atomically clear the `deferred_tif` flag:** If the flag *is* set, it will be cleared. This is the "clear" part, and the atomicity is key.
3. **Potentially interact with the timer rearming logic:** While the function name focuses on the flag, the "rearm_deferred" implies that the underlying timer rearming mechanism is being exercised or checked. It's likely that the test's success hinges on the correct handling of this deferred rearm, and the `deferred_tif` flag is the indicator of that state.
From an expert's perspective, I'm also considering:
* **What are the potential race conditions this test is trying to prevent?** The atomic nature strongly suggests this. Perhaps a situation where the timer handler is interrupted between checking and clearing the flag, leading to a missed rearm or double-processing.
* **What is the underlying mechanism for deferred rearming?** Is it a separate workqueue item? A delayed interrupt? The test needs to cover a scenario where the system might be busy, and the rearm has to be pushed back.
* **What are the expected outcomes?** If the timer was indeed supposed to be deferred and the flag was set, the test should confirm that the flag is cleared, and the system correctly identifies that the rearm is pending (or has been handled, depending on the exact sequence). Conversely, if no rearming was deferred, the test should confirm the flag remains clear.
* **Why is this specific scenario important?** Deferred rearming might be used to batch timer events, reduce interrupt load, or handle rearming in a context where immediate execution isn't safe. This test is validating that such a carefully designed mechanism works as intended.
In essence, I'm looking at `hrtimer_test_and_clear_rearm_deferred_tif` as a critical piece of a larger puzzle, ensuring the reliability and correctness of the high-resolution timer subsystem, specifically around its ability to gracefully handle delayed rescheduling of timer events. It's about making sure the state of internal flags accurately reflects the intended asynchronous operations.
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tool |
codesearch-definition-source |
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Args: map[ContextFile: Name:hrtimer_test_and_clear_rearm_deferred_tif]
Results: map[SourceCode: 10: /*
11: * This is purely CPU local, so check the TIF bit first to avoid the overhead of
12: * the atomic test_and_clear_bit() operation for the common case where the bit
13: * is not set.
14: */
15: static __always_inline bool hrtimer_test_and_clear_rearm_deferred_tif(unsigned long tif_work)
16: {
17: lockdep_assert_irqs_disabled();
18:
19: if (unlikely(tif_work & _TIF_HRTIMER_REARM)) {
20: clear_thread_flag(TIF_HRTIMER_REARM);
21: return true;
22: }
23: return false;
24: }
SourceFile:include/linux/hrtimer_rearm.h]
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output: 43
thoughts: 198
Thoughts: **My Debugging Journey: Tracing a `lockdep` Assertion Failure**
Okay, so I've been wrestling with this `lockdep_assert_irqs_disabled();` warning, and I'm fairly certain I've pinned down the root cause. The issue arises precisely because `local_irq_enable();` is being invoked within the `__exit_to_user_mode_loop` function. This confirms the bug report I was looking at; it's exactly as described.
Now, to actually reproduce this, I've identified a couple of key conditions that need to be met. Firstly, `rseq_slice_extension_enabled()` must evaluate to true. This state is achieved when a `prctl` call is made with `PR_RSEQ_SLICE_EXTENSION` as the command, `PR_RSEQ_SLICE_EXTENSION_SET` for the sub-command, `PR_RSEQ_SLICE_EXT_ENABLE` as the argument, and the other arguments set to zero.
The second crucial condition is that `curr->rseq.slice.state.state` must have a non-zero value. Initially, I was thinking about how this `state` field gets set, and then I recalled this line: `state.enabled &= curr->rseq.event.user_irq;`. Here, `state` is a reference to `curr->rseq.slice.state`. This means the `state.enabled` field is being modified based on the value of `curr->rseq.event.user_irq`. My next step is to meticulously trace where `curr->rseq.slice.state` is actually initialized and modified throughout the code execution path to fully understand how it becomes non-zero under these specific circumstances.
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tool |
codesearch-find-references |
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Args: map[ContextFile: IncludeSnippetLines:0 Name:rseq_slice_state SourceTreePrefix:]
Results: map[References:[map[ReferenceKind:uses ReferencingEntityKind:function ReferencingEntityName:__rseq_grant_slice_extension SourceFile:include/linux/rseq_entry.h SourceLine:132]] TruncatedOutput:false]
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output: 30
thoughts: 14
Thoughts: **A Deep Dive into `rseq_slice_state`**
My initial thought process, upon encountering `rseq_slice_state`, was one of immediate, focused attention. The critical realization hit me: this isn't just a simple structure; it's a union. This single piece of information fundamentally alters how I need to approach its usage and interpretation. My internal monologue would have been something akin to: "Hold on a second, I need to re-evaluate my assumptions here. `rseq_slice_state` is a union? That changes everything."
This understanding immediately flags potential complexities. Unions, by their nature, allow for different data members to occupy the same memory location. This implies that only one member can be valid at any given time, and it's the programmer's responsibility to know *which* member is currently active. This introduces a requirement for careful state management and explicit type checking or tagging to avoid dereferencing incorrect data, which could lead to subtle and hard-to-debug errors.
Consequently, I'd be thinking about the implications for the code that uses `rseq_slice_state`. What mechanisms are in place to ensure the correct member is accessed? Is there a discriminant field, a convention, or a more robust pattern being employed? My thought process would be shifting towards scrutinizing the surrounding code for patterns that handle the union's ambiguity. I'd be particularly interested in how the different "states" or "slices" are represented and differentiated within this union. This isn't just about observing a data type; it's about understanding the *behavioral implications* of that data type within the system.
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codesearch-definition-source |
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Args: map[ContextFile: Name:rseq_slice_state]
Results: map[SourceCode: 84: /**
85: * union rseq_slice_state - Status information for rseq time slice extension
86: * @state: Compound to access the overall state
87: * @enabled: Time slice extension is enabled for the task
88: * @granted: Time slice extension was granted to the task
89: */
90: union rseq_slice_state {
91: u16 state;
92: struct {
93: u8 enabled;
94: u8 granted;
95: };
96: };
SourceFile:include/linux/rseq_types.h]
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Tokens:
input: 17804
output: 32
thoughts: 45
Thoughts: **My Thought Process Regarding RSEQ Slice Extension**
Okay, so I've just noticed something crucial: this `state.enabled` flag. My immediate instinct, based on my understanding of system calls and kernel interactions, is that this flag is being activated by a specific event. My mind quickly goes to `prctl(PR_RSEQ_SLICE_EXTENSION)`. This seems like the most logical place for such a flag, which likely signals the activation or initialization of some RSEQ (or similar low-level runtime feature) slice or extension mechanism, to be set. My next step, therefore, is to delve into the specifics of how `prctl(PR_RSEQ_SLICE_EXTENSION)` actually functions. I need to see the exact code or documentation that governs this call to understand precisely what conditions lead to `state.enabled` becoming true and what implications this has for the system's runtime behavior.
|
| 139/4 |
2026/08/12 12:50 |
tool |
codesearch-definition-source |
0m
Error:
Args: map[ContextFile: Name:rseq_slice_extension_set]
Results: map[SourceCode: SourceFile:]
|
| 140/4 |
2026/08/12 12:50 |
llm |
repro-generator |
0m
Model:
Tokens:
input: 17886
output: 22
thoughts: 15
Thoughts: **My Thought Process on `PR_RSEQ_SLICE_EXTENSION`**
My immediate instinct, faced with this task, is to understand what this specific identifier, `PR_RSEQ_SLICE_EXTENSION`, signifies and where it might be found. Given its name, I'm hypothesizing it's related to some kind of record, perhaps a performance record or protection record, involving a sequence or range, and a specific extension or feature tied to a slice or segment within that sequence. The `PR_` prefix strongly suggests "Protection Record" to me, and `RSEQ` likely stands for "Record Sequence" or "Resource Sequence." The "SLICE_EXTENSION" part is the most intriguing – it implies a granular modification or an additional piece of metadata applied to a subset of a larger sequence.
Therefore, my primary investigative step would be to perform a targeted search, specifically using `grep`. I would be looking for occurrences of `PR_RSEQ_SLICE_EXTENSION` across our codebase, or a relevant set of files. My goal here is to identify all contexts in which this identifier is defined or used. This will help me understand:
1. **Definition:** Where is `PR_RSEQ_SLICE_EXTENSION` declared? Is it a constant, a macro, a field name in a struct, or an enum value? Understanding its definition is crucial for grasping its purpose.
2. **Usage:** How is it being used? Is it being checked against, set, passed as an argument, or used in conditional logic? This will reveal its functional role.
3. **Context:** What other code elements surround its usage? Are there related structures, functions, or data types that provide further clues about its purpose? For example, if it's used in conjunction with memory management functions, it might relate to memory protection or slicing. If it's part of a network protocol, it might relate to data segmentation.
4. **Scope:** Is this a widely used identifier or something specific to a particular module or feature? This will inform the potential impact of any changes or the importance of understanding its nuances.
Ultimately, my search with `grep PR_RSEQ_SLICE_EXTENSION` is not just a mechanical command; it's the first step in a deeper dive to understand how this specific piece of the system operates, what guarantees or functionalities it provides, and where it fits into the larger architectural puzzle. I'm essentially trying to locate the "fingerprint" of this feature to begin understanding its purpose and implications.
|
| 141/4 |
2026/08/12 12:50 |
tool |
grepper |
0m
Args: map[Expression:PR_RSEQ_SLICE_EXTENSION]
Results: map[Output:Documentation/userspace-api/rseq.rst=134=The thread has to enable the functionality via prctl(2)::
Documentation/userspace-api/rseq.rst-135-
Documentation/userspace-api/rseq.rst:136: prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET,
Documentation/userspace-api/rseq.rst-137- PR_RSEQ_SLICE_EXT_ENABLE, 0, 0);
--
Documentation/userspace-api/rseq.rst=150=The state can be also queried via prctl(2)::
Documentation/userspace-api/rseq.rst-151-
Documentation/userspace-api/rseq.rst:152: prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET, 0, 0, 0);
Documentation/userspace-api/rseq.rst-153-
--
include/uapi/linux/prctl.h=134=struct prctl_mm_map {
--
include/uapi/linux/prctl.h-389-/* RSEQ time slice extensions */
include/uapi/linux/prctl.h:390:#define PR_RSEQ_SLICE_EXTENSION 79
include/uapi/linux/prctl.h:391:# define PR_RSEQ_SLICE_EXTENSION_GET 1
include/uapi/linux/prctl.h:392:# define PR_RSEQ_SLICE_EXTENSION_SET 2
include/uapi/linux/prctl.h-393-/*
--
kernel/rseq.c=746=int rseq_slice_extension_prctl(unsigned long arg2, unsigned long arg3)
--
kernel/rseq.c-748- switch (arg2) {
kernel/rseq.c:749: case PR_RSEQ_SLICE_EXTENSION_GET:
kernel/rseq.c-750- if (arg3)
--
kernel/rseq.c-753-
kernel/rseq.c:754: case PR_RSEQ_SLICE_EXTENSION_SET: {
kernel/rseq.c-755- u32 rflags, valid = RSEQ_CS_FLAG_SLICE_EXT_AVAILABLE;
--
kernel/sys.c=2534=SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
--
kernel/sys.c-2886- break;
kernel/sys.c:2887: case PR_RSEQ_SLICE_EXTENSION:
kernel/sys.c-2888- if (arg4 || arg5)
--
tools/perf/trace/beauty/include/uapi/linux/prctl.h=134=struct prctl_mm_map {
--
tools/perf/trace/beauty/include/uapi/linux/prctl.h-389-/* RSEQ time slice extensions */
tools/perf/trace/beauty/include/uapi/linux/prctl.h:390:#define PR_RSEQ_SLICE_EXTENSION 79
tools/perf/trace/beauty/include/uapi/linux/prctl.h:391:# define PR_RSEQ_SLICE_EXTENSION_GET 1
tools/perf/trace/beauty/include/uapi/linux/prctl.h:392:# define PR_RSEQ_SLICE_EXTENSION_SET 2
tools/perf/trace/beauty/include/uapi/linux/prctl.h-393-/*
--
tools/testing/selftests/rseq/slice_test.c-27-
tools/testing/selftests/rseq/slice_test.c:28:#ifndef PR_RSEQ_SLICE_EXTENSION
tools/testing/selftests/rseq/slice_test.c:29:# define PR_RSEQ_SLICE_EXTENSION 79
tools/testing/selftests/rseq/slice_test.c:30:# define PR_RSEQ_SLICE_EXTENSION_GET 1
tools/testing/selftests/rseq/slice_test.c:31:# define PR_RSEQ_SLICE_EXTENSION_SET 2
tools/testing/selftests/rseq/slice_test.c-32-# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
--
tools/testing/selftests/rseq/slice_test.c=123=FIXTURE_SETUP(slice_ext)
--
tools/testing/selftests/rseq/slice_test.c-129-
tools/testing/selftests/rseq/slice_test.c:130: if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET,
tools/testing/selftests/rseq/slice_test.c-131- PR_RSEQ_SLICE_EXT_ENABLE, 0, 0))
]
|
| 142/4 |
2026/08/12 12:50 |
llm |
repro-generator |
0m
Model:
Tokens:
input: 19146
output: 18
thoughts: 74
Thoughts: **My Thought Process Regarding `prctl` and RSEQ Slices**
Ah, I see. So, after reviewing the `prctl` system call with the arguments `PR_RSEQ_SLICE_EXTENSION`, `PR_RSEQ_SLICE_EXTENSION_SET`, `PR_RSEQ_SLICE_EXT_ENABLE`, and the two zeros, I've concluded that this sequence of operations is indeed the correct way to enable the RSEQ slice extension. My initial contemplation led me to this confirmation.
However, a new question has arisen in my mind: what precisely is `curr->rseq.event.user_irq`? This variable's purpose and origin are not immediately clear to me. To resolve this, I need to delve deeper and investigate the exact point in the code where `curr->rseq.event.user_irq` is assigned a value. Tracing its assignment is the logical next step to fully understand its role within this context.
|
| 143/4 |
2026/08/12 12:50 |
tool |
grepper |
0m
Args:
Results: map[Output:
Full output is too long, showing 500 out of 539 lines.
Use more precise expression if possible.
arch/arm64/kernel/entry-common.c=77=static __always_inline void arm64_enter_from_user_mode(struct pt_regs *regs)
--
arch/arm64/kernel/entry-common.c-79- enter_from_user_mode(regs);
arch/arm64/kernel/entry-common.c:80: rseq_note_user_irq_entry();
arch/arm64/kernel/entry-common.c-81- mte_disable_tco_entry(current);
--
arch/m68k/kernel/entry.S-45-.globl auto_irqhandler_fixup
arch/m68k/kernel/entry.S:46:.globl user_irqvec_fixup
arch/m68k/kernel/entry.S-47-
--
arch/m68k/kernel/entry.S=305=ENTRY(user_inthandler)
--
arch/m68k/kernel/entry.S-309- bfextu %sp@(PT_OFF_FORMATVEC){#4,#10},%d0
arch/m68k/kernel/entry.S:310:user_irqvec_fixup = . + 2
arch/m68k/kernel/entry.S-311- subw #VEC_USER,%d0
--
arch/m68k/kernel/ints.c=31=extern u32 auto_irqhandler_fixup[];
arch/m68k/kernel/ints.c:32:extern u16 user_irqvec_fixup[];
arch/m68k/kernel/ints.c-33-
--
arch/m68k/kernel/ints.c=36=static struct irq_chip auto_irq_chip = {
--
arch/m68k/kernel/ints.c-41-
arch/m68k/kernel/ints.c:42:static struct irq_chip user_irq_chip = {
arch/m68k/kernel/ints.c-43- .name = "user",
--
arch/m68k/kernel/ints.c=93=void __init m68k_setup_user_interrupt(unsigned int vec, unsigned int cnt)
--
arch/m68k/kernel/ints.c-99- for (i = 0; i < cnt; i++)
arch/m68k/kernel/ints.c:100: irq_set_chip_and_handler(i, &user_irq_chip, handle_simple_irq);
arch/m68k/kernel/ints.c:101: *user_irqvec_fixup = vec - IRQ_USER;
arch/m68k/kernel/ints.c-102- flush_icache();
--
drivers/accel/habanalabs/gaudi2/gaudi2.c=4660=static int gaudi2_enable_msix(struct hl_device *hdev)
--
drivers/accel/habanalabs/gaudi2/gaudi2.c-4663- struct gaudi2_device *gaudi2 = hdev->asic_specific;
drivers/accel/habanalabs/gaudi2/gaudi2.c:4664: int rc, irq, i, j, user_irq_init_cnt;
drivers/accel/habanalabs/gaudi2/gaudi2.c-4665- struct hl_cq *cq;
--
drivers/accel/habanalabs/gaudi2/gaudi2.c-4719-
drivers/accel/habanalabs/gaudi2/gaudi2.c:4720: for (i = GAUDI2_IRQ_NUM_USER_FIRST, j = prop->user_dec_intr_count, user_irq_init_cnt = 0;
drivers/accel/habanalabs/gaudi2/gaudi2.c:4721: user_irq_init_cnt < prop->user_interrupt_count;
drivers/accel/habanalabs/gaudi2/gaudi2.c:4722: i++, j++, user_irq_init_cnt++) {
drivers/accel/habanalabs/gaudi2/gaudi2.c-4723-
--
drivers/accel/habanalabs/gaudi2/gaudi2.c-4729- dev_err(hdev->dev, "Failed to request IRQ %d", irq);
drivers/accel/habanalabs/gaudi2/gaudi2.c:4730: goto free_user_irq;
drivers/accel/habanalabs/gaudi2/gaudi2.c-4731- }
--
drivers/accel/habanalabs/gaudi2/gaudi2.c-4739- dev_err(hdev->dev, "Failed to request IRQ %d", irq);
drivers/accel/habanalabs/gaudi2/gaudi2.c:4740: goto free_user_irq;
drivers/accel/habanalabs/gaudi2/gaudi2.c-4741- }
--
drivers/accel/habanalabs/gaudi2/gaudi2.c-4746-
drivers/accel/habanalabs/gaudi2/gaudi2.c:4747:free_user_irq:
drivers/accel/habanalabs/gaudi2/gaudi2.c-4748- for (i = GAUDI2_IRQ_NUM_USER_FIRST, j = prop->user_dec_intr_count;
drivers/accel/habanalabs/gaudi2/gaudi2.c:4749: i < GAUDI2_IRQ_NUM_USER_FIRST + user_irq_init_cnt ; i++, j++) {
drivers/accel/habanalabs/gaudi2/gaudi2.c-4750-
--
drivers/dma/xilinx/xdma.c=1026=static int xdma_irq_init(struct xdma_device *xdev)
--
drivers/dma/xilinx/xdma.c-1028- u32 irq = xdev->irq_start;
drivers/dma/xilinx/xdma.c:1029: u32 user_irq_start;
drivers/dma/xilinx/xdma.c-1030- int i, j, ret;
--
drivers/dma/xilinx/xdma.c-1072- /* config user IRQ registers if needed */
drivers/dma/xilinx/xdma.c:1073: user_irq_start = XDMA_CHAN_NUM(xdev);
drivers/dma/xilinx/xdma.c:1074: if (xdev->irq_num > user_irq_start) {
drivers/dma/xilinx/xdma.c-1075- ret = xdma_set_vector_reg(xdev, XDMA_IRQ_USER_VEC_NUM,
drivers/dma/xilinx/xdma.c:1076: user_irq_start,
drivers/dma/xilinx/xdma.c:1077: xdev->irq_num - user_irq_start);
drivers/dma/xilinx/xdma.c-1078- if (ret) {
--
drivers/dma/xilinx/xdma.c=1101=static bool xdma_filter_fn(struct dma_chan *chan, void *param)
--
drivers/dma/xilinx/xdma.c-1109-/**
drivers/dma/xilinx/xdma.c:1110: * xdma_disable_user_irq - Disable user interrupt
drivers/dma/xilinx/xdma.c-1111- * @pdev: Pointer to the platform_device structure
--
drivers/dma/xilinx/xdma.c-1113- */
drivers/dma/xilinx/xdma.c:1114:void xdma_disable_user_irq(struct platform_device *pdev, u32 irq_num)
drivers/dma/xilinx/xdma.c-1115-{
--
drivers/dma/xilinx/xdma.c-1127-}
drivers/dma/xilinx/xdma.c:1128:EXPORT_SYMBOL(xdma_disable_user_irq);
drivers/dma/xilinx/xdma.c-1129-
drivers/dma/xilinx/xdma.c-1130-/**
drivers/dma/xilinx/xdma.c:1131: * xdma_enable_user_irq - Enable user logic interrupt
drivers/dma/xilinx/xdma.c-1132- * @pdev: Pointer to the platform_device structure
--
drivers/dma/xilinx/xdma.c-1134- */
drivers/dma/xilinx/xdma.c:1135:int xdma_enable_user_irq(struct platform_device *pdev, u32 irq_num)
drivers/dma/xilinx/xdma.c-1136-{
--
drivers/dma/xilinx/xdma.c-1153-}
drivers/dma/xilinx/xdma.c:1154:EXPORT_SYMBOL(xdma_enable_user_irq);
drivers/dma/xilinx/xdma.c-1155-
drivers/dma/xilinx/xdma.c-1156-/**
drivers/dma/xilinx/xdma.c:1157: * xdma_get_user_irq - Get system IRQ number
drivers/dma/xilinx/xdma.c-1158- * @pdev: Pointer to the platform_device structure
drivers/dma/xilinx/xdma.c:1159: * @user_irq_index: User logic IRQ wire index
drivers/dma/xilinx/xdma.c-1160- *
--
drivers/dma/xilinx/xdma.c-1162- */
drivers/dma/xilinx/xdma.c:1163:int xdma_get_user_irq(struct platform_device *pdev, u32 user_irq_index)
drivers/dma/xilinx/xdma.c-1164-{
--
drivers/dma/xilinx/xdma.c-1166-
drivers/dma/xilinx/xdma.c:1167: if (XDMA_CHAN_NUM(xdev) + user_irq_index >= xdev->irq_num) {
drivers/dma/xilinx/xdma.c-1168- xdma_err(xdev, "invalid user irq index");
--
drivers/dma/xilinx/xdma.c-1171-
drivers/dma/xilinx/xdma.c:1172: return xdev->irq_start + XDMA_CHAN_NUM(xdev) + user_irq_index;
drivers/dma/xilinx/xdma.c-1173-}
drivers/dma/xilinx/xdma.c:1174:EXPORT_SYMBOL(xdma_get_user_irq);
drivers/dma/xilinx/xdma.c-1175-
--
drivers/gpio/gpio-virtuser.c=64=struct gpio_virtuser_dbgfs_attr_descr {
--
drivers/gpio/gpio-virtuser.c-68-
drivers/gpio/gpio-virtuser.c:69:struct gpio_virtuser_irq_work_context {
drivers/gpio/gpio-virtuser.c-70- struct irq_work work;
--
drivers/gpio/gpio-virtuser.c-85-
drivers/gpio/gpio-virtuser.c:86:static struct gpio_virtuser_irq_work_context *
drivers/gpio/gpio-virtuser.c:87:to_gpio_virtuser_irq_work_context(struct irq_work *work)
drivers/gpio/gpio-virtuser.c-88-{
drivers/gpio/gpio-virtuser.c:89: return container_of(work, struct gpio_virtuser_irq_work_context, work);
drivers/gpio/gpio-virtuser.c-90-}
--
drivers/gpio/gpio-virtuser.c=92=static void
drivers/gpio/gpio-virtuser.c:93:gpio_virtuser_init_irq_work_context(struct gpio_virtuser_irq_work_context *ctx)
drivers/gpio/gpio-virtuser.c-94-{
--
drivers/gpio/gpio-virtuser.c=99=static void
drivers/gpio/gpio-virtuser.c:100:gpio_virtuser_irq_work_queue_sync(struct gpio_virtuser_irq_work_context *ctx)
drivers/gpio/gpio-virtuser.c-101-{
--
drivers/gpio/gpio-virtuser.c=118=static void gpio_virtuser_get_value_array_atomic(struct irq_work *work)
drivers/gpio/gpio-virtuser.c-119-{
drivers/gpio/gpio-virtuser.c:120: struct gpio_virtuser_irq_work_context *ctx =
drivers/gpio/gpio-virtuser.c:121: to_gpio_virtuser_irq_work_context(work);
drivers/gpio/gpio-virtuser.c-122- struct gpio_descs *descs = ctx->descs;
--
drivers/gpio/gpio-virtuser.c=129=static int gpio_virtuser_get_array_value(struct gpio_descs *descs,
--
drivers/gpio/gpio-virtuser.c-131-{
drivers/gpio/gpio-virtuser.c:132: struct gpio_virtuser_irq_work_context ctx;
drivers/gpio/gpio-virtuser.c-133-
--
drivers/gpio/gpio-virtuser.c-143-
drivers/gpio/gpio-virtuser.c:144: gpio_virtuser_irq_work_queue_sync(&ctx);
drivers/gpio/gpio-virtuser.c-145-
--
drivers/gpio/gpio-virtuser.c=198=static void gpio_virtuser_set_value_array_atomic(struct irq_work *work)
drivers/gpio/gpio-virtuser.c-199-{
drivers/gpio/gpio-virtuser.c:200: struct gpio_virtuser_irq_work_context *ctx =
drivers/gpio/gpio-virtuser.c:201: to_gpio_virtuser_irq_work_context(work);
drivers/gpio/gpio-virtuser.c-202- struct gpio_descs *descs = ctx->descs;
--
drivers/gpio/gpio-virtuser.c=209=static int gpio_virtuser_set_array_value(struct gpio_descs *descs,
--
drivers/gpio/gpio-virtuser.c-211-{
drivers/gpio/gpio-virtuser.c:212: struct gpio_virtuser_irq_work_context ctx;
drivers/gpio/gpio-virtuser.c-213-
--
drivers/gpio/gpio-virtuser.c-221-
drivers/gpio/gpio-virtuser.c:222: gpio_virtuser_irq_work_queue_sync(&ctx);
drivers/gpio/gpio-virtuser.c-223-
--
drivers/gpio/gpio-virtuser.c=312=static void gpio_virtuser_do_get_direction_atomic(struct irq_work *work)
drivers/gpio/gpio-virtuser.c-313-{
drivers/gpio/gpio-virtuser.c:314: struct gpio_virtuser_irq_work_context *ctx =
drivers/gpio/gpio-virtuser.c:315: to_gpio_virtuser_irq_work_context(work);
drivers/gpio/gpio-virtuser.c-316-
--
drivers/gpio/gpio-virtuser.c=321=static int gpio_virtuser_get_direction_atomic(struct gpio_desc *desc)
drivers/gpio/gpio-virtuser.c-322-{
drivers/gpio/gpio-virtuser.c:323: struct gpio_virtuser_irq_work_context ctx;
drivers/gpio/gpio-virtuser.c-324-
--
drivers/gpio/gpio-virtuser.c-328-
drivers/gpio/gpio-virtuser.c:329: gpio_virtuser_irq_work_queue_sync(&ctx);
drivers/gpio/gpio-virtuser.c-330-
--
drivers/gpio/gpio-virtuser.c=364=static void gpio_virtuser_do_set_direction_atomic(struct irq_work *work)
drivers/gpio/gpio-virtuser.c-365-{
drivers/gpio/gpio-virtuser.c:366: struct gpio_virtuser_irq_work_context *ctx =
drivers/gpio/gpio-virtuser.c:367: to_gpio_virtuser_irq_work_context(work);
drivers/gpio/gpio-virtuser.c-368-
--
drivers/gpio/gpio-virtuser.c=373=static int gpio_virtuser_set_direction_atomic(struct gpio_desc *desc,
--
drivers/gpio/gpio-virtuser.c-375-{
drivers/gpio/gpio-virtuser.c:376: struct gpio_virtuser_irq_work_context ctx;
drivers/gpio/gpio-virtuser.c-377-
--
drivers/gpio/gpio-virtuser.c-383-
drivers/gpio/gpio-virtuser.c:384: gpio_virtuser_irq_work_queue_sync(&ctx);
drivers/gpio/gpio-virtuser.c-385-
--
drivers/gpio/gpio-virtuser.c=508=static void gpio_virtuser_get_value_atomic(struct irq_work *work)
drivers/gpio/gpio-virtuser.c-509-{
drivers/gpio/gpio-virtuser.c:510: struct gpio_virtuser_irq_work_context *ctx =
drivers/gpio/gpio-virtuser.c:511: to_gpio_virtuser_irq_work_context(work);
drivers/gpio/gpio-virtuser.c-512-
--
drivers/gpio/gpio-virtuser.c=517=static int gpio_virtuser_value_atomic_get(void *data, u64 *val)
--
drivers/gpio/gpio-virtuser.c-519- struct gpio_virtuser_line_data *ld = data;
drivers/gpio/gpio-virtuser.c:520: struct gpio_virtuser_irq_work_context ctx;
drivers/gpio/gpio-virtuser.c-521-
--
drivers/gpio/gpio-virtuser.c-525-
drivers/gpio/gpio-virtuser.c:526: gpio_virtuser_irq_work_queue_sync(&ctx);
drivers/gpio/gpio-virtuser.c-527-
--
drivers/gpio/gpio-virtuser.c=536=static void gpio_virtuser_set_value_atomic(struct irq_work *work)
drivers/gpio/gpio-virtuser.c-537-{
drivers/gpio/gpio-virtuser.c:538: struct gpio_virtuser_irq_work_context *ctx =
drivers/gpio/gpio-virtuser.c:539: to_gpio_virtuser_irq_work_context(work);
drivers/gpio/gpio-virtuser.c-540-
--
drivers/gpio/gpio-virtuser.c=545=static int gpio_virtuser_value_atomic_set(void *data, u64 val)
--
drivers/gpio/gpio-virtuser.c-547- struct gpio_virtuser_line_data *ld = data;
drivers/gpio/gpio-virtuser.c:548: struct gpio_virtuser_irq_work_context ctx;
drivers/gpio/gpio-virtuser.c-549-
--
drivers/gpio/gpio-virtuser.c-557-
drivers/gpio/gpio-virtuser.c:558: gpio_virtuser_irq_work_queue_sync(&ctx);
drivers/gpio/gpio-virtuser.c-559-
--
drivers/gpio/gpio-virtuser.c=652=static int gpio_virtuser_interrupts_get(void *data, u64 *val)
--
drivers/gpio/gpio-virtuser.c-660-
drivers/gpio/gpio-virtuser.c:661:static irqreturn_t gpio_virtuser_irq_handler(int irq, void *data)
drivers/gpio/gpio-virtuser.c-662-{
--
drivers/gpio/gpio-virtuser.c=670=static int gpio_virtuser_interrupts_set(void *data, u64 val)
--
drivers/gpio/gpio-virtuser.c-683- ret = request_threaded_irq(irq, NULL,
drivers/gpio/gpio-virtuser.c:684: gpio_virtuser_irq_handler,
drivers/gpio/gpio-virtuser.c-685- IRQF_TRIGGER_RISING |
--
drivers/hv/mshv_eventfd.c=386=static int mshv_irqfd_assign(struct mshv_partition *pt,
drivers/hv/mshv_eventfd.c:387: struct mshv_user_irqfd *args)
drivers/hv/mshv_eventfd.c-388-{
--
drivers/hv/mshv_eventfd.c=533=static int mshv_irqfd_deassign(struct mshv_partition *pt,
drivers/hv/mshv_eventfd.c:534: struct mshv_user_irqfd *args)
drivers/hv/mshv_eventfd.c-535-{
--
drivers/hv/mshv_eventfd.c=564=int mshv_set_unset_irqfd(struct mshv_partition *pt,
drivers/hv/mshv_eventfd.c:565: struct mshv_user_irqfd *args)
drivers/hv/mshv_eventfd.c-566-{
--
drivers/hv/mshv_eventfd.h=51=int mshv_set_unset_irqfd(struct mshv_partition *partition,
drivers/hv/mshv_eventfd.h:52: struct mshv_user_irqfd *args);
drivers/hv/mshv_eventfd.h-53-
--
drivers/hv/mshv_irq.c=18=int mshv_update_routing_table(struct mshv_partition *partition,
drivers/hv/mshv_irq.c:19: const struct mshv_user_irq_entry *ue,
drivers/hv/mshv_irq.c-20- unsigned int numents)
--
drivers/hv/mshv_root.h=229=int mshv_update_routing_table(struct mshv_partition *partition,
drivers/hv/mshv_root.h:230: const struct mshv_user_irq_entry *entries,
drivers/hv/mshv_root.h-231- unsigned int numents);
--
drivers/hv/mshv_root_main.c=1475=mshv_partition_ioctl_irqfd(struct mshv_partition *partition,
--
drivers/hv/mshv_root_main.c-1477-{
drivers/hv/mshv_root_main.c:1478: struct mshv_user_irqfd args;
drivers/hv/mshv_root_main.c-1479-
--
drivers/hv/mshv_root_main.c=1571=mshv_partition_ioctl_set_msi_routing(struct mshv_partition *partition,
--
drivers/hv/mshv_root_main.c-1573-{
drivers/hv/mshv_root_main.c:1574: struct mshv_user_irq_entry *entries = NULL;
drivers/hv/mshv_root_main.c:1575: struct mshv_user_irq_table args;
drivers/hv/mshv_root_main.c-1576- long ret;
--
drivers/hv/mshv_root_main.c-1585- if (args.nr) {
drivers/hv/mshv_root_main.c:1586: struct mshv_user_irq_table __user *urouting = user_args;
drivers/hv/mshv_root_main.c-1587-
--
drivers/media/pci/mgb4/mgb4_core.c=161=static int init_spi(struct mgb4_dev *mgbdev, u32 devid)
--
drivers/media/pci/mgb4/mgb4_core.c-192-
drivers/media/pci/mgb4/mgb4_core.c:193: irq = xdma_get_user_irq(mgbdev->xdev, 14);
drivers/media/pci/mgb4/mgb4_core.c:194: xdma_enable_user_irq(mgbdev->xdev, irq);
drivers/media/pci/mgb4/mgb4_core.c-195-
--
drivers/media/pci/mgb4/mgb4_core.c=269=static int init_i2c(struct mgb4_dev *mgbdev)
--
drivers/media/pci/mgb4/mgb4_core.c-293-
drivers/media/pci/mgb4/mgb4_core.c:294: irq = xdma_get_user_irq(mgbdev->xdev, 15);
drivers/media/pci/mgb4/mgb4_core.c:295: xdma_enable_user_irq(mgbdev->xdev, irq);
drivers/media/pci/mgb4/mgb4_core.c-296-
--
drivers/media/pci/mgb4/mgb4_trigger.c=47=static int trigger_set_state(struct iio_trigger *trig, bool state)
--
drivers/media/pci/mgb4/mgb4_trigger.c-50- struct trigger_data *st = iio_priv(indio_dev);
drivers/media/pci/mgb4/mgb4_trigger.c:51: int irq = xdma_get_user_irq(st->mgbdev->xdev, 11);
drivers/media/pci/mgb4/mgb4_trigger.c-52-
drivers/media/pci/mgb4/mgb4_trigger.c-53- if (state)
drivers/media/pci/mgb4/mgb4_trigger.c:54: xdma_enable_user_irq(st->mgbdev->xdev, irq);
drivers/media/pci/mgb4/mgb4_trigger.c-55- else
drivers/media/pci/mgb4/mgb4_trigger.c:56: xdma_disable_user_irq(st->mgbdev->xdev, irq);
drivers/media/pci/mgb4/mgb4_trigger.c-57-
--
drivers/media/pci/mgb4/mgb4_trigger.c=150=struct iio_dev *mgb4_trigger_create(struct mgb4_dev *mgbdev)
--
drivers/media/pci/mgb4/mgb4_trigger.c-170-
drivers/media/pci/mgb4/mgb4_trigger.c:171: irq = xdma_get_user_irq(mgbdev->xdev, 11);
drivers/media/pci/mgb4/mgb4_trigger.c-172- rv = probe_trigger(indio_dev, irq);
--
drivers/media/pci/mgb4/mgb4_trigger.c=201=void mgb4_trigger_free(struct iio_dev *indio_dev)
--
drivers/media/pci/mgb4/mgb4_trigger.c-206- iio_triggered_buffer_cleanup(indio_dev);
drivers/media/pci/mgb4/mgb4_trigger.c:207: remove_trigger(indio_dev, xdma_get_user_irq(st->mgbdev->xdev, 11));
drivers/media/pci/mgb4/mgb4_trigger.c-208- iio_device_free(indio_dev);
--
drivers/media/pci/mgb4/mgb4_vin.c=281=static void stop_streaming(struct vb2_queue *vq)
--
drivers/media/pci/mgb4/mgb4_vin.c-285- const struct mgb4_vin_config *config = vindev->config;
drivers/media/pci/mgb4/mgb4_vin.c:286: int irq = xdma_get_user_irq(vindev->mgbdev->xdev, config->vin_irq);
drivers/media/pci/mgb4/mgb4_vin.c-287-
drivers/media/pci/mgb4/mgb4_vin.c:288: xdma_disable_user_irq(vindev->mgbdev->xdev, irq);
drivers/media/pci/mgb4/mgb4_vin.c-289-
--
drivers/media/pci/mgb4/mgb4_vin.c=305=static int start_streaming(struct vb2_queue *vq, unsigned int count)
--
drivers/media/pci/mgb4/mgb4_vin.c-309- const struct mgb4_vin_config *config = vindev->config;
drivers/media/pci/mgb4/mgb4_vin.c:310: int irq = xdma_get_user_irq(vindev->mgbdev->xdev, config->vin_irq);
drivers/media/pci/mgb4/mgb4_vin.c-311-
--
drivers/media/pci/mgb4/mgb4_vin.c-323-
drivers/media/pci/mgb4/mgb4_vin.c:324: xdma_enable_user_irq(vindev->mgbdev->xdev, irq);
drivers/media/pci/mgb4/mgb4_vin.c-325-
--
drivers/media/pci/mgb4/mgb4_vin.c=941=struct mgb4_vin_dev *mgb4_vin_create(struct mgb4_dev *mgbdev, int id)
--
drivers/media/pci/mgb4/mgb4_vin.c-964- /* IRQ callbacks */
drivers/media/pci/mgb4/mgb4_vin.c:965: vin_irq = xdma_get_user_irq(mgbdev->xdev, vindev->config->vin_irq);
drivers/media/pci/mgb4/mgb4_vin.c-966- rv = request_irq(vin_irq, vin_handler, 0, "mgb4-vin", vindev);
--
drivers/media/pci/mgb4/mgb4_vin.c-970- }
drivers/media/pci/mgb4/mgb4_vin.c:971: err_irq = xdma_get_user_irq(mgbdev->xdev, vindev->config->err_irq);
drivers/media/pci/mgb4/mgb4_vin.c-972- rv = request_irq(err_irq, err_handler, 0, "mgb4-err", vindev);
--
drivers/media/pci/mgb4/mgb4_vin.c-1024- /* Enable the video signal change watcher */
drivers/media/pci/mgb4/mgb4_vin.c:1025: xdma_enable_user_irq(vindev->mgbdev->xdev, err_irq);
drivers/media/pci/mgb4/mgb4_vin.c-1026-
--
drivers/media/pci/mgb4/mgb4_vin.c=1059=void mgb4_vin_free(struct mgb4_vin_dev *vindev)
drivers/media/pci/mgb4/mgb4_vin.c-1060-{
drivers/media/pci/mgb4/mgb4_vin.c:1061: int vin_irq = xdma_get_user_irq(vindev->mgbdev->xdev,
drivers/media/pci/mgb4/mgb4_vin.c-1062- vindev->config->vin_irq);
drivers/media/pci/mgb4/mgb4_vin.c:1063: int err_irq = xdma_get_user_irq(vindev->mgbdev->xdev,
drivers/media/pci/mgb4/mgb4_vin.c-1064- vindev->config->err_irq);
drivers/media/pci/mgb4/mgb4_vin.c-1065-
drivers/media/pci/mgb4/mgb4_vin.c:1066: xdma_disable_user_irq(vindev->mgbdev->xdev, err_irq);
drivers/media/pci/mgb4/mgb4_vin.c-1067-
--
drivers/media/pci/mgb4/mgb4_vout.c=180=static void stop_streaming(struct vb2_queue *vq)
--
drivers/media/pci/mgb4/mgb4_vout.c-183- struct mgb4_dev *mgbdev = voutdev->mgbdev;
drivers/media/pci/mgb4/mgb4_vout.c:184: int irq = xdma_get_user_irq(mgbdev->xdev, voutdev->config->irq);
drivers/media/pci/mgb4/mgb4_vout.c-185-
drivers/media/pci/mgb4/mgb4_vout.c:186: xdma_disable_user_irq(mgbdev->xdev, irq);
drivers/media/pci/mgb4/mgb4_vout.c-187- cancel_work_sync(&voutdev->dma_work);
--
drivers/media/pci/mgb4/mgb4_vout.c=195=static int start_streaming(struct vb2_queue *vq, unsigned int count)
--
drivers/media/pci/mgb4/mgb4_vout.c-202- const struct mgb4_vout_config *config = voutdev->config;
drivers/media/pci/mgb4/mgb4_vout.c:203: int irq = xdma_get_user_irq(mgbdev->xdev, config->irq);
drivers/media/pci/mgb4/mgb4_vout.c-204- int rv;
--
drivers/media/pci/mgb4/mgb4_vout.c-229-
drivers/media/pci/mgb4/mgb4_vout.c:230: xdma_enable_user_irq(mgbdev->xdev, irq);
drivers/media/pci/mgb4/mgb4_vout.c-231-
--
drivers/media/pci/mgb4/mgb4_vout.c=757=struct mgb4_vout_dev *mgb4_vout_create(struct mgb4_dev *mgbdev, int id)
--
drivers/media/pci/mgb4/mgb4_vout.c-778- /* IRQ callback */
drivers/media/pci/mgb4/mgb4_vout.c:779: irq = xdma_get_user_irq(mgbdev->xdev, voutdev->config->irq);
drivers/media/pci/mgb4/mgb4_vout.c-780- rv = request_irq(irq, handler, 0, "mgb4-vout", voutdev);
--
drivers/media/pci/mgb4/mgb4_vout.c=862=void mgb4_vout_free(struct mgb4_vout_dev *voutdev)
drivers/media/pci/mgb4/mgb4_vout.c-863-{
drivers/media/pci/mgb4/mgb4_vout.c:864: int irq = xdma_get_user_irq(voutdev->mgbdev->xdev, voutdev->config->irq);
drivers/media/pci/mgb4/mgb4_vout.c-865-
--
include/linux/dma/amd_xdma.h-11-
include/linux/dma/amd_xdma.h:12:int xdma_enable_user_irq(struct platform_device *pdev, u32 irq_num);
include/linux/dma/amd_xdma.h:13:void xdma_disable_user_irq(struct platform_device *pdev, u32 irq_num);
include/linux/dma/amd_xdma.h:14:int xdma_get_user_irq(struct platform_device *pdev, u32 user_irq_index);
include/linux/dma/amd_xdma.h-15-
--
include/linux/futex.h=121=static inline void futex_fixup_robust_unlock(struct pt_regs *regs)
--
include/linux/futex.h-129- */
include/linux/futex.h:130: if (!current->rseq.event.user_irq)
include/linux/futex.h-131- return;
--
include/linux/hrtimer_rearm.h=29=static __always_inline bool
include/linux/hrtimer_rearm.h:30:hrtimer_rearm_deferred_user_irq(unsigned long *tif_work, const unsigned long tif_mask)
include/linux/hrtimer_rearm.h-31-{
--
include/linux/hrtimer_rearm.h=78=static __always_inline bool
include/linux/hrtimer_rearm.h:79:hrtimer_rearm_deferred_user_irq(unsigned long *tif_work, const unsigned long tif_mask) { return false; }
include/linux/hrtimer_rearm.h-80-static __always_inline bool hrtimer_test_and_clear_rearm_deferred(void) { return false; }
--
include/linux/irq-entry-common.h=194=static __always_inline void __exit_to_user_mode_prepare(struct pt_regs *regs,
--
include/linux/irq-entry-common.h-205- if (unlikely(ti_work & work_mask)) {
include/linux/irq-entry-common.h:206: if (!hrtimer_rearm_deferred_user_irq(&ti_work, work_mask))
include/linux/irq-entry-common.h-207- ti_work = exit_to_user_mode_loop(regs, ti_work);
--
include/linux/irq-entry-common.h=291=static __always_inline void irqentry_enter_from_user_mode(struct pt_regs *regs)
--
include/linux/irq-entry-common.h-293- enter_from_user_mode(regs);
include/linux/irq-entry-common.h:294: rseq_note_user_irq_entry();
include/linux/irq-entry-common.h-295-}
--
include/linux/rseq.h=35=static inline void rseq_signal_deliver(struct ksignal *ksig, struct pt_regs *regs)
--
include/linux/rseq.h-38- /* has_rseq is implied in rseq_v2() */
include/linux/rseq.h:39: if (current->rseq.event.user_irq)
include/linux/rseq.h-40- __rseq_signal_deliver(ksig->sig, regs);
--
include/linux/rseq.h=53=static __always_inline void rseq_sched_switch_event(struct task_struct *t)
--
include/linux/rseq.h-57- /*
include/linux/rseq.h:58: * Only apply the user_irq optimization for RSEQ ABI V2 registrations.
include/linux/rseq.h-59- * Legacy users like TCMalloc rely on the original ABI V1 behaviour
--
include/linux/rseq.h-71- */
include/linux/rseq.h:72: bool raise = ev->user_irq | ev->ids_changed;
include/linux/rseq.h-73-
--
include/linux/rseq_entry.h=128=static __always_inline bool __rseq_grant_slice_extension(bool work_pending)
--
include/linux/rseq_entry.h-139- state = curr->rseq.slice.state;
include/linux/rseq_entry.h:140: state.enabled &= curr->rseq.event.user_irq;
include/linux/rseq_entry.h-141- if (likely(!state.state))
--
include/linux/rseq_entry.h=250=bool rseq_debug_update_user_cs(struct task_struct *t, struct pt_regs *regs, unsigned long csaddr);
include/linux/rseq_entry.h-251-
include/linux/rseq_entry.h:252:static __always_inline void rseq_note_user_irq_entry(void)
include/linux/rseq_entry.h-253-{
include/linux/rseq_entry.h-254- if (IS_ENABLED(CONFIG_GENERIC_IRQ_ENTRY))
include/linux/rseq_entry.h:255: current->rseq.event.user_irq = true;
include/linux/rseq_entry.h-256-}
--
include/linux/rseq_entry.h=291=bool rseq_debug_update_user_cs(struct task_struct *t, struct pt_regs *regs,
--
include/linux/rseq_entry.h-344-
include/linux/rseq_entry.h:345: /* rseq_event.user_irq is only valid if CONFIG_GENERIC_IRQ_ENTRY=y */
include/linux/rseq_entry.h-346- if (IS_ENABLED(CONFIG_GENERIC_IRQ_ENTRY)) {
include/linux/rseq_entry.h-347- /* If not in interrupt from user context, let it die */
include/linux/rseq_entry.h:348: if (unlikely(!t->rseq.event.user_irq))
include/linux/rseq_entry.h-349- goto die;
--
include/linux/rseq_entry.h=531=static rseq_inline bool rseq_update_usr(struct task_struct *t, struct pt_regs *regs,
--
include/linux/rseq_entry.h-545- if (!static_branch_unlikely(&rseq_debug_enabled)) {
include/linux/rseq_entry.h:546: if (likely(!t->rseq.event.user_irq))
include/linux/rseq_entry.h-547- return true;
--
include/linux/rseq_entry.h=598=static __always_inline bool rseq_exit_user_update(struct pt_regs *regs, struct task_struct *t)
--
include/linux/rseq_entry.h-615- /*
include/linux/rseq_entry.h:616: * If IDs have not changed rseq_event::user_irq must be true
include/linux/rseq_entry.h-617- * See rseq_sched_switch_event().
--
include/linux/rseq_entry.h=737=static __always_inline void rseq_irqentry_exit_to_user_mode(void)
--
include/linux/rseq_entry.h-745- /*
include/linux/rseq_entry.h:746: * Ensure that event (especially user_irq) is cleared when the
include/linux/rseq_entry.h-747- * interrupt did not result in a schedule and therefore the
--
include/linux/rseq_entry.h=755=static __always_inline void rseq_debug_syscall_return(struct pt_regs *regs)
--
include/linux/rseq_entry.h-760-#else /* CONFIG_RSEQ */
include/linux/rseq_entry.h:761:static inline void rseq_note_user_irq_entry(void) { }
include/linux/rseq_entry.h-762-static inline bool rseq_exit_to_user_mode_restart(struct pt_regs *regs, unsigned long ti_work)
--
include/linux/rseq_types.h=10=struct rseq;
--
include/linux/rseq_types.h-24- * @ids_changed: Indicator that IDs need to be updated
include/linux/rseq_types.h:25: * @user_irq: True on interrupt entry from user mode
include/linux/rseq_types.h-26- * @has_rseq: Greater than 0 if the task has a rseq pointer installed.
--
include/linux/rseq_types.h=37=struct rseq_event {
--
include/linux/rseq_types.h-45- u8 ids_changed;
include/linux/rseq_types.h:46: u8 user_irq;
include/linux/rseq_types.h-47- };
]
|
| 144/4 |
2026/08/12 12:50 |
llm |
repro-generator |
0m
Model:
Tokens:
input: 31270
output: 34
thoughts: 281
Thoughts: **My Thought Process Regarding RSEQ and User IRQs**
My understanding is that when a thread enters the kernel from user mode via an interrupt, specifically a timer interrupt in this scenario, the function `rseq_note_user_irq_entry()` is invoked. This function's crucial action is to set the `current->rseq.event.user_irq` flag to `true`. This flag, as I see it, acts as a signal indicating that the thread was in user space and was interrupted by a user-level interrupt.
Following this, when the thread is preparing to exit the kernel and return to user mode, the execution path goes through `__exit_to_user_mode_prepare`. Within this function, a check is performed on `ti_work & work_mask`. If this bitwise AND operation results in a non-zero value, it signifies that certain deferred work needs to be processed. Consequently, `hrtimer_rearm_deferred_user_irq(&ti_work, work_mask)` is called.
Crucially, my investigation reveals that this `hrtimer_rearm_deferred_user_irq` call occurs *before* the `exit_to_user_mode_loop` function is entered. This sequencing is important because `exit_to_user_mode_loop` itself is called from `__exit_to_user_mode_loop`.
It is within `__exit_to_user_mode_loop` that the `ti_work & _TIF_NEED_RESCHED` condition is evaluated. If `_TIF_NEED_RESCHED` is indeed set, it triggers the call to `rseq_grant_slice_extension`. Therefore, the presence of a user IRQ, which sets `user_irq` to true, can indirectly lead to this resched check and, potentially, a slice extension being granted, by virtue of the deferred timer rearming logic. This forms a chain of events from the initial user IRQ to the potential resched decision upon returning to user space.
|
| 145/4 |
2026/08/12 12:50 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile: Name:__exit_to_user_mode_prepare]
Results: map[SourceCode: 181: /**
182: * __exit_to_user_mode_prepare - call exit_to_user_mode_loop() if required
183: * @regs: Pointer to pt_regs on entry stack
184: * @work_mask: Which TIF bits need to be evaluated
185: *
186: * 1) check that interrupts are disabled
187: * 2) call tick_nohz_user_enter_prepare()
188: * 3) call exit_to_user_mode_loop() if any flags from
189: * EXIT_TO_USER_MODE_WORK are set
190: * 4) check that interrupts are still disabled
191: *
192: * Don't invoke directly, use the syscall/irqentry_ prefixed variants below
193: */
194: static __always_inline void __exit_to_user_mode_prepare(struct pt_regs *regs,
195: const unsigned long work_mask)
196: {
197: unsigned long ti_work;
198:
199: lockdep_assert_irqs_disabled();
200:
201: /* Flush pending rcuog wakeup before the last need_resched() check */
202: tick_nohz_user_enter_prepare();
203:
204: ti_work = read_thread_flags();
205: if (unlikely(ti_work & work_mask)) {
206: if (!hrtimer_rearm_deferred_user_irq(&ti_work, work_mask))
207: ti_work = exit_to_user_mode_loop(regs, ti_work);
208: }
209:
210: arch_exit_to_user_mode_prepare(regs, ti_work);
211: }
SourceFile:include/linux/irq-entry-common.h]
|
| 146/4 |
2026/08/12 12:50 |
llm |
repro-generator |
0m
Model:
Tokens:
input: 32122
output: 36
thoughts: 56
Thoughts: **My Thought Process Unfolding**
Alright, so I've just encountered the `hrtimer_rearm_deferred_user_irq` function being invoked. My immediate reaction is to trace its execution flow. Specifically, I'm looking at the return value: if this function signals `false`, then the system is destined to enter the `exit_to_user_mode_loop`. This tells me that the deferred rearming of the high-resolution timer has failed in some fundamental way, prompting an immediate transition out of kernel mode and back to user space. To fully understand *why* this is happening, my next logical step, and indeed the focus of my current investigation, is to delve into the intricacies of `hrtimer_rearm_deferred_user_irq` itself. I need to dissect its internal logic, examine its parameters, and understand the conditions under which it might return `false` to get to the root of this exit condition.
|
| 147/4 |
2026/08/12 12:50 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile: Name:hrtimer_rearm_deferred_user_irq]
Results: map[SourceCode: 28: /* Invoked from the exit to user before invoking exit_to_user_mode_loop() */
29: static __always_inline bool
30: hrtimer_rearm_deferred_user_irq(unsigned long *tif_work, const unsigned long tif_mask)
31: {
32: /* Help the compiler to optimize the function out for syscall returns */
33: if (!(tif_mask & _TIF_HRTIMER_REARM))
34: return false;
35: /*
36: * Rearm the timer if none of the resched flags is set before going into
37: * the loop which re-enables interrupts.
38: */
39: if (unlikely((*tif_work & TIF_REARM_MASK) == _TIF_HRTIMER_REARM)) {
40: clear_thread_flag(TIF_HRTIMER_REARM);
41: __hrtimer_rearm_deferred();
42: /* Don't go into the loop if HRTIMER_REARM was the only flag */
43: *tif_work &= ~TIF_HRTIMER_REARM;
44: return !*tif_work;
45: }
46: return false;
47: }
SourceFile:include/linux/hrtimer_rearm.h]
|
| 148/4 |
2026/08/12 12:50 |
llm |
repro-generator |
0m
Model:
Tokens:
input: 32563
output: 45
thoughts: 232
Thoughts: **My Thought Process Regarding the Scheduler and High-Resolution Timers**
Alright, let's trace this thought through. My initial observation is about how the scheduler handles rescheduling events, specifically in the context of high-resolution timers (`hrtimers`). I'm looking at a condition where `_TIF_NEED_RESCHED` is set, which normally signals that a rescheduling event has occurred and the kernel needs to yield to a potentially new process.
My first deductive leap is that if `_TIF_NEED_RESCHED` is active, then the check `(*tif_work & TIF_REARM_MASK) == _TIF_HRTIMER_REARM` will *necessarily* evaluate to false. This is a key insight for me because I know that `TIF_REARM_MASK` is a bitmask that *includes* the `_TIF_NEED_RESCHED` flag. Therefore, if `_TIF_NEED_RESCHED` is set, the `tif_work` will have that bit set, and since `TIF_REARM_MASK` contains `_TIF_NEED_RESCHED`, the entire masked value `(*tif_work & TIF_REARM_MASK)` cannot possibly *only* equal `_TIF_HRTIMER_REARM` (unless `_TIF_HRTIMER_REARM` itself somehow also implies `_TIF_NEED_RESCHED` and nothing else, which seems unlikely and would be a peculiar design). So, the condition is false.
Because that condition is false, the code path then leads to the execution of `exit_to_user_mode_loop`. This is where the kernel prepares to transition back to user space. My understanding is that `exit_to_user_mode_loop` itself is a wrapper that then calls `__exit_to_user_mode_loop`.
Now, the crucial step: `__exit_to_user_mode_loop` performs some setup for returning to user mode. Specifically, it *enables interrupts* and then proceeds to call `rseq_grant_slice_extension`. This is where the interaction with the high-resolution timer rearming logic comes into play.
Following the flow, `rseq_grant_slice_extension` then invokes `hrtimer_rearm_deferred_tif`. My knowledge tells me that this function is designed to handle the rearming of high-resolution timers that might have been deferred. It checks the `_TIF_HRTIMER_REARM` flag and, if set, clears it. However, it does so *under the assumption that interrupts are disabled*. This is evident from the `lockdep_assert_irqs_disabled()` call within `hrtimer_rearm_deferred_tif`.
And here's the crux of my confusion and the point where my thought process hits a snag: Since `__exit_to_user_mode_loop` *just enabled interrupts*, `lockdep` will indeed trigger. This means the assertion `lockdep_assert_irqs_disabled()` will fail because interrupts are *not* disabled when `hrtimer_rearm_deferred_tif` is called. This smells like a potential race condition or an architectural flaw.
This immediately raises a question in my mind: How does `_TIF_HRTIMER_REARM` even get set in the first place if this path seems to lead to a lockdep violation? I need to backtrack and understand the lifecycle of the `_TIF_HRTIMER_REARM` flag. Where exactly is it being set, and under what conditions? That's the next logical step for me to resolve this apparent inconsistency.
|
| 149/4 |
2026/08/12 12:51 |
tool |
codesearch-find-references |
0m
Error:
Args: map[ContextFile: IncludeSnippetLines:0 Name:TIF_HRTIMER_REARM SourceTreePrefix:]
Results: map[References:<nil> TruncatedOutput:false]
|
| 150/4 |
2026/08/12 12:51 |
llm |
repro-generator |
0m
Model:
Tokens:
input: 32839
output: 22
thoughts: 15
Thoughts: **A Deep Dive into Kernel Tick Management: My Thought Process**
My primary objective here is to understand the mechanism by which high-resolution timers (HRTIMERS) are rearmed within the Linux kernel. To achieve this, I'm initiating a search using `grep` for the specific symbol `TIF_HRTIMER_REARM`. This symbol likely represents a thread-related flag or a specific state transition within the kernel's task structure, indicating that a high-resolution timer needs to be re-armed. My expectation is that by examining the code where this flag is set and cleared, I'll gain insight into the precise conditions and logic that trigger a timer rearm. This, in turn, should illuminate the kernel's strategy for maintaining timer accuracy and responsiveness at a high resolution, especially in the context of task scheduling and potential preemption events. I'm particularly interested in how the kernel ensures that the rearming process is efficient and doesn't introduce unnecessary overhead.
|
| 151/4 |
2026/08/12 12:51 |
tool |
grepper |
0m
Args: map[Expression:TIF_HRTIMER_REARM]
Results: map[Output:include/asm-generic/thread_info_tif.h-50-
include/asm-generic/thread_info_tif.h:51:#define TIF_HRTIMER_REARM 12 // re-arm the timer
include/asm-generic/thread_info_tif.h:52:#define _TIF_HRTIMER_REARM BIT(TIF_HRTIMER_REARM)
include/asm-generic/thread_info_tif.h-53-
--
include/linux/hrtimer_rearm.h=15=static __always_inline bool hrtimer_test_and_clear_rearm_deferred_tif(unsigned long tif_work)
--
include/linux/hrtimer_rearm.h-18-
include/linux/hrtimer_rearm.h:19: if (unlikely(tif_work & _TIF_HRTIMER_REARM)) {
include/linux/hrtimer_rearm.h:20: clear_thread_flag(TIF_HRTIMER_REARM);
include/linux/hrtimer_rearm.h-21- return true;
--
include/linux/hrtimer_rearm.h-25-
include/linux/hrtimer_rearm.h:26:#define TIF_REARM_MASK (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY | _TIF_HRTIMER_REARM)
include/linux/hrtimer_rearm.h-27-
--
include/linux/hrtimer_rearm.h=30=hrtimer_rearm_deferred_user_irq(unsigned long *tif_work, const unsigned long tif_mask)
--
include/linux/hrtimer_rearm.h-32- /* Help the compiler to optimize the function out for syscall returns */
include/linux/hrtimer_rearm.h:33: if (!(tif_mask & _TIF_HRTIMER_REARM))
include/linux/hrtimer_rearm.h-34- return false;
--
include/linux/hrtimer_rearm.h-38- */
include/linux/hrtimer_rearm.h:39: if (unlikely((*tif_work & TIF_REARM_MASK) == _TIF_HRTIMER_REARM)) {
include/linux/hrtimer_rearm.h:40: clear_thread_flag(TIF_HRTIMER_REARM);
include/linux/hrtimer_rearm.h-41- __hrtimer_rearm_deferred();
include/linux/hrtimer_rearm.h-42- /* Don't go into the loop if HRTIMER_REARM was the only flag */
include/linux/hrtimer_rearm.h:43: *tif_work &= ~TIF_HRTIMER_REARM;
include/linux/hrtimer_rearm.h-44- return !*tif_work;
--
include/linux/irq-entry-common.h-38-# define EXIT_TO_USER_MODE_WORK_SYSCALL (EXIT_TO_USER_MODE_WORK)
include/linux/irq-entry-common.h:39:# define EXIT_TO_USER_MODE_WORK_IRQ (EXIT_TO_USER_MODE_WORK | _TIF_HRTIMER_REARM)
include/linux/irq-entry-common.h-40-#else
--
kernel/time/hrtimer.c=2165=hrtimer_interrupt_rearm(struct hrtimer_cpu_base *cpu_base, ktime_t expires_next)
--
kernel/time/hrtimer.c-2170- cpu_base->deferred_expires_next = expires_next;
kernel/time/hrtimer.c:2171: set_thread_flag(TIF_HRTIMER_REARM);
kernel/time/hrtimer.c-2172-}
]
|
| 152/4 |
2026/08/12 12:51 |
llm |
repro-generator |
0m
Model:
Tokens:
input: 33819
output: 31
thoughts: 39
Thoughts: **My Thought Process Regarding `hrtimer_interrupt_rearm`**
Okay, I've just observed that the `TIF_HRTIMER_REARM` flag is being set within the `hrtimer_interrupt_rearm` function. My immediate next step, naturally, is to delve into the `hrtimer_interrupt_rearm` function itself. I need to understand precisely *why* and *how* this flag is being set there, and what implications that has for the overall timer handling mechanism.
|
| 153/4 |
2026/08/12 12:51 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile: Name:hrtimer_interrupt_rearm]
Results: map[SourceCode:2164: static __always_inline void
2165: hrtimer_interrupt_rearm(struct hrtimer_cpu_base *cpu_base, ktime_t expires_next)
2166: {
2167: /* hrtimer_interrupt() just re-evaluated the first expiring timer */
2168: cpu_base->deferred_needs_update = false;
2169: /* Cache the expiry time */
2170: cpu_base->deferred_expires_next = expires_next;
2171: set_thread_flag(TIF_HRTIMER_REARM);
2172: }
SourceFile:kernel/time/hrtimer.c]
|
| 154/4 |
2026/08/12 12:51 |
llm |
repro-generator |
0m
Model:
Tokens:
input: 34063
output: 23
thoughts: 638
Thoughts: **My Thoughts onhrtimer and RSEQ Interaction**
Okay, let's trace this through. I'm seeing that `hrtimer_interrupt_rearm` is being invoked directly from `hrtimer_interrupt`. This means that when a timer interrupt fires, it's setting the `TIF_HRTIMER_REARM` flag. Now, the scenario gets interesting when this timer interrupt *also* sets the `_TIF_NEED_RESCHED` flag – perhaps due to a scheduler tick. In this case, both `_TIF_HRTIMER_REARM` and `_TIF_NEED_RESCHED` end up being set.
When the system is returning to user space, the `__exit_to_user_mode_prepare` function is checking `ti_work & work_mask`. The `work_mask` here includes `EXIT_TO_USER_MODE_WORK_IRQ`, which, crucially, contains `_TIF_HRTIMER_REARM`. This leads to the call to `hrtimer_rearm_deferred_user_irq`.
My initial thought here is to look at the condition within `hrtimer_rearm_deferred_user_irq`: `(*tif_work & TIF_REARM_MASK) == _TIF_HRTIMER_REARM`. Since `_TIF_NEED_RESCHED` is also set in this scenario, the expression `(*tif_work & TIF_REARM_MASK)` won't *strictly* equal `_TIF_HRTIMER_REARM` (because other flags are likely set in `tif_work`). This means the function returns `false`.
Consequently, `exit_to_user_mode_loop` is called. Inside this loop, interrupts are enabled. The code then checks `_TIF_NEED_RESCHED`, and if it's set, it calls `rseq_grant_slice_extension`. This, in turn, calls `__rseq_grant_slice_extension`.
Now, `__rseq_grant_slice_extension` is designed to return `true` under specific conditions. From my understanding, it returns `true` if:
1. `rseq_slice_extension_enabled()` is active.
2. `state.enabled` is true. This implies `curr->rseq.event.user_irq` is true, which makes sense since we entered user mode via an interrupt.
3. `state.state` is non-zero, which again points to `enabled` being true, likely due to a previous `prctl(PR_RSEQ_SLICE_EXTENSION)` call.
4. `work_pending` is `false`.
This `work_pending` variable is where things get tricky. It's defined as `ti_work & mask`. The `mask` here, within `__exit_to_user_mode_loop`, is `TIF_SLICE_EXT_DENY`. So, the condition for `work_pending` being false is that `ti_work` does *not* have `TIF_SLICE_EXT_DENY` set.
This is where the problem arises. If `__rseq_grant_slice_extension` returns `true`, it leads to `hrtimer_rearm_deferred_tif`. This function attempts to check `_TIF_HRTIMER_REARM` and clear it, importantly calling `lockdep_assert_irqs_disabled()` in the process. However, we know that in `exit_to_user_mode_loop`, interrupts are *enabled*. This mismatch – interrupts being enabled when `lockdep_assert_irqs_disabled()` is called – is precisely what triggers the lockdep assertion failure.
So, the core issue seems to be a race condition or a logical flaw where the state of interrupts during the `hrtimer_rearm_deferred_tif` call doesn't align with the assumption made by `lockdep_assert_irqs_disabled()`, all stemming from the interplay between `hrtimer` flags and the RSEQ slice extension logic when both `_TIF_HRTIMER_REARM` and `_TIF_NEED_RESCHED` are set simultaneously. I need to re-examine the exact definition and application of `TIF_SLICE_EXT_DENY` in this context to fully grasp why `work_pending` might be false when it shouldn't be, or how `hrtimer_rearm_deferred_tif` is being entered in the first place under these interrupt-enabled conditions.
|
| 155/4 |
2026/08/12 12:51 |
tool |
grepper |
0m
Args: map[Expression:TIF_SLICE_EXT_DENY]
Results: map[Output:kernel/entry/common.c=13=void __weak arch_do_signal_or_restart(struct pt_regs *regs) { }
--
kernel/entry/common.c-39-#endif
kernel/entry/common.c:40:#define TIF_SLICE_EXT_DENY (EXIT_TO_USER_MODE_WORK & ~TIF_SLICE_EXT_SCHED)
kernel/entry/common.c-41-
kernel/entry/common.c=42=static __always_inline unsigned long __exit_to_user_mode_loop(struct pt_regs *regs,
--
kernel/entry/common.c-53- if (ti_work & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)) {
kernel/entry/common.c:54: if (!rseq_grant_slice_extension(ti_work, TIF_SLICE_EXT_DENY))
kernel/entry/common.c-55- schedule();
]
|
| 156/4 |
2026/08/12 12:51 |
llm |
repro-generator |
0m
Model:
Tokens:
input: 34965
output: 25
thoughts: 158
Thoughts: **Deconstructing the Slice Extension Denial Mechanism**
My current line of thought is focused on understanding the precise implications of the `TIF_SLICE_EXT_DENY` flag. I'm working through its definition by breaking it down. My understanding is that `TIF_SLICE_EXT_DENY` is essentially defined as `EXIT_TO_USER_MODE_WORK` *excluding* `TIF_SLICE_EXT_SCHED`.
Now, to fully grasp what `TIF_SLICE_EXT_DENY` encompasses, I need to understand what `TIF_SLICE_EXT_SCHED` represents. My working hypothesis is that `TIF_SLICE_EXT_SCHED` is composed of the reschedule flags: `_TIF_NEED_RESCHED` and `_TIF_NEED_RESCHED_LAZY`.
Therefore, if my assumption about `TIF_SLICE_EXT_SCHED` is correct, then `TIF_SLICE_EXT_DENY` must represent *all other* work flags that are part of `EXIT_TO_USER_MODE_WORK`, but are *not* related to scheduling. This would logically include flags like `_TIF_SIGPENDING`, `_TIF_NOTIFY_RESUME`, and so on.
However, a critical question arises at this point: does `TIF_SLICE_EXT_DENY` also include `_TIF_HRTIMER_REARM`? To resolve this uncertainty and confirm the full scope of `TIF_SLICE_EXT_DENY`, I need to directly examine the definition and the flags contributing to `EXIT_TO_USER_MODE_WORK`. My next step is to investigate that definition.
|
| 157/4 |
2026/08/12 12:52 |
tool |
grepper |
0m
Args: map[Expression:#define EXIT_TO_USER_MODE_WORK]
Results: map[Output:include/linux/irq-entry-common.h-30-
include/linux/irq-entry-common.h:31:#define EXIT_TO_USER_MODE_WORK \
include/linux/irq-entry-common.h-32- (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
--
kernel/entry/common.c=13=void __weak arch_do_signal_or_restart(struct pt_regs *regs) { }
--
kernel/entry/common.c-15-#ifdef CONFIG_HAVE_GENERIC_TIF_BITS
kernel/entry/common.c:16:#define EXIT_TO_USER_MODE_WORK_LOOP (EXIT_TO_USER_MODE_WORK & ~_TIF_RSEQ)
kernel/entry/common.c-17-#else
kernel/entry/common.c:18:#define EXIT_TO_USER_MODE_WORK_LOOP (EXIT_TO_USER_MODE_WORK)
kernel/entry/common.c-19-#endif
]
|
| 158/4 |
2026/08/12 12:52 |
llm |
repro-generator |
2m
Model:
Tokens:
input: 35409
output: 1122
thoughts: 9919
Thoughts: **The Root of the Lockdep Warning: A Slice Extension Mishap**
I've been digging into a peculiar lockdep warning that appears when the kernel tries to grant a RSEQ time slice extension. My analysis points to a specific race condition that occurs during the exit-to-user-mode transition.
It all boils down to how the `EXIT_TO_USER_MODE_WORK` flags interact with the `_TIF_HRTIMER_REARM` flag. I noticed that `EXIT_TO_USER_MODE_WORK` *doesn't* include `_TIF_HRTIMER_REARM`, while `EXIT_TO_USER_MODE_WORK_IRQ` *does*. This distinction is critical.
Consequently, if `TIF_SLICE_EXT_DENY` is the only relevant flag apart from `_TIF_NEED_RESCHED` and `_TIF_HRTIMER_REARM` being set, then `ti_work & TIF_SLICE_EXT_DENY` will evaluate to zero. This means that `work_pending` (which is derived from `ti_work & TIF_SLICE_EXT_DENY`) will be false.
For the kernel to grant a slice extension, two conditions must be met:
1. `state.granted` must be false.
2. `usr_ctrl.request` must be true.
When these conditions are met, the kernel grants the slice extension, sets `usr_ctrl.request` to 0, `usr_ctrl.granted` to 1, and returns `true`.
The problem arises immediately after, when `rseq_grant_slice_extension` calls `hrtimer_rearm_deferred_tif(ti_work)`. This function, in turn, checks `ti_work & _TIF_HRTIMER_REARM`. If this flag is set (which it will be in my triggering scenario), it proceeds to call `clear_thread_flag(TIF_HRTIMER_REARM)` and `__hrtimer_rearm_deferred()`.
Here's the crucial part: `hrtimer_rearm_deferred_tif` (and its internal helper `hrtimer_test_and_clear_rearm_deferred_tif`) has a `lockdep_assert_irqs_disabled()` check at its very beginning. However, when the kernel is exiting to user mode (`__exit_to_user_mode_loop`), interrupts are *enabled*. This mismatch – interrupts being enabled while the kernel asserts they should be disabled – is what triggers the lockdep warning.
The warning occurs regardless of whether `_TIF_HRTIMER_REARM` is actually set. As long as `__rseq_grant_slice_extension` returns true (meaning `request` was set by user space and no other blocking work flags are pending), `hrtimer_rearm_deferred_tif` is called, and the `lockdep_assert_irqs_disabled()` check will fail, printing the warning.
To reliably reproduce this, I've devised a strategy:
1. **Register RSEQ:** I register a custom RSEQ area with a size of at least 33 bytes, ensuring it has enough space for the slice control structure.
2. **Enable Slice Extension:** I enable the slice extension feature using `prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, ...)`.
3. **Spin and Request:** I create two threads, pin them to the same CPU (CPU 0), and have them spin in a tight loop. Inside this loop, each thread continuously sets its `slice_ctrl.request` field to 1. This ensures that RSEQ's `request` bit is always set for slice extension.
4. **Scheduler Tick:** By having two threads contending for CPU 0, the scheduler tick will inevitably preempt one thread to run the other. This scheduler tick is a timer interrupt that, critically, sets both `_TIF_NEED_RESCHED` and `_TIF_HRTIMER_REARM`.
When the preempted thread returns to user mode, the conditions for `__rseq_grant_slice_extension` to return true are met (`request` is 1, `state.granted` is 0, and `work_pending` is effectively false because `TIF_SLICE_EXT_DENY` isn't set by the RSEQ slice extension logic itself). This triggers the call to `hrtimer_rearm_deferred_tif`, which in turn trips the `lockdep_assert_irqs_disabled()` assertion, exposing the bug. The `sleep(5)` at the end of the main function ensures enough time for this sequence of events to unfold.
|
| 159/4 |
2026/08/12 12:54 |
tool |
set-results |
0m
Args: map[IsProbe:false RawCandidateReproC:#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <sched.h>
#include <string.h>
#include <errno.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_SET 2
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
#endif
#ifndef SYS_rseq
#define SYS_rseq 334
#endif
struct my_rseq_slice_ctrl {
union {
uint32_t all;
struct {
uint8_t request;
uint8_t granted;
uint16_t __reserved;
};
};
};
struct my_rseq {
uint32_t cpu_id_start;
uint32_t cpu_id;
uint64_t rseq_cs;
uint32_t flags;
uint32_t node_id;
uint32_t mm_cid;
struct my_rseq_slice_ctrl slice_ctrl;
uint8_t __reserved;
char end[];
} __attribute__((aligned(64)));
int thread_fn(void *arg) {
struct my_rseq *rseq_area = NULL;
if (posix_memalign((void **)&rseq_area, 64, sizeof(struct my_rseq)) != 0) {
printf("[-] posix_memalign failed: %s\n", strerror(errno));
exit(1);
}
memset(rseq_area, 0, sizeof(struct my_rseq));
/* Register our custom RSEQ area */
int ret = syscall(SYS_rseq, rseq_area, sizeof(struct my_rseq), 0, 0x53053053);
if (ret != 0) {
printf("[-] rseq syscall failed: %s\n", strerror(errno));
exit(1);
}
/* Enable the RSEQ time slice extension feature */
if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0) != 0) {
printf("[-] prctl PR_RSEQ_SLICE_EXTENSION failed: %s\n", strerror(errno));
exit(1);
}
/*
* Spin in user space requesting a slice extension.
* A timer interrupt will eventually hit, set _TIF_NEED_RESCHED,
* and trigger the lockdep warning on return to user space.
*/
while (1) {
rseq_area->slice_ctrl.request = 1;
/* Prevent compiler from optimizing out the store */
asm volatile("" ::: "memory");
}
return 0;
}
int main() {
cpu_set_t set;
CPU_ZERO(&set);
CPU_SET(0, &set);
if (sched_setaffinity(0, sizeof(set), &set) != 0) {
printf("[-] sched_setaffinity failed: %s\n", strerror(errno));
exit(1);
}
printf("[+] sched_setaffinity successful.\n");
for (int i = 0; i < 2; i++) {
char *stack = malloc(1024 * 1024);
if (!stack) {
printf("[-] malloc failed: %s\n", strerror(errno));
exit(1);
}
void *stack_top = (void *)(((uintptr_t)stack + 1024 * 1024) & ~0xF);
pid_t pid = clone(thread_fn, stack_top,
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD, NULL);
if (pid == -1) {
printf("[-] clone failed: %s\n", strerror(errno));
exit(1);
}
}
printf("[+] Created 2 spinning threads on CPU 0.\n");
/* Wait enough time for the scheduler tick to hit the spinning threads */
sleep(5);
printf("[+] Done.\n");
return 0;
}
]
Results: map[IsProbe:false RawCandidateReproC:#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <sched.h>
#include <string.h>
#include <errno.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_SET 2
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
#endif
#ifndef SYS_rseq
#define SYS_rseq 334
#endif
struct my_rseq_slice_ctrl {
union {
uint32_t all;
struct {
uint8_t request;
uint8_t granted;
uint16_t __reserved;
};
};
};
struct my_rseq {
uint32_t cpu_id_start;
uint32_t cpu_id;
uint64_t rseq_cs;
uint32_t flags;
uint32_t node_id;
uint32_t mm_cid;
struct my_rseq_slice_ctrl slice_ctrl;
uint8_t __reserved;
char end[];
} __attribute__((aligned(64)));
int thread_fn(void *arg) {
struct my_rseq *rseq_area = NULL;
if (posix_memalign((void **)&rseq_area, 64, sizeof(struct my_rseq)) != 0) {
printf("[-] posix_memalign failed: %s\n", strerror(errno));
exit(1);
}
memset(rseq_area, 0, sizeof(struct my_rseq));
/* Register our custom RSEQ area */
int ret = syscall(SYS_rseq, rseq_area, sizeof(struct my_rseq), 0, 0x53053053);
if (ret != 0) {
printf("[-] rseq syscall failed: %s\n", strerror(errno));
exit(1);
}
/* Enable the RSEQ time slice extension feature */
if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0) != 0) {
printf("[-] prctl PR_RSEQ_SLICE_EXTENSION failed: %s\n", strerror(errno));
exit(1);
}
/*
* Spin in user space requesting a slice extension.
* A timer interrupt will eventually hit, set _TIF_NEED_RESCHED,
* and trigger the lockdep warning on return to user space.
*/
while (1) {
rseq_area->slice_ctrl.request = 1;
/* Prevent compiler from optimizing out the store */
asm volatile("" ::: "memory");
}
return 0;
}
int main() {
cpu_set_t set;
CPU_ZERO(&set);
CPU_SET(0, &set);
if (sched_setaffinity(0, sizeof(set), &set) != 0) {
printf("[-] sched_setaffinity failed: %s\n", strerror(errno));
exit(1);
}
printf("[+] sched_setaffinity successful.\n");
for (int i = 0; i < 2; i++) {
char *stack = malloc(1024 * 1024);
if (!stack) {
printf("[-] malloc failed: %s\n", strerror(errno));
exit(1);
}
void *stack_top = (void *)(((uintptr_t)stack + 1024 * 1024) & ~0xF);
pid_t pid = clone(thread_fn, stack_top,
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD, NULL);
if (pid == -1) {
printf("[-] clone failed: %s\n", strerror(errno));
exit(1);
}
}
printf("[+] Created 2 spinning threads on CPU 0.\n");
/* Wait enough time for the scheduler tick to hit the spinning threads */
sleep(5);
printf("[+] Done.\n");
return 0;
}
]
|
| 160/3 |
2026/08/12 12:54 |
loop |
|
0m
|
| 161/4 |
2026/08/12 12:54 |
iteration |
0 |
0m
|
| 162/5 |
2026/08/12 12:54 |
action |
merge-repro-c |
0m
Results: map[CurrentCandidateReproC:#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <sched.h>
#include <string.h>
#include <errno.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_SET 2
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
#endif
#ifndef SYS_rseq
#define SYS_rseq 334
#endif
struct my_rseq_slice_ctrl {
union {
uint32_t all;
struct {
uint8_t request;
uint8_t granted;
uint16_t __reserved;
};
};
};
struct my_rseq {
uint32_t cpu_id_start;
uint32_t cpu_id;
uint64_t rseq_cs;
uint32_t flags;
uint32_t node_id;
uint32_t mm_cid;
struct my_rseq_slice_ctrl slice_ctrl;
uint8_t __reserved;
char end[];
} __attribute__((aligned(64)));
int thread_fn(void *arg) {
struct my_rseq *rseq_area = NULL;
if (posix_memalign((void **)&rseq_area, 64, sizeof(struct my_rseq)) != 0) {
printf("[-] posix_memalign failed: %s\n", strerror(errno));
exit(1);
}
memset(rseq_area, 0, sizeof(struct my_rseq));
/* Register our custom RSEQ area */
int ret = syscall(SYS_rseq, rseq_area, sizeof(struct my_rseq), 0, 0x53053053);
if (ret != 0) {
printf("[-] rseq syscall failed: %s\n", strerror(errno));
exit(1);
}
/* Enable the RSEQ time slice extension feature */
if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0) != 0) {
printf("[-] prctl PR_RSEQ_SLICE_EXTENSION failed: %s\n", strerror(errno));
exit(1);
}
/*
* Spin in user space requesting a slice extension.
* A timer interrupt will eventually hit, set _TIF_NEED_RESCHED,
* and trigger the lockdep warning on return to user space.
*/
while (1) {
rseq_area->slice_ctrl.request = 1;
/* Prevent compiler from optimizing out the store */
asm volatile("" ::: "memory");
}
return 0;
}
int main() {
cpu_set_t set;
CPU_ZERO(&set);
CPU_SET(0, &set);
if (sched_setaffinity(0, sizeof(set), &set) != 0) {
printf("[-] sched_setaffinity failed: %s\n", strerror(errno));
exit(1);
}
printf("[+] sched_setaffinity successful.\n");
for (int i = 0; i < 2; i++) {
char *stack = malloc(1024 * 1024);
if (!stack) {
printf("[-] malloc failed: %s\n", strerror(errno));
exit(1);
}
void *stack_top = (void *)(((uintptr_t)stack + 1024 * 1024) & ~0xF);
pid_t pid = clone(thread_fn, stack_top,
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD, NULL);
if (pid == -1) {
printf("[-] clone failed: %s\n", strerror(errno));
exit(1);
}
}
printf("[+] Created 2 spinning threads on CPU 0.\n");
/* Wait enough time for the scheduler tick to hit the spinning threads */
sleep(5);
printf("[+] Done.\n");
return 0;
}
]
|
| 163/5 |
2026/08/12 12:54 |
action |
compile-c-prog |
0m
Results: map[CompilerError: FormattedReproC:#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <sched.h>
#include <string.h>
#include <errno.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_SET 2
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
#endif
#ifndef SYS_rseq
#define SYS_rseq 334
#endif
struct my_rseq_slice_ctrl {
union {
uint32_t all;
struct {
uint8_t request;
uint8_t granted;
uint16_t __reserved;
};
};
};
struct my_rseq {
uint32_t cpu_id_start;
uint32_t cpu_id;
uint64_t rseq_cs;
uint32_t flags;
uint32_t node_id;
uint32_t mm_cid;
struct my_rseq_slice_ctrl slice_ctrl;
uint8_t __reserved;
char end[];
} __attribute__((aligned(64)));
int thread_fn(void *arg) {
struct my_rseq *rseq_area = NULL;
if (posix_memalign((void **)&rseq_area, 64, sizeof(struct my_rseq)) != 0) {
printf("[-] posix_memalign failed: %s\n", strerror(errno));
exit(1);
}
memset(rseq_area, 0, sizeof(struct my_rseq));
/* Register our custom RSEQ area */
int ret = syscall(SYS_rseq, rseq_area, sizeof(struct my_rseq), 0, 0x53053053);
if (ret != 0) {
printf("[-] rseq syscall failed: %s\n", strerror(errno));
exit(1);
}
/* Enable the RSEQ time slice extension feature */
if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0) != 0) {
printf("[-] prctl PR_RSEQ_SLICE_EXTENSION failed: %s\n", strerror(errno));
exit(1);
}
/*
* Spin in user space requesting a slice extension.
* A timer interrupt will eventually hit, set _TIF_NEED_RESCHED,
* and trigger the lockdep warning on return to user space.
*/
while (1) {
rseq_area->slice_ctrl.request = 1;
/* Prevent compiler from optimizing out the store */
asm volatile("" ::: "memory");
}
return 0;
}
int main() {
cpu_set_t set;
CPU_ZERO(&set);
CPU_SET(0, &set);
if (sched_setaffinity(0, sizeof(set), &set) != 0) {
printf("[-] sched_setaffinity failed: %s\n", strerror(errno));
exit(1);
}
printf("[+] sched_setaffinity successful.\n");
for (int i = 0; i < 2; i++) {
char *stack = malloc(1024 * 1024);
if (!stack) {
printf("[-] malloc failed: %s\n", strerror(errno));
exit(1);
}
void *stack_top = (void *)(((uintptr_t)stack + 1024 * 1024) & ~0xF);
pid_t pid = clone(thread_fn, stack_top,
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD, NULL);
if (pid == -1) {
printf("[-] clone failed: %s\n", strerror(errno));
exit(1);
}
}
printf("[+] Created 2 spinning threads on CPU 0.\n");
/* Wait enough time for the scheduler tick to hit the spinning threads */
sleep(5);
printf("[+] Done.\n");
return 0;
}
]
|
| 164/5 |
2026/08/12 12:54 |
action |
If |
0m
Args:
|
| 165/3 |
2026/08/12 12:54 |
action |
run-c-repro |
2m
Results: map[CandidateBugTitle:WARNING in irqentry_exit CandidateCrashReport:------------[ cut here ]------------
__lockdep_enabled && this_cpu_read(hardirqs_enabled)
WARNING: include/linux/hrtimer_rearm.h:17 at hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_loop kernel/entry/common.c:54 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at exit_to_user_mode_loop kernel/entry/common.c:101 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit+0x484/0x8f0 kernel/entry/common.c:165, CPU#0: syz-executor381/5899
Modules linked in:
CPU: 0 UID: 0 PID: 5899 Comm: syz-executor381 Not tainted syzkaller #1 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline]
RIP: 0010:hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline]
RIP: 0010:rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline]
RIP: 0010:__exit_to_user_mode_loop kernel/entry/common.c:54 [inline]
RIP: 0010:exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
RIP: 0010:__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
RIP: 0010:irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
RIP: 0010:irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
RIP: 0010:irqentry_exit+0x484/0x8f0 kernel/entry/common.c:165
Code: 00 00 00 00 00 0f 01 ca c6 83 59 16 00 00 00 0f 1f 44 00 00 48 83 3c 24 00 0f 85 46 01 00 00 e8 02 e5 fc f5 e9 d4 fe ff ff 90 <0f> 0b 90 e9 74 ff ff ff 48 89 df e8 9c e4 fc f5 41 89 c7 89 44 24
RSP: 0000:ffffc90003c9fef0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: ffff88810d470000 RCX: 0000000000000046
RDX: 0000000000000000 RSI: ffffffff8e167570 RDI: ffffffff8c321580
RBP: 00000000ffffe000 R08: ffffffff90608537 R09: 1ffffffff20c10a6
R10: dffffc0000000000 R11: fffffbfff20c10a7 R12: ffff88810d471648
R13: 0000000000001010 R14: ffffc90003c9ff48 R15: 0000000000001388
FS: 000055558794e400(0000) GS:ffff8881a50f5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1060ef0fe8 CR3: 00000001fcd34000 CR4: 0000000000352ef0
Call Trace:
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0033:0x7f1060f019ab
Code: 00 00 e8 f8 2e 00 00 45 31 c0 31 c9 31 c0 ba 01 00 00 00 be 02 00 00 00 bf 4f 00 00 00 e8 7d de 01 00 85 c0 75 0a c6 43 1c 01 <c6> 43 1c 01 eb f6 e8 0a 29 00 00 8b 38 e8 33 55 01 00 48 8d 3d 74
RSP: 002b:00007f1060ef0ff0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00005555879507c0 RCX: 00007f1060f1f82a
RDX: 0000000000000001 RSI: 0000000000000002 RDI: 000000000000004f
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe9234cc68
R13: 0000000000000002 R14: 00007f1060fa2cc0 R15: 0000000000000002
</TASK>
CandidateReproduced:true ConsoleOutput:[ 109.999112][ T33] kauditd_printk_skb: 10 callbacks suppressed
[ 109.999127][ T33] audit: type=1400 audit(1786539375.703:201): avc: denied { transition } for pid=5831 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
[ 110.015852][ T33] audit: type=1400 audit(1786539375.703:202): avc: denied { noatsecure } for pid=5831 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 110.028316][ T33] audit: type=1400 audit(1786539375.703:203): avc: denied { rlimitinh } for pid=5831 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 110.044679][ T33] audit: type=1400 audit(1786539375.703:204): avc: denied { siginh } for pid=5831 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 113.238950][ T33] audit: type=1400 audit(1786539378.943:205): avc: denied { write } for pid=5839 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
[ 113.318891][ T33] audit: type=1400 audit(1786539379.023:206): avc: denied { write } for pid=5843 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
[ 114.085808][ T33] audit: type=1400 audit(1786539379.783:207): avc: denied { write } for pid=5848 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
[ 114.191779][ T33] audit: type=1400 audit(1786539379.893:208): avc: denied { write } for pid=5851 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
[ 114.382518][ T33] audit: type=1400 audit(1786539380.083:209): avc: denied { write } for pid=5854 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
[ 114.479526][ T33] audit: type=1400 audit(1786539380.183:210): avc: denied { write } for pid=5857 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
[ 115.465890][ T33] kauditd_printk_skb: 2 callbacks suppressed
[ 115.465905][ T33] audit: type=1400 audit(1786539381.163:213): avc: denied { write } for pid=5866 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
[ 115.574718][ T33] audit: type=1400 audit(1786539381.273:214): avc: denied { write } for pid=5869 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
[ 115.726078][ T33] audit: type=1400 audit(1786539381.423:215): avc: denied { write } for pid=5872 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
[ 115.824621][ T33] audit: type=1400 audit(1786539381.523:216): avc: denied { write } for pid=5875 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
[ 116.082243][ T33] audit: type=1400 audit(1786539381.783:217): avc: denied { write } for pid=5878 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
[ 116.230021][ T33] audit: type=1400 audit(1786539381.933:218): avc: denied { write } for pid=5881 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
[ 116.385628][ T33] audit: type=1400 audit(1786539382.083:219): avc: denied { write } for pid=5885 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
[ 116.496382][ T33] audit: type=1400 audit(1786539382.193:220): 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
Warning: Permanently added '[localhost]:43074' (ED25519) to the list of known hosts.
[ 117.215890][ T5899] ------------[ cut here ]------------
[ 117.220102][ T5899] __lockdep_enabled && this_cpu_read(hardirqs_enabled)
[ 117.220118][ T5899] WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit+0x484/0x8f0, CPU#0: syz-executor381/5899
[ 117.233082][ T5899] Modules linked in:
[ 117.234807][ T5899] CPU: 0 UID: 0 PID: 5899 Comm: syz-executor381 Not tainted syzkaller #1 PREEMPT(full)
[ 117.242285][ T5899] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 117.250439][ T5899] RIP: 0010:irqentry_exit+0x484/0x8f0
[ 117.254177][ T5899] Code: 00 00 00 00 00 0f 01 ca c6 83 59 16 00 00 00 0f 1f 44 00 00 48 83 3c 24 00 0f 85 46 01 00 00 e8 02 e5 fc f5 e9 d4 fe ff ff 90 <0f> 0b 90 e9 74 ff ff ff 48 89 df e8 9c e4 fc f5 41 89 c7 89 44 24
[ 117.265339][ T5899] RSP: 0000:ffffc90003c9fef0 EFLAGS: 00010202
[ 117.269110][ T5899] RAX: 0000000000000001 RBX: ffff88810d470000 RCX: 0000000000000046
[ 117.274644][ T5899] RDX: 0000000000000000 RSI: ffffffff8e167570 RDI: ffffffff8c321580
[ 117.281033][ T5899] RBP: 00000000ffffe000 R08: ffffffff90608537 R09: 1ffffffff20c10a6
[ 117.285573][ T5899] R10: dffffc0000000000 R11: fffffbfff20c10a7 R12: ffff88810d471648
[ 117.292188][ T5899] R13: 0000000000001010 R14: ffffc90003c9ff48 R15: 0000000000001388
[ 117.298144][ T5899] FS: 000055558794e400(0000) GS:ffff8881a50f5000(0000) knlGS:0000000000000000
[ 117.304090][ T5899] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 117.308030][ T5899] CR2: 00007f1060ef0fe8 CR3: 00000001fcd34000 CR4: 0000000000352ef0
[ 117.312446][ T5899] Call Trace:
[ 117.316782][ T5899] <TASK>
[ 117.317987][ T5899] asm_sysvec_apic_timer_interrupt+0x1a/0x20
[ 117.323184][ T5899] RIP: 0033:0x7f1060f019ab
[ 117.326070][ T5899] Code: 00 00 e8 f8 2e 00 00 45 31 c0 31 c9 31 c0 ba 01 00 00 00 be 02 00 00 00 bf 4f 00 00 00 e8 7d de 01 00 85 c0 75 0a c6 43 1c 01 <c6> 43 1c 01 eb f6 e8 0a 29 00 00 8b 38 e8 33 55 01 00 48 8d 3d 74
[ 117.337060][ T5899] RSP: 002b:00007f1060ef0ff0 EFLAGS: 00000246
[ 117.341051][ T5899] RAX: 0000000000000000 RBX: 00005555879507c0 RCX: 00007f1060f1f82a
[ 117.345926][ T5899] RDX: 0000000000000001 RSI: 0000000000000002 RDI: 000000000000004f
[ 117.350832][ T5899] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[ 117.354338][ T5899] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe9234cc68
[ 117.359404][ T5899] R13: 0000000000000002 R14: 00007f1060fa2cc0 R15: 0000000000000002
[ 117.363067][ T5899] </TASK>
[ 117.364997][ T5899] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 117.369695][ T5899] CPU: 0 UID: 0 PID: 5899 Comm: syz-executor381 Not tainted syzkaller #1 PREEMPT(full)
[ 117.375464][ T5899] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 117.381423][ T5899] Call Trace:
[ 117.382935][ T5899] <TASK>
[ 117.384820][ T5899] vpanic+0x56c/0xa60
[ 117.387239][ T5899] ? __pfx__printk+0x10/0x10
[ 117.390392][ T5899] ? __pfx_vpanic+0x10/0x10
[ 117.392180][ T5899] ? is_bpf_text_address+0x292/0x2b0
[ 117.394530][ T5899] ? is_bpf_text_address+0x26/0x2b0
[ 117.396508][ T5899] panic+0xc5/0xd0
[ 117.397796][ T5899] ? __pfx_panic+0x10/0x10
[ 117.400814][ T5899] __warn+0x315/0x4c0
[ 117.403259][ T5899] ? irqentry_exit+0x484/0x8f0
[ 117.405632][ T5899] ? irqentry_exit+0x484/0x8f0
[ 117.408479][ T5899] __report_bug+0x276/0x570
[ 117.411420][ T5899] ? irqentry_exit+0x484/0x8f0
[ 117.413276][ T5899] ? __pfx___report_bug+0x10/0x10
[ 117.415441][ T5899] ? ktime_get_update_offsets_now+0x5d/0x3e0
[ 117.418006][ T5899] ? __hrtimer_get_next_event+0x51c/0x600
[ 117.421050][ T5899] ? irqentry_exit+0x484/0x8f0
[ 117.423418][ T5899] report_bug+0x16a/0x220
[ 117.425241][ T5899] ? irqentry_exit+0x484/0x8f0
[ 117.427076][ T5899] ? irqentry_exit+0x486/0x8f0
[ 117.429863][ T5899] handle_bug+0x9c/0x200
[ 117.432056][ T5899] exc_invalid_op+0x1a/0x50
[ 117.433995][ T5899] asm_exc_invalid_op+0x1a/0x20
[ 117.436083][ T5899] RIP: 0010:irqentry_exit+0x484/0x8f0
[ 117.439251][ T5899] Code: 00 00 00 00 00 0f 01 ca c6 83 59 16 00 00 00 0f 1f 44 00 00 48 83 3c 24 00 0f 85 46 01 00 00 e8 02 e5 fc f5 e9 d4 fe ff ff 90 <0f> 0b 90 e9 74 ff ff ff 48 89 df e8 9c e4 fc f5 41 89 c7 89 44 24
[ 117.449132][ T5899] RSP: 0000:ffffc90003c9fef0 EFLAGS: 00010202
[ 117.451954][ T5899] RAX: 0000000000000001 RBX: ffff88810d470000 RCX: 0000000000000046
[ 117.456566][ T5899] RDX: 0000000000000000 RSI: ffffffff8e167570 RDI: ffffffff8c321580
[ 117.460237][ T5899] RBP: 00000000ffffe000 R08: ffffffff90608537 R09: 1ffffffff20c10a6
[ 117.465088][ T5899] R10: dffffc0000000000 R11: fffffbfff20c10a7 R12: ffff88810d471648
[ 117.470108][ T5899] R13: 0000000000001010 R14: ffffc90003c9ff48 R15: 0000000000001388
[ 117.474874][ T5899] asm_sysvec_apic_timer_interrupt+0x1a/0x20
[ 117.477283][ T5899] RIP: 0033:0x7f1060f019ab
[ 117.479833][ T5899] Code: 00 00 e8 f8 2e 00 00 45 31 c0 31 c9 31 c0 ba 01 00 00 00 be 02 00 00 00 bf 4f 00 00 00 e8 7d de 01 00 85 c0 75 0a c6 43 1c 01 <c6> 43 1c 01 eb f6 e8 0a 29 00 00 8b 38 e8 33 55 01 00 48 8d 3d 74
[ 117.491470][ T5899] RSP: 002b:00007f1060ef0ff0 EFLAGS: 00000246
[ 117.494966][ T5899] RAX: 0000000000000000 RBX: 00005555879507c0 RCX: 00007f1060f1f82a
[ 117.499322][ T5899] RDX: 0000000000000001 RSI: 0000000000000002 RDI: 000000000000004f
[ 117.504560][ T5899] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[ 117.509391][ T5899] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe9234cc68
[ 117.513961][ T5899] R13: 0000000000000002 R14: 00007f1060fa2cc0 R15: 0000000000000002
[ 117.519344][ T5899] </TASK>
[ 117.522695][ T5899] Kernel Offset: disabled
[ 117.525876][ T5899] Rebooting in 86400 seconds..
OtherCrashReports:<nil> StraceOutput: TestError:]
|
| 166/3 |
2026/08/12 12:56 |
action |
truncate-log |
0m
Results: map[TruncatedConsoleOutput:[ 109.999112][ T33] kauditd_printk_skb: 10 callbacks suppressed
[ 109.999127][ T33] audit: type=1400 audit(1786539375.703:201): avc: denied { transition } for pid=5831 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
[ 110.015852][ T33] audit: type=1400 audit(1786539375.703:202): avc: denied { noatsecure } for pid=5831 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 110.028316][ T33] audit: type=1400 audit(1786539375.703:203): avc: denied { rlimitinh } for pid=5831 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 110.044679][ T33] audit: type=1400 audit(1786539375.703:204): avc: denied { siginh } for pid=5831 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 113.238950][ T33] audit: type=1400 audit(1786539378.943:205): avc: denied { write } for pid=5839 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
[ 113.318891][ T33] audit: type=1400 audit(1786539379.023:206): avc: denied { write } for pid=5843 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
[ 114.085808][ T33] audit: type=1400 audit(1786539379.783:207): avc: denied { write } for pid=5848 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
[ 114.191779][ T33] audit: type=1400 audit(1786539379.893:208): avc: denied { write } for pid=5851 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
[ 114.382518][ T33] audit: type=1400 audit(1786539380.083:209): avc: denied { write } for pid=5854 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
[ 114.479526][ T33] audit: type=1400 audit(1786539380.183:210): avc: denied { write } for pid=5857 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
[ 115.465890][ T33] kauditd_printk_skb: 2 callbacks suppressed
[ 115.465905][ T33] audit: type=1400 audit(1786539381.163:213): avc: denied { write } for pid=5866 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
[ 115.574718][ T33] audit: type=1400 audit(1786539381.273:214): avc: denied { write } for pid=5869 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
[ 115.726078][ T33] audit: type=1400 audit(1786539381.423:215): avc: denied { write } for pid=5872 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
[ 115.824621][ T33] audit: type=1400 audit(1786539381.523:216): avc: denied { write } for pid=5875 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
[ 116.082243][ T33] audit: type=1400 audit(1786539381.783:217): avc: denied { write } for pid=5878 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
[ 116.230021][ T33] audit: type=1400 audit(1786539381.933:218): avc: denied { write } for pid=5881 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
[ 116.385628][ T33] audit: type=1400 audit(1786539382.083:219): avc: denied { write } for pid=5885 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
[ 116.496382][ T33] audit: type=1400 audit(1786539382.193:220): 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
Warning: Permanently added '[localhost]:43074' (ED25519) to the list of known hosts.
[ 117.215890][ T5899] ------------[ cut here ]------------
[ 117.220102][ T5899] __lockdep_enabled && this_cpu_read(hardirqs_enabled)
[ 117.220118][ T5899] WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit+0x484/0x8f0, CPU#0: syz-executor381/5899
[ 117.233082][ T5899] Modules linked in:
[ 117.234807][ T5899] CPU: 0 UID: 0 PID: 5899 Comm: syz-executor381 Not tainted syzkaller #1 PREEMPT(full)
[ 117.242285][ T5899] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 117.250439][ T5899] RIP: 0010:irqentry_exit+0x484/0x8f0
[ 117.254177][ T5899] Code: 00 00 00 00 00 0f 01 ca c6 83 59 16 00 00 00 0f 1f 44 00 00 48 83 3c 24 00 0f 85 46 01 00 00 e8 02 e5 fc f5 e9 d4 fe ff ff 90 <0f> 0b 90 e9 74 ff ff ff 48 89 df e8 9c e4 fc f5 41 89 c7 89 44 24
[ 117.265339][ T5899] RSP: 0000:ffffc90003c9fef0 EFLAGS: 00010202
[ 117.269110][ T5899] RAX: 0000000000000001 RBX: ffff88810d470000 RCX: 0000000000000046
[ 117.274644][ T5899] RDX: 0000000000000000 RSI: ffffffff8e167570 RDI: ffffffff8c321580
[ 117.281033][ T5899] RBP: 00000000ffffe000 R08: ffffffff90608537 R09: 1ffffffff20c10a6
[ 117.285573][ T5899] R10: dffffc0000000000 R11: fffffbfff20c10a7 R12: ffff88810d471648
[ 117.292188][ T5899] R13: 0000000000001010 R14: ffffc90003c9ff48 R15: 0000000000001388
[ 117.298144][ T5899] FS: 000055558794e400(0000) GS:ffff8881a50f5000(0000) knlGS:0000000000000000
[ 117.304090][ T5899] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 117.308030][ T5899] CR2: 00007f1060ef0fe8 CR3: 00000001fcd34000 CR4: 0000000000352ef0
[ 117.312446][ T5899] Call Trace:
[ 117.316782][ T5899] <TASK>
[ 117.317987][ T5899] asm_sysvec_apic_timer_interrupt+0x1a/0x20
[ 117.323184][ T5899] RIP: 0033:0x7f1060f019ab
[ 117.326070][ T5899] Code: 00 00 e8 f8 2e 00 00 45 31 c0 31 c9 31 c0 ba 01 00 00 00 be 02 00 00 00 bf 4f 00 00 00 e8 7d de 01 00 85 c0 75 0a c6 43 1c 01 <c6> 43 1c 01 eb f6 e8 0a 29 00 00 8b 38 e8 33 55 01 00 48 8d 3d 74
[ 117.337060][ T5899] RSP: 002b:00007f1060ef0ff0 EFLAGS: 00000246
[ 117.341051][ T5899] RAX: 0000000000000000 RBX: 00005555879507c0 RCX: 00007f1060f1f82a
[ 117.345926][ T5899] RDX: 0000000000000001 RSI: 0000000000000002 RDI: 000000000000004f
[ 117.350832][ T5899] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[ 117.354338][ T5899] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe9234cc68
[ 117.359404][ T5899] R13: 0000000000000002 R14: 00007f1060fa2cc0 R15: 0000000000000002
[ 117.363067][ T5899] </TASK>
[ 117.364997][ T5899] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 117.369695][ T5899] CPU: 0 UID: 0 PID: 5899 Comm: syz-executor381 Not tainted syzkaller #1 PREEMPT(full)
[ 117.375464][ T5899] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 117.381423][ T5899] Call Trace:
[ 117.382935][ T5899] <TASK>
[ 117.384820][ T5899] vpanic+0x56c/0xa60
[ 117.387239][ T5899] ? __pfx__printk+0x10/0x10
[ 117.390392][ T5899] ? __pfx_vpanic+0x10/0x10
[ 117.392180][ T5899] ? is_bpf_text_address+0x292/0x2b0
[ 117.394530][ T5899] ? is_bpf_text_address+0x26/0x2b0
[ 117.396508][ T5899] panic+0xc5/0xd0
[ 117.397796][ T5899] ? __pfx_panic+0x10/0x10
[ 117.400814][ T5899] __warn+0x315/0x4c0
[ 117.403259][ T5899] ? irqentry_exit+0x484/0x8f0
[ 117.405632][ T5899] ? irqentry_exit+0x484/0x8f0
[ 117.408479][ T5899] __report_bug+0x276/0x570
[ 117.411420][ T5899] ? irqentry_exit+0x484/0x8f0
[ 117.413276][ T5899] ? __pfx___report_bug+0x10/0x10
[ 117.415441][ T5899] ? ktime_get_update_offsets_now+0x5d/0x3e0
[ 117.418006][ T5899] ? __hrtimer_get_next_event+0x51c/0x600
[ 117.421050][ T5899] ? irqentry_exit+0x484/0x8f0
[ 117.423418][ T5899] report_bug+0x16a/0x220
[ 117.425241][ T5899] ? irqentry_exit+0x484/0x8f0
[ 117.427076][ T5899] ? irqentry_exit+0x486/0x8f0
[ 117.429863][ T5899] handle_bug+0x9c/0x200
[ 117.432056][ T5899] exc_invalid_op+0x1a/0x50
[ 117.433995][ T5899] asm_exc_invalid_op+0x1a/0x20
[ 117.436083][ T5899] RIP: 0010:irqentry_exit+0x484/0x8f0
[ 117.439251][ T5899] Code: 00 00 00 00 00 0f 01 ca c6 83 59 16 00 00 00 0f 1f 44 00 00 48 83 3c 24 00 0f 85 46 01 00 00 e8 02 e5 fc f5 e9 d4 fe ff ff 90 <0f> 0b 90 e9 74 ff ff ff 48 89 df e8 9c e4 fc f5 41 89 c7 89 44 24
[ 117.449132][ T5899] RSP: 0000:ffffc90003c9fef0 EFLAGS: 00010202
[ 117.451954][ T5899] RAX: 0000000000000001 RBX: ffff88810d470000 RCX: 0000000000000046
[ 117.456566][ T5899] RDX: 0000000000000000 RSI: ffffffff8e167570 RDI: ffffffff8c321580
[ 117.460237][ T5899] RBP: 00000000ffffe000 R08: ffffffff90608537 R09: 1ffffffff20c10a6
[ 117.465088][ T5899] R10: dffffc0000000000 R11: fffffbfff20c10a7 R12: ffff88810d471648
[ 117.470108][ T5899] R13: 0000000000001010 R14: ffffc90003c9ff48 R15: 0000000000001388
[ 117.474874][ T5899] asm_sysvec_apic_timer_interrupt+0x1a/0x20
[ 117.477283][ T5899] RIP: 0033:0x7f1060f019ab
[ 117.479833][ T5899] Code: 00 00 e8 f8 2e 00 00 45 31 c0 31 c9 31 c0 ba 01 00 00 00 be 02 00 00 00 bf 4f 00 00 00 e8 7d de 01 00 85 c0 75 0a c6 43 1c 01 <c6> 43 1c 01 eb f6 e8 0a 29 00 00 8b 38 e8 33 55 01 00 48 8d 3d 74
[ 117.491470][ T5899] RSP: 002b:00007f1060ef0ff0 EFLAGS: 00000246
[ 117.494966][ T5899] RAX: 0000000000000000 RBX: 00005555879507c0 RCX: 00007f1060f1f82a
[ 117.499322][ T5899] RDX: 0000000000000001 RSI: 0000000000000002 RDI: 000000000000004f
[ 117.504560][ T5899] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[ 117.509391][ T5899] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe9234cc68
[ 117.513961][ T5899] R13: 0000000000000002 R14: 00007f1060fa2cc0 R15: 0000000000000002
[ 117.519344][ T5899] </TASK>
[ 117.522695][ T5899] Kernel Offset: disabled
[ 117.525876][ T5899] Rebooting in 86400 seconds..
TruncatedCrashReport:------------[ cut here ]------------
__lockdep_enabled && this_cpu_read(hardirqs_enabled)
WARNING: include/linux/hrtimer_rearm.h:17 at hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_loop kernel/entry/common.c:54 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at exit_to_user_mode_loop kernel/entry/common.c:101 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit+0x484/0x8f0 kernel/entry/common.c:165, CPU#0: syz-executor381/5899
Modules linked in:
CPU: 0 UID: 0 PID: 5899 Comm: syz-executor381 Not tainted syzkaller #1 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline]
RIP: 0010:hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline]
RIP: 0010:rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline]
RIP: 0010:__exit_to_user_mode_loop kernel/entry/common.c:54 [inline]
RIP: 0010:exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
RIP: 0010:__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
RIP: 0010:irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
RIP: 0010:irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
RIP: 0010:irqentry_exit+0x484/0x8f0 kernel/entry/common.c:165
Code: 00 00 00 00 00 0f 01 ca c6 83 59 16 00 00 00 0f 1f 44 00 00 48 83 3c 24 00 0f 85 46 01 00 00 e8 02 e5 fc f5 e9 d4 fe ff ff 90 <0f> 0b 90 e9 74 ff ff ff 48 89 df e8 9c e4 fc f5 41 89 c7 89 44 24
RSP: 0000:ffffc90003c9fef0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: ffff88810d470000 RCX: 0000000000000046
RDX: 0000000000000000 RSI: ffffffff8e167570 RDI: ffffffff8c321580
RBP: 00000000ffffe000 R08: ffffffff90608537 R09: 1ffffffff20c10a6
R10: dffffc0000000000 R11: fffffbfff20c10a7 R12: ffff88810d471648
R13: 0000000000001010 R14: ffffc90003c9ff48 R15: 0000000000001388
FS: 000055558794e400(0000) GS:ffff8881a50f5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1060ef0fe8 CR3: 00000001fcd34000 CR4: 0000000000352ef0
Call Trace:
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0033:0x7f1060f019ab
Code: 00 00 e8 f8 2e 00 00 45 31 c0 31 c9 31 c0 ba 01 00 00 00 be 02 00 00 00 bf 4f 00 00 00 e8 7d de 01 00 85 c0 75 0a c6 43 1c 01 <c6> 43 1c 01 eb f6 e8 0a 29 00 00 8b 38 e8 33 55 01 00 48 8d 3d 74
RSP: 002b:00007f1060ef0ff0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00005555879507c0 RCX: 00007f1060f1f82a
RDX: 0000000000000001 RSI: 0000000000000002 RDI: 000000000000004f
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe9234cc68
R13: 0000000000000002 R14: 00007f1060fa2cc0 R15: 0000000000000002
</TASK>
TruncatedStraceOutput:]
|
| 167/3 |
2026/08/12 12:56 |
agent |
repro-oracle |
0m
Model:
Results: map[Feedback:The reproducer successfully triggered the exact bug. The crash report shows the same WARNING in irqentry_exit originating from hrtimer_test_and_clear_rearm_deferred_tif as the original bug description. The call traces match perfectly. ProbePassed:false TerminalError: TitleMatches:true]
Instruction: 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.
Prompt: Bug Description: WARNING in irqentry_exit
------------[ cut here ]------------
__lockdep_enabled && this_cpu_read(hardirqs_enabled)
WARNING: ./include/linux/hrtimer_rearm.h:17 at hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_loop kernel/entry/common.c:54 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at exit_to_user_mode_loop kernel/entry/common.c:101 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline], CPU#0: syz.2.3762/30761
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit+0x718/0xa00 kernel/entry/common.c:165, CPU#0: syz.2.3762/30761
Modules linked in:
CPU: 0 UID: 0 PID: 30761 Comm: syz.2.3762 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:hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline]
RIP: 0010:hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline]
RIP: 0010:rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline]
RIP: 0010:__exit_to_user_mode_loop kernel/entry/common.c:54 [inline]
RIP: 0010:exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
RIP: 0010:__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
RIP: 0010:irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
RIP: 0010:irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
RIP: 0010:irqentry_exit+0x718/0xa00 kernel/entry/common.c:165
Code: 00 00 00 80 e8 c9 ee 58 f6 fb 83 3d 95 d1 69 05 00 74 1a 65 8b 05 d8 2a ab 08 85 c0 75 0f 65 8b 05 29 26 ab 08 85 c0 74 04 90 <0f> 0b 90 41 f7 c5 00 10 00 00 0f 84 74 fc ff ff f0 41 80 64 24 01
RSP: 0000:ffffc9000414ff00 EFLAGS: 00010202
RAX: 0000000000000001 RBX: ffffc9000414ff48 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8e1a8f2e RDI: ffffffff8c400a80
RBP: ffffc9000414ff38 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888022f39f00
R13: 0000000000000010 R14: 000001efbbd43bba R15: 0000000000000000
FS: 00007f3e64dd56c0(0000) GS:ffff888123de1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ddddff8 CR3: 0000000034bd6000 CR4: 00000000003526f0
Call Trace:
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0033:0x7f3e66b9e019
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:00007f3e64dd50e8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f3e66e26098 RCX: 00007f3e66b9e019
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3e66e26098
RBP: 00007f3e66e26090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3e66e26128 R14: 00007ffe410c4bf0 R15: 00007ffe410c4cd8
</TASK>
IsProbe: false
Reproduced: true
Console Output: [ 109.999112][ T33] kauditd_printk_skb: 10 callbacks suppressed
[ 109.999127][ T33] audit: type=1400 audit(1786539375.703:201): avc: denied { transition } for pid=5831 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
[ 110.015852][ T33] audit: type=1400 audit(1786539375.703:202): avc: denied { noatsecure } for pid=5831 comm="sshd-session" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 110.028316][ T33] audit: type=1400 audit(1786539375.703:203): avc: denied { rlimitinh } for pid=5831 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 110.044679][ T33] audit: type=1400 audit(1786539375.703:204): avc: denied { siginh } for pid=5831 comm="sh" scontext=system_u:system_r:sshd_t tcontext=root:sysadm_r:sysadm_t tclass=process permissive=1
[ 113.238950][ T33] audit: type=1400 audit(1786539378.943:205): avc: denied { write } for pid=5839 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
[ 113.318891][ T33] audit: type=1400 audit(1786539379.023:206): avc: denied { write } for pid=5843 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
[ 114.085808][ T33] audit: type=1400 audit(1786539379.783:207): avc: denied { write } for pid=5848 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
[ 114.191779][ T33] audit: type=1400 audit(1786539379.893:208): avc: denied { write } for pid=5851 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
[ 114.382518][ T33] audit: type=1400 audit(1786539380.083:209): avc: denied { write } for pid=5854 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
[ 114.479526][ T33] audit: type=1400 audit(1786539380.183:210): avc: denied { write } for pid=5857 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
[ 115.465890][ T33] kauditd_printk_skb: 2 callbacks suppressed
[ 115.465905][ T33] audit: type=1400 audit(1786539381.163:213): avc: denied { write } for pid=5866 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
[ 115.574718][ T33] audit: type=1400 audit(1786539381.273:214): avc: denied { write } for pid=5869 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
[ 115.726078][ T33] audit: type=1400 audit(1786539381.423:215): avc: denied { write } for pid=5872 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
[ 115.824621][ T33] audit: type=1400 audit(1786539381.523:216): avc: denied { write } for pid=5875 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
[ 116.082243][ T33] audit: type=1400 audit(1786539381.783:217): avc: denied { write } for pid=5878 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
[ 116.230021][ T33] audit: type=1400 audit(1786539381.933:218): avc: denied { write } for pid=5881 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
[ 116.385628][ T33] audit: type=1400 audit(1786539382.083:219): avc: denied { write } for pid=5885 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
[ 116.496382][ T33] audit: type=1400 audit(1786539382.193:220): 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
Warning: Permanently added '[localhost]:43074' (ED25519) to the list of known hosts.
[ 117.215890][ T5899] ------------[ cut here ]------------
[ 117.220102][ T5899] __lockdep_enabled && this_cpu_read(hardirqs_enabled)
[ 117.220118][ T5899] WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit+0x484/0x8f0, CPU#0: syz-executor381/5899
[ 117.233082][ T5899] Modules linked in:
[ 117.234807][ T5899] CPU: 0 UID: 0 PID: 5899 Comm: syz-executor381 Not tainted syzkaller #1 PREEMPT(full)
[ 117.242285][ T5899] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 117.250439][ T5899] RIP: 0010:irqentry_exit+0x484/0x8f0
[ 117.254177][ T5899] Code: 00 00 00 00 00 0f 01 ca c6 83 59 16 00 00 00 0f 1f 44 00 00 48 83 3c 24 00 0f 85 46 01 00 00 e8 02 e5 fc f5 e9 d4 fe ff ff 90 <0f> 0b 90 e9 74 ff ff ff 48 89 df e8 9c e4 fc f5 41 89 c7 89 44 24
[ 117.265339][ T5899] RSP: 0000:ffffc90003c9fef0 EFLAGS: 00010202
[ 117.269110][ T5899] RAX: 0000000000000001 RBX: ffff88810d470000 RCX: 0000000000000046
[ 117.274644][ T5899] RDX: 0000000000000000 RSI: ffffffff8e167570 RDI: ffffffff8c321580
[ 117.281033][ T5899] RBP: 00000000ffffe000 R08: ffffffff90608537 R09: 1ffffffff20c10a6
[ 117.285573][ T5899] R10: dffffc0000000000 R11: fffffbfff20c10a7 R12: ffff88810d471648
[ 117.292188][ T5899] R13: 0000000000001010 R14: ffffc90003c9ff48 R15: 0000000000001388
[ 117.298144][ T5899] FS: 000055558794e400(0000) GS:ffff8881a50f5000(0000) knlGS:0000000000000000
[ 117.304090][ T5899] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 117.308030][ T5899] CR2: 00007f1060ef0fe8 CR3: 00000001fcd34000 CR4: 0000000000352ef0
[ 117.312446][ T5899] Call Trace:
[ 117.316782][ T5899] <TASK>
[ 117.317987][ T5899] asm_sysvec_apic_timer_interrupt+0x1a/0x20
[ 117.323184][ T5899] RIP: 0033:0x7f1060f019ab
[ 117.326070][ T5899] Code: 00 00 e8 f8 2e 00 00 45 31 c0 31 c9 31 c0 ba 01 00 00 00 be 02 00 00 00 bf 4f 00 00 00 e8 7d de 01 00 85 c0 75 0a c6 43 1c 01 <c6> 43 1c 01 eb f6 e8 0a 29 00 00 8b 38 e8 33 55 01 00 48 8d 3d 74
[ 117.337060][ T5899] RSP: 002b:00007f1060ef0ff0 EFLAGS: 00000246
[ 117.341051][ T5899] RAX: 0000000000000000 RBX: 00005555879507c0 RCX: 00007f1060f1f82a
[ 117.345926][ T5899] RDX: 0000000000000001 RSI: 0000000000000002 RDI: 000000000000004f
[ 117.350832][ T5899] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[ 117.354338][ T5899] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe9234cc68
[ 117.359404][ T5899] R13: 0000000000000002 R14: 00007f1060fa2cc0 R15: 0000000000000002
[ 117.363067][ T5899] </TASK>
[ 117.364997][ T5899] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 117.369695][ T5899] CPU: 0 UID: 0 PID: 5899 Comm: syz-executor381 Not tainted syzkaller #1 PREEMPT(full)
[ 117.375464][ T5899] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 117.381423][ T5899] Call Trace:
[ 117.382935][ T5899] <TASK>
[ 117.384820][ T5899] vpanic+0x56c/0xa60
[ 117.387239][ T5899] ? __pfx__printk+0x10/0x10
[ 117.390392][ T5899] ? __pfx_vpanic+0x10/0x10
[ 117.392180][ T5899] ? is_bpf_text_address+0x292/0x2b0
[ 117.394530][ T5899] ? is_bpf_text_address+0x26/0x2b0
[ 117.396508][ T5899] panic+0xc5/0xd0
[ 117.397796][ T5899] ? __pfx_panic+0x10/0x10
[ 117.400814][ T5899] __warn+0x315/0x4c0
[ 117.403259][ T5899] ? irqentry_exit+0x484/0x8f0
[ 117.405632][ T5899] ? irqentry_exit+0x484/0x8f0
[ 117.408479][ T5899] __report_bug+0x276/0x570
[ 117.411420][ T5899] ? irqentry_exit+0x484/0x8f0
[ 117.413276][ T5899] ? __pfx___report_bug+0x10/0x10
[ 117.415441][ T5899] ? ktime_get_update_offsets_now+0x5d/0x3e0
[ 117.418006][ T5899] ? __hrtimer_get_next_event+0x51c/0x600
[ 117.421050][ T5899] ? irqentry_exit+0x484/0x8f0
[ 117.423418][ T5899] report_bug+0x16a/0x220
[ 117.425241][ T5899] ? irqentry_exit+0x484/0x8f0
[ 117.427076][ T5899] ? irqentry_exit+0x486/0x8f0
[ 117.429863][ T5899] handle_bug+0x9c/0x200
[ 117.432056][ T5899] exc_invalid_op+0x1a/0x50
[ 117.433995][ T5899] asm_exc_invalid_op+0x1a/0x20
[ 117.436083][ T5899] RIP: 0010:irqentry_exit+0x484/0x8f0
[ 117.439251][ T5899] Code: 00 00 00 00 00 0f 01 ca c6 83 59 16 00 00 00 0f 1f 44 00 00 48 83 3c 24 00 0f 85 46 01 00 00 e8 02 e5 fc f5 e9 d4 fe ff ff 90 <0f> 0b 90 e9 74 ff ff ff 48 89 df e8 9c e4 fc f5 41 89 c7 89 44 24
[ 117.449132][ T5899] RSP: 0000:ffffc90003c9fef0 EFLAGS: 00010202
[ 117.451954][ T5899] RAX: 0000000000000001 RBX: ffff88810d470000 RCX: 0000000000000046
[ 117.456566][ T5899] RDX: 0000000000000000 RSI: ffffffff8e167570 RDI: ffffffff8c321580
[ 117.460237][ T5899] RBP: 00000000ffffe000 R08: ffffffff90608537 R09: 1ffffffff20c10a6
[ 117.465088][ T5899] R10: dffffc0000000000 R11: fffffbfff20c10a7 R12: ffff88810d471648
[ 117.470108][ T5899] R13: 0000000000001010 R14: ffffc90003c9ff48 R15: 0000000000001388
[ 117.474874][ T5899] asm_sysvec_apic_timer_interrupt+0x1a/0x20
[ 117.477283][ T5899] RIP: 0033:0x7f1060f019ab
[ 117.479833][ T5899] Code: 00 00 e8 f8 2e 00 00 45 31 c0 31 c9 31 c0 ba 01 00 00 00 be 02 00 00 00 bf 4f 00 00 00 e8 7d de 01 00 85 c0 75 0a c6 43 1c 01 <c6> 43 1c 01 eb f6 e8 0a 29 00 00 8b 38 e8 33 55 01 00 48 8d 3d 74
[ 117.491470][ T5899] RSP: 002b:00007f1060ef0ff0 EFLAGS: 00000246
[ 117.494966][ T5899] RAX: 0000000000000000 RBX: 00005555879507c0 RCX: 00007f1060f1f82a
[ 117.499322][ T5899] RDX: 0000000000000001 RSI: 0000000000000002 RDI: 000000000000004f
[ 117.504560][ T5899] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[ 117.509391][ T5899] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe9234cc68
[ 117.513961][ T5899] R13: 0000000000000002 R14: 00007f1060fa2cc0 R15: 0000000000000002
[ 117.519344][ T5899] </TASK>
[ 117.522695][ T5899] Kernel Offset: disabled
[ 117.525876][ T5899] Rebooting in 86400 seconds..
Strace Output:
Crash Report: ------------[ cut here ]------------
__lockdep_enabled && this_cpu_read(hardirqs_enabled)
WARNING: include/linux/hrtimer_rearm.h:17 at hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_loop kernel/entry/common.c:54 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at exit_to_user_mode_loop kernel/entry/common.c:101 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit+0x484/0x8f0 kernel/entry/common.c:165, CPU#0: syz-executor381/5899
Modules linked in:
CPU: 0 UID: 0 PID: 5899 Comm: syz-executor381 Not tainted syzkaller #1 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline]
RIP: 0010:hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline]
RIP: 0010:rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline]
RIP: 0010:__exit_to_user_mode_loop kernel/entry/common.c:54 [inline]
RIP: 0010:exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
RIP: 0010:__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
RIP: 0010:irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
RIP: 0010:irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
RIP: 0010:irqentry_exit+0x484/0x8f0 kernel/entry/common.c:165
Code: 00 00 00 00 00 0f 01 ca c6 83 59 16 00 00 00 0f 1f 44 00 00 48 83 3c 24 00 0f 85 46 01 00 00 e8 02 e5 fc f5 e9 d4 fe ff ff 90 <0f> 0b 90 e9 74 ff ff ff 48 89 df e8 9c e4 fc f5 41 89 c7 89 44 24
RSP: 0000:ffffc90003c9fef0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: ffff88810d470000 RCX: 0000000000000046
RDX: 0000000000000000 RSI: ffffffff8e167570 RDI: ffffffff8c321580
RBP: 00000000ffffe000 R08: ffffffff90608537 R09: 1ffffffff20c10a6
R10: dffffc0000000000 R11: fffffbfff20c10a7 R12: ffff88810d471648
R13: 0000000000001010 R14: ffffc90003c9ff48 R15: 0000000000001388
FS: 000055558794e400(0000) GS:ffff8881a50f5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1060ef0fe8 CR3: 00000001fcd34000 CR4: 0000000000352ef0
Call Trace:
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0033:0x7f1060f019ab
Code: 00 00 e8 f8 2e 00 00 45 31 c0 31 c9 31 c0 ba 01 00 00 00 be 02 00 00 00 bf 4f 00 00 00 e8 7d de 01 00 85 c0 75 0a c6 43 1c 01 <c6> 43 1c 01 eb f6 e8 0a 29 00 00 8b 38 e8 33 55 01 00 48 8d 3d 74
RSP: 002b:00007f1060ef0ff0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00005555879507c0 RCX: 00007f1060f1f82a
RDX: 0000000000000001 RSI: 0000000000000002 RDI: 000000000000004f
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe9234cc68
R13: 0000000000000002 R14: 00007f1060fa2cc0 R15: 0000000000000002
</TASK>
|
| 168/4 |
2026/08/12 12:56 |
llm |
repro-oracle |
0m
Model:
Tokens:
input: 14428
output: 83
thoughts: 838
Thoughts: **Analyzing the reproducer results and identifying the bug**
My primary objective here is to analyze the output from a reproducer run, specifically focusing on a crash report. The bug description points to a `WARNING in irqentry_exit` that originates from the `hrtimer_test_and_clear_rearm_deferred_tif` function, located in `include/linux/hrtimer_rearm.h:17`. The reproducer, as intended, has indeed triggered a crash.
Upon examining the crash report, I see a chain of `WARNING` messages that directly correspond to the bug description. The crucial part is the consistent appearance of `WARNING: include/linux/hrtimer_rearm.h:17 at hrtimer_test_and_clear_rearm_deferred_tif`. This is an exact match to the bug's origin point. The call trace provided further elaborates on how this warning is reached, showing its propagation through functions like `hrtimer_rearm_deferred_tif`, `rseq_grant_slice_extension`, `exit_to_user_mode_loop`, and ultimately `irqentry_exit`.
Given this precise match, I am confident in my assessment. I will proceed to use the `set-results` function with the following parameters: `TitleMatches: true` because the observed warning exactly matches the title of the bug, and `ProbePassed: false` as this is a crash reproducer, not a probe. The feedback provided will explicitly state that the reproducer successfully triggered the exact bug, detailing that the crash report displays the same `WARNING in irqentry_exit` originating from `hrtimer_test_and_clear_rearm_deferred_tif` as specified in the original bug description. I also note that `IsProbe: false` is a requirement, which confirms `ProbePassed` should be `false`.
|
| 169/4 |
2026/08/12 12:56 |
tool |
set-results |
0m
Args: map[Feedback:The reproducer successfully triggered the exact bug. The crash report shows the same WARNING in irqentry_exit originating from hrtimer_test_and_clear_rearm_deferred_tif as the original bug description. The call traces match perfectly. ProbePassed:false TerminalError: TitleMatches:true]
Results: map[Feedback:The reproducer successfully triggered the exact bug. The crash report shows the same WARNING in irqentry_exit originating from hrtimer_test_and_clear_rearm_deferred_tif as the original bug description. The call traces match perfectly. ProbePassed:false TerminalError: TitleMatches:true]
|
| 170/3 |
2026/08/12 12:56 |
action |
loop-controller |
0m
Results: map[CapabilitiesVerified:true ContinueSignal: EquivalenceAnalysis:The reproducer successfully triggered the exact bug. The crash report shows the same WARNING in irqentry_exit originating from hrtimer_test_and_clear_rearm_deferred_tif as the original bug description. The call traces match perfectly. OracleFeedback:The reproducer successfully triggered the exact bug. The crash report shows the same WARNING in irqentry_exit originating from hrtimer_test_and_clear_rearm_deferred_tif as the original bug description. The call traces match perfectly. ReproC:#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/prctl.h>
#include <stdint.h>
#include <sched.h>
#include <string.h>
#include <errno.h>
#ifndef PR_RSEQ_SLICE_EXTENSION
# define PR_RSEQ_SLICE_EXTENSION 79
# define PR_RSEQ_SLICE_EXTENSION_SET 2
# define PR_RSEQ_SLICE_EXT_ENABLE 0x01
#endif
#ifndef SYS_rseq
#define SYS_rseq 334
#endif
struct my_rseq_slice_ctrl {
union {
uint32_t all;
struct {
uint8_t request;
uint8_t granted;
uint16_t __reserved;
};
};
};
struct my_rseq {
uint32_t cpu_id_start;
uint32_t cpu_id;
uint64_t rseq_cs;
uint32_t flags;
uint32_t node_id;
uint32_t mm_cid;
struct my_rseq_slice_ctrl slice_ctrl;
uint8_t __reserved;
char end[];
} __attribute__((aligned(64)));
int thread_fn(void *arg) {
struct my_rseq *rseq_area = NULL;
if (posix_memalign((void **)&rseq_area, 64, sizeof(struct my_rseq)) != 0) {
printf("[-] posix_memalign failed: %s\n", strerror(errno));
exit(1);
}
memset(rseq_area, 0, sizeof(struct my_rseq));
/* Register our custom RSEQ area */
int ret = syscall(SYS_rseq, rseq_area, sizeof(struct my_rseq), 0, 0x53053053);
if (ret != 0) {
printf("[-] rseq syscall failed: %s\n", strerror(errno));
exit(1);
}
/* Enable the RSEQ time slice extension feature */
if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET, PR_RSEQ_SLICE_EXT_ENABLE, 0, 0) != 0) {
printf("[-] prctl PR_RSEQ_SLICE_EXTENSION failed: %s\n", strerror(errno));
exit(1);
}
/*
* Spin in user space requesting a slice extension.
* A timer interrupt will eventually hit, set _TIF_NEED_RESCHED,
* and trigger the lockdep warning on return to user space.
*/
while (1) {
rseq_area->slice_ctrl.request = 1;
/* Prevent compiler from optimizing out the store */
asm volatile("" ::: "memory");
}
return 0;
}
int main() {
cpu_set_t set;
CPU_ZERO(&set);
CPU_SET(0, &set);
if (sched_setaffinity(0, sizeof(set), &set) != 0) {
printf("[-] sched_setaffinity failed: %s\n", strerror(errno));
exit(1);
}
printf("[+] sched_setaffinity successful.\n");
for (int i = 0; i < 2; i++) {
char *stack = malloc(1024 * 1024);
if (!stack) {
printf("[-] malloc failed: %s\n", strerror(errno));
exit(1);
}
void *stack_top = (void *)(((uintptr_t)stack + 1024 * 1024) & ~0xF);
pid_t pid = clone(thread_fn, stack_top,
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD, NULL);
if (pid == -1) {
printf("[-] clone failed: %s\n", strerror(errno));
exit(1);
}
}
printf("[+] Created 2 spinning threads on CPU 0.\n");
/* Wait enough time for the scheduler tick to hit the spinning threads */
sleep(5);
printf("[+] Done.\n");
return 0;
}
Reproduced:true ReproducedBugTitle:WARNING in irqentry_exit ReproducedCrashReport:------------[ cut here ]------------
__lockdep_enabled && this_cpu_read(hardirqs_enabled)
WARNING: include/linux/hrtimer_rearm.h:17 at hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_loop kernel/entry/common.c:54 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at exit_to_user_mode_loop kernel/entry/common.c:101 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline], CPU#0: syz-executor381/5899
WARNING: include/linux/hrtimer_rearm.h:17 at irqentry_exit+0x484/0x8f0 kernel/entry/common.c:165, CPU#0: syz-executor381/5899
Modules linked in:
CPU: 0 UID: 0 PID: 5899 Comm: syz-executor381 Not tainted syzkaller #1 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:hrtimer_test_and_clear_rearm_deferred_tif include/linux/hrtimer_rearm.h:17 [inline]
RIP: 0010:hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:52 [inline]
RIP: 0010:rseq_grant_slice_extension include/linux/rseq_entry.h:236 [inline]
RIP: 0010:__exit_to_user_mode_loop kernel/entry/common.c:54 [inline]
RIP: 0010:exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
RIP: 0010:__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
RIP: 0010:irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
RIP: 0010:irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
RIP: 0010:irqentry_exit+0x484/0x8f0 kernel/entry/common.c:165
Code: 00 00 00 00 00 0f 01 ca c6 83 59 16 00 00 00 0f 1f 44 00 00 48 83 3c 24 00 0f 85 46 01 00 00 e8 02 e5 fc f5 e9 d4 fe ff ff 90 <0f> 0b 90 e9 74 ff ff ff 48 89 df e8 9c e4 fc f5 41 89 c7 89 44 24
RSP: 0000:ffffc90003c9fef0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: ffff88810d470000 RCX: 0000000000000046
RDX: 0000000000000000 RSI: ffffffff8e167570 RDI: ffffffff8c321580
RBP: 00000000ffffe000 R08: ffffffff90608537 R09: 1ffffffff20c10a6
R10: dffffc0000000000 R11: fffffbfff20c10a7 R12: ffff88810d471648
R13: 0000000000001010 R14: ffffc90003c9ff48 R15: 0000000000001388
FS: 000055558794e400(0000) GS:ffff8881a50f5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1060ef0fe8 CR3: 00000001fcd34000 CR4: 0000000000352ef0
Call Trace:
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0033:0x7f1060f019ab
Code: 00 00 e8 f8 2e 00 00 45 31 c0 31 c9 31 c0 ba 01 00 00 00 be 02 00 00 00 bf 4f 00 00 00 e8 7d de 01 00 85 c0 75 0a c6 43 1c 01 <c6> 43 1c 01 eb f6 e8 0a 29 00 00 8b 38 e8 33 55 01 00 48 8d 3d 74
RSP: 002b:00007f1060ef0ff0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00005555879507c0 RCX: 00007f1060f1f82a
RDX: 0000000000000001 RSI: 0000000000000002 RDI: 000000000000004f
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe9234cc68
R13: 0000000000000002 R14: 00007f1060fa2cc0 R15: 0000000000000002
</TASK>
]
|
| 171/1 |
2026/08/12 12:56 |
action |
save-repro-c |
0m
Results:
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