syzbot


possible deadlock in __bpf_ringbuf_reserve

Status: upstream: reported C repro on 2024/03/08 23:13
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+f85ef54ebfb2b7619272@syzkaller.appspotmail.com
First crash: 589d, last: 1d12h
Fix bisection: the issue occurs on the latest tested release (bisect log)
Crash: possible deadlock in __bpf_ringbuf_reserve (log)
Repro: C syz .config
  
Bug presence (3)
Date Name Commit Repro Result
2025/01/23 linux-6.1.y (ToT) f4f677285b38 C [report] possible deadlock in __bpf_ringbuf_reserve
2024/03/09 upstream (ToT) 10d48d70e82d C [report] possible deadlock in __bpf_ringbuf_reserve
2025/01/23 upstream (ToT) 7004a2e46d16 C Didn't crash
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in __bpf_ringbuf_reserve (2) bpf 4 C done error 22 39d 54d 0/29 upstream: reported C repro on 2025/08/25 17:39
linux-5.15 possible deadlock in __bpf_ringbuf_reserve 4 1 44d 44d 0/3 upstream: reported on 2025/09/04 22:27
linux-6.6 possible deadlock in __bpf_ringbuf_reserve origin:lts-only 4 C 20 23d 106d 0/2 upstream: reported C repro on 2025/07/04 03:51
upstream possible deadlock in __bpf_ringbuf_reserve bpf 4 C error 2490 180d 585d 28/29 fixed on 2025/06/10 16:19
Fix bisection attempts (6)
Created Duration User Patch Repo Result
2025/04/27 19:32 2h44m fix candidate upstream OK (0) job log
2025/01/18 17:22 1h29m bisect fix linux-6.1.y OK (0) job log log
2024/11/26 16:19 3h02m bisect fix linux-6.1.y OK (0) job log log
2024/10/20 11:45 3h30m bisect fix linux-6.1.y OK (0) job log log
2024/09/19 04:24 1h31m bisect fix linux-6.1.y OK (0) job log log
2024/04/09 05:19 1h54m bisect fix linux-6.1.y OK (0) job log log

Sample crash report:
============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.3.359/4854 is trying to acquire lock:
ffffc90004b710d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c4/0x5a0 kernel/bpf/ringbuf.c:413

but task is already holding lock:
ffffc90004e8e0d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c4/0x5a0 kernel/bpf/ringbuf.c:413

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&rb->spinlock);
  lock(&rb->spinlock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

4 locks held by syz.3.359/4854:
 #0: ffffffff8cb71b08 (tracepoints_mutex){+.+.}-{3:3}, at: tracepoint_probe_unregister+0x2c/0x930 kernel/tracepoint.c:548
 #1: ffffffff8cb2a9e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #1: ffffffff8cb2a9e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #1: ffffffff8cb2a9e0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline]
 #1: ffffffff8cb2a9e0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xda/0x3b0 kernel/trace/bpf_trace.c:2324
 #2: ffffc90004e8e0d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c4/0x5a0 kernel/bpf/ringbuf.c:413
 #3: ffffffff8cb2a9e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #3: ffffffff8cb2a9e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #3: ffffffff8cb2a9e0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline]
 #3: ffffffff8cb2a9e0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xda/0x3b0 kernel/trace/bpf_trace.c:2324

stack backtrace:
CPU: 0 PID: 4854 Comm: syz.3.359 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 __lock_acquire+0x122f/0x7c50 kernel/locking/lockdep.c:-1
 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
 __bpf_ringbuf_reserve+0x1c4/0x5a0 kernel/bpf/ringbuf.c:413
 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:464 [inline]
 bpf_ringbuf_reserve+0x58/0x70 kernel/bpf/ringbuf.c:456
 bpf_prog_fe0ed97373b08409+0x25/0x42
 bpf_dispatcher_nop_func include/linux/bpf.h:1011 [inline]
 __bpf_prog_run include/linux/filter.h:603 [inline]
 bpf_prog_run include/linux/filter.h:610 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline]
 bpf_trace_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324
 __traceiter_contention_end+0x74/0xa0 include/trace/events/lock.h:122
 trace_contention_end+0x13f/0x190 include/trace/events/lock.h:122
 __pv_queued_spin_lock_slowpath+0x7e8/0x9c0 kernel/locking/qspinlock.c:560
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline]
 queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock+0x217/0x280 kernel/locking/spinlock_debug.c:115
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
 _raw_spin_lock_irqsave+0xb0/0xf0 kernel/locking/spinlock.c:162
 __bpf_ringbuf_reserve+0x1c4/0x5a0 kernel/bpf/ringbuf.c:413
 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:464 [inline]
 bpf_ringbuf_reserve+0x58/0x70 kernel/bpf/ringbuf.c:456
 bpf_prog_fe0ed97373b08409+0x25/0x42
 bpf_dispatcher_nop_func include/linux/bpf.h:1011 [inline]
 __bpf_prog_run include/linux/filter.h:603 [inline]
 bpf_prog_run include/linux/filter.h:610 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline]
 bpf_trace_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324
 __traceiter_contention_end+0x74/0xa0 include/trace/events/lock.h:122
 trace_contention_end+0x123/0x170 include/trace/events/lock.h:122
 __mutex_lock_common kernel/locking/mutex.c:612 [inline]
 __mutex_lock+0x194/0xaf0 kernel/locking/mutex.c:747
 tracepoint_probe_unregister+0x2c/0x930 kernel/tracepoint.c:548
 bpf_raw_tp_link_release+0x5f/0x80 kernel/bpf/syscall.c:3197
 bpf_link_free kernel/bpf/syscall.c:2766 [inline]
 bpf_link_put+0x22a/0x2c0 kernel/bpf/syscall.c:2792
 bpf_link_release+0x37/0x40 kernel/bpf/syscall.c:2801
 __fput+0x22c/0x920 fs/file_table.c:320
 task_work_run+0x1ca/0x250 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fad2718eba9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffe2197158 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 000000000001b1ab RCX: 00007fad2718eba9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000001 R09: 00000004e219744f
R10: 0000001b2d720000 R11: 0000000000000246 R12: 00007fad273d5fac
R13: 00007fad273d5fa0 R14: ffffffffffffffff R15: 0000000000000003
 </TASK>

Crashes (82):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/10 06:39 linux-6.1.y f97f1002271b fdeaa69b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2025/08/07 03:36 linux-6.1.y 3594f306da12 9a42d6b1 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2025/05/25 10:02 linux-6.1.y da3c5173c55f ed351ea7 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2025/03/08 08:38 linux-6.1.y 6ae7ac5c4251 7e3bd60d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/12/19 16:01 linux-6.1.y 52f863f820fd 1432fc84 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/05/08 20:39 linux-6.1.y 909ba1f1b414 20bf80e1 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/03/08 23:12 linux-6.1.y 61adba85cc40 8e75c913 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2025/10/17 14:43 linux-6.1.y c2fda4b3f577 7adf5298 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2025/10/16 03:15 linux-6.1.y c2fda4b3f577 19568248 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2025/10/15 21:36 linux-6.1.y c2fda4b3f577 19568248 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2025/10/07 05:01 linux-6.1.y 882efbdd9d34 8ef35d49 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2025/09/18 15:35 linux-6.1.y 3db754f56897 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2025/09/18 00:12 linux-6.1.y 3db754f56897 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2025/09/13 19:17 linux-6.1.y 3db754f56897 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2025/04/12 23:29 linux-6.1.y 420102835862 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2025/03/20 08:23 linux-6.1.y 344a09659766 9209bc22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2025/03/18 00:45 linux-6.1.y 344a09659766 ce3352cd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2025/03/15 05:48 linux-6.1.y 344a09659766 e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2025/03/13 17:56 linux-6.1.y 344a09659766 44be8b44 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2025/03/02 02:58 linux-6.1.y 3a8358583626 c3901742 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2025/03/02 00:46 linux-6.1.y 3a8358583626 c3901742 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2025/02/28 19:56 linux-6.1.y 3a8358583626 67cf5345 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2025/02/21 22:19 linux-6.1.y 3a8358583626 d34966d1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2025/02/21 17:22 linux-6.1.y 3a8358583626 0808a665 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2025/02/19 02:43 linux-6.1.y 0cbb5f65e52f 9a14138f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2025/02/18 01:36 linux-6.1.y 0cbb5f65e52f 429ea007 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2025/02/17 13:30 linux-6.1.y 0cbb5f65e52f 4121cf9d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2025/02/15 10:00 linux-6.1.y 0cbb5f65e52f 40a34ec9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2025/01/31 21:02 linux-6.1.y 75cefdf153f5 aa47157c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/08/16 23:53 linux-6.1.y 117ac406ba90 e1c76ab2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2024/08/16 16:23 linux-6.1.y 117ac406ba90 e1c76ab2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/08/13 09:07 linux-6.1.y 36790ef5e00b 7b0f4b46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/07/25 07:36 linux-6.1.y 9b3f9a5b12dc d1a1b0ca .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/07/25 07:35 linux-6.1.y 9b3f9a5b12dc d1a1b0ca .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/07/25 07:34 linux-6.1.y 9b3f9a5b12dc d1a1b0ca .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/07/25 07:34 linux-6.1.y 9b3f9a5b12dc d1a1b0ca .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/07/13 08:29 linux-6.1.y 266ee8e06d5b eaeb5c15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/06/18 17:46 linux-6.1.y eb44d83053d6 639d6cdf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/06/18 17:46 linux-6.1.y eb44d83053d6 639d6cdf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/06/18 17:05 linux-6.1.y eb44d83053d6 639d6cdf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/05/29 01:12 linux-6.1.y 88690811da69 34889ee3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2024/05/29 01:12 linux-6.1.y 88690811da69 34889ee3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2024/05/29 00:43 linux-6.1.y 88690811da69 34889ee3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2024/05/29 00:43 linux-6.1.y 88690811da69 34889ee3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in __bpf_ringbuf_reserve
2024/05/28 19:58 linux-6.1.y 88690811da69 34889ee3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/05/28 19:57 linux-6.1.y 88690811da69 34889ee3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/05/28 19:36 linux-6.1.y 88690811da69 34889ee3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/05/28 19:34 linux-6.1.y 88690811da69 34889ee3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/05/26 03:46 linux-6.1.y 88690811da69 a10a183e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/05/26 03:46 linux-6.1.y 88690811da69 a10a183e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
2024/05/26 03:07 linux-6.1.y 88690811da69 a10a183e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in __bpf_ringbuf_reserve
* Struck through repros no longer work on HEAD.