syzbot
INFO: rcu detected stall in sys_close_range
Status:
upstream: reported C repro on 2025/08/13 16:29
Bug presence:
origin:lts-only
[Documentation on labels]
Reported-by: syzbot+793af646fd66df0b254e@syzkaller.appspotmail.com
First crash: 368d, last: 17d
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Bug presence (2)
| Date |
Name |
Commit |
Repro |
Result |
| 2025/12/22 |
linux-6.6.y (ToT) |
5fa4793a2d2d |
C
|
[report] INFO: rcu detected stall in smp_call_function
|
| 2025/12/22 |
upstream (ToT) |
9448598b22c5 |
C
|
Didn't crash |
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▼
Fix bisection attempts (2)
| Created |
Duration |
User |
Patch |
Repo |
Result |
| 2026/01/04 23:24 |
2h33m
|
fix candidate
|
|
upstream |
OK
(0)
job log
|
| 2025/11/19 15:50 |
2h26m (2)
|
fix candidate
|
|
upstream |
OK
(0)
job log
|
Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 1-....: (9759 ticks this GP) idle=23b4/1/0x4000000000000000 softirq=14057/14071 fqs=5171
rcu: hardirqs softirqs csw/system
rcu: number: 1384489 54 0
rcu: cputime: 15507 36981 34 ==> 52500(ms)
rcu: (t=10502 jiffies g=12169 q=1570 ncpus=2)
CPU: 1 PID: 6093 Comm: syz.0.24 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5758
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc900001f0800 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 8f57df12e2bd0500
RDX: 0000000000000000 RSI: ffffffff8acadd60 RDI: ffffffff8b1d0660
RBP: ffffc900001f0908 R08: dffffc0000000000 R09: 1ffffffff223d6a0
R10: dffffc0000000000 R11: fffffbfff223d6a1 R12: 1ffff9200003e10c
R13: ffffffff8d7ef160 R14: 0000000000000246 R15: dffffc0000000000
FS: 000055557e61b500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000483cc CR3: 000000007e030000 CR4: 00000000003506e0
Call Trace:
<IRQ>
debug_objects_fill_pool+0xab/0x790 lib/debugobjects.c:653
debug_object_assert_init+0x66/0x300 lib/debugobjects.c:940
debug_timer_assert_init kernel/time/timer.c:792 [inline]
debug_assert_init kernel/time/timer.c:837 [inline]
__mod_timer+0x55/0xd60 kernel/time/timer.c:1020
call_timer_fn+0x189/0x540 kernel/time/timer.c:1701
expire_timers kernel/time/timer.c:1752 [inline]
__run_timers+0x570/0x810 kernel/time/timer.c:2023
run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036
handle_softirqs+0x27d/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:preempt_schedule_irq+0xba/0x150 kernel/sched/core.c:7011
Code: 00 00 43 c6 44 37 04 f8 74 0b 0f 0b 48 f7 03 08 00 00 00 74 6f bf 01 00 00 00 e8 f1 d2 c7 f6 e8 7c c7 f8 f6 fb bf 01 00 00 00 <e8> 31 b4 ff ff 43 c6 44 37 08 00 48 c7 44 24 40 00 00 00 00 9c 8f
RSP: 0018:ffffc9000380f6c0 EFLAGS: 00000282
RAX: 8f57df12e2bd0500 RBX: 0000000000000000 RCX: 8f57df12e2bd0500
RDX: dffffc0000000000 RSI: ffffffff8acacbe0 RDI: 0000000000000001
RBP: ffffc9000380f770 R08: ffffffff8e8c7caf R09: 1ffffffff1d18f95
R10: dffffc0000000000 R11: fffffbfff1d18f96 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92000701ed8
irqentry_exit+0x67/0x70 kernel/entry/common.c:438
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:preempt_schedule+0x0/0xd0 kernel/sched/core.c:6885
Code: 4c 89 f7 e8 72 da 4a f7 eb af 66 0f 1f 00 bf 01 00 00 00 e8 f2 d7 c7 f6 e8 fd fd ff ff bf 01 00 00 00 e8 43 d6 c7 f6 c3 66 90 <f3> 0f 1e fa 55 48 89 e5 41 56 53 48 83 e4 e0 48 83 ec 60 65 48 8b
RSP: 0018:ffffc9000380f838 EFLAGS: 00000293
RAX: ffffffff813bc3e7 RBX: 0000000000000000 RCX: ffff888024179e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000380f888 R08: ffff888024179e00 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000000 R12: ffffc9000380fdb8
R13: ffffc9000380f968 R14: ffffc9000380fde8 R15: ffffc9000380f978
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
unwind_next_frame+0x201c/0x2990 arch/x86/kernel/unwind_orc.c:672
arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:46
__kasan_record_aux_stack+0xaf/0xc0 mm/kasan/generic.c:492
task_work_add+0xdd/0x470 kernel/task_work.c:82
fput+0xdd/0x1a0 fs/file_table.c:474
filp_close+0x10f/0x150 fs/open.c:1548
__range_close fs/file.c:698 [inline]
__close_range+0x379/0x690 fs/file.c:755
__do_sys_close_range fs/open.c:1600 [inline]
__se_sys_close_range fs/open.c:1597 [inline]
__x64_sys_close_range+0x7a/0x90 fs/open.c:1597
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f2a0999e019
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:00007fff4f0abca8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: ffffffffffffffda RBX: 00007fff4f0abd90 RCX: 00007f2a0999e019
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00000000000483cc R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b31b20000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2a09c25fac R14: 00007f2a09c25fa8 R15: 00007f2a09c25fa0
</TASK>
Struck through repros no longer work on HEAD.