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INFO: rcu detected stall in __run_timers (2)

Status: upstream: reported syz repro on 2025/10/12 10:55
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+1b46870025d4a727b569@syzkaller.appspotmail.com
First crash: 6d22h, last: 6d22h
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2025/10/16 upstream (ToT) 7ea30958b305 syz [report] INFO: rcu detected stall in vms_complete_munmap_vmas
▶ ▼ Similar bugs (15)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in __run_timers (4) tomoyo 1 4 2082d 2097d 0/29 auto-closed as invalid on 2020/05/06 02:55
linux-5.15 INFO: rcu detected stall in __run_timers 1 1 915d 915d 0/3 auto-obsoleted due to no activity on 2023/08/15 19:18
upstream INFO: rcu detected stall in __run_timers net 1 2 2596d 2598d 0/29 closed as invalid on 2018/09/11 10:51
upstream INFO: rcu detected stall in __run_timers (2) block 1 58 2469d 2592d 0/29 closed as dup on 2019/01/02 16:40
upstream INFO: rcu detected stall in __run_timers (7) kernfs 1 25 404d 509d 0/29 auto-obsoleted due to no activity on 2024/11/08 17:44
linux-6.1 INFO: rcu detected stall in __run_timers 1 1 363d 363d 0/3 auto-obsoleted due to no activity on 2025/01/28 16:20
upstream INFO: rcu detected stall in __run_timers (6) kernel 1 2 1324d 1340d 0/29 auto-closed as invalid on 2022/06/02 21:46
linux-5.15 INFO: rcu detected stall in __run_timers (2) 1 2 7d20h 45d 0/3 upstream: reported on 2025/09/03 11:07
upstream INFO: rcu detected stall in __run_timers (3) mm 1 4 2209d 2230d 0/29 auto-closed as invalid on 2019/12/31 08:04
upstream INFO: rcu detected stall in __run_timers (5) kernel 1 C error error 63 1356d 1869d 0/29 closed as invalid on 2022/02/08 10:39
android-5-10 BUG: soft lockup in __run_timers 1 2 425d 493d 0/2 auto-obsoleted due to no activity on 2024/11/18 04:44
android-54 BUG: soft lockup in __run_timers 1 1 478d 478d 0/2 auto-obsoleted due to no activity on 2024/09/26 00:22
android-5-15 BUG: soft lockup in __run_timers 1 1 396d 396d 0/2 auto-obsoleted due to no activity on 2024/12/16 23:50
upstream BUG: soft lockup in __run_timers kernel 1 1 986d 982d 0/29 auto-obsoleted due to no activity on 2023/05/06 12:08
android-54 BUG: soft lockup in __run_timers (2) 1 2 197d 260d 0/2 auto-obsoleted due to no activity on 2025/07/03 11:27

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2667 jiffies s: 3477 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4357 Comm: kworker/0:8 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: wg-kex-wg0 wg_packet_handshake_receive_worker
RIP: 0010:check_preemption_disabled+0x3/0x110 lib/smp_processor_id.c:13
Code: bc 8c 4c 89 f6 e8 fd f8 16 fa e9 6e ff ff ff 00 00 cc cc 00 00 cc cc 48 c7 c7 c0 fc de 8a 48 c7 c6 00 fd de 8a eb 00 55 41 57 <41> 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 65
RSP: 0018:ffffc90000007860 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffff88802b933b80 RCX: 0000000000000001
RDX: ffff88802b933b80 RSI: ffffffff8a8c1680 RDI: ffffffff8adefd20
RBP: 0000000000000001 R08: dffffc0000000000 R09: ffff88802f14c340
R10: ffffed1005e2986b R11: 1ffff11005e29868 R12: 0000000000000001
R13: 0000000000000046 R14: ffff8880b8e2a598 R15: ffff88802b934688
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000600 CR3: 000000001d381000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline]
 lock_is_held_type+0x100/0x190 kernel/locking/lockdep.c:5706
 lock_is_held include/linux/lockdep.h:283 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1713 [inline]
 __hrtimer_run_queues+0x2b3/0xd60 kernel/time/hrtimer.c:1811
 hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1873
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1118
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f5 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 6e c8 41 f7 48 89 df e8 c6 8d 42 f7 e8 f1 7f 65 f7 fb bf 01 00 00 00 <e8> 16 0b 36 f7 65 8b 05 17 c4 e0 75 85 c0 74 02 5b c3 e8 64 d5 de
RSP: 0018:ffffc90000007c70 EFLAGS: 00000282
RAX: d1342833496d5a00 RBX: ffff8880b8e28400 RCX: d1342833496d5a00
RDX: dffffc0000000000 RSI: ffffffff8a8c0500 RDI: 0000000000000001
RBP: ffffc90000007dd0 R08: dffffc0000000000 R09: fffffbfff215c46c
R10: fffffbfff215c46c R11: 1ffffffff215c46b R12: ffff8880b8e28400
R13: 1ffff110171c5088 R14: ffffffff96fbc400 R15: ffffc90000007d20
 expire_timers kernel/time/timer.c:1548 [inline]
 __run_timers+0x516/0x7c0 kernel/time/timer.c:1820
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833
 handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:lock_acquire+0x20f/0x490 kernel/locking/lockdep.c:5666
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b
RSP: 0018:ffffc900032f7b20 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: d1342833496d5a00
RDX: ffffffff90652160 RSI: ffffffff8a8c1680 RDI: ffffffff8adefd20
RBP: ffffc900032f7c28 R08: dffffc0000000000 R09: 000000000001cb71
R10: 1ffffffff2176bb8 R11: 1ffffffff20c55c6 R12: 0000000000000000
R13: 1ffff9200065ef70 R14: 0000000000000246 R15: dffffc0000000000
 process_one_work+0x7b7/0x1160 kernel/workqueue.c:2267
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/12 10:55 linux-6.1.y 882efbdd9d34 ff1712fe .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in __run_timers
* Struck through repros no longer work on HEAD.