WARNING in __run_timer_base (3)

Status: upstream: reported C repro on 2026/10/18 02:07
Subsystems: arm
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+c4582e7bc680cba1fcfb@syzkaller.appspotmail.com
First crash: 21h47m, last: 21h47m
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
711a449d assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ WARNING in __run_timer_base (3) 2026/10/18 00:52 2026/10/18 00:52 2026/10/18 01:05 432c0077
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [arm?] WARNING in __run_timer_base (3) 0 (1) 2026/10/18 02:07
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in __run_timer_base (2) kernel prio:high -1 1 234d 230d 0/29 auto-obsoleted due to no activity on 2026/06/06 18:20
upstream WARNING in __run_timer_base kernel -1 11 345d 407d 0/29 auto-obsoleted due to no activity on 2026/02/05 21:57

Sample crash report:
------------[ cut here ]------------
WARNING: kernel/time/timer.c:1786 at expire_timers kernel/time/timer.c:1786 [inline], CPU#1: swapper/1/0
WARNING: kernel/time/timer.c:1786 at __run_timers kernel/time/timer.c:2374 [inline], CPU#1: swapper/1/0
WARNING: kernel/time/timer.c:1786 at __run_timer_base+0x598/0x744 kernel/time/timer.c:2386, CPU#1: swapper/1/0
Modules linked in:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G   M                syzkaller #0 PREEMPT 
Tainted: [M]=MACHINE_CHECK
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/23/2026
pstate: 434000c5 (nZcv daIF +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : expire_timers kernel/time/timer.c:1786 [inline]
pc : __run_timers kernel/time/timer.c:2374 [inline]
pc : __run_timer_base+0x598/0x744 kernel/time/timer.c:2386
lr : expire_timers kernel/time/timer.c:1786 [inline]
lr : __run_timers kernel/time/timer.c:2374 [inline]
lr : __run_timer_base+0x598/0x744 kernel/time/timer.c:2386
sp : ffff80008f7f7d40
x29: ffff80008f7f7e50 x28: ffff0001a4fdfd00 x27: 0000000000000000
x26: ffff0000c8d96970 x25: 00000000ffff98f0 x24: ffff80008f7f7dc8
x23: ffff0000c8d96988 x22: 1fffe000349fbfa0 x21: 1ffff00011efefb9
x20: dfff800000000000 x19: ffff0001a4fdfcc0 x18: 1fffe000349fbc28
x17: ffff80011b89c000 x16: ffff80008f7f0000 x15: 0000000000000000
x14: 00000000001e00c1 x13: 0000000000000001 x12: 0000000000000003
x11: 0000000000000000 x10: 0000000000000003 x9 : 0000000000000102
x8 : 0000000000000000 x7 : ffff8000819951c0 x6 : 0000000000000000
x5 : 0000000000000001 x4 : 0000000000000001 x3 : ffff800080538560
x2 : 0000000000000002 x1 : ffff0000c1aa8000 x0 : 0000000000000000
Call trace:
 expire_timers kernel/time/timer.c:1786 [inline] (P)
 __run_timers kernel/time/timer.c:2374 [inline] (P)
 __run_timer_base+0x598/0x744 kernel/time/timer.c:2386 (P)
 run_timer_base+0x84/0x1b8 kernel/time/timer.c:2395
 run_timer_softirq+0x20/0x48 kernel/time/timer.c:2405
 handle_softirqs+0x324/0xcbc kernel/softirq.c:645
 __do_softirq+0x14/0x20 kernel/softirq.c:679
 ____do_softirq+0x10/0x1c arch/arm64/kernel/irq.c:78
 call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:901
 do_softirq_own_stack+0x1c/0x28 arch/arm64/kernel/irq.c:83
 invoke_softirq kernel/softirq.c:526 [inline]
 __irq_exit_rcu+0x10c/0x318 kernel/softirq.c:758
 irq_exit_rcu+0x14/0x84 kernel/softirq.c:775
 __el1_irq arch/arm64/kernel/entry-common.c:569 [inline]
 el1_interrupt+0x40/0x60 arch/arm64/kernel/entry-common.c:581
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:586
 el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:602
 __daif_local_irq_enable arch/arm64/include/asm/irqflags.h:26 [inline] (P)
 arch_local_irq_enable arch/arm64/include/asm/irqflags.h:48 [inline] (P)
 default_idle_call+0xa0/0xb8 kernel/sched/idle.c:129 (P)
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x1ec/0x450 kernel/sched/idle.c:355
 cpu_startup_entry+0x5c/0x74 kernel/sched/idle.c:454
 secondary_start_kernel+0x1d8/0x1fc arch/arm64/kernel/smp.c:275
 __secondary_switched+0xc0/0xc4 arch/arm64/kernel/head.S:400
irq event stamp: 286461
hardirqs last  enabled at (286460): [<ffff80008030a4e0>] handle_softirqs+0x1e8/0xcbc kernel/softirq.c:629
hardirqs last disabled at (286461): [<ffff8000868a164c>] __raw_spin_lock_irq include/linux/spinlock_api_smp.h:163 [inline]
hardirqs last disabled at (286461): [<ffff8000868a164c>] _raw_spin_lock_irq+0x28/0x70 kernel/locking/spinlock.c:189
softirqs last  enabled at (283904): [<ffff80008030ae24>] softirq_handle_end kernel/softirq.c:491 [inline]
softirqs last  enabled at (283904): [<ffff80008030ae24>] handle_softirqs+0xb2c/0xcbc kernel/softirq.c:673
softirqs last disabled at (286459): [<ffff8000800203f0>] __do_softirq+0x14/0x20 kernel/softirq.c:679
---[ end trace 0000000000000000 ]---

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/18 00:44 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 432c0077 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in __run_timer_base
* Struck through repros no longer work on HEAD.