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INFO: rcu detected stall in call_timer_fn

Status: upstream: reported on 2025/09/20 00:57
Reported-by: syzbot+c4956fba553abbcc9f30@syzkaller.appspotmail.com
First crash: 185d, last: 5d17h
▶ ▼ Similar bugs (14)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream BUG: soft lockup in call_timer_fn net mm 1 19 602d 644d 0/29 auto-obsoleted due to no activity on 2024/10/08 10:43
linux-6.1 INFO: rcu detected stall in call_timer_fn 1 2 527d 599d 0/3 auto-obsoleted due to no activity on 2025/01/21 02:15
linux-4.19 INFO: rcu detected stall in call_timer_fn (2) 1 16 1966d 2240d 0/1 auto-closed as invalid on 2021/03/04 12:30
upstream INFO: rcu detected stall in call_timer_fn (5) net input usb 1 C 9 256d 390d 0/29 upstream: reported C repro on 2025/02/27 04:11
linux-4.14 INFO: rcu detected stall in call_timer_fn (2) 1 1 2028d 2028d 0/1 auto-closed as invalid on 2020/12/31 22:00
upstream INFO: rcu detected stall in call_timer_fn (2) kernel 1 C done error 47 1525d 2381d 0/29 closed as invalid on 2022/02/08 10:46
upstream INFO: rcu detected stall in call_timer_fn bpf net 1 2 2719d 2731d 0/29 closed as dup on 2019/01/02 16:26
linux-4.19 INFO: rcu detected stall in call_timer_fn 1 1 2379d 2379d 0/1 auto-closed as invalid on 2020/01/15 18:43
linux-6.1 INFO: rcu detected stall in call_timer_fn (2) 1 2 22d 43d 0/3 upstream: reported on 2026/02/09 05:30
linux-4.14 INFO: rcu detected stall in call_timer_fn 1 5 2153d 2272d 0/1 auto-closed as invalid on 2020/08/29 09:07
upstream INFO: rcu detected stall in call_timer_fn (4) mm 1 1 783d 783d 0/29 auto-obsoleted due to no activity on 2024/03/31 10:44
upstream INFO: rcu detected stall in call_timer_fn (3) kernel 1 3 1264d 1280d 0/29 auto-obsoleted due to no activity on 2023/01/12 18:45
linux-4.19 BUG: soft lockup in call_timer_fn 1 C error 31 1115d 1718d 0/1 upstream: reported C repro on 2021/07/10 02:48
upstream BUG: soft lockup in call_timer_fn (2) trace 1 1 528d 524d 0/29 auto-obsoleted due to no activity on 2025/01/10 05:15

Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (10500 ticks this GP) idle=d25/1/0x4000000000000000 softirq=30247/30247 fqs=5233 
	(t=10501 jiffies g=43045 q=1221)
NMI backtrace for cpu 0
CPU: 0 PID: 11422 Comm: syz.5.2027 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_dump_cpu_stacks+0x22f/0x380 kernel/rcu/tree_stall.h:349
 print_cpu_stall+0x31d/0x5f0 kernel/rcu/tree_stall.h:633
 check_cpu_stall kernel/rcu/tree_stall.h:727 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x6ea/0x1120 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:2021
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4b4/0xb70 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1108
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:call_timer_fn+0xcd/0x540 kernel/time/timer.c:1645
Code: 44 3e 08 00 49 8d 74 24 28 ba 28 00 00 00 4c 89 ef e8 d7 9d 55 00 48 8d 7c 24 48 ba 10 00 00 00 31 f6 e8 26 9d 55 00 4c 89 ef <31> f6 31 d2 31 c9 41 b8 01 00 00 00 45 31 c9 68 fa 90 68 81 e8 ba
RSP: 0018:ffffc90000007ba0 EFLAGS: 00000202
RAX: ffffc90000007be8 RBX: 0000000000000101 RCX: 0000000000000000
RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc90000007be0
RBP: ffffc90000007c90 R08: ffffc90000007bf7 R09: ffffc90000007be8
R10: dffffc0000000000 R11: fffff52000000f7f R12: ffff88805f1a85f8
R13: ffffc90000007be0 R14: 1ffff92000000f78 R15: dffffc0000000000
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x53e/0x800 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x339/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:generic_exec_single+0x373/0x460 kernel/smp.c:532
Code: df eb 27 e8 7f 6c 0b 00 0f 0b e9 b6 fd ff ff e8 73 6c 0b 00 e8 2e b4 4e 08 48 85 db 0f 84 5c ff ff ff e8 60 6c 0b 00 fb 31 c0 <48> c7 44 24 20 0e 36 e0 45 4b c7 44 3d 00 00 00 00 00 43 c7 44 3d
RSP: 0018:ffffc9000301fa60 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000200 RCX: ffff88802449bb80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000301fb30 R08: ffffffff901d41cf R09: 1ffffffff203a839
R10: dffffc0000000000 R11: fffffbfff203a83a R12: ffffc9000301fb88
R13: 1ffff92000603f50 R14: 0000000000000000 R15: dffffc0000000000
 smp_call_function_single+0x202/0x4c0 kernel/smp.c:755
 task_function_call kernel/events/core.c:120 [inline]
 perf_install_in_context+0x5c7/0x920 kernel/events/core.c:3016
 __do_sys_perf_event_open kernel/events/core.c:12793 [inline]
 __se_sys_perf_event_open+0x12b3/0x1bb0 kernel/events/core.c:12387
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f99b8613799
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:00007f99b684c028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f99b888d090 RCX: 00007f99b8613799
RDX: ffffffffffffffff RSI: 0000000000000126 RDI: 0000200000000480
RBP: 00007f99b86a9c99 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f99b888d128 R14: 00007f99b888d090 R15: 00007ffebd84bef8
 </TASK>

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/18 20:54 linux-5.15.y 91d48252ad4b 0199f9a1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in call_timer_fn
2026/02/25 21:08 linux-5.15.y 3330a8d33e08 94a9671e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in call_timer_fn
2026/01/25 11:13 linux-5.15.y 9eec9a14ee10 40acda8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in call_timer_fn
2025/11/30 15:21 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in call_timer_fn
2025/11/30 11:57 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in call_timer_fn
2025/10/23 14:22 linux-5.15.y ac56c046adf4 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in call_timer_fn
2025/09/20 00:57 linux-5.15.y 43bb85222e53 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in call_timer_fn
* Struck through repros no longer work on HEAD.