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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: 95d, last: 24d
▶ ▼ Similar bugs (13)
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 512d 555d 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 437d 509d 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 1876d 2150d 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 167d 300d 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 1939d 1939d 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 1435d 2292d 0/29 closed as invalid on 2022/02/08 10:46
upstream INFO: rcu detected stall in call_timer_fn bpf net 1 2 2629d 2642d 0/29 closed as dup on 2019/01/02 16:26
linux-4.19 INFO: rcu detected stall in call_timer_fn 1 1 2290d 2290d 0/1 auto-closed as invalid on 2020/01/15 18:43
linux-4.14 INFO: rcu detected stall in call_timer_fn 1 5 2063d 2183d 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 693d 693d 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 1175d 1190d 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 1026d 1628d 0/1 upstream: reported C repro on 2021/07/10 02:48
upstream BUG: soft lockup in call_timer_fn (2) trace 1 1 438d 434d 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-....: (1 GPs behind) idle=583/1/0x4000000000000000 softirq=14333/14334 fqs=4757 
	(t=10500 jiffies g=17753 q=1022)
NMI backtrace for cpu 0
CPU: 0 PID: 6802 Comm: syz.5.612 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 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+0x6d8/0x1110 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:1818
 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+0x4fe/0xc40 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:check_kcov_mode kernel/kcov.c:172 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x23/0x60 kernel/kcov.c:206
Code: 00 00 cc cc 00 00 cc 48 8b 04 24 65 48 8b 0d a4 a3 8a 7e 65 8b 15 a5 a3 8a 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 <83> b9 34 16 00 00 00 74 2c 8b 91 10 16 00 00 83 fa 02 75 21 48 8b
RSP: 0018:ffffc90000007b98 EFLAGS: 00000246
RAX: ffffffff816768eb RBX: ffffffff88c02e60 RCX: ffff88807dd6bb80
RDX: 0000000000000100 RSI: ffffffff88c02e60 RDI: ffff88805f4e6c30
RBP: ffffc90000007c90 R08: dffffc0000000000 R09: ffffed1017207662
R10: ffffed1017207662 R11: 1ffff11017207661 R12: ffff88805f4e6c30
R13: 00000000ffffc6c8 R14: 1ffff92000000f78 R15: ffffc90000007be0
 call_timer_fn+0x8b/0x530 kernel/time/timer.c:1428
 expire_timers kernel/time/timer.c:1496 [inline]
 __run_timers+0x525/0x7c0 kernel/time/timer.c:1767
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
 handle_softirqs+0x328/0x820 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x12f/0x220 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:finish_lock_switch+0x134/0x280 kernel/sched/core.c:4804
Code: be ff ff ff ff e8 7c fc 55 08 85 c0 74 4a 4d 85 ff 75 66 0f 1f 44 00 00 48 89 df e8 76 67 5f 08 e8 11 76 2a 00 fb 48 83 c4 08 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 48 89 df e8 d9 0f fe ff 43 80 3c
RSP: 0018:ffffc9000262f7c8 EFLAGS: 00000282
RAX: 01111015aa5c0a00 RBX: ffff8880b903a340 RCX: 01111015aa5c0a00
RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: ffffffff8a59e580
RBP: 1ffff11017207613 R08: dffffc0000000000 R09: ffffed1017207662
R10: ffffed1017207662 R11: 1ffff11017207661 R12: 1ffff110172075c1
R13: dffffc0000000000 R14: ffff8880b903ae08 R15: 0000000000000000
 finish_task_switch+0x12f/0x640 kernel/sched/core.c:4921
 context_switch kernel/sched/core.c:5052 [inline]
 __schedule+0x11c3/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 freezable_schedule include/linux/freezer.h:172 [inline]
 futex_wait_queue_me+0x22d/0x440 kernel/futex/core.c:2863
 futex_wait+0x202/0x5c0 kernel/futex/core.c:2964
 do_futex+0xd1c/0x1240 kernel/futex/core.c:3982
 __do_sys_futex kernel/futex/core.c:4059 [inline]
 __se_sys_futex+0x3a3/0x430 kernel/futex/core.c:4040
 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: 0033:0x7f66d2a59749
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:00007f66d0cc00e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f66d2caffa8 RCX: 00007f66d2a59749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f66d2caffa8
RBP: 00007f66d2caffa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f66d2cb0038 R14: 00007ffd0a6c6990 R15: 00007ffd0a6c6a78
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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.