INFO: rcu detected stall in __run_timers (2)

Status: upstream: reported on 2025/09/03 11:07
Reported-by: syzbot+cd14d7355b2f09d8aa58@syzkaller.appspotmail.com
First crash: 353d, last: 23h37m
▶ ▼ Similar bugs (17)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in __run_timers (8) prio:normal kernel 1 1 112d 112d 0/29 auto-obsoleted due to no activity on 2026/07/31 00:54
upstream INFO: rcu detected stall in __run_timers (4) tomoyo 1 4 2389d 2404d 0/29 auto-closed as invalid on 2020/05/06 02:55
linux-5.15 INFO: rcu detected stall in __run_timers 1 1 1222d 1222d 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 2904d 2906d 0/29 closed as invalid on 2018/09/11 10:51
upstream INFO: rcu detected stall in __run_timers (2) block 1 58 2776d 2900d 0/29 closed as dup on 2019/01/02 16:40
linux-6.1 INFO: rcu detected stall in __run_timers (2) origin:upstream 1 syz error 3 29d 314d 0/3 upstream: reported syz repro on 2025/10/12 10:55
upstream INFO: rcu detected stall in __run_timers (7) kernfs 1 25 712d 816d 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 671d 671d 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 1631d 1648d 0/29 auto-closed as invalid on 2022/06/02 21:46
linux-6.6 INFO: rcu detected stall in __run_timers 1 2 34d 73d 0/2 upstream: reported on 2026/06/10 07:15
upstream INFO: rcu detected stall in __run_timers (3) mm 1 4 2516d 2537d 0/29 auto-closed as invalid on 2019/12/31 08:04
upstream INFO: rcu detected stall in __run_timers (5) kernel 1 syz, C error error 63 1663d 2177d 0/29 closed as invalid on 2022/02/08 10:39
android-5-10 BUG: soft lockup in __run_timers 1 2 732d 801d 0/2 auto-obsoleted due to no activity on 2024/11/18 04:44
android-54 BUG: soft lockup in __run_timers 1 1 785d 785d 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 703d 703d 0/2 auto-obsoleted due to no activity on 2024/12/16 23:50
upstream BUG: soft lockup in __run_timers kernel 1 1 1294d 1290d 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 505d 567d 0/2 auto-obsoleted due to no activity on 2025/07/03 11:27

Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (1 GPs behind) idle=2d1/1/0x4000000000000000 softirq=45010/45011 fqs=4963 
	(t=10500 jiffies g=62393 q=2104)
NMI backtrace for cpu 0
CPU: 0 PID: 13553 Comm: syz.3.2033 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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+0x22d/0x380 kernel/rcu/tree_stall.h:349
 print_cpu_stall+0x31f/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+0x6ec/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+0x4b0/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x397/0x8b0 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:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: 00 00 00 66 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 7e 53 93 f7 48 89 df e8 b6 2a 94 f7 e8 11 1c b5 f7 fb bf 01 00 00 00 <e8> 96 40 88 f7 65 8b 05 07 68 38 76 85 c0 74 02 5b c3 e8 44 75 36
RSP: 0018:ffffc90000007c70 EFLAGS: 00000282
RAX: 3dcaa384c305aa00 RBX: ffff8880b90280c0 RCX: 3dcaa384c305aa00
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: 0000000000000001
RBP: ffffc90000007df0 R08: ffffffff901ef0cf R09: 1ffffffff203de19
R10: dffffc0000000000 R11: fffffbfff203de1a R12: 1ffff11017205020
R13: ffff8880b90280c0 R14: ffff88804891ed10 R15: ffffc90000007d40
 expire_timers kernel/time/timer.c:1698 [inline]
 __run_timers+0x55c/0x810 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x336/0x830 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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 1f 41 88 f7 65 8b 05 90 68 38 76 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc90002f0f440 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000246 RCX: 3dcaa384c305aa00
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: 0000000000000001
RBP: ffffc90002f0f4d8 R08: ffffffff901ef0cf R09: 1ffffffff203de19
R10: dffffc0000000000 R11: fffffbfff203de1a R12: dffffc0000000000
R13: 1ffffffff1864600 R14: ffffffff8c3233c0 R15: 1ffff920005e1e88
 rcu_report_qs_rsp+0xad/0x1a0 kernel/rcu/tree.c:2170
 rcu_report_unblock_qs_rnp kernel/rcu/tree.c:2275 [inline]
 rcu_preempt_deferred_qs_irqrestore+0x993/0xbd0 kernel/rcu/tree_plugin.h:552
 rcu_read_unlock_special+0x3d9/0x4a0 kernel/rcu/tree_plugin.h:673
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 inet_twsk_purge+0x784/0x820 net/ipv4/inet_timewait_sock.c:309
 ops_exit_list net/core/net_namespace.c:177 [inline]
 setup_net+0x842/0xa10 net/core/net_namespace.c:365
 copy_net_ns+0x33e/0x5b0 net/core/net_namespace.c:503
 create_new_namespaces+0x3ce/0x700 kernel/nsproxy.c:110
 copy_namespaces+0x378/0x3d0 kernel/nsproxy.c:178
 copy_process+0x1844/0x3ec0 kernel/fork.c:2294
 kernel_clone+0x23f/0x990 kernel/fork.c:2681
 __do_sys_clone kernel/fork.c:2798 [inline]
 __se_sys_clone kernel/fork.c:2782 [inline]
 __x64_sys_clone+0x19a/0x210 kernel/fork.c:2782
 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: 0033:0x7faa660880d9
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:00007faa642dffd8 EFLAGS: 00000202 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007faa6630ffa0 RCX: 00007faa660880d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000c0126080
RBP: 00007faa6611f024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007faa66310038 R14: 00007faa6630ffa0 R15: 00007ffc2a81c818
 </TASK>

Crashes (10):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/21 18:06 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in __run_timers
2026/07/30 11:03 linux-5.15.y 674f684f7c61 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in __run_timers
2026/06/25 03:38 linux-5.15.y eceeec79dbc6 302586aa .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in __run_timers
2026/05/14 13:19 linux-5.15.y de8dfb3f0278 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in __run_timers
2026/04/27 17:20 linux-5.15.y b9d57c40a767 0f700595 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in __run_timers
2026/04/26 08:42 linux-5.15.y b9d57c40a767 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in __run_timers
2026/01/24 21:23 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 __run_timers
2025/12/01 14:20 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 __run_timers
2025/10/11 12:15 linux-5.15.y 29e53a5b1c4f ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in __run_timers
2025/09/03 11:07 linux-5.15.y 01879f56bdde 96a211bc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in __run_timers
* Struck through repros no longer work on HEAD.