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INFO: rcu detected stall in sys_epoll_wait (3)

Status: closed as invalid on 2020/01/08 05:33
Subsystems: kernel
[Documentation on labels]
First crash: 2348d, last: 2348d
▶ ▼ Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_epoll_wait (6) ext4 1 3 708d 722d 0/29 auto-obsoleted due to no activity on 2024/10/03 13:07
upstream INFO: rcu detected stall in sys_epoll_wait (2) kernel 1 15 2348d 2348d 0/29 closed as invalid on 2020/01/08 05:23
upstream INFO: rcu detected stall in sys_epoll_wait (8) kernel 1 1 169d 169d 0/29 auto-obsoleted due to no activity on 2026/03/26 09:15
upstream INFO: rcu detected stall in sys_epoll_wait mm cgroups 1 148 2383d 2385d 0/29 closed as invalid on 2019/12/04 14:14
upstream INFO: rcu detected stall in sys_epoll_wait (7) fs 1 3 595d 602d 0/29 auto-obsoleted due to no activity on 2025/01/24 21:05
upstream INFO: rcu detected stall in sys_epoll_wait (4) kernel 1 21 2348d 2348d 0/29 closed as invalid on 2020/01/09 08:13
upstream INFO: rcu detected stall in sys_epoll_wait (5) usb fs input 1 syz error 2 1329d 1847d 0/29 closed as dup on 2021/05/25 09:57

Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10499 ticks this GP) idle=09a/1/0x4000000000000002 softirq=14452/14452 fqs=37 
	(t=10501 jiffies g=7193 q=680)
rcu: rcu_preempt kthread starved for 10425 jiffies! g7193 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    28984    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3385 [inline]
 __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081
 schedule+0x181/0x210 kernel/sched/core.c:4155
 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895
 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline]
 rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821
 kthread+0x332/0x350 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 1
CPU: 1 PID: 4313 Comm: udevd Not tainted 5.5.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fb/0x318 lib/dump_stack.c:118
 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x15a/0x220 kernel/rcu/tree_stall.h:254
 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:529 [inline]
 rcu_pending kernel/rcu/tree.c:2827 [inline]
 rcu_sched_clock_irq+0xe25/0x1ad0 kernel/rcu/tree.c:2271
 update_process_times+0x12d/0x180 kernel/time/timer.c:1726
 tick_sched_handle kernel/time/tick-sched.c:167 [inline]
 tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310
 __run_hrtimer kernel/time/hrtimer.c:1517 [inline]
 __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1579
 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1641
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:free_thread_stack+0x18b/0x590 kernel/fork.c:284
Code: ff ff e8 28 04 00 00 43 80 3c 2e 00 74 08 4c 89 e7 e8 39 94 6a 00 49 8b 1c 24 48 83 c3 08 48 89 d8 48 c1 e8 03 42 80 3c 28 00 <74> 08 48 89 df e8 1b 94 6a 00 48 8b 1b e9 82 ff ff ff e8 be 2b 2e
RSP: 0018:ffffc90001817b10 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 1ffff11012c80721 RBX: ffff888096403908 RCX: ffff8880a95022c0
RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea00027edf00
RBP: ffffc90001817b48 R08: 000000000003a728 R09: ffffed1011810709
R10: ffffed1011810709 R11: 0000000000000000 R12: ffff8880964039a0
R13: dffffc0000000000 R14: 1ffff11012c80734 R15: ffff88808c083838
 release_task_stack kernel/fork.c:440 [inline]
 put_task_stack+0xa3/0x130 kernel/fork.c:451
 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256
 context_switch kernel/sched/core.c:3388 [inline]
 __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081
 schedule+0x181/0x210 kernel/sched/core.c:4155
 schedule_hrtimeout_range_clock+0x108/0x510 kernel/time/hrtimer.c:2121
 schedule_hrtimeout_range+0x2a/0x40 kernel/time/hrtimer.c:2175
 ep_poll+0xa4d/0xe80 fs/eventpoll.c:1894
 do_epoll_wait+0x1ee/0x260 fs/eventpoll.c:2273
 __do_sys_epoll_wait fs/eventpoll.c:2283 [inline]
 __se_sys_epoll_wait fs/eventpoll.c:2280 [inline]
 __x64_sys_epoll_wait+0x9a/0xb0 fs/eventpoll.c:2280
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fbac1ddd943
Code: 00 31 d2 48 29 c2 64 89 11 48 83 c8 ff eb ea 90 90 90 90 90 90 90 90 83 3d b5 dc 2a 00 00 75 13 49 89 ca b8 e8 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 3b c4 00 00 48 89 04 24
RSP: 002b:00007ffdbde26098 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8
RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00007fbac1ddd943
RDX: 0000000000000008 RSI: 00007ffdbde26190 RDI: 000000000000000a
RBP: 00000000017c3170 R08: 0000000000000000 R09: 0000000000000001
R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000010 R14: 00000000017c3150 R15: 00000000017aa250

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/01/08 05:23 upstream ae6088216ce4 6738e0b3 .config console log report ci-upstream-kasan-gce-smack-root
* Struck through repros no longer work on HEAD.