syzbot


INFO: rcu detected stall in wait4

Status: auto-closed as invalid on 2021/09/04 10:15
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 598d, last: 542d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in wait4 (2) 2 127d 208d 0/24 auto-obsoleted due to no activity on 2022/10/24 16:24

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1):
	(detected by 0, t=10502 jiffies, g=109477, q=248)
rcu: All QSes seen, last rcu_preempt kthread activity 10496 (4295022429-4295011933), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread timer wakeup didn't happen for 10495 jiffies! g109477 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=50314
rcu: rcu_preempt kthread starved for 10496 jiffies! g109477 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:I stack:29032 pid:   14 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:4339 [inline]
 __schedule+0x916/0x23e0 kernel/sched/core.c:5147
 schedule+0xcf/0x270 kernel/sched/core.c:5226
 schedule_timeout+0x14a/0x250 kernel/time/timer.c:1892
 rcu_gp_fqs_loop kernel/rcu/tree.c:2004 [inline]
 rcu_gp_kthread+0xd07/0x2300 kernel/rcu/tree.c:2177
 kthread+0x3b1/0x4a0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8733 Comm: syz-executor.5 Not tainted 5.13.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__lock_release kernel/locking/lockdep.c:5172 [inline]
RIP: 0010:lock_release+0x180/0x720 kernel/locking/lockdep.c:5532
Code: a6 fa bc 07 48 89 da 83 e3 07 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 c7 44 24 40 01 00 00 00 83 c3 03 65 ff 05 00 45 a8 7e <0f> b6 04 02 65 4c 8b 3c 25 00 f0 01 00 38 c3 7c 08 84 c0 0f 85 e1
RSP: 0018:ffffc90000dd8c68 EFLAGS: 00000002
RAX: dffffc0000000000 RBX: 0000000000000007 RCX: 0000000000000001
RDX: 1ffffffff1b92e21 RSI: 0000000000010003 RDI: 0000000000000000
RBP: 1ffff920001bb18f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff9091dd50
R13: ffffffff896d9140 R14: ffff8880728b2180 R15: ffff888038222340
FS:  0000000001db0400(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000541198 CR3: 0000000022577000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:158 [inline]
 _raw_spin_unlock_irqrestore+0x16/0x70 kernel/locking/spinlock.c:191
 debug_object_deactivate lib/debugobjects.c:752 [inline]
 debug_object_deactivate+0x264/0x300 lib/debugobjects.c:718
 debug_hrtimer_deactivate kernel/time/hrtimer.c:425 [inline]
 debug_deactivate kernel/time/hrtimer.c:481 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1505 [inline]
 __hrtimer_run_queues+0x3f8/0xe40 kernel/time/hrtimer.c:1601
 hrtimer_interrupt+0x330/0xa00 kernel/time/hrtimer.c:1663
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline]
 __sysvec_apic_timer_interrupt+0x146/0x540 arch/x86/kernel/apic/apic.c:1106
 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1100
 </IRQ>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:647
RIP: 0010:wait_consider_task+0x0/0x3b40 kernel/exit.c:1283
Code: 00 e8 c4 56 74 00 e9 eb ed ff ff e8 aa 56 74 00 e9 56 f9 ff ff 48 89 ef e8 0d 57 74 00 e9 92 f9 ff ff 0f 1f 84 00 00 00 00 00 <41> 57 49 89 d7 41 56 41 55 41 54 55 48 bd 00 00 00 00 00 fc ff df
RSP: 0018:ffffc90001947c40 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff888079bd0080 RCX: 0000000000000000
RDX: ffff888079bd0080 RSI: 0000000000000000 RDI: ffffc90001947d18
RBP: ffffc90001947d18 R08: 0000000000000000 R09: ffffffff8bc0a083
R10: ffffffff81448970 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff8880728b2180 R14: 0000000000000000 R15: ffff8880728b26f8
 do_wait_thread kernel/exit.c:1398 [inline]
 do_wait+0x724/0xd40 kernel/exit.c:1515
 kernel_wait4+0x14c/0x260 kernel/exit.c:1678
 __do_sys_wait4+0x13f/0x150 kernel/exit.c:1706
 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x464a77
Code: 89 7c 24 10 48 89 4c 24 18 e8 d5 44 02 00 4c 8b 54 24 18 8b 54 24 14 41 89 c0 48 8b 74 24 08 8b 7c 24 10 b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 89 44 24 10 e8 05 45 02 00 8b 44
RSP: 002b:00007ffcdedf2cb0 EFLAGS: 00000293 ORIG_RAX: 000000000000003d
RAX: ffffffffffffffda RBX: 0000000000000734 RCX: 0000000000464a77
RDX: 0000000040000001 RSI: 00007ffcdedf2d4c RDI: 00000000ffffffff
RBP: 00007ffcdedf2d4c R08: 0000000000000000 R09: 00007ffcdedf5080
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000032
R13: 00000000000b681d R14: 0000000000000009 R15: 00007ffcdedf2db0

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-selinux-root 2021/06/06 10:11 upstream f5b6eb1e0182 500c2339 .config log report info INFO: rcu detected stall in wait4
ci-upstream-kasan-gce-root 2021/04/11 06:09 upstream 52e44129fba5 bfeda1b1 .config log report info INFO: rcu detected stall in wait4
* Struck through repros no longer work on HEAD.