syzbot


INFO: rcu detected stall in pwq_unbound_release_workfn

Status: closed as invalid on 2022/02/08 10:10
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 362d, last: 362d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in pwq_unbound_release_workfn (2) 1 141d 141d 0/24 auto-closed as invalid on 2022/09/06 17:05

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=10502 jiffies, g=78745, q=63)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295011423-4295000921), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10502 jiffies! g78745 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:28656 pid:   14 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4972 [inline]
 __schedule+0xa9a/0x4940 kernel/sched/core.c:6253
 schedule+0xd2/0x260 kernel/sched/core.c:6326
 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881
 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1955
 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2128
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
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: 2950 Comm: kworker/1:3 Not tainted 5.16.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events pwq_unbound_release_workfn
RIP: 0010:lock_is_held_type+0x0/0x140 kernel/locking/lockdep.c:5665
Code: 48 c7 c6 a0 0f ac 89 48 c7 c7 20 0c ac 89 89 44 24 04 e8 1d 70 bc ff 0f 0b 8b 44 24 04 eb bd 66 66 2e 0f 1f 84 00 00 00 00 00 <41> 57 41 56 41 55 41 bd ff ff ff ff 41 54 55 53 48 83 ec 08 8b 0d
RSP: 0018:ffffc90000dc0df8 EFLAGS: 00000002
RAX: 0000000000000001 RBX: ffff8880b9d2a500 RCX: 0000000000000000
RDX: 1ffffffff177194e RSI: 00000000ffffffff RDI: ffffffff8bb83be0
RBP: ffff888078b54b40 R08: 0000000000000000 R09: 0000000000000001
R10: ffffffff8166ea0c R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000000 R14: ffff8880b9d2a400 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc97494ff8 CR3: 000000007253f000 CR4: 0000000000350ee0
Call Trace:
 <IRQ>
 lock_is_held include/linux/lockdep.h:283 [inline]
 rcu_read_lock_sched_held+0x3a/0x70 kernel/rcu/update.c:125
 trace_hrtimer_start include/trace/events/timer.h:195 [inline]
 debug_activate kernel/time/hrtimer.c:476 [inline]
 enqueue_hrtimer+0x2bd/0x3e0 kernel/time/hrtimer.c:1084
 __run_hrtimer kernel/time/hrtimer.c:1702 [inline]
 __hrtimer_run_queues+0xb02/0xe50 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]
 __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103
 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:lockdep_unregister_key+0x1c9/0x250 kernel/locking/lockdep.c:6326
Code: 00 00 00 48 89 ee e8 46 fd ff ff 4c 89 f7 e8 5e c9 ff ff e8 09 cc ff ff 9c 58 f6 c4 02 75 26 41 f7 c4 00 02 00 00 74 01 fb 5b <5d> 41 5c 41 5d 41 5e 41 5f e9 19 24 08 00 0f 0b 5b 5d 41 5c 41 5d
RSP: 0018:ffffc90001cefcb0 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffff888093482498 RCX: 0000000000000001
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff888092c0a128 R08: ffffffff8bb8ca00 R09: ffffffff9069ad0b
R10: fffffbfff20d35a1 R11: 000000000000f2e3 R12: 0000000000000246
R13: 0000000000000000 R14: ffffffff8ff6a9b8 R15: ffffffff900f7838
 wq_unregister_lockdep kernel/workqueue.c:3499 [inline]
 pwq_unbound_release_workfn+0x235/0x340 kernel/workqueue.c:3737
 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
----------------
Code disassembly (best guess):
   0:	48 c7 c6 a0 0f ac 89 	mov    $0xffffffff89ac0fa0,%rsi
   7:	48 c7 c7 20 0c ac 89 	mov    $0xffffffff89ac0c20,%rdi
   e:	89 44 24 04          	mov    %eax,0x4(%rsp)
  12:	e8 1d 70 bc ff       	callq  0xffbc7034
  17:	0f 0b                	ud2
  19:	8b 44 24 04          	mov    0x4(%rsp),%eax
  1d:	eb bd                	jmp    0xffffffdc
  1f:	66 66 2e 0f 1f 84 00 	data16 nopw %cs:0x0(%rax,%rax,1)
  26:	00 00 00 00
* 2a:	41 57                	push   %r15 <-- trapping instruction
  2c:	41 56                	push   %r14
  2e:	41 55                	push   %r13
  30:	41 bd ff ff ff ff    	mov    $0xffffffff,%r13d
  36:	41 54                	push   %r12
  38:	55                   	push   %rbp
  39:	53                   	push   %rbx
  3a:	48 83 ec 08          	sub    $0x8,%rsp
  3e:	8b                   	.byte 0x8b
  3f:	0d                   	.byte 0xd

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-root 2021/11/29 10:19 upstream d06c942efea4 63eeac02 .config log report info INFO: rcu detected stall in pwq_unbound_release_workfn
* Struck through repros no longer work on HEAD.