syzbot

 sign-in | mailing list | source | docs
🐞 Open [851]
🐞 Fixed [87]
🐞 Invalid [1250]
⬇ Missing Backports [132]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
💬 Send us feedback

INFO: rcu detected stall in pwq_unbound_release_workfn

Status: auto-obsoleted due to no activity on 2025/02/15 16:46
Reported-by: syzbot+e4841a39a230d70ba704@syzkaller.appspotmail.com
First crash: 502d, last: 502d
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in pwq_unbound_release_workfn kernel 1 1 1577d 1577d 0/29 closed as invalid on 2022/02/08 10:10
upstream INFO: rcu detected stall in pwq_unbound_release_workfn (2) kernel 1 1 1355d 1355d 0/29 auto-closed as invalid on 2022/09/06 17:05
linux-5.15 INFO: rcu detected stall in pwq_unbound_release_workfn (2) origin:lts-only 1 syz error 2 204d 300d 0/3 upstream: reported syz repro on 2025/05/28 17:46
linux-6.1 INFO: rcu detected stall in pwq_unbound_release_workfn 1 1 592d 592d 0/3 auto-obsoleted due to no activity on 2024/11/17 13:02
upstream INFO: rcu detected stall in pwq_unbound_release_workfn (3) kernel 1 1 1154d 1154d 0/29 auto-obsoleted due to no activity on 2023/04/25 19:12
upstream INFO: rcu detected stall in pwq_unbound_release_workfn (4) kernel 1 2 988d 1037d 0/29 auto-obsoleted due to no activity on 2023/10/08 15:59

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (3 ticks this GP) idle=0cb/1/0x4000000000000000 softirq=20380/20380 fqs=12 
	(detected by 1, t=10506 jiffies, g=35145, q=528)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4804 Comm: kworker/0:14 Not tainted 5.15.170-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events pwq_unbound_release_workfn
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:84 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x71/0x290 mm/kasan/generic.c:189
Code: 54 37 ff 49 c1 ea 03 49 bb 01 00 00 00 00 fc ff df 4f 8d 34 1a 4c 89 f5 4c 29 cd 48 83 fd 10 7f 26 48 85 ed 0f 84 3a 01 00 00 <49> f7 d2 49 01 da 41 80 39 00 0f 85 c4 01 00 00 49 ff c1 49 ff c2
RSP: 0018:ffffc90000007a38 EFLAGS: 00000002
RAX: 0000000000000001 RBX: 1ffffffff20ec65e RCX: ffffffff8162c78b
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff907632f0
RBP: 0000000000000001 R08: dffffc0000000000 R09: fffffbfff20ec65e
R10: 1ffffffff20ec65e R11: dffffc0000000001 R12: 000000000000003e
R13: ffff888029706428 R14: fffffbfff20ec65f R15: ffff8880297064a0
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0786552538 CR3: 0000000022831000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
 hlock_class kernel/locking/lockdep.c:197 [inline]
 check_wait_context kernel/locking/lockdep.c:4686 [inline]
 __lock_acquire+0x49b/0x1ff0 kernel/locking/lockdep.c:4962
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:363 [inline]
 advance_sched+0x47/0x940 net/sched/sch_taprio.c:716
 __run_hrtimer kernel/time/hrtimer.c:1688 [inline]
 __hrtimer_run_queues+0x598/0xcf0 kernel/time/hrtimer.c:1752
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x13b/0x4b0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/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:lockdep_unregister_key+0x54e/0x5c0 kernel/locking/lockdep.c:6331
Code: 00 00 00 0f 85 8b 00 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 df 11 d1 08 41 f7 c4 00 02 00 00 74 86 fb 45 84 f6 <75> 85 eb 96 0f 0b 45 31 f6 e9 1a ff ff ff 0f 0b e9 5a fe ff ff 0f
RSP: 0018:ffffc900033d7b40 EFLAGS: 00000202
RAX: dffffc0000000000 RBX: 1ffff9200067af70 RCX: ffffffff96869f03
RDX: 0000000000000001 RSI: ffffffff8a8b3880 RDI: ffffffff8ad90480
RBP: ffffc900033d7c08 R08: dffffc0000000000 R09: fffffbfff20e6a04
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000203
R13: 1ffff9200067af6c R14: ffff88807dce1101 R15: ffffc900033d7b80
 wq_unregister_lockdep kernel/workqueue.c:3518 [inline]
 pwq_unbound_release_workfn+0x23d/0x290 kernel/workqueue.c:3756
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 9671 jiffies! g35145 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=10533
rcu: rcu_preempt kthread starved for 9672 jiffies! g35145 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:26776 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 schedule+0x11b/0x1f0 kernel/sched/core.c:6456
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 6535 Comm: syz.1.584 Not tainted 5.15.170-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3932 [inline]
 rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619
 update_process_times+0x196/0x200 kernel/time/timer.c:1818
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1688 [inline]
 __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1752
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x13b/0x4b0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/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:__sanitizer_cov_trace_pc+0x37/0x60 kernel/kcov.c:209
Code: 8b 15 f5 fb 81 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 91 18 16 00 00 48 8b 32 48 8d 7e 01 8b 89 14 16 00 00 48 39
RSP: 0018:ffffc90003037878 EFLAGS: 00000246
RAX: ffffffff8174a1f4 RBX: 1ffff11017208541 RCX: ffff888075c63b80
RDX: 0000000000000002 RSI: 000000000003ffff RDI: 0000000000040000
RBP: ffffc900030379c0 R08: ffffffff8174a1c4 R09: fffffbfff20ec635
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: ffff8880b9042a08 R14: ffff8880b913b380 R15: 0000000000000001
 csd_lock_wait kernel/smp.c:440 [inline]
 smp_call_function_many_cond+0xab4/0xd90 kernel/smp.c:969
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1135
 invalidate_bdev+0x8a/0xb0 block/bdev.c:86
 ext4_fill_super+0x104b/0xa110 fs/ext4/super.c:5114
 mount_bdev+0x2c9/0x3f0 fs/super.c:1400
 legacy_get_tree+0xeb/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x2ba/0xb40 fs/namespace.c:3012
 do_mount fs/namespace.c:3355 [inline]
 __do_sys_mount fs/namespace.c:3563 [inline]
 __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f4912a9feba
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007f4910f15e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f4910f15ef0 RCX: 00007f4912a9feba
RDX: 0000000020000080 RSI: 0000000020001100 RDI: 00007f4910f15eb0
RBP: 0000000020000080 R08: 00007f4910f15ef0 R09: 0000000003000490
R10: 0000000003000490 R11: 0000000000000246 R12: 0000000020001100
R13: 00007f4910f15eb0 R14: 00000000000007b1 R15: 000000000000002c
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/07 16:45 linux-5.15.y 72244eab0dad 867e44df .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in pwq_unbound_release_workfn
* Struck through repros no longer work on HEAD.