INFO: rcu detected stall in worker_thread (3)

Status: upstream: reported on 2026/09/15 04:10
Reported-by: syzbot+dcc5956a72c528978ade@syzkaller.appspotmail.com
First crash: 23d, last: 10d
▶ ▼ Similar bugs (19)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in worker_thread (3) mm cgroups 1 1 2465d 2465d 0/29 closed as invalid on 2020/01/08 05:33
upstream INFO: rcu detected stall in worker_thread (4) mm cgroups 1 28 2465d 2465d 0/29 closed as invalid on 2020/01/09 08:13
linux-5.15 INFO: rcu detected stall in worker_thread 1 1 1105d 1105d 0/3 auto-obsoleted due to no activity on 2024/01/09 18:17
upstream INFO: rcu detected stall in worker_thread (8) kernel 1 1 1248d 1248d 0/29 auto-obsoleted due to no activity on 2023/08/07 05:14
upstream INFO: rcu detected stall in worker_thread (5) kernel 1 2 1589d 1626d 0/29 auto-closed as invalid on 2022/08/31 00:50
android-6-12 INFO: rcu detected stall in worker_thread 1 1 362d 362d 0/1 auto-obsoleted due to no activity on 2026/01/09 16:24
upstream INFO: rcu detected stall in worker_thread (9) prio:low wireless 1 syz, C done 6092 5h47m 1097d 0/29 upstream: reported C repro on 2023/10/07 18:33
upstream INFO: rcu detected stall in worker_thread (2) cgroups mm 1 12 2465d 2465d 0/29 closed as invalid on 2020/01/08 05:23
upstream INFO: rcu detected stall in worker_thread mm cgroups 1 150 2500d 2502d 0/29 closed as invalid on 2019/12/04 14:14
linux-6.1 INFO: rcu detected stall in worker_thread 1 6 841d 871d 0/3 auto-obsoleted due to no activity on 2024/09/27 16:46
linux-6.6 INFO: rcu detected stall in worker_thread origin:lts-only 1 syz, C done 373 16h25m 477d 0/2 upstream: reported C repro on 2025/06/18 07:15
upstream INFO: rcu detected stall in worker_thread (6) kernel 1 1 1465d 1465d 0/29 auto-obsoleted due to no activity on 2023/01/12 15:50
linux-6.1 INFO: rcu detected stall in worker_thread (3) 1 2 52d 80d 0/3 upstream: reported on 2026/07/20 15:45
linux-5.15 INFO: rcu detected stall in worker_thread (2) 1 4 844d 849d 0/3 auto-obsoleted due to no activity on 2024/09/24 04:34
upstream INFO: rcu detected stall in worker_thread (7) kernel 1 1 1358d 1358d 0/29 auto-obsoleted due to no activity on 2023/04/27 16:37
linux-6.1 INFO: rcu detected stall in worker_thread (2) 1 1 625d 625d 0/3 auto-obsoleted due to no activity on 2025/05/01 18:18
upstream INFO: task hung in crda_timeout_work (8) wireless prio:high 1 syz, C done error 1022 2h22m 741d 0/29 upstream: reported C repro on 2024/09/27 16:53
android-5-15 BUG: soft lockup in worker_thread origin:lts 1 syz, C done 1 773d 773d 0/2 auto-obsoleted due to no activity on 2024/12/04 04:19
upstream INFO: task hung in synchronize_rcu (4) prio:high fs bluetooth 1 syz, C done error 4876 1h48m 1253d 0/29 upstream: reported C repro on 2023/05/04 02:01

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-....: (1 GPs behind) idle=e91/1/0x4000000000000002 softirq=18445/18446 fqs=5248 
	(detected by 1, t=10502 jiffies, g=22853, q=2212)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6491 Comm: kworker/0:44 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue:  0x0 (rcu_gp)
RIP: 0010:unwind_next_frame+0x9e7/0x1cf0 arch/x86/kernel/unwind_orc.c:549
Code: 28 84 c0 4c 8d 73 35 4c 8b 7c 24 08 0f 85 e3 0f 00 00 41 c6 06 00 ba 10 00 00 00 48 8d 7b 50 31 f6 e8 ed 21 89 00 4c 8b 04 24 <e9> b0 04 00 00 4c 89 7c 24 08 48 8d 7b 08 48 89 f8 48 c1 e8 03 80
RSP: 0018:ffffc90000006fc8 EFLAGS: 00000002
RAX: ffffc90000007110 RBX: ffffc900000070c0 RCX: 0000000000000000
RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc90000007120
RBP: dffffc0000000000 R08: ffffc90003e2ff58 R09: ffffc90000007110
R10: dffffc0000000000 R11: fffff52000000e24 R12: 1ffffffff1c0cc0f
R13: 1ffffffff1c0cc0f R14: ffffc900000070f5 R15: ffffffff8e06607c
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000000c08e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 perf_callchain_kernel+0x470/0x760 arch/x86/events/core.c:2783
 get_perf_callchain+0x356/0x460 kernel/events/callchain.c:200
 perf_callchain kernel/events/core.c:7616 [inline]
 perf_prepare_sample+0x352/0x1cb0 kernel/events/core.c:7643
 __perf_event_output kernel/events/core.c:7812 [inline]
 perf_event_output_forward+0x185/0x2e0 kernel/events/core.c:7832
 __perf_event_overflow+0x35f/0x550 kernel/events/core.c:9525
 perf_tp_event+0x324/0xbe0 kernel/events/core.c:10057
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10031
 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14
 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 42 0b 9d 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc900000079c0 EFLAGS: 00000206
RAX: 8efbdd30296be100 RBX: 1ffff92000000f3c RCX: 8efbdd30296be100
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a48c0
RBP: ffffc90000007aa0 R08: ffffffff901f11bf R09: 1ffffffff203e237
R10: dffffc0000000000 R11: fffffbfff203e238 R12: ffffffff8c323400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 hsr_announce+0x29a/0x310 net/hsr/hsr_device.c:409
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x56c/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_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 2e c4 92 f7 48 89 df e8 66 9b 93 f7 e8 a1 97 b4 f7 fb bf 01 00 00 00 <e8> b6 b0 87 f7 65 8b 05 e7 c6 37 76 85 c0 74 02 5b c3 e8 24 d4 35
RSP: 0018:ffffc90003e2fdb8 EFLAGS: 00000286
RAX: 8efbdd30296be100 RBX: ffff8880b9039b40 RCX: 8efbdd30296be100
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: 0000000000000001
RBP: ffff88805e73c508 R08: ffff8880b903b30b R09: 1ffff11017207661
R10: dffffc0000000000 R11: ffffed1017207662 R12: ffff8880279397a0
R13: dffffc0000000000 R14: ffff88805e73c500 R15: ffff8880b9039b40
 worker_thread+0xf8b/0x12a0 kernel/workqueue.c:2477
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/27 23:11 linux-5.15.y 0248c33e835e a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in worker_thread
2026/09/15 04:10 linux-5.15.y 0248c33e835e 81a27d1a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in worker_thread
* Struck through repros no longer work on HEAD.