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: 7h31m, last: 7h31m
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 2442d 2442d 0/29 closed as invalid on 2020/01/08 05:33
upstream INFO: rcu detected stall in worker_thread (4) mm cgroups 1 28 2441d 2442d 0/29 closed as invalid on 2020/01/09 08:13
linux-5.15 INFO: rcu detected stall in worker_thread 1 1 1082d 1082d 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 1225d 1225d 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 1566d 1603d 0/29 auto-closed as invalid on 2022/08/31 00:50
android-6-12 INFO: rcu detected stall in worker_thread 1 1 338d 338d 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 netfilter 1 syz, C done 5953 8h11m 1073d 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 2442d 2442d 0/29 closed as invalid on 2020/01/08 05:23
upstream INFO: rcu detected stall in worker_thread mm cgroups 1 150 2476d 2478d 0/29 closed as invalid on 2019/12/04 14:14
linux-6.1 INFO: rcu detected stall in worker_thread 1 6 817d 848d 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 345 12h57m 454d 0/2 upstream: reported C repro on 2025/06/18 07:15
upstream INFO: rcu detected stall in worker_thread (6) kernel 1 1 1442d 1442d 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 28d 56d 0/3 upstream: reported on 2026/07/20 15:45
linux-5.15 INFO: rcu detected stall in worker_thread (2) 1 4 821d 826d 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 1334d 1334d 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 601d 601d 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 816 14h45m 717d 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 750d 750d 0/2 auto-obsoleted due to no activity on 2024/12/04 04:19
upstream INFO: task hung in synchronize_rcu (4) prio:high net 1 syz, C done error 4658 1h52m 1230d 0/29 upstream: reported C repro on 2023/05/04 02:01

Sample crash report:
bridge0: received packet on veth0_to_bridge with own address as source address (addr:da:9d:c0:61:cc:98, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-....: (1 GPs behind) idle=96d/1/0x4000000000000002 softirq=26331/26332 fqs=1651 
	(detected by 1, t=10506 jiffies, g=33473, q=568)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 9 Comm: kworker/u4:0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue:  0x0 (events_unbound)
RIP: 0010:debug_lockdep_rcu_enabled+0x25/0x30 kernel/rcu/update.c:281
Code: 00 00 cc cc 00 31 c0 83 3d 5b e5 c9 03 00 74 1d 83 3d d2 17 ca 03 00 74 14 65 48 8b 0d 04 35 41 76 31 c0 83 b9 ec 0a 00 00 00 <0f> 94 c0 c3 00 00 cc cc 00 00 cc 41 56 53 89 fb e8 16 0a 00 00 41
RSP: 0018:ffffc90000007458 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff8880788d11e8 RCX: ffff88813fe90000
RDX: 0000000000000000 RSI: ffffffff8a2b3e80 RDI: ffffffff8a7a48c0
RBP: ffffc90000007580 R08: dffffc0000000000 R09: 1ffffffff203e218
R10: dffffc0000000000 R11: fffffbfff203e219 R12: dffffc0000000000
R13: 1ffff92000000e90 R14: dffffc0000000000 R15: ffffc900000076c0
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f33014d8700 CR3: 00000000620aa000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 rcu_read_lock include/linux/rcupdate.h:741 [inline]
 __perf_event_output kernel/events/core.c:7810 [inline]
 perf_event_output_forward+0xc1/0x2e0 kernel/events/core.c:7832
 __perf_event_overflow+0x35f/0x550 kernel/events/core.c:9525
 perf_swevent_overflow kernel/events/core.c:9601 [inline]
 perf_swevent_event+0x4b8/0x540 kernel/events/core.c:9639
 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:ffffc90000007ae0 EFLAGS: 00000206
RAX: 06a640da8b61c800 RBX: 1ffff92000000f60 RCX: 06a640da8b61c800
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a48c0
RBP: ffffc90000007bc0 R08: ffff8880b903b30b R09: 1ffff11017207661
R10: dffffc0000000000 R11: ffffed1017207662 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]
 ieee80211_rx_napi+0x216/0x390 net/mac80211/rx.c:5021
 ieee80211_rx include/net/mac80211.h:4573 [inline]
 ieee80211_handle_queued_frames+0x104/0x1a0 net/mac80211/main.c:237
 tasklet_action_common+0x2ad/0x410 kernel/softirq.c:806
 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:finish_lock_switch+0x12f/0x290 kernel/sched/core.c:4804
Code: 83 c7 18 be ff ff ff ff e8 8e da 6c 08 85 c0 74 46 4d 85 ff 75 62 0f 1f 44 00 00 48 89 df e8 78 4a 76 08 e8 93 e3 2a 00 fb 5b <41> 5c 41 5d 41 5e 41 5f 5d c3 48 89 df e8 2f 0e fe ff 43 80 3c 2c
RSP: 0018:ffffc90000ce7b38 EFLAGS: 00000286
RAX: 06a640da8b61c800 RBX: ffff88801bc11dc0 RCX: 06a640da8b61c800
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a48c0
RBP: 1ffff11017207613 R08: ffff8880b903b30b R09: 1ffff11017207661
R10: dffffc0000000000 R11: ffffed1017207662 R12: 1ffff110172075c1
R13: dffffc0000000000 R14: ffff8880b903ae08 R15: 0000000000000000
 finish_task_switch+0x12f/0x650 kernel/sched/core.c:4921
 context_switch kernel/sched/core.c:5052 [inline]
 __schedule+0x11cb/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 worker_thread+0xf90/0x12a0 kernel/workqueue.c:2478
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
net_ratelimit: 3810 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:da:9d:c0:61:cc:98, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:da:9d:c0:61:cc:98, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:da:9d:c0:61:cc:98, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:da:9d:c0:61:cc:98, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:da:9d:c0:61:cc:98, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
net_ratelimit: 3773 callbacks suppressed
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:da:9d:c0:61:cc:98, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:da:9d:c0:61:cc:98, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:da:9d:c0:61:cc:98, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:da:9d:c0:61:cc:98, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:da:9d:c0:61:cc:98, vlan:0)

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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.