INFO: rcu detected stall in cfg80211_wiphy_work (2)

Status: upstream: reported syz repro on 2026/06/08 04:12
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+cf15f6b60d9bbb7fc27e@syzkaller.appspotmail.com
First crash: 118d, last: 2d12h
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2026/06/08 linux-5.15.y (ToT) dc027a595035 syz [report] INFO: rcu detected stall in kthread
2026/06/08 upstream (ToT) 2d3090a8aeb5 syz Didn't crash
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in cfg80211_wiphy_work wireless 1 syz, C done done 4 997d 1147d 0/29 auto-obsoleted due to no activity on 2024/04/20 07:53
linux-5.15 INFO: rcu detected stall in cfg80211_wiphy_work 1 1 234d 234d 0/3 auto-obsoleted due to no activity on 2026/05/23 07:13
linux-6.1 INFO: rcu detected stall in cfg80211_wiphy_work (2) 1 syz, C 2 6d11h 77d 0/3 upstream: reported C repro on 2026/07/18 16:31
linux-6.1 INFO: rcu detected stall in cfg80211_wiphy_work 1 1 191d 191d 0/3 auto-obsoleted due to no activity on 2026/07/04 20:13
upstream INFO: rcu detected stall in cfg80211_wiphy_work (2) prio:normal wireless 1 syz, C done error 101 49d 685d 0/29 upstream: reported C repro on 2024/11/18 08:54
▶ ▼ Last patch testing requests (2)
Created Duration User Patch Repo Result
2026/09/01 14:29 17m retest repro linux-5.15.y report job log log
2026/07/18 17:40 23m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (1)
Created Duration User Patch Repo Result
2026/08/10 20:51 2h56m bisect fix linux-5.15.y OK (0) job log log

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5088/1:b..l
	(detected by 1, t=10502 jiffies, g=15721, q=28)
task:kworker/u4:7    state:R  running task     stack:25264 pid: 5088 ppid:     2 flags:0x00004000
Workqueue: events_unbound cfg80211_wiphy_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:435
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:35 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:106 [inline]
RIP: 0010:lock_release+0x145/0x8a0 kernel/locking/lockdep.c:5641
Code: 04 00 00 48 89 5c 24 18 43 c6 44 2c 08 00 48 c7 84 24 a0 00 00 00 00 00 00 00 9c 8f 84 24 a0 00 00 00 4c 8b bc 24 a0 00 00 00 <4c> 89 64 24 50 43 c6 44 2c 08 f8 fa 48 c7 c7 e0 39 2b 8a e8 c3 d7
RSP: 0018:ffffc9000344f800 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff888023bebb80 RCX: f4bd40fe930a7e00
RDX: 0000000000000000 RSI: ffffffff8a7a48a0 RDI: ffffffff8a7a4860
RBP: ffffc9000344f920 R08: ffffffff8d8b1eef R09: 1ffffffff1b163dd
R10: dffffc0000000000 R11: fffffbfff1b163de R12: 1ffff92000689f0c
R13: dffffc0000000000 R14: ffff888023bec66c R15: 0000000000000246
 rcu_read_unlock include/linux/rcupdate.h:773 [inline]
 sta_info_get+0x220/0x230 net/mac80211/sta_info.c:-1
 ieee80211_update_sta_info net/mac80211/ibss.c:1004 [inline]
 ieee80211_rx_bss_info net/mac80211/ibss.c:1121 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1614 [inline]
 ieee80211_ibss_rx_queued_mgmt+0xf34/0x2b50 net/mac80211/ibss.c:1643
 ieee80211_iface_process_skb net/mac80211/iface.c:1465 [inline]
 ieee80211_iface_work+0x714/0xc50 net/mac80211/iface.c:1519
 cfg80211_wiphy_work+0x224/0x260 net/wireless/core.c:433
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: rcu_preempt kthread starved for 10430 jiffies! g15721 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:26896 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571
 preempt_schedule+0xbc/0xd0 kernel/sched/core.c:6596
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
 _raw_spin_unlock_irqrestore+0x10d/0x120 kernel/locking/spinlock.c:194
 prepare_to_swait_event+0x33d/0x360 kernel/sched/swait.c:120
 rcu_gp_fqs_loop+0x289/0x11f0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145
 kthread+0x42e/0x520 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: 9443 Comm: syz.2.2497 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x1110/0x1270 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x845/0x1120 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:2021
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4b0/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1108
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0033:0x7f7918f9a6d0
Code: 83 c0 16 83 e0 f7 74 12 50 48 8d 3d aa 2c 07 00 e8 65 65 f9 ff 0f 1f 44 00 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <83> ff 21 74 0b c3 66 2e 0f 1f 84 00 00 00 00 00 55 53 48 89 f3 48
RSP: 002b:00007f79185dab38 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f7919202fa8 RCX: 00007f7918f7b159
RDX: 00007f79185dab40 RSI: 00007f79185dac70 RDI: 0000000000000021
RBP: 00007f7919202fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7919203038 R14: 00007ffe0798d940 R15: 00007ffe0798da28
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/02 00:38 linux-5.15.y 0248c33e835e f5cdae2f .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in cfg80211_wiphy_work
2026/09/27 14:23 linux-5.15.y 0248c33e835e a3c7249d .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in cfg80211_wiphy_work
2026/06/29 23:47 linux-5.15.y eceeec79dbc6 6a0c72dc .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in cfg80211_wiphy_work
2026/06/08 04:12 linux-5.15.y dc027a595035 cc095639 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in cfg80211_wiphy_work
* Struck through repros no longer work on HEAD.