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: 58d, last: 36d
▶ ▼ 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 937d 1087d 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 174d 174d 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 1 18d 18d 0/3 upstream: reported on 2026/07/18 16:31
linux-6.1 INFO: rcu detected stall in cfg80211_wiphy_work 1 1 131d 131d 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 99 3d20h 625d 0/29 upstream: reported C repro on 2024/11/18 08:54
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/07/18 17:40 23m retest repro linux-5.15.y report log

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4428/1:b..l P144/2:b..l P4434/1:b..l
	(detected by 1, t=10503 jiffies, g=9425, q=47)
task:kworker/u4:9    state:R  running task     stack:26416 pid: 4434 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_notrace+0xd9/0x120 kernel/sched/core.c:6650
 preempt_schedule_notrace_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35
 rcu_is_watching+0x72/0xa0 kernel/rcu/tree.c:1124
 trace_lock_release include/trace/events/lock.h:58 [inline]
 lock_release+0xb5/0x8a0 kernel/locking/lockdep.c:5634
 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:1459 [inline]
 ieee80211_iface_work+0x714/0xc50 net/mac80211/iface.c:1513
 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>
task:kworker/u4:1    state:R  running task     stack:22672 pid:  144 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:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:jhash+0x41a/0x6d0 include/linux/jhash.h:95
Code: f8 48 c1 e8 03 0f b6 04 10 84 c0 0f 85 e5 01 00 00 41 0f b6 07 c1 e0 10 41 01 c4 4d 8d 7e 05 4c 89 f8 48 c1 e8 03 0f b6 04 10 <84> c0 0f 85 9f 01 00 00 41 0f b6 07 c1 e0 08 41 01 c4 4d 8d 7e 04
RSP: 0018:ffffc9000166f860 EFLAGS: 00000a03
RAX: 0000000000000000 RBX: 000000001bf3c7d4 RCX: ffff88801bc03b80
RDX: dffffc0000000000 RSI: ffffffff8d66ee30 RDI: 0000000000000006
RBP: 000000001bf3c7d4 R08: ffff88801bc03b80 R09: 000000000000000c
R10: 000000000000000c R11: 0000000000000000 R12: 000000001bf3c7d4
R13: 1ffff920002cdf48 R14: ffff88805b3ab05a R15: ffff88805b3ab05f
 rht_key_get_hash include/linux/rhashtable.h:140 [inline]
 rht_key_hashfn include/linux/rhashtable.h:159 [inline]
 __rhashtable_lookup include/linux/rhashtable.h:596 [inline]
 rhltable_lookup include/linux/rhashtable.h:688 [inline]
 sta_info_hash_lookup+0x10c/0x580 net/mac80211/sta_info.c:162
 sta_info_get+0xcc/0x230 net/mac80211/sta_info.c:174
 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:1459 [inline]
 ieee80211_iface_work+0x714/0xc50 net/mac80211/iface.c:1513
 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>
task:kworker/u4:8    state:R  running task     stack:24640 pid: 4428 ppid:     2 flags:0x00004000
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
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:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:lock_acquire+0x208/0x400 kernel/locking/lockdep.c:5627
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f1 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04
RSP: 0018:ffffc90003e0f900 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 4db36afd9d792000
RDX: 0000000000000000 RSI: ffffffff8a2b3e80 RDI: ffffffff8a79c980
RBP: ffffc90003e0fa20 R08: dffffc0000000000 R09: 1ffffffff2039618
R10: dffffc0000000000 R11: fffffbfff2039619 R12: ffffffff8c31ef20
R13: 1ffff920007c1f2c R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:760 [inline]
 batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:840 [inline]
 batadv_iv_ogm_schedule+0x434/0x1000 net/batman-adv/bat_iv_ogm.c:899
 batadv_iv_send_outstanding_bat_ogm_packet+0x6bb/0x7d0 net/batman-adv/bat_iv_ogm.c:1796
 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 10582 jiffies! g9425 f0x0 RCU_GP_INIT(4) ->state=0x0 ->cpu=0
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: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_irq include/linux/spinlock_api_smp.h:169 [inline]
 _raw_spin_unlock_irq+0x3c/0x40 kernel/locking/spinlock.c:202
 rcu_gp_init+0xd04/0x10f0 kernel/rcu/tree.c:1869
 rcu_gp_kthread+0x187/0x370 kernel/rcu/tree.c:2135
 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4782 Comm: syz.1.207 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:context_tracking_recursion_exit kernel/context_tracking.c:50 [inline]
RIP: 0010:__context_tracking_enter+0x73/0x90 kernel/context_tracking.c:102
Code: 76 83 fb 01 75 11 84 c0 74 0d e8 d8 4c e3 f7 4c 89 f7 e8 70 d9 9a f7 48 c7 c7 00 e8 32 8a e8 34 02 00 00 65 89 1d fd 6e 49 76 <48> c7 c7 60 e9 32 8a e8 21 02 00 00 65 ff 0d e6 6e 49 76 5b 41 5e
RSP: 0018:ffffc90003997ef8 EFLAGS: 00000082
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 772a85ee680a4200
RDX: 0000000000000000 RSI: ffffffff8a32e800 RDI: ffffffff8a79c980
RBP: ffffc90003997f48 R08: ffffffff8d89e06f R09: 1ffffffff1b13c0d
R10: dffffc0000000000 R11: fffffbfff1b13c0e R12: 0000000000000000
R13: 0000000000000000 R14: ffff88801df1d940 R15: 0000000000000027
FS:  00007fe637b946c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 0000000072ff2000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 user_enter_irqoff include/linux/context_tracking.h:41 [inline]
 __exit_to_user_mode kernel/entry/common.c:136 [inline]
 syscall_exit_to_user_mode+0x3c/0x40 kernel/entry/common.c:309
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fe63852cbd7
Code: 8d 3d d7 8b 0b 00 e8 58 1d fa ff e8 a3 87 00 00 0f 1f 00 b8 68 00 00 00 0f 05 c3 0f 1f 84 00 00 00 00 00 b8 27 00 00 00 0f 05 <c3> 0f 1f 84 00 00 00 00 00 b8 6e 00 00 00 0f 05 c3 0f 1f 84 00 00
RSP: 002b:00007fe637b93b08 EFLAGS: 00000202 ORIG_RAX: 0000000000000027
RAX: 0000000000000007 RBX: 00007fe637b93c70 RCX: 00007fe63852cbd7
RDX: 00007fe637b93b40 RSI: 00007fe637b93c70 RDI: 0000000000000021
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007fe6387ac038 R14: 00007ffc0f79a6b0 R15: 00007ffc0f79a798
 </TASK>
sched: RT throttling activated

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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.