syzbot


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: 9d09h, last: 9d09h
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 (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in cfg80211_wiphy_work wireless 1 C done done 4 888d 1038d 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 125d 125d 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 1 1 82d 82d 0/3 upstream: reported on 2026/03/26 20:13
upstream INFO: rcu detected stall in cfg80211_wiphy_work (2) wireless prio:normal 1 C done error 93 40d 576d 0/29 upstream: reported C repro on 2024/11/18 08:54

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9/2:b..l
	(detected by 0, t=10502 jiffies, g=8581, q=120)
task:kworker/u4:0    state:R  running task     stack:21104 pid:    9 ppid:     2 flags:0x00004000
Workqueue: events_unbound cfg80211_wiphy_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 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:rcu_read_unlock include/linux/rcupdate.h:772 [inline]
RIP: 0010:sta_info_get+0x216/0x230 net/mac80211/sta_info.c:-1
Code: e0 1f 37 f8 eb 24 e8 d9 1f 37 f8 c6 05 78 30 34 04 01 48 c7 c7 40 59 39 8b be 02 03 00 00 48 c7 c2 e0 59 39 8b e8 fa 7d 70 00 <e8> 55 78 23 f8 e8 20 2a 01 00 48 89 d8 5b 41 5c 41 5e 41 5f 5d c3
RSP: 0018:ffffc90000ce7930 EFLAGS: 00000293
RAX: ffffffff89422869 RBX: ffff88807a350000 RCX: ffff88813fe90000
RDX: 0000000000000000 RSI: ffffffff8a7a09a0 RDI: ffffffff8a7a0960
RBP: 0000000000000001 R08: 0000000000000000 R09: 000000000000000c
R10: 000000000000000c R11: 0000000000000000 R12: dffffc0000000000
R13: 1ffff9200019cf48 R14: ffff88807e2d8c80 R15: ffff88807a350050
 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+0xf1a/0x2ab0 net/mac80211/ibss.c:1643
 ieee80211_iface_process_skb net/mac80211/iface.c:1459 [inline]
 ieee80211_iface_work+0x70e/0xc60 net/mac80211/iface.c:1513
 cfg80211_wiphy_work+0x221/0x260 net/wireless/core.c:433
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: rcu_preempt kthread starved for 10517 jiffies! g8581 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:28016 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5032 Comm: syz.3.319 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__lock_acquire+0xe51/0x7d10 kernel/locking/lockdep.c:-1
Code: 00 84 c0 0f 85 2c 5e 00 00 83 3d e9 b6 d0 14 00 0f 95 c0 49 83 ff ff 0f 94 c1 08 c1 0f 84 fc 4d 00 00 c7 44 24 68 00 00 00 00 <48> 8b 5c 24 78 48 89 d8 48 c1 e8 03 42 80 3c 00 00 74 12 48 89 df
RSP: 0018:ffffc900048ff420 EFLAGS: 00000002
RAX: 0000000000000000 RBX: ffff8880247d28a0 RCX: ffffffff962def01
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff901d80c0
RBP: ffffc900048ff670 R08: dffffc0000000000 R09: 1ffffffff203b018
R10: dffffc0000000000 R11: fffffbfff203b019 R12: ffff8880247d28d0
R13: ffff8880247d1dc0 R14: 1ffff110048fa514 R15: ffffffffffffffff
FS:  00007fca1405b6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 000000001fd21000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 _raw_spin_lock_nested+0x2e/0x40 kernel/locking/spinlock.c:368
 raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
 raw_spin_rq_lock kernel/sched/sched.h:1326 [inline]
 rq_lock kernel/sched/sched.h:1621 [inline]
 __schedule+0x2d4/0x43c0 kernel/sched/core.c:6309
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 freezable_schedule include/linux/freezer.h:172 [inline]
 futex_wait_queue_me+0x22d/0x440 kernel/futex/core.c:2863
 futex_wait+0x256/0x680 kernel/futex/core.c:2964
 do_futex+0xdb2/0x12b0 kernel/futex/core.c:3983
 __do_sys_futex kernel/futex/core.c:4060 [inline]
 __se_sys_futex+0x389/0x420 kernel/futex/core.c:4041
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fca149f9e59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fca1405b0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007fca14c72fa8 RCX: 00007fca149f9e59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fca14c72fa8
RBP: 00007fca14c72fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fca14c73038 R14: 00007ffeadcae910 R15: 00007ffeadcae9f8
 </TASK>

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