INFO: rcu detected stall in cfg80211_wiphy_work (2)

Status: upstream: reported on 2026/07/18 16:31
Reported-by: syzbot+b753c7154176e6621555@syzkaller.appspotmail.com
First crash: 6d20h, last: 6d20h
▶ ▼ 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 C done done 4 926d 1076d 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 163d 163d 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 120d 120d 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 C done error 94 19d 614d 0/29 upstream: reported C repro on 2024/11/18 08:54
linux-5.15 INFO: rcu detected stall in cfg80211_wiphy_work (2) origin:lts-only 1 syz 2 25d 47d 0/3 upstream: reported syz repro on 2026/06/08 04:12

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4417/1:b..l P4436/1:b..l P4490/1:b..l
	(detected by 0, t=10502 jiffies, g=12017, q=67 ncpus=2)
task:kworker/u4:17   state:R  running task     stack:22400 pid:4490  ppid:2      flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6562
 preempt_schedule_notrace+0xd9/0x120 kernel/sched/core.c:6824
 preempt_schedule_notrace_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35
 rcu_is_watching+0x76/0xa0 kernel/rcu/tree.c:722
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0xe3/0x4a0 kernel/locking/lockdep.c:5647
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 percpu_ref_put_many include/linux/percpu-refcount.h:330 [inline]
 percpu_ref_put include/linux/percpu-refcount.h:351 [inline]
 blk_mq_sched_insert_requests+0x5e4/0x890 block/blk-mq-sched.c:494
 blk_mq_dispatch_plug_list block/blk-mq.c:2808 [inline]
 blk_mq_flush_plug_list+0xb3b/0xc50 block/blk-mq.c:2857
 __blk_flush_plug+0x3e0/0x460 block/blk-core.c:1179
 blk_flush_plug include/linux/blkdev.h:1025 [inline]
 io_schedule_prepare kernel/sched/core.c:8767 [inline]
 io_schedule+0x74/0xd0 kernel/sched/core.c:8797
 rq_qos_wait+0x227/0x350 block/blk-rq-qos.c:282
 __wbt_wait block/blk-wbt.c:522 [inline]
 wbt_wait+0x384/0x650 block/blk-wbt.c:586
 __rq_qos_throttle+0x61/0xa0 block/blk-rq-qos.c:66
 rq_qos_throttle block/blk-rq-qos.h:207 [inline]
 blk_mq_get_new_requests block/blk-mq.c:2924 [inline]
 blk_mq_submit_bio+0x8ef/0x2100 block/blk-mq.c:3023
 __submit_bio+0x1a2/0x290 block/blk-core.c:591
 __submit_bio_noacct_mq block/blk-core.c:668 [inline]
 submit_bio_noacct_nocheck+0x79b/0xaa0 block/blk-core.c:697
 ext4_io_submit+0xd8/0x140 fs/ext4/page-io.c:378
 ext4_writepages+0xf76/0x2e70 fs/ext4/inode.c:2877
 do_writepages+0x3c6/0x640 mm/page-writeback.c:2491
 __writeback_single_inode+0x153/0x1170 fs/fs-writeback.c:1622
 writeback_sb_inodes+0xad5/0x17f0 fs/fs-writeback.c:1913
 __writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:1984
 wb_writeback+0x484/0xd40 fs/fs-writeback.c:2089
 wb_check_old_data_flush fs/fs-writeback.c:2189 [inline]
 wb_do_writeback fs/fs-writeback.c:2242 [inline]
 wb_workfn+0xb68/0xee0 fs/fs-writeback.c:2270
 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
task:kworker/u4:14   state:R  running task     stack:26256 pid:4436  ppid:2      flags:0x00004000
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6562
 preempt_schedule_notrace+0xd9/0x120 kernel/sched/core.c:6824
 preempt_schedule_notrace_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35
 rcu_is_watching+0x76/0xa0 kernel/rcu/tree.c:722
 rcu_read_lock include/linux/rcupdate.h:792 [inline]
 batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:769 [inline]
 batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:849 [inline]
 batadv_iv_ogm_schedule+0x475/0x1080 net/batman-adv/bat_iv_ogm.c:908
 batadv_iv_send_outstanding_bat_ogm_packet+0x6e9/0x800 net/batman-adv/bat_iv_ogm.c:1805
 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
task:kworker/u4:12   state:R  running task     stack:25648 pid:4417  ppid:2      flags:0x00004000
Workqueue: events_unbound cfg80211_wiphy_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6562
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:ieee80211_sta_get_rates+0x42b/0x6c0 net/mac80211/util.c:2189
Code: 44 24 10 44 09 f0 48 89 44 24 10 80 7c 24 07 00 74 1d e8 f8 dd cb f7 e9 66 ff ff ff e8 ee dd cb f7 41 39 dc 0f 85 6b ff ff ff <e9> ea 00 00 00 e8 db dd cb f7 48 8b 54 24 28 48 89 d0 48 c1 e8 03
RSP: 0018:ffffc90002e977d8 EFLAGS: 00000246
RAX: ffffffff89b643b2 RBX: 000000000000000b RCX: ffff88802fe4bc00
RDX: 0000000000000000 RSI: 000000000000003c RDI: 000000000000021c
RBP: 000000000000021c R08: ffffffff8e2121af R09: 1ffffffff1c42435
R10: dffffc0000000000 R11: fffffbfff1c42436 R12: 000000000000000b
R13: 000000000000003c R14: dffffc0000000000 R15: ffff88807e12b350
 ieee80211_update_sta_info net/mac80211/ibss.c:1003 [inline]
 ieee80211_rx_bss_info net/mac80211/ibss.c:1118 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1609 [inline]
 ieee80211_ibss_rx_queued_mgmt+0x112a/0x2eb0 net/mac80211/ibss.c:1638
 ieee80211_iface_process_skb net/mac80211/iface.c:1679 [inline]
 ieee80211_iface_work+0x72c/0xc70 net/mac80211/iface.c:1733
 cfg80211_wiphy_work+0x224/0x260 net/wireless/core.c:433
 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10597 jiffies! g12017 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=8890
rcu: rcu_preempt kthread starved for 10603 jiffies! g12017 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26928 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x303/0x1350 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:742
Code: 48 89 df e8 67 01 99 f7 e9 44 ff ff ff e8 8d 03 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d f7 60 4c 00 fb f4 <c3> 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffffff8c807d88 EFLAGS: 000002c6
RAX: bf43b4d812050700 RBX: ffffffff8a3a4b17 RCX: bf43b4d812050700
RDX: 0000000000000001 RSI: ffffffff8a8c17a0 RDI: ffffffff8adf42e0
RBP: ffffffff8c807ec0 R08: ffff8880b8e3580b R09: 1ffff110171c6b01
R10: dffffc0000000000 R11: ffffed10171c6b02 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8c8bc740 R15: 1ffffffff1900fbc
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2fd23ffc CR3: 00000000734da000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 default_idle_call+0x84/0xc0 kernel/sched/idle.c:109
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x250/0x680 kernel/sched/idle.c:323
 cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:422
 rest_init+0x2dc/0x300 init/main.c:745
 arch_call_rest_init+0xa/0xa init/main.c:904
 start_kernel+0x493/0x53c init/main.c:1151
 secondary_startup_64_no_verify+0xcf/0xdb
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/18 16:30 linux-6.1.y 090666d3cc90 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in cfg80211_wiphy_work
* Struck through repros no longer work on HEAD.