syzbot


INFO: task hung in ath6kl_usb_power_off (5)

Status: upstream: reported on 2026/01/29 06:40
Reported-by: syzbot+9b8909ebe75a0e3e758e@syzkaller.appspotmail.com
First crash: 103d, last: 16h02m
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in ath6kl_usb_power_off wireless 1 7454 1370d 2136d 22/29 fixed on 2023/02/24 13:50
linux-5.15 INFO: task hung in ath6kl_usb_power_off (3) 1 1 592d 592d 0/3 auto-obsoleted due to no activity on 2025/01/05 17:18
linux-5.15 INFO: task hung in ath6kl_usb_power_off (4) 1 1 247d 247d 0/3 auto-obsoleted due to no activity on 2025/12/16 04:15
linux-5.15 INFO: task hung in ath6kl_usb_power_off (2) 1 2 773d 795d 0/3 auto-obsoleted due to no activity on 2024/07/08 14:28
linux-5.15 INFO: task hung in ath6kl_usb_power_off 1 1 1036d 1036d 0/3 auto-obsoleted due to no activity on 2023/10/19 06:26

Sample crash report:
INFO: task kworker/0:7:4264 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:7     state:D stack:22736 pid: 4264 ppid:     2 flags:0x00004000
Workqueue: usb_hub_wq hub_event
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+0xbd/0x2d0 kernel/time/timer.c:2093
 do_wait_for_common+0x2a2/0x450 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 flush_workqueue+0x664/0x13d0 kernel/workqueue.c:2882
 hif_detach_htc drivers/net/wireless/ath/ath6kl/usb.c:861 [inline]
 ath6kl_usb_power_off+0x34/0x40 drivers/net/wireless/ath/ath6kl/usb.c:1060
 ath6kl_hif_power_off drivers/net/wireless/ath/ath6kl/hif-ops.h:143 [inline]
 ath6kl_core_init+0xac4/0x1090 drivers/net/wireless/ath/ath6kl/core.c:257
 ath6kl_usb_probe+0x1302/0x1410 drivers/net/wireless/ath/ath6kl/usb.c:1160
 usb_probe_interface+0x5c5/0xb20 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x284/0xc80 drivers/base/dd.c:595
 __driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
 __device_attach_driver+0x2b0/0x500 drivers/base/dd.c:907
 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
 __device_attach+0x2a8/0x480 drivers/base/dd.c:979
 bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
 device_add+0xa00/0xfb0 drivers/base/core.c:3412
 usb_set_configuration+0x1991/0x1fd0 drivers/usb/core/message.c:2223
 usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
 usb_probe_device+0x139/0x270 drivers/usb/core/driver.c:293
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x284/0xc80 drivers/base/dd.c:595
 __driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
 __device_attach_driver+0x2b0/0x500 drivers/base/dd.c:907
 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
 __device_attach+0x2a8/0x480 drivers/base/dd.c:979
 bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
 device_add+0xa00/0xfb0 drivers/base/core.c:3412
 usb_new_device+0xd65/0x1660 drivers/usb/core/hub.c:2632
 hub_port_connect drivers/usb/core/hub.c:5497 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5637 [inline]
 port_event drivers/usb/core/hub.c:5799 [inline]
 hub_event+0x2e4a/0x55e0 drivers/usb/core/hub.c:5881
 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>
INFO: task udevd:6908 blocked for more than 146 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:23120 pid: 6908 ppid:  3560 flags:0x00004002
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_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xcfc/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 device_lock include/linux/device.h:764 [inline]
 uevent_show+0x17a/0x330 drivers/base/core.c:2408
 dev_attr_show+0x50/0xb0 drivers/base/core.c:2110
 sysfs_kf_seq_show+0x316/0x4c0 fs/sysfs/file.c:61
 seq_read_iter+0x49b/0xd50 fs/seq_file.c:230
 call_read_iter include/linux/fs.h:2167 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x759/0xd60 fs/read_write.c:485
 ksys_read+0x152/0x260 fs/read_write.c:623
 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: 0033:0x7fd12dd39407
RSP: 002b:00007ffefc125e00 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fd12dc4b880 RCX: 00007fd12dd39407
RDX: 0000000000001000 RSI: 000055b58e2cb4d0 RDI: 0000000000000008
RBP: 00007fd12de81ff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a
R13: 00007fd12de81ea0 R14: 0000000000000000 R15: 000055b58e2436d0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c31eb20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3940:
 #0: ffff88802c62f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900026562e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158
5 locks held by kworker/0:7/4264:
 #0: ffff88801bb84938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc9000320fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffff888147f55220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline]
 #2: ffff888147f55220 (&dev->mutex){....}-{3:3}, at: hub_event+0x19f/0x55e0 drivers/usb/core/hub.c:5827
 #3: ffff88802a3ad220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline]
 #3: ffff88802a3ad220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:954
 #4: ffff88802881f1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline]
 #4: ffff88802881f1a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:954
2 locks held by kworker/u4:7/4345:
3 locks held by kworker/0:13/4519:
 #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc900035ffd00 (key_gc_work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffffffff8c3235a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #2: ffffffff8c3235a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845
4 locks held by udevd/6908:
 #0: ffff88805b4cf540 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xad/0xd50 fs/seq_file.c:182
 #1: ffff88805fde3c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x51/0x3c0 fs/kernfs/file.c:112
 #2: ffff888060b320f0 (kn->active#32){++++}-{0:0}, at: kernfs_seq_start+0x71/0x3c0 fs/kernfs/file.c:113
 #3: ffff88802a3ad220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline]
 #3: ffff88802a3ad220 (&dev->mutex){....}-{3:3}, at: uevent_show+0x17a/0x330 drivers/base/core.c:2408
2 locks held by kworker/0:6/9068:
 #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc9000345fd00 ((work_completion)(&m->mpeg_thread)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
3 locks held by kworker/0:15/9079:

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe0f/0xe50 kernel/hung_task.c:369
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 423 Comm: kworker/u4:3 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:lockdep_hardirqs_on_prepare+0x26/0x770 kernel/locking/lockdep.c:4231
Code: 00 00 66 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec 80 00 00 00 65 48 8b 04 25 28 00 00 00 48 89 44 24 60 <48> ba 00 00 00 00 00 fc ff df 48 c7 44 24 20 b3 8a b5 41 48 c7 44
RSP: 0018:ffffc900031ef2c0 EFLAGS: 00000086
RAX: fcc72596d9a2fe00 RBX: 0000000000000000 RCX: ffff88801f010000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff81494d76
RBP: ffffc900031ef380 R08: ffff88807d828153 R09: 1ffff1100fb0502a
R10: dffffc0000000000 R11: ffffed100fb0502b R12: ffffffff892bce99
R13: ffffc900031ef6a0 R14: dffffc0000000000 R15: 1ffff9200063de74
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c37f80d CR3: 0000000023b07000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 trace_hardirqs_on+0x67/0x80 kernel/trace/trace_preemptirq.c:49
 __local_bh_enable_ip+0x136/0x1c0 kernel/softirq.c:406
 spin_unlock_bh include/linux/spinlock.h:409 [inline]
 cfg80211_bss_update+0x1c79/0x2250 net/wireless/scan.c:1913
 cfg80211_inform_single_bss_frame_data net/wireless/scan.c:2549 [inline]
 cfg80211_inform_bss_frame_data+0x89f/0x1fc0 net/wireless/scan.c:2582
 ieee80211_bss_info_update+0x6be/0xa70 net/mac80211/scan.c:190
 ieee80211_rx_bss_info net/mac80211/ibss.c:1123 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1614 [inline]
 ieee80211_ibss_rx_queued_mgmt+0x1700/0x2ab0 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>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/12 03:49 linux-5.15.y de8dfb3f0278 d168f260 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in ath6kl_usb_power_off
2026/04/13 10:42 linux-5.15.y 91d48252ad4b 9530ccf9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in ath6kl_usb_power_off
2026/03/12 18:11 linux-5.15.y 91d48252ad4b 4efadf07 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in ath6kl_usb_power_off
2026/01/29 06:40 linux-5.15.y 9eec9a14ee10 0adc945e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in ath6kl_usb_power_off
* Struck through repros no longer work on HEAD.