INFO: task kworker/1:4:20475 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:4     state:D stack:23624 pid:20475 tgid:20475 ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5260 [inline]
 __schedule+0xeb0/0x3e50 kernel/sched/core.c:6867
 __schedule_loop kernel/sched/core.c:6949 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:6964
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7021
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
 device_lock include/linux/device.h:895 [inline]
 hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899
 process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x5da/0xe40 kernel/workqueue.c:3421
 kthread+0x3b3/0x730 kernel/kthread.c:463
 ret_from_fork+0x6c3/0xa20 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff894da3a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff894da3a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff894da3a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
5 locks held by kworker/1:1/42:
 #0: ffff8881026e3148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x11ae/0x1840 kernel/workqueue.c:3232
 #1: ffffc900004d7ca8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x927/0x1840 kernel/workqueue.c:3233
 #2: ffff88810a78d198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
 #2: ffff88810a78d198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899
 #3: ffff88811e966198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
 #3: ffff88811e966198 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9a0 drivers/usb/core/hub.c:2336
 #4: ffff88813a094160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
 #4: ffff88813a094160 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1104 [inline]
 #4: ffff88813a094160 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xaa/0x600 drivers/base/dd.c:1302
2 locks held by getty/2922:
 #0: ffff8881160210a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc900000452f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211
3 locks held by kworker/0:3/5232:
5 locks held by kworker/0:5/5266:
4 locks held by udevd/5303:
 #0: ffff888142906c30 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:182
 #1: ffff8881203c0088 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
 #2: ffff88810a784f08 (kn->active#23){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff88810a784f08 (kn->active#23){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173
 #3: ffff88811e966198 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:900 [inline]
 #3: ffff88811e966198 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
4 locks held by kworker/u8:0/12814:
 #0: ffff888100ac4948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x11ae/0x1840 kernel/workqueue.c:3232
 #1: ffffc9001510fca8 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x927/0x1840 kernel/workqueue.c:3233
 #2: ffffffff8a8b4af0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xab/0x900 net/core/net_namespace.c:670
 #3: ffffffff894e6a40 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6d0 kernel/rcu/tree.c:3816
2 locks held by kworker/0:0/13992:
5 locks held by kworker/1:9/14565:
 #0: ffff8881026e3148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x11ae/0x1840 kernel/workqueue.c:3232
 #1: ffffc90001d1fca8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x927/0x1840 kernel/workqueue.c:3233
 #2: ffff88810ab55198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
 #2: ffff88810ab55198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899
 #3: ffff888139cb1198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
 #3: ffff888139cb1198 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9a0 drivers/usb/core/hub.c:2336
 #4: ffff888115498160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
 #4: ffff888115498160 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1104 [inline]
 #4: ffff888115498160 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xaa/0x600 drivers/base/dd.c:1302
3 locks held by kworker/1:4/20475:
 #0: ffff8881026e3148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x11ae/0x1840 kernel/workqueue.c:3232
 #1: ffffc9001595fca8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x927/0x1840 kernel/workqueue.c:3233
 #2: ffff88810a75d198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
 #2: ffff88810a75d198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x141/0x190 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xcc3/0xfe0 kernel/hung_task.c:515
 kthread+0x3b3/0x730 kernel/kthread.c:463
 ret_from_fork+0x6c3/0xa20 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5266 Comm: kworker/0:5 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Workqueue: usb_hub_wq hub_event
RIP: 0010:check_preemption_disabled+0x1a/0xe0 lib/smp_processor_id.c:16
Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 54 55 53 48 83 ec 08 65 8b 1d d5 ab 77 05 65 f7 05 c6 ab 77 05 ff ff ff 7f <74> 0f 48 83 c4 08 89 d8 5b 5d 41 5c c3 cc cc cc cc 9c 58 f6 c4 02
RSP: 0018:ffffc90000007650 EFLAGS: 00000002
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000005
RDX: ffffffff816f287d RSI: ffffffff878e9720 RDI: ffffffff878e9760
RBP: ffffc90000007748 R08: 0000000086db7919 R09: 0000000000000007
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff819c9780
R13: ffffc90000007700 R14: 0000000000000000 R15: ffff888117913a80
FS:  0000000000000000(0000) GS:ffff88826896a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32124218 CR3: 00000000092a8000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
 rcu_is_watching+0x12/0xc0 kernel/rcu/tree.c:751
 rcu_read_lock include/linux/rcupdate.h:868 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0x6fa/0x1ea0 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x43/0x70 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2540 [inline]
 slab_free mm/slub.c:6670 [inline]
 kmem_cache_free+0x124/0x6d0 mm/slub.c:6781
 kfree_skbmem+0x19a/0x210 net/core/skbuff.c:1130
 __kfree_skb net/core/skbuff.c:1197 [inline]
 consume_skb net/core/skbuff.c:1428 [inline]
 consume_skb+0xd1/0x110 net/core/skbuff.c:1422
 ath6kl_usb_cleanup_recv_urb drivers/net/wireless/ath/ath6kl/usb.c:171 [inline]
 ath6kl_usb_recv_complete+0x2e6/0x460 drivers/net/wireless/ath/ath6kl/usb.c:551
 __usb_hcd_giveback_urb+0x38d/0x610 drivers/usb/core/hcd.c:1657
 usb_hcd_giveback_urb+0x3ca/0x4a0 drivers/usb/core/hcd.c:1741
 dummy_timer+0xd85/0x3670 drivers/usb/gadget/udc/dummy_hcd.c:1995
 __run_hrtimer kernel/time/hrtimer.c:1777 [inline]
 __hrtimer_run_queues+0x516/0x990 kernel/time/hrtimer.c:1841
 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1858
 handle_softirqs+0x1dd/0x8f0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xed/0x150 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0x8f/0xb0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_get_return_address+0x5d/0xa0 arch/x86/kernel/unwind_orc.c:385
Code: cc cc 48 b8 00 00 00 00 00 fc ff df 48 8d 6b 48 48 89 ea 48 c1 ea 03 80 3c 02 00 75 36 48 8b 7b 48 e8 17 59 0f 00 85 c0 74 cf <48> b8 00 00 00 00 00 fc ff df 48 89 ea 48 c1 ea 03 80 3c 02 00 75
RSP: 0018:ffffc900023f68d0 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffc900023f68e8 RCX: ffffc900023f683c
RDX: 1ffff9200047ed26 RSI: ffffffff88dcbbf7 RDI: ffffffff817f3b13
RBP: ffffc900023f6930 R08: 0000000000000001 R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000007ce8 R12: ffffffff819c9780
R13: ffffc900023f69a8 R14: 0000000000000000 R15: ffff888117913a80
 arch_stack_walk+0xa6/0xf0 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5657 [inline]
 __kmalloc_node_track_caller_noprof+0x34e/0x9a0 mm/slub.c:5764
 kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:608
 __alloc_skb+0x186/0x410 net/core/skbuff.c:690
 __netdev_alloc_skb+0x7a/0x8f0 net/core/skbuff.c:754
 netdev_alloc_skb include/linux/skbuff.h:3484 [inline]
 dev_alloc_skb include/linux/skbuff.h:3497 [inline]
 ath6kl_usb_post_recv_transfers.constprop.0+0x55/0x3d0 drivers/net/wireless/ath/ath6kl/usb.c:428
 ath6kl_usb_start_recv_pipes drivers/net/wireless/ath/ath6kl/usb.c:498 [inline]
 hif_start drivers/net/wireless/ath/ath6kl/usb.c:703 [inline]
 ath6kl_usb_power_on+0x8e/0x160 drivers/net/wireless/ath/ath6kl/usb.c:1062
 ath6kl_hif_power_on drivers/net/wireless/ath/ath6kl/hif-ops.h:136 [inline]
 ath6kl_core_init+0x173/0x11b0 drivers/net/wireless/ath/ath6kl/core.c:97
 ath6kl_usb_probe+0xcd0/0x13e0 drivers/net/wireless/ath/ath6kl/usb.c:1168
 usb_probe_interface+0x303/0x8f0 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:581 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:659
 __driver_probe_device+0x1de/0x400 drivers/base/dd.c:801
 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:831
 __device_attach_driver+0x1df/0x340 drivers/base/dd.c:959
 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1031
 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1086
 bus_probe_device+0x64/0x160 drivers/base/bus.c:574
 device_add+0x11d9/0x1950 drivers/base/core.c:3689
 usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2210
 usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250
 usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:291
 call_driver_probe drivers/base/dd.c:581 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:659
 __driver_probe_device+0x1de/0x400 drivers/base/dd.c:801
 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:831
 __device_attach_driver+0x1df/0x340 drivers/base/dd.c:959
 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1031
 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1086
 bus_probe_device+0x64/0x160 drivers/base/bus.c:574
 device_add+0x11d9/0x1950 drivers/base/core.c:3689
 usb_new_device.cold+0x685/0x115c drivers/usb/core/hub.c:2695
 hub_port_connect drivers/usb/core/hub.c:5567 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 port_event drivers/usb/core/hub.c:5871 [inline]
 hub_event+0x314d/0x4af0 drivers/usb/core/hub.c:5953
 process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x5da/0xe40 kernel/workqueue.c:3421
 kthread+0x3b3/0x730 kernel/kthread.c:463
 ret_from_fork+0x6c3/0xa20 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>