INFO: task kworker/u8:6:161 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:6    state:D
 stack:25160 pid:161   tgid:161   ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: events_unbound fsnotify_connector_destroy_workfn

Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x1325/0x47d0 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 schedule+0xdd/0x2c0 kernel/sched/core.c:7326
 schedule_timeout+0x1b2/0x280 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common+0x2e7/0x4c0 kernel/sched/completion.c:121
 __synchronize_srcu+0x216/0x300 kernel/rcu/srcutree.c:1496
 fsnotify_connector_destroy_workfn+0x4d/0xa0 fs/notify/mark.c:385
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
 process_scheduled_works kernel/workqueue.c:3405 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/0:0/9:
6 locks held by kworker/1:0/23:
 #0: 
ffff8881062e4940
 (
(wq_completion)usb_hub_wq
){+.+.}-{0:0}
, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
 #1: 
ffffc9000018fd18
 (
(work_completion)(&hub->events)
){+.+.}-{0:0}
, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
 #2: 
ffff88810bb271d8
 (
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1104 [inline]
, at: hub_event+0x1bb/0x4510 drivers/usb/core/hub.c:5912
 #3: 
ffff88811902e1d8
 (
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1104 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
 #4: 
ffff888105be61a0
 (
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1104 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
 #5: 
ffffffff8a542d20
 (
input_mutex
){+.+.}-{4:4}
, at: class_mutex_intr_constructor include/linux/mutex.h:255 [inline]
, at: input_register_device.cold+0x5b/0x375 drivers/input/input.c:2394
1 lock held by khungtaskd/30:
 #0: 
ffffffff896e2bc0
 (
rcu_read_lock
){....}-{1:3}
, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
7 locks held by kworker/0:2/782:
4 locks held by udevd/2859:
 #0: 
ffff88811572c428
 (
sb_writers
#8
){.+.+}-{0:0}
, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #1: 
ffff888137f35080
 (
&of->mutex
){+.+.}-{4:4}
, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
 #2: 
ffff88810e684008
 (
kn->active
#3
){.+.+}-{0:0}
, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
 #3: 
ffffffff8ae1f860
 (
uevent_sock_mutex
){+.+.}-{4:4}
, at: uevent_net_broadcast_untagged lib/kobject_uevent.c:317 [inline]
, at: kobject_uevent_net_broadcast lib/kobject_uevent.c:410 [inline]
, at: kobject_uevent_env+0xba8/0x18b0 lib/kobject_uevent.c:611
2 locks held by getty/2921:
 #0: 
ffff88811508b0a0
 (
&tty->ldisc_sem
){++++}-{0:0}
, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: 
ffffc900000452e8
 (
&ldata->atomic_read_lock
){+.+.}-{4:4}
, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
4 locks held by udevd/5766:
 #0: 
ffff88811845abd8
 (
&p->lock
){+.+.}-{4:4}
, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
 #1: 
ffff88811dc5d080
 (
&of->mutex
#2
){+.+.}-{4:4}
, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:165
 #2: 
ffff888114652968
 (
kn->active
#9
){.+.+}-{0:0}
, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:166
 #3: 
ffff8881063b81d8
 (
&dev->mutex
){....}-{4:4}
, at: device_lock_interruptible include/linux/device.h:1109 [inline]
, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
4 locks held by udevd/5769:
 #0: 
ffff888123e5ce18
 (
&p->lock
){+.+.}-{4:4}
, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
 #1: 
ffff888124bf0480
 (
&of->mutex
#2
){+.+.}-{4:4}
, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:165
 #2: 
ffff8881146564b8
 (
kn->active
#9
){.+.+}-{0:0}
, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:166
 #3: 
ffff88812de3f1d8
 (
&dev->mutex
){....}-{4:4}
, at: device_lock_interruptible include/linux/device.h:1109 [inline]
, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
6 locks held by kworker/0:3/5783:
 #0: 
ffff8881062e4940
 (
(wq_completion)usb_hub_wq
){+.+.}-{0:0}
, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
 #1: 
ffffc90001d4fd18
 (
(work_completion)(&hub->events)
){+.+.}-{0:0}
, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
 #2: 
ffff88810b77f1d8
 (
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1104 [inline]
, at: hub_event+0x1bb/0x4510 drivers/usb/core/hub.c:5912
 #3: 
ffff888104e9d1d8
 (
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1104 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
 #4: 
ffff888120e0c1a0
 (
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1104 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
 #5: 
ffffffff8a542d20
 (
input_mutex
){+.+.}-{4:4}
, at: class_mutex_intr_constructor include/linux/mutex.h:255 [inline]
, at: input_register_device.cold+0x5b/0x375 drivers/input/input.c:2394
3 locks held by kworker/0:4/5787:
4 locks held by udevd/5791:
 #0: 
ffff8881140132d8
 (
&p->lock
){+.+.}-{4:4}
, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
 #1: 
ffff888124ecd480
 (
&of->mutex
#2
){+.+.}-{4:4}
, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:165
 #2: 
ffff8881149892d8
 (
kn->active
#9
){.+.+}-{0:0}
, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:166
 #3: 
ffff888104e9d1d8
 (
&dev->mutex
){....}-{4:4}
, at: device_lock_interruptible include/linux/device.h:1109 [inline]
, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
8 locks held by kworker/0:5/5792:
4 locks held by udevd/5793:
 #0: 
ffff88812643f2d8
 (
&p->lock
){+.+.}-{4:4}
, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
 #1: 
ffff888124bf1c80
 (
&of->mutex
#2
){+.+.}-{4:4}
, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:165
 #2: 
ffff8881141412d8
 (
kn->active
#9
){.+.+}-{0:0}
, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:166
 #3: 
ffff88811902e1d8
 (
&dev->mutex
){....}-{4:4}
, at: device_lock_interruptible include/linux/device.h:1109 [inline]
, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
1 lock held by syz.7.259/6034:
 #0: 
ffffffff8ae1f860
 (
uevent_sock_mutex
){+.+.}-{4:4}
, at: uevent_net_broadcast_untagged lib/kobject_uevent.c:317 [inline]
, at: kobject_uevent_net_broadcast lib/kobject_uevent.c:410 [inline]
, at: kobject_uevent_env+0xba8/0x18b0 lib/kobject_uevent.c:611
2 locks held by syz.5.260/6035:
 #0: 
ffff88810a7c0e00
 (
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1104 [inline]
, at: __device_driver_lock drivers/base/dd.c:1171 [inline]
, at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1369
 #1: 
ffffffff8ae1f860
 (
uevent_sock_mutex
){+.+.}-{4:4}
, at: uevent_net_broadcast_untagged lib/kobject_uevent.c:317 [inline]
, at: kobject_uevent_net_broadcast lib/kobject_uevent.c:410 [inline]
, at: kobject_uevent_env+0xba8/0x18b0 lib/kobject_uevent.c:611
2 locks held by syz.6.261/6036:
 #0: 
ffff88810a7e4e00
 (
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1104 [inline]
, at: __device_driver_lock drivers/base/dd.c:1171 [inline]
, at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1369
 #1: 
ffffffff8ae1f860
 (
uevent_sock_mutex
){+.+.}-{4:4}
, at: uevent_net_broadcast_untagged lib/kobject_uevent.c:317 [inline]
, at: kobject_uevent_net_broadcast lib/kobject_uevent.c:410 [inline]
, at: kobject_uevent_env+0xba8/0x18b0 lib/kobject_uevent.c:611
2 locks held by syz.0.262/6037:
 #0: 
ffff88810becce00
 (
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1104 [inline]
, at: __device_driver_lock drivers/base/dd.c:1171 [inline]
, at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1369
 #1: 
ffffffff8ae1f860
 (
uevent_sock_mutex
){+.+.}-{4:4}
, at: uevent_net_broadcast_untagged lib/kobject_uevent.c:317 [inline]
, at: kobject_uevent_net_broadcast lib/kobject_uevent.c:410 [inline]
, at: kobject_uevent_env+0xba8/0x18b0 lib/kobject_uevent.c:611
2 locks held by syz.1.263/6038:
 #0: 
ffff88810bec8e00
 (&dev->mutex){....}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:536 [inline]
 (&dev->mutex){....}-{4:4}, at: exit_mmap+0x22c/0xa00 mm/mmap.c:1308
 #1: 
ffff8881f57397a0
 (
&rq->__lock){-.-.}-{2:2}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
&rq->__lock){-.-.}-{2:2}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
&rq->__lock){-.-.}-{2:2}, at: percpu_ref_tryget_many include/linux/percpu-refcount.h:241 [inline]
&rq->__lock){-.-.}-{2:2}, at: percpu_ref_tryget include/linux/percpu-refcount.h:266 [inline]
&rq->__lock){-.-.}-{2:2}, at: css_tryget include/linux/cgroup_refcnt.h:45 [inline]
&rq->__lock){-.-.}-{2:2}, at: css_tryget include/linux/cgroup_refcnt.h:42 [inline]
&rq->__lock){-.-.}-{2:2}, at: get_mem_cgroup_from_objcg+0x183/0x330 include/linux/memcontrol.h:491

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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:122
 nmi_trigger_cpumask_backtrace+0x21c/0x2a0 lib/nmi_backtrace.c:65
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [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:353 [inline]
 watchdog+0xcb1/0x1030 kernel/hung_task.c:561
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
yealink 2-1:36.0: unexpected response 0
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5792 Comm: kworker/0:5 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events free_obj_work
RIP: 0010:io_serial_out+0x8f/0xb0 drivers/tty/serial/8250/8250_port.c:408
Code: 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 1c 66 03 5d 40 44 89 e8 89 da ee <5b> 5d 41 5c 41 5d c3 cc cc cc cc e8 d1 c9 f0 fe eb a0 e8 5a ca f0
RSP: 0018:ffffc900000074a8 EFLAGS: 00000002
RAX: 0000000000000034 RBX: 00000000000003f8 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: ffffffff832bb805 RDI: ffffffff9424d0e0
RBP: ffffffff9424d0a0 R08: 0000000000000001 R09: 000000000000001f
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000034 R14: ffffffff9408d8a3 R15: ffffffff832bb7a0
FS:  0000000000000000(0000) GS:ffff888268633000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff95fcf4e0 CR3: 00000000094ac000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 serial_port_out include/linux/serial_core.h:813 [inline]
 serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3245 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3307 [inline]
 serial8250_console_write+0xe2c/0x1a50 drivers/tty/serial/8250/8250_port.c:3385
 console_emit_next_record kernel/printk/printk.c:3183 [inline]
 console_flush_one_record+0x790/0xe50 kernel/printk/printk.c:3269
 console_flush_all kernel/printk/printk.c:3343 [inline]
 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
 console_unlock+0x103/0x260 kernel/printk/printk.c:3413
 vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2479
 dev_vprintk_emit+0x391/0x3e0 drivers/base/core.c:4996
 dev_printk_emit+0xd2/0x10d drivers/base/core.c:5007
 __dev_printk+0xcb/0x100 drivers/base/core.c:5019
 _dev_err+0xef/0x127 drivers/base/core.c:5062
 urb_irq_callback.cold+0x81/0xfd drivers/input/misc/yealink.c:426
 __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+0xdb2/0x36f0 drivers/usb/gadget/udc/dummy_hcd.c:2019
 __run_hrtimer kernel/time/hrtimer.c:2032 [inline]
 __hrtimer_run_queues+0x462/0x9c0 kernel/time/hrtimer.c:2096
 hrtimer_run_softirq+0x17d/0x2c0 kernel/time/hrtimer.c:2113
 handle_softirqs+0x1dd/0x990 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x160/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x8f/0xb0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:kasan_quarantine_put+0x95/0x240 mm/kasan/quarantine.c:237
Code: 00 00 00 00 00 48 03 5a 10 48 89 5a 10 48 81 fb 00 00 10 00 0f 87 8d 00 00 00 4d 85 e4 75 75 9c 58 f6 c4 02 0f 85 72 01 00 00 <5b> b8 01 00 00 00 5d 41 5c 41 5d 41 5e c3 cc cc cc cc 9c 58 f6 c4
RSP: 0018:ffffc9000141fae0 EFLAGS: 00000246
RAX: 0000000000000006 RBX: 00000000000ff428 RCX: 0000000000000040
RDX: 0000000000000000 RSI: ffffffff890f4061 RDI: ffffffff87b15700
RBP: ffff88810004b8c0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 000000000000596b R12: 0000000000000200
R13: ffff888122c908f8 R14: ffffffff82dc9298 R15: 0000000000000000
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2677 [inline]
 slab_free mm/slub.c:6377 [inline]
 kmem_cache_free+0x108/0x650 mm/slub.c:6504
 free_object_list.isra.0+0xf8/0x2a0 lib/debugobjects.c:326
 free_obj_work+0x18c/0x390 lib/debugobjects.c:530
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
 process_scheduled_works kernel/workqueue.c:3405 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>