INFO: task kworker/0:0:9 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:0     state:D
 stack:21544 pid:9     tgid:9     ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: usb_hub_wq hub_event

Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1138/0x47e0 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7283
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340
 rwsem_down_write_slowpath+0x4c2/0x12c0 kernel/locking/rwsem.c:1215
 __down_write_common kernel/locking/rwsem.c:1347 [inline]
 __down_write kernel/locking/rwsem.c:1356 [inline]
 down_write+0x1c7/0x1f0 kernel/locking/rwsem.c:1626
 kernfs_add_one+0x38/0x850 fs/kernfs/dir.c:826
 kernfs_create_link+0x1a9/0x240 fs/kernfs/symlink.c:48
 sysfs_do_create_link_sd+0x90/0x140 fs/sysfs/symlink.c:44
 sysfs_do_create_link fs/sysfs/symlink.c:80 [inline]
 sysfs_create_link+0x61/0xc0 fs/sysfs/symlink.c:92
 driver_sysfs_add+0x112/0x2d0 drivers/base/dd.c:495
 really_probe+0x146/0xa60 drivers/base/dd.c:697
 __driver_probe_device+0x22e/0x480 drivers/base/dd.c:871
 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:901
 __device_attach_driver+0x1df/0x340 drivers/base/dd.c:1029
 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1101
 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1156
 bus_probe_device+0x64/0x160 drivers/base/bus.c:613
 device_add+0x1210/0x1950 drivers/base/core.c:3706
 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+0xa0e/0x1980 kernel/workqueue.c:3314
 process_scheduled_works kernel/workqueue.c:3397 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478
 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:
5 locks held by kworker/0:0/9:
5 locks held by ksoftirqd/1/22:
2 locks held by kdevtmpfs/25:
1 lock held by khungtaskd/30:
 #0: 
ffffffff896de960
 (
rcu_read_lock
){....}-{1:3}
, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:6/116:
 #0: 
ffff8881000ac940
 (
(wq_completion)events_unbound
#2
){+.+.}-{0:0}
, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289
 #1: 
ffffc900015afd18
 (
(work_completion)(&sub_info->work)
){+.+.}-{0:0}
, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290
6 locks held by kworker/1:2/1126:
 #0: 
ffff888105af8940
 (
(wq_completion)usb_hub_wq
){+.+.}-{0:0}
, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289
 #1: 
ffffc9000367fd18
 (
(work_completion)(&hub->events)
){+.+.}-{0:0}
, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290
 #2: 
ffff88810c3cc1d8
 (
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1040 [inline]
, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899
 #3: 
ffff88813725c1d8
 (
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1040 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076
 #4: 
ffff88811b8021a0
 (
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1040 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076
 #5: 
ffffffff8a515a20
 (
input_mutex){+.+.}-{4:4}, at: class_mutex_intr_constructor include/linux/mutex.h:255 [inline]
input_mutex){+.+.}-{4:4}, at: input_register_device.cold+0x5b/0x375 drivers/input/input.c:2391
2 locks held by getty/2920:
 #0: 
ffff8881163c30a0
 (
&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+0x419/0x14f0 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/2973:
 #0: ffffffff896ea4a8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
1 lock held by syz-executor/2979:
 #0: ffffffff896ea4a8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
4 locks held by udevd/5214:
 #0: 
ffff88813b9fcf38
 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
 #1: 
ffff888119ece080
 (
&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
 #2: 
ffff888120e64e18
 (kn->active#19){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 (kn->active#19){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173
 #3: 
ffff88813725c1d8
 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1045 [inline]
 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
6 locks held by kworker/1:3/5218:
2 locks held by kworker/0:4/5247:
 #0: 
ffff88810006b140
 (
(wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289
 #1: 
ffffc900020efd18
 (
free_ipc_work
){+.+.}-{0:0}
, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290
5 locks held by kworker/0:5/5250:
 #0: 
ffff888105af8940
 (
(wq_completion)usb_hub_wq
){+.+.}-{0:0}
, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289
 #1: 
ffffc9000216fd18
 (
(work_completion)(&hub->events)
){+.+.}-{0:0}
, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290
 #2: 
ffff88810bfbc1d8
 (
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1040 [inline]
, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899
 #3: 
ffff88810c349560
 (
&port_dev->status_lock
){+.+.}-{4:4}
, at: usb_lock_port drivers/usb/core/hub.c:3252 [inline]
, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline]
, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
, at: port_event drivers/usb/core/hub.c:5871 [inline]
, at: hub_event+0x2bd2/0x4af0 drivers/usb/core/hub.c:5953
 #4: 
ffff88810bb33160
 (
hcd->address0_mutex
){+.+.}-{4:4}
, at: hub_port_connect drivers/usb/core/hub.c:5465 [inline]
, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
, at: port_event drivers/usb/core/hub.c:5871 [inline]
, at: hub_event+0x2bfb/0x4af0 drivers/usb/core/hub.c:5953
4 locks held by udevd/5692:
 #0: 
ffff88813b9fccf8
 (
&p->lock
){+.+.}-{4:4}
, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
 #1: 
ffff888119ecec80
 (
&of->mutex
#2
){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
 #2: ffff88810caf5008
 (
kn->active
#19
){++++}-{0:0}
, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173
 #3: 
ffff8881372581d8
 (
&dev->mutex
){....}-{4:4}
, at: device_lock_interruptible include/linux/device.h:1045 [inline]
, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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: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 0 to CPUs 1:
yealink 5-1:36.0: urb_irq_callback - urb status -71
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 22 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:io_serial_out+0x90/0xb0 drivers/tty/serial/8250/8250_port.c:408
Code: 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 e9 96 fa 4d 04 e8 61 ab f5 fe eb a0 e8 ea ab f5 fe
RSP: 0018:ffffc9000017f2c8 EFLAGS: 00000002
RAX: 0000000000000035 RBX: ffffffff941da7c0 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: ffffffff8322f515 RDI: ffffffff941da800
RBP: ffffffff941da7c0 R08: 0000000000000001 R09: 000000000000001f
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000035 R14: 0000000000000010 R15: ffffffff8322f4b0
FS:  0000000000000000(0000) GS:ffff8882687a5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f415a79fe9c CR3: 0000000116764000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 serial_port_out include/linux/serial_core.h:811 [inline]
 serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3220 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3282 [inline]
 serial8250_console_write+0xde8/0x1900 drivers/tty/serial/8250/8250_port.c:3360
 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+0x394/0x3e0 drivers/base/core.c:4930
 dev_printk_emit+0xd2/0x10d drivers/base/core.c:4941
 __dev_printk+0xcb/0x100 drivers/base/core.c:4953
 _dev_err+0xef/0x127 drivers/base/core.c:4996
 urb_irq_callback.cold+0x41/0xfd drivers/input/misc/yealink.c:418
 __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+0xda1/0x36c0 drivers/usb/gadget/udc/dummy_hcd.c:2005
 __run_hrtimer kernel/time/hrtimer.c:1930 [inline]
 __hrtimer_run_queues+0x470/0xa00 kernel/time/hrtimer.c:1994
 hrtimer_run_softirq+0x17d/0x2c0 kernel/time/hrtimer.c:2011
 handle_softirqs+0x1dd/0x9e0 kernel/softirq.c:622
 run_ksoftirqd kernel/softirq.c:1076 [inline]
 run_ksoftirqd+0x38/0x60 kernel/softirq.c:1068
 smpboot_thread_fn+0x3d3/0xaa0 kernel/smpboot.c:160
 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>