INFO: task syz.0.1615:11775 blocked for more than 143 seconds.
      Not tainted syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.1615      state:D
  running task    
 stack:27432 pid:11775 tgid:11774 ppid:2964   task_flags:0x40044c flags:0x00080003
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0xeb1/0x4220 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7008
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
 uevent_net_broadcast_untagged lib/kobject_uevent.c:317 [inline]
 kobject_uevent_net_broadcast lib/kobject_uevent.c:410 [inline]
 kobject_uevent_env+0xba8/0x18b0 lib/kobject_uevent.c:608
 device_remove+0xcb/0x180 drivers/base/dd.c:571
 __device_release_driver drivers/base/dd.c:1284 [inline]
 device_release_driver_internal+0x42e/0x600 drivers/base/dd.c:1307
 driver_detach+0xd8/0x1b0 drivers/base/dd.c:1370
 bus_remove_driver+0x13b/0x2e0 drivers/base/bus.c:784
 driver_unregister+0x76/0xb0 drivers/base/driver.c:277
 usb_gadget_unregister_driver+0x49/0x70 drivers/usb/gadget/udc/core.c:1752
 raw_release+0x19b/0x260 drivers/usb/gadget/legacy/raw_gadget.c:463
 __fput+0x3ff/0xb40 fs/file_table.c:469
 task_work_run+0x150/0x240 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x8b8/0x2b60 kernel/exit.c:976
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1118
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x7e/0x430 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x671/0x7b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa28bc3c4ab
RSP: 002b:00007fa28a68cf00 EFLAGS: 00000246
 ORIG_RAX: 0000000000000010
RAX: fffffffffffffffc RBX: 0000000000000003 RCX: 00007fa28bc3c4ab
RDX: 00007fa28a68dfd0 RSI: 0000000080085502 RDI: 0000000000000003
RBP: 00007fa28a68dfd0 R08: 0000000000000008 R09: 00007fa28a68cfc8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000080085502
R13: 0000000800000000 R14: 0000000000000008 R15: 00007fa28bcf0ede
 </TASK>

Showing all locks held in the system:
10 locks held by kworker/0:0/9:
1 lock held by khungtaskd/30:
 #0: ffffffff896de6e0
 (
rcu_read_lock){....}-{1:3}
, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by kworker/0:2/1117:
5 locks held by kworker/0:3/2813:
2 locks held by getty/2916:
 #0: ffff8881126ec0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc900000432f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211
1 lock held by sshd-session/2950:
4 locks held by udevd/5198:
 #0: 
ffff888134baf0a0
 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
 #1: ffff88811f0e6888 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
 #2: 
ffff8881205ef788
 (
kn->active
#21){++++}-{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: 
ffff88813a3ed198
 (
&dev->mutex
){....}-{4:4}
, at: device_lock_interruptible include/linux/device.h:900 [inline]
, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
3 locks held by kworker/0:4/5266:
5 locks held by kworker/0:7/6300:
4 locks held by kworker/u8:0/10011:
 #0: 
ffff888101291148
 (
(wq_completion)netns){+.+.}-{0:0}
, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
 #1: ffffc90001aafd18
 (
net_cleanup_work
){+.+.}-{0:0}
, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
 #2: 
ffffffff8aacf630
 (
pernet_ops_rwsem
){++++}-{4:4}
, at: cleanup_net+0xb8/0x9e0 net/core/net_namespace.c:675
 #3: 
ffffffff896ea1c0
 (
rcu_state.barrier_mutex
){+.+.}-{4:4}
, at: rcu_barrier+0x48/0x6d0 kernel/rcu/tree.c:3828
1 lock held by syz-executor/11799:
 #0: 
ffffffff8aacf630
 (
pernet_ops_rwsem
){++++}-{4:4}
, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577
1 lock held by syz-executor/11820:
 #0: 
ffffffff8aacf630
 (
pernet_ops_rwsem
){++++}-{4:4}
, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577
2 locks held by syz-executor/11845:
 #0: 
ffffffff8aacf630
 (
pernet_ops_rwsem
){++++}-{4:4}
, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577
 #1: 
ffffffff896ea2f8
 (
rcu_state.exp_mutex
){+.+.}-{4:4}
, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
1 lock held by syz-executor/11855:
 #0: 
ffffffff8aacf630
 (
pernet_ops_rwsem
){++++}-{4:4}
, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577
1 lock held by syz-executor/11866:
 #0: 
ffffffff8aacf630
 (
pernet_ops_rwsem
){++++}-{4:4}
, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577
2 locks held by syz-executor/11868:
 #0: 
ffffffff8aacf630
 (
pernet_ops_rwsem
){++++}-{4:4}
, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577
 #1: 
ffffffff896ea2f8
 (rcu_state.exp_mutex
){+.+.}-{4:4}
, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
1 lock held by syz-executor/11883:
 #0: 
ffffffff8aacf630
 (
pernet_ops_rwsem
){++++}-{4:4}
, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577
1 lock held by modprobe/11947:
 #0: 
ffff888101290188
 (
&root->kernfs_rwsem
){++++}-{4:4}
, at: kernfs_dop_revalidate+0xa5/0x740 fs/kernfs/dir.c:1185

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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+0xd25/0x1050 kernel/hung_task.c:515
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x6c3/0xcb0 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 3-1:36.0: unexpected response 0
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 1117 Comm: kworker/0:2 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: events_power_efficient gc_worker
RIP: 0010:io_serial_out+0x8f/0xb0 drivers/tty/serial/8250/8250_port.c:407
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 61 b5 f5 fe eb a0 e8 ea b5 f5
RSP: 0018:ffffc90000007450 EFLAGS: 00000002
RAX: 000000000000005b RBX: 00000000000003f8 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: ffffffff832001f5 RDI: ffffffff9418b700
RBP: ffffffff9418b6c0 R08: 0000000000000001 R09: 000000000000001f
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 000000000000005b R14: 0000000000000010 R15: ffffffff83200190
FS:  0000000000000000(0000) GS:ffff8882686f6000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f08a39656b8 CR3: 00000000094ae000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 serial_port_out include/linux/serial_core.h:811 [inline]
 serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3192 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3264 [inline]
 serial8250_console_write+0xde8/0x1900 drivers/tty/serial/8250/8250_port.c:3342
 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:4913
 dev_printk_emit+0xd2/0x10d drivers/base/core.c:4924
 __dev_printk+0xcb/0x100 drivers/base/core.c:4936
 _dev_err+0xef/0x127 drivers/base/core.c:4979
 urb_irq_callback.cold+0x81/0xfd drivers/input/misc/yealink.c:435
 __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:1785 [inline]
 __hrtimer_run_queues+0x50e/0xa70 kernel/time/hrtimer.c:1849
 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1866
 handle_softirqs+0x1de/0x9d0 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:__seqprop_spinlock_sequence include/linux/seqlock.h:228 [inline]
RIP: 0010:nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:343 [inline]
RIP: 0010:gc_worker+0x2bb/0x1630 net/netfilter/nf_conntrack_core.c:1548
Code: 00 00 48 c7 c7 88 f2 ee 8a e8 b1 7e 18 fb 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 5f 7d 3b fb 58 48 85 db 0f 85 93 0f 00 00 <e8> 70 82 3b fb 8b 1d ca af 78 04 89 dd 31 ff 83 e5 01 89 ee e8 0c
RSP: 0018:ffffc90002e0fb58 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff86764d46
RDX: ffff88810f781d80 RSI: ffffffff86764d55 RDI: ffff88810f781d80
RBP: 0000000000002319 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000040000 R14: 000000000000118d R15: 0000000000001770
 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276
 process_scheduled_works kernel/workqueue.c:3359 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x6c3/0xcb0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>