INFO: task kworker/u4:1:11 blocked for more than 143 seconds.
      Not tainted 6.8.0-rc2-next-20240202-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:1    state:D stack:19120 pid:11    tgid:11    ppid:2      flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5400 [inline]
 __schedule+0x17df/0x4a40 kernel/sched/core.c:6727
 __schedule_loop kernel/sched/core.c:6804 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6819
 schedule_timeout+0xb0/0x310 kernel/time/timer.c:2159
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common kernel/sched/completion.c:127 [inline]
 wait_for_completion+0x355/0x620 kernel/sched/completion.c:148
 __flush_workqueue+0x730/0x1630 kernel/workqueue.c:3617
 drain_workqueue+0xc9/0x390 kernel/workqueue.c:3730
 destroy_workqueue+0xba/0xc40 kernel/workqueue.c:5319
 bond_destructor+0x4d/0x80 drivers/net/bonding/bond_main.c:5846
 netdev_run_todo+0xd4f/0xf40 net/core/dev.c:10581
 default_device_exit_batch+0x975/0x9f0 net/core/dev.c:11625
 ops_exit_list net/core/net_namespace.c:175 [inline]
 cleanup_net+0x775/0xb90 net/core/net_namespace.c:618
 process_one_work kernel/workqueue.c:3049 [inline]
 process_scheduled_works+0x913/0x14f0 kernel/workqueue.c:3125
 worker_thread+0xa60/0x1000 kernel/workqueue.c:3206
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:242
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/u4:1/11:
 #0: ffff888015acd948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3024 [inline]
 #0: ffff888015acd948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x825/0x14f0 kernel/workqueue.c:3125
 #1: ffffc90000107d20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3024 [inline]
 #1: ffffc90000107d20 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x825/0x14f0 kernel/workqueue.c:3125
 #2: ffffffff8f36da50 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xf5/0xb90 net/core/net_namespace.c:580
1 lock held by khungtaskd/29:
 #0: ffffffff8e130d60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline]
 #0: ffffffff8e130d60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline]
 #0: ffffffff8e130d60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614
3 locks held by kworker/0:2/783:
 #0: ffff888018ac7548 ((wq_completion)pm){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3024 [inline]
 #0: ffff888018ac7548 ((wq_completion)pm){+.+.}-{0:0}, at: process_scheduled_works+0x825/0x14f0 kernel/workqueue.c:3125
 #1: ffffc9000404fd20 ((work_completion)(&hcd->wakeup_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3024 [inline]
 #1: ffffc9000404fd20 ((work_completion)(&hcd->wakeup_work)){+.+.}-{0:0}, at: process_scheduled_works+0x825/0x14f0 kernel/workqueue.c:3125
 #2: ffff888023b23190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:990 [inline]
 #2: ffff888023b23190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1fe/0x5150 drivers/usb/core/hub.c:5840
2 locks held by getty/4826:
 #0: ffff88802e8020a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900031332f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b5/0x1e10 drivers/tty/n_tty.c:2201
2 locks held by syz-executor.1/3940:
2 locks held by syz-executor.0/3944:

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

NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted 6.8.0-rc2-next-20240202-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xfb0/0xff0 kernel/hung_task.c:379
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:242
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 783 Comm: kworker/0:2 Not tainted 6.8.0-rc2-next-20240202-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Workqueue: usb_hub_wq hub_event
RIP: 0010:io_serial_out+0x7e/0xc0 drivers/tty/serial/8250/8250_port.c:417
Code: fc 89 e9 41 d3 e7 48 83 c3 40 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 9c b0 c6 fc 44 03 3b 44 89 f0 44 89 fa ee <5b> 41 5c 41 5e 41 5f 5d c3 cc cc cc cc 89 e9 80 e1 07 38 c1 7c a7
RSP: 0018:ffffc9000404ee70 EFLAGS: 00000002
RAX: 000000000000005b RBX: ffffffff947c8100 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 000000000002b199 RDI: 000000000002b19a
RBP: 0000000000000000 R08: ffffffff8530144b R09: 1ffff11003efc046
R10: dffffc0000000000 R11: ffffffff85301400 R12: dffffc0000000000
R13: 000000000000005b R14: 000000000000005b R15: 00000000000003f8
FS:  0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f38b30158e5 CR3: 000000004a92c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 serial8250_console_write+0x12ea/0x18c0 drivers/tty/serial/8250/8250_port.c:3451
 console_emit_next_record kernel/printk/printk.c:2890 [inline]
 console_flush_all+0x809/0xec0 kernel/printk/printk.c:2956
 console_unlock+0x13b/0x4d0 kernel/printk/printk.c:3025
 vprintk_emit+0x509/0x720 kernel/printk/printk.c:2292
 dev_vprintk_emit+0x2ae/0x330 drivers/base/core.c:4850
 dev_printk_emit+0xdd/0x120 drivers/base/core.c:4861
 _dev_info+0x122/0x170 drivers/base/core.c:4919
 hub_port_init+0x7bf/0x2620 drivers/usb/core/hub.c:4942
 hub_port_connect drivers/usb/core/hub.c:5441 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5652 [inline]
 port_event drivers/usb/core/hub.c:5812 [inline]
 hub_event+0x295f/0x5150 drivers/usb/core/hub.c:5894
 process_one_work kernel/workqueue.c:3049 [inline]
 process_scheduled_works+0x913/0x14f0 kernel/workqueue.c:3125
 worker_thread+0xa60/0x1000 kernel/workqueue.c:3206
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:242
 </TASK>