INFO: task kworker/u8:3:5666 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:3    state:D stack:23520 pid:5666  tgid:5666  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: ipv6_addrconf addrconf_verify_work
Call Trace:
 <TASK>
 __schedule+0x17d9/0x56c0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7bf/0x1550
 addrconf_verify_work+0x19/0x30
 process_scheduled_works+0xa8e/0x14e0
 worker_thread+0xa47/0xfb0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8e959c60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by kworker/1:1H/52:
 #0: ffff888160ef0140 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc90000bc7c40 ((work_completion)(&q->timeout_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
2 locks held by kworker/0:1H/895:
 #0: ffff888160ef0140 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc9000678fc40 ((work_completion)(&q->timeout_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
2 locks held by getty/5439:
 #0: ffff888172df60a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034732e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
1 lock held by udevd/5612:
 #0: ffff88816d5e0350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70
