INFO: task kworker/u8:4:5883 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:4    state:D stack:23624 pid:5883  tgid:5883  ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_verify_work
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 addrconf_verify_work+0x19/0x30
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e13a120 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
8 locks held by kworker/u10:3/64:
3 locks held by kworker/u9:3/1089:
 #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90006dc7bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f53a208 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60
3 locks held by kworker/u9:4/1090:
3 locks held by syslogd/5280:
1 lock held by dhcpcd/5594:
 #0: ffffffff8f53a208 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x5b7/0xd20
2 locks held by getty/5676:
 #0: ffff8880266c80a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
1 lock held by syz-executor/5845:
 #0: ffffffff8f53a208 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
4 locks held by kworker/u8:2/5857:
3 locks held by kworker/u8:3/5866:
3 locks held by kworker/u8:4/5883:
 #0: ffff88810a0d5948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000388fbc0 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f53a208 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x19/0x30
3 locks held by kworker/0:20/10022:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900038ffbc0 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f53a208 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20
3 locks held by kworker/0:29/10031:
