INFO: task kworker/R-ipv6_:1971 blocked for more than 443 seconds.
      Tainted: G        W    L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/R-ipv6_ state:D stack:0     pid:1971  tgid:1971  ppid:2      task_flags:0x4208060 flags:0x00000000
Workqueue: ipv6_addrconf addrconf_verify_work