INFO: task kworker/u8:1:13 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:1    state:D stack:24184 pid:13    tgid:13    ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 __schedule+0x1550/0x5060
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x829/0x1340
 cfg802154_pernet_exit+0x19/0xe0
 ops_undo_list+0x49f/0x940
 cleanup_net+0x4df/0x7b0
