INFO: task kworker/u4:4:56 blocked for more than 143 seconds.
      Not tainted 6.4.0-rc5-syzkaller-00915-ge7c5433c5aaa #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:4    state:D stack:23320 pid:56    ppid:2      flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5343 [inline]
 __schedule+0xc9a/0x5880 kernel/sched/core.c:6669
 schedule+0xde/0x1a0 kernel/sched/core.c:6745
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6804
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0xa3b/0x1350 kernel/locking/mutex.c:747
 fib6_rules_net_exit_batch+0x15/0xe0 net/ipv6/fib6_rules.c:500