INFO: task kworker/u4:11:9506 blocked for more than 143 seconds.
      Not tainted 6.3.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:11   state:D stack:26448 pid:9506  ppid:2      flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5307 [inline]
 __schedule+0xc91/0x5770 kernel/sched/core.c:6625
 schedule+0xde/0x1a0 kernel/sched/core.c:6701
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6760
 rwsem_down_write_slowpath+0x3e2/0x1220 kernel/locking/rwsem.c:1178
 __down_write_common kernel/locking/rwsem.c:1306 [inline]
 __down_write kernel/locking/rwsem.c:1315 [inline]
 down_write+0x1d2/0x200 kernel/locking/rwsem.c:1574
 rdma_dev_exit_net+0x16d/0x5a0 drivers/infiniband/core/device.c:1123
 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:169
 cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:613
 process_one_work+0x991/0x15c0 kernel/workqueue.c:2390
 worker_thread+0x669/0x1090 kernel/workqueue.c:2537
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8c794a30 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x31/0xd80 kernel/rcu/tasks.h:510