INFO: task syz.8.16640:2779 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.16640     state:D stack:23552 pid:2779  tgid:2775  ppid:25440  task_flags:0x400140 flags:0x00080003
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x14bc/0x5000 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6960
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017
 rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185
 __down_write_common kernel/locking/rwsem.c:1317 [inline]
 __down_write kernel/locking/rwsem.c:1326 [inline]
 down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1591
 rdma_dev_exit_net+0x8c/0x340 drivers/infiniband/core/device.c:1159
 ops_exit_list net/core/net_namespace.c:199 [inline]
 ops_undo_list+0x49a/0x990 net/core/net_namespace.c:252
 setup_net+0x2e8/0x330 net/core/net_namespace.c:462
 copy_net_ns+0x3e3/0x570 net/core/net_namespace.c:581
 create_new_namespaces+0x3e7/0x6a0 kernel/nsproxy.c:130
 unshare_nsproxy_namespaces+0x11c/0x170 kernel/nsproxy.c:226
 ksys_unshare+0x4c8/0x8c0 kernel/fork.c:3128
 __do_sys_unshare kernel/fork.c:3199 [inline]
 __se_sys_unshare kernel/fork.c:3197 [inline]
 __x64_sys_unshare+0x38/0x50 kernel/fork.c:3197
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe546b8f749
RSP: 002b:00007fe547987038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fe546de5fa0 RCX: 00007fe546b8f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000006a040000
RBP: 00007fe546c13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe546de6038 R14: 00007fe546de5fa0 R15: 00007ffcf75e8428
 </TASK>