INFO: task kworker/u8:3:5876 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:3    state:D stack:23904 pid:5876  tgid:5876  ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 rdma_dev_change_netns+0x39/0x300
 rdma_dev_exit_net+0x203/0x340
 ops_undo_list+0x49a/0x990
 cleanup_net+0x4c5/0x800
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
INFO: task syz.0.1886:13065 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.1886      state:D stack:25080 pid:13065 tgid:13064 ppid:5839   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_timeout+0x9a/0x270
 wait_for_completion+0x2bf/0x5d0
 disable_device+0x1c6/0x320
 __ib_unregister_device+0x2cb/0x3f0
 ib_unregister_device_and_put+0xb8/0xf0
 nldev_dellink+0x2d1/0x320
 rdma_nl_rcv+0x6ae/0x980
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0b3bd8ebe9
RSP: 002b:00007f0b3cb79038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f0b3bfc5fa0 RCX: 00007f0b3bd8ebe9
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000007
RBP: 00007f0b3be11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0b3bfc6038 R14: 00007f0b3bfc5fa0 R15: 00007fff4b1290f8
 </TASK>
INFO: task syz.1.2005:13510 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.2005      state:D stack:26024 pid:13510 tgid:13509 ppid:5848   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 rdma_dev_change_netns+0x39/0x300
 rdma_dev_exit_net+0x203/0x340
 ops_undo_list+0x49a/0x990
 setup_net+0x2d3/0x320
 copy_net_ns+0x31b/0x4d0
 create_new_namespaces+0x3f3/0x720
 unshare_nsproxy_namespaces+0x11c/0x170
 ksys_unshare+0x4c8/0x8c0
 __x64_sys_unshare+0x38/0x50
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbc5338ebe9
RSP: 002b:00007fbc5426a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fbc535c5fa0 RCX: 00007fbc5338ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000064000600
RBP: 00007fbc53411e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbc535c6038 R14: 00007fbc535c5fa0 R15: 00007ffeddc81088
 </TASK>
INFO: lockdep is turned off.
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 34 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf93/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 20473 Comm: syz.1.3865 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:rcu_is_watching+0x44/0xb0
Code: 73 65 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd 10 fd bd 8d 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 9c b9 7c 00 <48> c7 c3 98 8f a1 92 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38
RSP: 0018:ffffc9000400f890 EFLAGS: 00000246
RAX: 1ffffffff1b7bfa2 RBX: 0000000000000000 RCX: 3b6d8630aad5f600
RDX: ffff888044580000 RSI: ffffffff8be33660 RDI: ffffffff8be33620
RBP: 0000000000000000 R08: ffffffff8fa38537 R09: 1ffffffff1f470a6
R10: dffffc0000000000 R11: fffffbfff1f470a7 R12: 0000000000000001
R13: 0000000000000000 R14: ffffffff8dbdfd10 R15: dffffc0000000000
FS:  00007fb02ae986c0(0000) GS:ffff8880b861a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558590f5c8 CR3: 0000000069a72000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 skb_copy_datagram_iter+0x8a/0x230
 unix_stream_read_actor+0x6c/0xb0
 unix_stream_read_generic+0xac3/0x2480
 unix_stream_recvmsg+0x15d/0x1b0
 sock_recvmsg+0x22c/0x270
 __sys_recvfrom+0x1f6/0x340
 __x64_sys_recvfrom+0xde/0x100
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb029f8ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb02ae98038 EFLAGS: 00000246 ORIG_RAX: 000000000000002d
RAX: ffffffffffffffda RBX: 00007fb02a1c5fa0 RCX: 00007fb029f8ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000008
RBP: 00007fb02a011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000010102 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb02a1c6038 R14: 00007fb02a1c5fa0 R15: 00007ffc053d6968
 </TASK>
