INFO: task kworker/u8:1:13 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:1    state:D stack:22080 pid:13    tgid:13    ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 __schedule+0x14ef/0x4fb0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x829/0x1340
 rdma_dev_change_netns+0x39/0x300
 rdma_dev_exit_net+0x209/0x350
 ops_undo_list+0x49f/0x940
 cleanup_net+0x4df/0x7b0
 process_scheduled_works+0xaec/0x17a0
 worker_thread+0x89f/0xd90
 kthread+0x726/0x8b0
 ret_from_fork+0x51b/0xa40
 ret_from_fork_asm+0x1a/0x30
 </TASK>
INFO: task syz.1.21366:22570 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.21366     state:D stack:25272 pid:22570 tgid:22569 ppid:5831   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x14ef/0x4fb0
 schedule+0x164/0x360
 schedule_timeout+0xc3/0x2c0
 wait_for_completion+0x2cc/0x5e0
 disable_device+0x1c6/0x330
 __ib_unregister_device+0x2cb/0x3f0
 ib_unregister_device_and_put+0xb8/0xf0
 nldev_dellink+0x288/0x320
 rdma_nl_rcv+0x6d7/0xa10
 netlink_unicast+0x80f/0x9b0
 netlink_sendmsg+0x813/0xb40
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x4d7/0x810
 ___sys_sendmsg+0x2a5/0x360
 __x64_sys_sendmsg+0x1bd/0x2a0
 do_syscall_64+0xe2/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0c77d9acb9
RSP: 002b:00007f0c78cbc028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f0c78005fa0 RCX: 00007f0c77d9acb9
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000005
RBP: 00007f0c77e08bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0c78006038 R14: 00007f0c78005fa0 R15: 00007ffd7728ef68
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/u8:1/13:
 #0: ffff888100ef7948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0
 #1: ffffc90000127bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0
 #2: ffffffff8f707b50 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xfe/0x7b0
 #3: ffff888168ac0700 (&device->unregistration_lock){+.+.}-{4:4}, at: rdma_dev_change_netns+0x39/0x300
1 lock held by khungtaskd/36:
 #0: ffffffff8e341b20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5657:
 #0: ffff8881751900a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000356b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0
2 locks held by kworker/u9:0/8431:
 #0: ffff888100089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0
 #1: ffff888121024588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880
2 locks held by syz.1.21366/22570:
 #0: ffffffff9a093df8 (&rdma_nl_types[idx].sem){.+.+}-{4:4}, at: rdma_nl_rcv+0x32b/0xa10
 #1: ffff888168ac0700 (&device->unregistration_lock){+.+.}-{4:4}, at: __ib_unregister_device+0x284/0x3f0
2 locks held by syz.4.22327/24748:
 #0: ffffffff8f707b50 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x3cb/0x570
 #1: ffff888168ac0700 (&device->unregistration_lock){+.+.}-{4:4}, at: rdma_dev_change_netns+0x39/0x300
2 locks held by syz.3.22656/25540:
 #0: ffffffff8f707b50 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x3cb/0x570
 #1: ffff888168ac0700 (&device->unregistration_lock){+.+.}-{4:4}, at: rdma_dev_change_netns+0x39/0x300
2 locks held by syz.5.22881/26045:
 #0: ffffffff8f707b50 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x3cb/0x570
 #1: ffff888168ac0700 (&device->unregistration_lock){+.+.}-{4:4}, at: rdma_dev_change_netns+0x39/0x300
2 locks held by syz.7.23630/27823:
 #0: ffffffff8f707b50 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x3cb/0x570
 #1: ffff888168ac0700 (&device->unregistration_lock){+.+.}-{4:4}, at: rdma_dev_change_netns+0x39/0x300
2 locks held by syz.8.23954/28565:
 #0: ffffffff8f707b50 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x3cb/0x570
 #1: ffff888168ac0700 (&device->unregistration_lock){+.+.}-{4:4}, at: rdma_dev_change_netns+0x39/0x300
1 lock held by syz-executor/28672:
3 locks held by kworker/0:0/28696:
 #0: ffff888100075948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0
 #1: ffffc900092ffbc0 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0
 #2: ffffffff8e347678 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770
5 locks held by syz-executor/29248:
 #0: ffff88801c2c0ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x5a0
 #1: ffff88801c2c00c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x640/0x10e0
 #2: ffffffff8f886888 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x260
 #3: ffff88816a6bcb38 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x7b/0x5b0
 #4: ffffffff8e347678 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770
2 locks held by syz.6.24815/30538:
 #0: ffffffff8f707b50 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x3cb/0x570
 #1: ffff888168ac0700 (&device->unregistration_lock){+.+.}-{4:4}, at: rdma_dev_change_netns+0x39/0x300

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 36 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+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xf90/0xfe0
 kthread+0x726/0x8b0
 ret_from_fork+0x51b/0xa40
 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: 0 Comm: swapper/0 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:pv_native_safe_halt+0xf/0x20
Code: 48 51 02 e9 03 e8 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d 63 73 13 00 fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffffff8e007dc0 EFLAGS: 00000286
RAX: 00000000007795ef RBX: ffffffff819821ed RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8d9b688e RDI: ffffffff8be08de0
RBP: ffffffff8e007eb0 R08: ffff8881210336db R09: 1ffff110242066db
R10: dffffc0000000000 R11: ffffed10242066dc R12: ffffffff8fc25270
R13: 1ffffffff1c12a68 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88818e40e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc03e537e20 CR3: 000000000e13a000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 default_idle+0x13/0x20
 default_idle_call+0x72/0xb0
 do_idle+0x1bd/0x500
 cpu_startup_entry+0x43/0x60
 rest_init+0x2de/0x300
 start_kernel+0x380/0x3d0
 x86_64_start_reservations+0x24/0x30
 x86_64_start_kernel+0x143/0x1c0
 common_startup_64+0x13e/0x147
 </TASK>
