INFO: task syz.2.3910:16802 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.3910      state:D stack:24016 pid:16802 tgid:16800 ppid:5815   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17e4/0x4de0
 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
 ____sys_sendmsg+0xa84/0xaf0
 ___sys_sendmsg+0x2a5/0x360
 __x64_sys_sendmsg+0x1bd/0x2a0
 do_syscall_64+0xf0/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0440d9c819
RSP: 002b:00007f0441cc5028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f0441015fa0 RCX: 00007f0440d9c819
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000004
RBP: 00007f0440e32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0441016038 R14: 00007f0441015fa0 R15: 00007ffcf4bcdac8
 </TASK>

Showing all locks held in the system:
5 locks held by kworker/u10:0/27:
1 lock held by khungtaskd/34:
 #0: ffffffff8e33eba0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5636:
 #0: ffff8881767e60a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000356e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45f/0x14a0
4 locks held by kworker/u8:3/5839:
 #0: ffff888100ef7948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17d0
 #1: ffffc90004d37ba0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17d0
 #2: ffffffff8f6ccad0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xfe/0x820
 #3: ffff88811d1bc700 (&device->unregistration_lock){+.+.}-{4:4}, at: rdma_dev_change_netns+0x39/0x300
2 locks held by syz.2.3910/16802:
 #0: ffffffff99fc5ed8 (&rdma_nl_types[idx].sem){.+.+}-{4:4}, at: rdma_nl_rcv+0x32b/0xa10
 #1: ffff88811d1bc700 (&device->unregistration_lock){+.+.}-{4:4}, at: __ib_unregister_device+0x284/0x3f0
2 locks held by syz.1.4848/19482:
 #0: ffffffff8f6ccad0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x336/0x4e0
 #1: ffff88811d1bc700 (&device->unregistration_lock){+.+.}-{4:4}, at: rdma_dev_change_netns+0x39/0x300
1 lock held by udevd/20692:
 #0: ffff88810a9d3358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
2 locks held by syz.0.5672/22047:
 #0: ffffffff8f6ccad0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x336/0x4e0
 #1: ffff88811d1bc700 (&device->unregistration_lock){+.+.}-{4:4}, at: rdma_dev_change_netns+0x39/0x300
1 lock held by syz.4.6472/24589:
 #0: ffffffff8e344500 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580
5 locks held by syz.5.6505/24688:
2 locks held by syz.3.6509/24706:
 #0: ffffffff8f6d98c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
 #1: ffffffff8e344638 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x32f/0x7e0

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

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+0x1a9/0x280
 nmi_cpu_backtrace+0x3a9/0x3e0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf5b/0xfa0
 kthread+0x726/0x8b0
 ret_from_fork+0x4d3/0x870
 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: 27 Comm: kworker/u10:0 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
Workqueue: ib-unreg-wq ib_unregister_work
RIP: 0010:unwind_next_frame+0xc86/0x2380
Code: e8 0f e9 b5 00 49 89 1f 48 8b 44 24 58 80 3c 28 00 48 8b 5c 24 70 4c 8b 6c 24 50 4c 8b 64 24 10 74 08 48 89 df e8 ea e8 b5 00 <4c> 89 23 ba 10 00 00 00 4c 89 ef 31 f6 e8 b8 ea b5 00 48 8b 14 24
RSP: 0018:ffffc90000a27218 EFLAGS: 00000246
RAX: 1ffff92000144e64 RBX: ffffc90000a27320 RCX: 1ffff92000144e01
RDX: ffffffff904a0ee6 RSI: 0000000000000002 RDI: ffffc90000a27f40
RBP: dffffc0000000000 R08: 0000000000000003 R09: ffffffff817540c5
R10: ffffc90000a27338 R11: ffffffff81aeef80 R12: ffffc90000a27f48
R13: ffffc90000a27338 R14: ffffc90000a272e8 R15: ffffc90000a27330
FS:  0000000000000000(0000) GS:ffff88818e4dc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f399e5e9f00 CR3: 0000000175796000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 arch_stack_walk+0x11b/0x150
 stack_trace_save+0xa9/0x100
 kasan_save_stack+0x3e/0x60
 kasan_record_aux_stack+0xbd/0xd0
 call_rcu+0x152/0x9e0
 kernfs_put+0x19e/0x480
 kernfs_remove_by_name_ns+0xb7/0x130
 sysfs_remove_group+0xfc/0x2c0
 sysfs_remove_groups+0x54/0xb0
 ib_free_port_attrs+0xc5/0x3b0
 disable_device+0x240/0x330
 __ib_unregister_device+0x2cb/0x3f0
 ib_unregister_work+0x19/0x30
 process_scheduled_works+0xafc/0x17d0
 worker_thread+0xda6/0x1360
 kthread+0x726/0x8b0
 ret_from_fork+0x4d3/0x870
 ret_from_fork_asm+0x1a/0x30
 </TASK>
