INFO: task syz.8.4576:17737 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.4576      state:D stack:25032 pid:17737 tgid:17736 ppid:16605  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: 0033:0x7f5a55f8ec29
RSP: 002b:00007f5a56dcb038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f5a561d5fa0 RCX: 00007f5a55f8ec29
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000004
RBP: 00007f5a56011e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5a561d6038 R14: 00007f5a561d5fa0 R15: 00007ffdd39e42c8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8dd3aca0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5650:
 #0: ffff888027cd90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
4 locks held by kworker/u8:2/5701:
 #0: ffff88801aef7148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90002defbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f0bf9f0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x820
 #3: ffff888107e04700 (&device->unregistration_lock){+.+.}-{4:4}, at: rdma_dev_change_netns+0x39/0x300
3 locks held by kworker/0:3/5855:
 #0: ffff88801b33e148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90003acfbc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff888023dde198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20
2 locks held by syz.8.4576/17737:
 #0: ffffffff99901878 (&rdma_nl_types[idx].sem){.+.+}-{4:4}, at: rdma_nl_rcv+0x302/0x980
 #1: ffff888107e04700 (&device->unregistration_lock){+.+.}-{4:4}, at: __ib_unregister_device+0x284/0x3f0

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

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+0x439/0x7d0
 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: 9 Comm: kworker/0:0 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: events legacy_dvb_usb_read_remote_control
RIP: 0010:asm_sysvec_apic_timer_interrupt+0x0/0x20
Code: b6 89 35 0a e9 61 06 00 00 90 f3 0f 1e fa 0f 1f 00 fc 6a ff e8 11 05 00 00 48 89 c4 48 89 e7 e8 c6 88 35 0a e9 41 06 00 00 90 <f3> 0f 1e fa 0f 1f 00 fc 6a ff e8 f1 04 00 00 48 89 c4 48 89 e7 e8
RSP: 0018:ffffc900000c7718 EFLAGS: 00000093
RAX: ffffffff819e9127 RBX: ffffffff819e8fe4 RCX: ffff88801bee8000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8dd2ef40
RBP: ffffc900000c7850 R08: ffffffff8f5cac37 R09: 1ffffffff1eb9586
R10: dffffc0000000000 R11: fffffbfff1eb9587 R12: dffffc0000000000
R13: 1ffff92000018eec R14: 0000000000000200 R15: 0000000000000017
FS:  0000000000000000(0000) GS:ffff8880b8d7e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055557e03c608 CR3: 000000000db36000 CR4: 00000000000006f0
Call Trace:
 <TASK>
RIP: 0010:vprintk_emit+0x58f/0x7a0
Code: 85 32 01 00 00 e8 11 85 1f 00 41 89 df 4d 85 f6 48 8b 1c 24 75 07 e8 00 85 1f 00 eb 06 e8 f9 84 1f 00 fb 48 c7 c7 40 ef d2 8d <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 b9 35
RSP: 0018:ffffc900000c7740 EFLAGS: 00000293
 _printk+0xcf/0x120
 m920x_rc_query+0x2f6/0x830
 legacy_dvb_usb_read_remote_control+0x100/0x470
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30
 </TASK>
