INFO: task kworker/u8:8:30624 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:8    state:D stack:23328 pid:30624 tgid:30624 ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 __schedule+0x1550/0x5060
 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+0x5b0/0xb20
 ret_from_fork_asm+0x1a/0x30
 </TASK>
INFO: task syz.5.12490:2806 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.12490     state:D stack:24264 pid:2806  tgid:2805  ppid:29446  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x1550/0x5060
 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+0xf0/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f784a19acb9
RSP: 002b:00007f784af86028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f784a405fa0 RCX: 00007f784a19acb9
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000005
RBP: 00007f784a208bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f784a406038 R14: 00007f784a405fa0 R15: 00007ffe0e304c88
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8e341aa0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5656:
 #0: ffff8881752970a0 (&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
4 locks held by kworker/u8:8/30624:
 #0: ffff888100ef7948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0
 #1: ffffc900054a7b80 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0
 #2: ffffffff8f707a30 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xfe/0x7b0
 #3: ffff88816bc48700 (&device->unregistration_lock){+.+.}-{4:4}, at: rdma_dev_change_netns+0x39/0x300
2 locks held by syz.5.12490/2806:
 #0: ffffffff9a07fe18 (&rdma_nl_types[idx].sem){.+.+}-{4:4}, at: rdma_nl_rcv+0x32b/0xa10
 #1: ffff88816bc48700 (&device->unregistration_lock){+.+.}-{4:4}, at: __ib_unregister_device+0x284/0x3f0

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 35 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
 sys_info+0x135/0x170
 watchdog+0xf90/0xfe0
 kthread+0x726/0x8b0
 ret_from_fork+0x5b0/0xb20
 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: 11257 Comm: syz.8.16122 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:check_preemption_disabled+0x50/0x110
Code: c1 ff ff ff 7f 74 23 65 48 8b 0d 0b 94 48 07 48 3b 4c 24 08 0f 85 cb 00 00 00 48 83 c4 10 5b 41 5e 41 5f 5d c3 cc cc cc cc cc <48> c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 74 c8 65
RSP: 0018:ffffc90007b1f9c8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000080000000
RDX: 000000005a44979c RSI: ffffffff8dc20f2e RDI: ffffffff8be08d60
RBP: ffffffff81e67ba1 R08: ffffffff81e67ba1 R09: ffffffff8e341aa0
R10: 000000000000001e R11: 0000000000000002 R12: 0000000000000002
R13: ffffffff8e341aa0 R14: 0000000000000000 R15: 0000000000000246
FS:  00007f4ef4d656c0(0000) GS:ffff88818e422000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f42ad7e8400 CR3: 0000000174e12000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x126/0x340
 bpf_percpu_array_update+0x102/0x4f0
 bpf_map_update_value+0x338/0x920
 generic_map_update_batch+0x5b5/0x810
 bpf_map_do_batch+0x39b/0x630
 __sys_bpf+0x709/0x920
 __x64_sys_bpf+0x7c/0x90
 do_syscall_64+0xf0/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4ef3f9acb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4ef4d65028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f4ef4205fa0 RCX: 00007f4ef3f9acb9
RDX: 0000000000000086 RSI: 0000200000000300 RDI: 000000000000001a
RBP: 00007f4ef4008bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4ef4206038 R14: 00007f4ef4205fa0 R15: 00007ffdec60ec98
 </TASK>
