INFO: task kworker/u8:3:5881 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:23344 pid:5881  tgid:5881  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+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30
 </TASK>
INFO: task syz.2.686:7526 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.686       state:D stack:21624 pid:7526  tgid:7525  ppid:5860   task_flags:0x400140 flags:0x00004006
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: 0033:0x7f12bef8eba9
RSP: 002b:00007f12bfe3c038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f12bf1d5fa0 RCX: 00007f12bef8eba9
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000009
RBP: 00007f12bf011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f12bf1d6038 R14: 00007f12bf1d5fa0 R15: 00007ffde498f648
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/0:0/9:
1 lock held by rcu_tasks_trace/32:
 #0: ffff888136639f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140
1 lock held by khungtaskd/34:
 #0: ffffffff8e13a120 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5679:
 #0: ffff888028ed90a0 (&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
3 locks held by kworker/0:3/5855:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900032bfbc0 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8e13fbb8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730
4 locks held by kworker/u8:3/5881:
 #0: ffff88801b2f7148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900033ffbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f52d350 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800
 #3: ffff88803d7bc700 (&device->unregistration_lock){+.+.}-{4:4}, at: rdma_dev_change_netns+0x39/0x300
2 locks held by syz.2.686/7526:
 #0: ffffffff99e6f8f8 (&rdma_nl_types[idx].sem){.+.+}-{4:4}, at: rdma_nl_rcv+0x302/0x980
 #1: ffff88803d7bc700 (&device->unregistration_lock){+.+.}-{4:4}, at: __ib_unregister_device+0x284/0x3f0
1 lock held by syz-executor/10176:
2 locks held by syz.6.1913/10556:
 #0: ffffffff99e6f8f8 (&rdma_nl_types[idx].sem){.+.+}-{4:4}, at: rdma_nl_rcv+0x302/0x980
 #1: ffff88803d7bc700 (&device->unregistration_lock){+.+.}-{4:4}, at: __ib_unregister_device+0x284/0x3f0
4 locks held by syz-executor/10728:
 #0: ffff88811f4c4dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x510
 #1: ffff88811f4c40b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x66a/0x1330
 #2: ffffffff8f69f088 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x230
 #3: ffff888035cc4338 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x70/0x680
2 locks held by syz.8.2106/11085:
 #0: ffffffff8e19d6c8 (event_mutex){+.+.}-{4:4}, at: perf_trace_destroy+0x2e/0x150
 #1: ffffffff8e13fbb8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730

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

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: 5855 Comm: kworker/0:3 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: rcu_gp wq_barrier_func
RIP: 0010:validate_chain+0xfd7/0x2140
Code: 25 ff 0f 00 00 39 05 f4 d1 0a 12 73 06 89 05 ec d1 0a 12 49 8b 04 24 48 89 de 48 39 e8 0f 84 33 fe ff ff 4c 89 68 30 48 8b 00 <48> 39 e8 75 f4 48 89 de e9 1f fe ff ff 48 c7 c7 f0 ae 00 8e 48 89
RSP: 0018:ffffc900032bf378 EFLAGS: 00000002
RAX: ffffffff9633c8b8 RBX: 00000000000003dd RCX: 0000000000000188
RDX: 0000000000000008 RSI: 00000000000003dd RDI: ffff88802298b980
RBP: ffffffff934a32a0 R08: ffffc900032bf340 R09: 0000000000000020
R10: dffffc0000000000 R11: ffffffff819de0d0 R12: ffffffff962f09c8
R13: ffffffff962c9828 R14: ffff88802298c538 R15: 0000000000000187
FS:  0000000000000000(0000) GS:ffff8880b8613000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f03a9707d60 CR3: 00000000292c2000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 __lock_acquire+0xab9/0xd20
 lock_acquire+0x120/0x360
 seqcount_lockdep_reader_access+0xc9/0x1c0
 ktime_get+0x3e/0x1f0
 start_dl_timer+0x212/0x520
 update_curr_dl_se+0x502/0x990
 update_curr+0x3fb/0x730
 enqueue_entity+0x5f/0x1120
 enqueue_task_fair+0x4a4/0x1470
 enqueue_task+0x75/0x420
 ttwu_do_activate+0x1f3/0x870
 try_to_wake_up+0x721/0x12b0
 complete+0xa9/0x1b0
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30
 </TASK>
