INFO: task kworker/1:1H:53 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:1H    state:D stack:26504 pid:53    tgid:53    ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: kblockd blk_mq_requeue_work
Call Trace:
 <TASK>
 __schedule+0x17b4/0x5680
 schedule+0x164/0x360
 schedule_timeout+0x158/0x2c0
 nbd_queue_rq+0x857/0x1100
 blk_mq_dispatch_rq_list+0xa70/0x1910
 __blk_mq_sched_dispatch_requests+0xdcc/0x1600
 blk_mq_sched_dispatch_requests+0xd7/0x190
 blk_mq_run_hw_queue+0x348/0x4f0
 blk_mq_run_hw_queues+0x26c/0x3f0
 blk_mq_requeue_work+0x71c/0x780
 process_scheduled_works+0xb5d/0x1860
 worker_thread+0xa53/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
4 locks held by kworker/1:1H/53:
 #0: ffff888162290940 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc90000bd7c40 ((work_completion)(&(&q->requeue_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffff888104300118 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_hw_queue+0x31f/0x4f0
 #3: ffff888104b08178 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xc6/0x1100
2 locks held by getty/5440:
 #0: ffff88810d6980a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000346b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0
1 lock held by udevd/5614:
 #0: ffff8881047b1350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
3 locks held by kworker/u8:4/6355:
 #0: ffff8881012b5940 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc900083efc40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffffffff8fdc0c28 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800
4 locks held by syz.0.4904/23136:
 #0: ffff8881b77a7a40 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: sock_close+0x9b/0x240
 #1: ffffffff8fe3d148 ((netlink_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain+0x54/0x90
 #2: ffff88816cd28cd0 (&nft_net->commit_mutex){+.+.}-{4:4}, at: nft_rcv_nl_event+0x13d/0xe00
 #3: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770

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

NMI backtrace for cpu 0
CPU: 0 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+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xfd3/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 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:native_apic_msr_write+0x39/0x50
Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 e9 c0 36 36 0a cc 89 f6 31 d2 e9 66 54 7a 03 66 0f 1f 44 00
RSP: 0018:ffffc90000197c10 EFLAGS: 00000046
RAX: 00000000000037cf RBX: ffff88823c623e40 RCX: 0000000000000838
RDX: 0000000000000000 RSI: 00000000000037cf RDI: 0000000000000838
RBP: ffffc90000197cc8 R08: ffffffff81b2dfc5 R09: ffffffff9a48d588
R10: 0000000000000003 R11: ffffffff817446c0 R12: 00000000000037cf
R13: dffffc0000000000 R14: 0000000010000f19 R15: 0000000000000020
FS:  0000000000000000(0000) GS:ffff8882a928d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f36c15ea2f8 CR3: 000000016db76000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lapic_next_event+0x11/0x20
 clockevents_program_event+0x385/0x630
 __hrtimer_rearm_deferred+0x270/0x450
 irqentry_exit+0x67d/0x730
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:pv_native_safe_halt+0xf/0x20
Code: ab 7d 02 e9 93 f6 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 53 b1 20 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:ffffc90000197e20 EFLAGS: 00000202
RAX: 00000000001dc329 RBX: ffffffff819a91ea RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8dfa69f2 RDI: ffffffff8c28ade0
RBP: ffffc90000197f10 R08: ffff88823c6339db R09: 1ffff110478c673b
R10: dffffc0000000000 R11: ffffed10478c673c R12: 0000000000000001
R13: 1ffff1102c09e000 R14: 0000000000000001 R15: 1ffff1102c09e000
 default_idle+0x9/0x20
 default_idle_call+0x72/0xb0
 do_idle+0x36a/0x5f0
 cpu_startup_entry+0x43/0x60
 start_secondary+0x101/0x110
 common_startup_64+0x13e/0x147
 </TASK>
