INFO: task syz.3.931:12523 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.931       state:D stack:19784 pid:12523 tgid:12522 ppid:11700  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 __closure_sync+0x163/0x220
 bch2_read_iter+0x1038/0x1440
 vfs_read+0x55a/0xa30
 ksys_read+0x145/0x250
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd15f18ec29
RSP: 002b:00007fd160087038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fd15f3d5fa0 RCX: 00007fd15f18ec29
RDX: 0000000000002000 RSI: 0000200000000000 RDI: 0000000000000006
RBP: 00007fd15f211e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd15f3d6038 R14: 00007fd15f3d5fa0 R15: 00007ffddac5e268
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/1:0/24:
1 lock held by khungtaskd/34:
 #0: ffffffff8e33d320 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
3 locks held by kworker/u10:5/1093:
 #0: ffff88801ac89948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90007167ba0 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8e342db8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730
2 locks held by getty/5674:
 #0: ffff8880255ec0a0 (&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
1 lock held by sshd/5772:
6 locks held by kworker/1:5/5895:
 #0: ffff88801c726d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90003affba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff88810a1d8198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20
 #3: ffff8881353df198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400
 #4: ffff888113d61160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400
 #5: ffff88813663a018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140
4 locks held by udevd/7207:
 #0: ffff88810d8b2d58 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe20
 #1: ffff888043503088 (&of->mutex#2){+.+.}-{4:4}
, at: kernfs_seq_start+0x5c/0x420
 #2: ffff88804b024048 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880
 #3: ffffffff8e0167c8 (rename_lock.seqcount){+.+.}-{0:0}, at: prepend_path+0x22a/0x830
1 lock held by syz.3.931/12523:
 #0: ffff88810e764ef8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320
2 locks held by syz.4.1432/16093:
 #0: ffff888034edb808 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: sock_close+0x9b/0x240
 #1: ffff88802944e258 (sk_lock-AF_CAN){+.+.}-{0:0}, at: j1939_sk_release+0xb3/0x7c0
2 locks held by syz.2.1435/16121:

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

NMI backtrace for cpu 0
CPU: 0 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+0xf60/0xfa0
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 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: 24 Comm: kworker/1:0 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 request_module_async
RIP: 0010:io_serial_out+0x7c/0xc0
Code: 87 69 fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 7c 29 cf fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d e9 47 b1 2b 06 cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc900001c70b0 EFLAGS: 00000002
RAX: 0000000000000036 RBX: 0000000000000036 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f8 R08: ffff888106fa0237 R09: 1ffff11020df4046
R10: dffffc0000000000 R11: ffffffff8556d2d0 R12: dffffc0000000000
R13: ffffffff99d198ed R14: ffffffff9a00f5a0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881a39fc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7e877ff000 CR3: 000000010f490000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 serial8250_console_write+0x1410/0x1ba0
 console_flush_all+0x6f3/0xb10
 console_unlock+0xbb/0x190
 vprintk_emit+0x4c5/0x590
 dev_vprintk_emit+0x337/0x3f0
 dev_printk_emit+0xe0/0x130
 _dev_info+0x10a/0x160
 em28xx_v4l2_init+0x1a65/0x2e70
 em28xx_init_extension+0x120/0x1c0
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 ret_from_fork_asm+0x1a/0x30
 </TASK>
