INFO: task udevd:7425 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:23656 pid:7425  tgid:7425  ppid:5045   task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 bdev_open+0xde/0xd70
 blkdev_open+0x461/0x600
 do_dentry_open+0x816/0x1380
 vfs_open+0x3b/0x340
 path_openat+0x1443/0x1d60
 do_file_open+0x23e/0x4a0
 do_sys_openat2+0x115/0x200
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb8cf75f9a4
RSP: 002b:00007ffe0854ef80 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 000055ffee203950 RCX: 00007fb8cf75f9a4
RDX: 00000000000a0800 RSI: 000055ffee202ad0 RDI: 00000000ffffff9c
RBP: 000055ffee202ad0 R08: 0000000000000008 R09: 3fffffffffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000a0800
R13: 000055ffee210950 R14: 0000000000000001 R15: 000055ffee1f9910
 </TASK>
INFO: task syz.7.977:10314 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.977       state:D stack:28552 pid:10314 tgid:10307 ppid:8957   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 bdev_open+0xde/0xd70
 blkdev_open+0x461/0x600
 do_dentry_open+0x816/0x1380
 vfs_open+0x3b/0x340
 path_openat+0x1443/0x1d60
 do_file_open+0x23e/0x4a0
 do_sys_openat2+0x115/0x200
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3c65b5e98e
RSP: 002b:00007f3c669ffb28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f3c66a006c0 RCX: 00007f3c65b5e98e
RDX: 0000000000000000 RSI: 00007f3c669ffc00 RDI: ffffffffffffff9c
RBP: 00007f3c669ffc00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f3c65e26218 R14: 00007f3c65e26180 R15: 00007ffeb1d99328
 </TASK>

Showing all locks held in the system:
locks held by pr/ttyS0/16: 2, last CPU#1:
 #0: ffffffff8ec367b8 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60
 #1: ffffffff9ad3f098 (&port_lock_key){-...}-{3:3}, at: univ8250_console_device_lock+0x67/0xc0
locks held by khungtaskd/35: 1, last CPU#0:
 #0: ffffffff8ed5cbe0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
locks held by kworker/1:3/1288: 3, on CPU#1:
 #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #1: ffffc90007247c40 ((work_completion)(&ub->partition_scan_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #2: ffff88816a521350 (&disk->open_mutex){+.+.}-{4:4}, at: ublk_partition_scan_work+0xd9/0x140
locks held by getty/5425: 2, on CPU#0:
 #0: ffff88816e4fe0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034762e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
locks held by udevd/7304: 4, on CPU#0:
 #0: ffff88810014bab8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xa4/0xca0
 #1: ffff88810f321c80 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5d/0x420
 #2: ffff888111860b48 (kn->active#25){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x420
 #3: ffff888114ef41d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0
locks held by udevd/7425: 1, on CPU#0:
 #0: ffff88816a521350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70
locks held by kworker/u10:15/7858: 5, last CPU#0:
 #0: ffff8881000ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #1: ffffc9000374fc40 ((work_completion)(&(&kfence_timer)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #2: ffffffff8ebe9dd0 (cpu_hotplug_lock){++++}-{0:0}, at: static_key_enable+0x12/0x20
 #3: ffffffff8ee386c0 (jump_label_mutex){+.+.}-{4:4}, at: static_key_enable_cpuslocked+0xcb/0x240
 #4: ffffffff8ebffb20 (text_mutex){+.+.}-{4:4}, at: arch_jump_label_transform_apply+0x17/0x30
locks held by kworker/0:7/9084: 5, on CPU#0:
 #0: ffff8881606b9d40 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #1: ffffc90003b8fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #2: ffff88816f5241d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30
 #3: ffff888114ef41d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450
 #4: ffff8881130be1a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450
locks held by syz.7.977/10314: 1, on CPU#0:
 #0: ffff88816a521350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70
locks held by syz.0.1678/13549: 1, last CPU#0:
 #0: ffff88810b852508 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500

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

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+0x17d/0x390
 sys_info+0x135/0x170
 watchdog+0xfd7/0x1030
 kthread+0x38b/0x480
 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: 16 Comm: pr/ttyS0 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:io_serial_out+0x7c/0xc0
Code: 47 54 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 1c 84 c4 fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d c3 cc cc cc cc cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc90000157900 EFLAGS: 00000002
RAX: 0000000000000031 RBX: 0000000000000031 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f8 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff857371f0 R12: dffffc0000000000
R13: 0000000000000031 R14: ffffffff9ad3f0c0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8882a8ccc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa5b5a27dac CR3: 00000000227c2000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 __serial8250_console_fifo_write+0x1e6/0x3e0
 serial8250_console_write+0xaa1/0x1200
 nbcon_emit_next_record+0xef5/0x1a90
 nbcon_kthread_func+0x679/0x880
 kthread+0x38b/0x480
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
