INFO: task syz.9.1394:13052 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.1394      state:D stack:27696 pid:13052 tgid:13044 ppid:10259  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x14ef/0x4fb0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7fe/0x1300
 sync_bdevs+0x27e/0x470
 __ia32_sys_sync+0xc5/0x120
 do_syscall_64+0xe2/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb819f9acb9
RSP: 002b:00007fb81adf2028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fb81a216090 RCX: 00007fb819f9acb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fb81a216090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb81a216128 R14: 00007fb81a216090 R15: 00007ffe3b1dbdd8
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/1:0/24:
1 lock held by khungtaskd/35:
 #0: ffffffff8e35a360 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5653:
 #0: ffff888174f5a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000356e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0
2 locks held by kworker/1:2H/6883:
1 lock held by udevd/10708:
 #0: ffff88810931b358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
1 lock held by syz.9.1394/13052:
 #0: ffff88810931b358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x27e/0x470
1 lock held by syz.7.1674/14637:
 #0: ffff88810931b358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x27e/0x470
1 lock held by syz.2.2101/16865:
 #0: ffff888176707870 (&runtime->sleep#2){....}-{3:3}, at: __debug_object_init+0x74/0x4e0

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 35 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
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+0xf90/0xfe0
 kthread+0x726/0x8b0
 ret_from_fork+0x51b/0xa40
 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: 16865 Comm: syz.2.2101 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:snd_rawmidi_write+0x63d/0xc00
Code: e3 4c 29 eb 49 bf 00 00 00 00 00 fc ff df 76 68 48 8b 44 24 60 42 0f b6 04 38 84 c0 0f 85 82 00 00 00 48 8b 44 24 30 44 8b 30 <be> 00 08 00 00 44 21 f6 31 ff e8 e4 75 b1 f8 31 ff 48 89 de e8 7a
RSP: 0018:ffffc90004957a60 EFLAGS: 00000246
RAX: ffff88811a6bae68 RBX: 0000000000001081 RCX: ffff888174b58000
RDX: 0000000000000002 RSI: 0000000000001082 RDI: 0000000000000001
RBP: ffffc90004957c10 R08: ffffffff8fcef877 R09: 1ffffffff1f9df0e
R10: dffffc0000000000 R11: fffffbfff1f9df0f R12: 0000000000001082
R13: 0000000000000001 R14: 0000000000149002 R15: dffffc0000000000
FS:  00007f09475026c0(0000) GS:ffff8882a9924000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000e000 CR3: 0000000198598000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 vfs_writev+0x4bd/0x990
 do_writev+0x154/0x2e0
 do_syscall_64+0xe2/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f094659acb9
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:00007f0947502028 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f0946815fa0 RCX: 00007f094659acb9
RDX: 0000000000000002 RSI: 0000200000000840 RDI: 0000000000000004
RBP: 00007f0946608bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0946816038 R14: 00007f0946815fa0 R15: 00007ffc43ed8ab8
 </TASK>
