INFO: task syz-executor:9881 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:21224 pid:9881  tgid:9881  ppid:1      task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 wb_wait_for_completion+0x15f/0x260
 __writeback_inodes_sb_nr+0x1f6/0x250
 sync_filesystem+0xa3/0x230
 generic_shutdown_super+0x6f/0x2c0
 bch2_kill_sb+0x41/0x50
 deactivate_locked_super+0xbc/0x130
 cleanup_mnt+0x425/0x4c0
 task_work_run+0x1d4/0x260
 exit_to_user_mode_loop+0xec/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f330798ff17
RSP: 002b:00007ffe335d5c98 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f3307a11c05 RCX: 00007f330798ff17
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe335d5d50
RBP: 00007ffe335d5d50 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe335d6de0
R13: 00007f3307a11c05 R14: 000000000003d786 R15: 00007ffe335d6e20
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by kworker/u9:2/53:
 #0: ffff8881001ae948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900007bfbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
2 locks held by kworker/u9:3/83:
 #0: ffff8881001ae948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000179fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
2 locks held by kworker/u10:5/3571:
 #0: ffff8881001ae948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90008e97bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
2 locks held by getty/5674:
 #0: ffff888026e9a0a0 (&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 syz-executor/9725:
 #0: ffff88810950e0e0 (&type->s_umount_key#52){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
1 lock held by syz-executor/9881:
 #0: ffff8881089fc0e0 (&type->s_umount_key#52){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
1 lock held by syz-executor/10574:
 #0: ffff88810a5300e0 (&type->s_umount_key#52){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
1 lock held by syz.6.844/13442:
 #0: ffff8881089fc0e0 (&type->s_umount_key#52){++++}-{4:4}, at: super_lock+0x25c/0x3b0
1 lock held by syz.5.845/13446:

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

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+0xf93/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 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: 13443 Comm: syz.3.843 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: 72 70 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 bc e0 d3 fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d e9 97 6f 2d 06 cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc900042aef90 EFLAGS: 00000002
RAX: 000000000000005b RBX: 000000000000005b RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 000000000004f6b7 RDI: 000000000004f6b8
RBP: 00000000000003f8 R08: ffff888107330237 R09: 1ffff11020e66046
R10: dffffc0000000000 R11: ffffffff854f3b00 R12: dffffc0000000000
R13: ffffffff99afd8c1 R14: ffffffff99df2420 R15: 0000000000000000
FS:  00007f57f61c16c0(0000) GS:ffff8881a3c18000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f58111ff000 CR3: 000000010644c000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 serial8250_console_write+0x1410/0x1ba0
 console_flush_all+0x728/0xc40
 console_unlock+0xc4/0x270
 vprintk_emit+0x5b7/0x7a0
 _printk+0xcf/0x120
 bch2_print_string_as_lines+0x135/0x250
 print_mount_opts+0x647/0x7a0
 bch2_fs_start+0x9e/0xda0
 bch2_fs_get_tree+0xb39/0x1520
 vfs_get_tree+0x92/0x2b0
 do_new_mount+0x2a2/0x9e0
 __se_sys_mount+0x317/0x410
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f57f539038a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f57f61c0e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f57f61c0ef0 RCX: 00007f57f539038a
RDX: 0000200000000240 RSI: 00002000000064c0 RDI: 00007f57f61c0eb0
RBP: 0000200000000240 R08: 00007f57f61c0ef0 R09: 000000000201c810
R10: 000000000201c810 R11: 0000000000000246 R12: 00002000000064c0
R13: 00007f57f61c0eb0 R14: 0000000000005aa1 R15: 0000200000006400
 </TASK>
