INFO: task syz-executor:11525 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:21832 pid:11525 tgid:11525 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: 0033:0x7febf158ff17
RSP: 002b:00007ffe3d85c698 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007febf1611c05 RCX: 00007febf158ff17
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe3d85c750
RBP: 00007ffe3d85c750 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe3d85d7e0
R13: 00007febf1611c05 R14: 0000000000088049 R15: 00007ffe3d85d820
 </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/u10:3/64:
 #0: ffff88801d2d6948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000172fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
3 locks held by kworker/u9:3/152:
 #0: ffff88801d2d6948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000263fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff888115da80e0 (&type->s_umount_key#59){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0
2 locks held by getty/5676:
 #0: ffff888026e630a0 (&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
2 locks held by syz.9.832/11022:
 #0: ffff88810ffffaf8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320
 #1: ffff888115da8428 (sb_writers#19){.+.+}-{0:0}, at: vfs_write+0x211/0xb30
1 lock held by syz-executor/11525:
 #0: ffff888127d3e0e0 (&type->s_umount_key#59){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
1 lock held by syz.5.1109/13292:
 #0: ffff888127d3e0e0 (&type->s_umount_key#59){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz-executor/13530:
1 lock held by syz.1.1387/15059:
 #0: ffff8880225ec428 (sb_writers#40){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90
3 locks held by syz.8.1390/15069:

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

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: 15069 Comm: syz.8.1390 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_in+0x77/0xc0
Code: e8 8e 78 70 fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 8f e6 d3 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc90002f4ef98 EFLAGS: 00000006
RAX: 1ffffffff33bde05 RBX: 00000000000003f9 RCX: 0000000000000000
RDX: 00000000000003f9 RSI: 0000000000035995 RDI: 0000000000035996
RBP: ffffc90002f4f170 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff854f32b0 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff99def420 R15: 0000000000000000
FS:  00007fb98d3266c0(0000) GS:ffff8881a3c1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb98c5733e0 CR3: 0000000128fc2000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 serial8250_console_write+0x584/0x1ba0
 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: 0033:0x7fb98c59038a
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:00007fb98d325e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fb98d325ef0 RCX: 00007fb98c59038a
RDX: 0000200000024c80 RSI: 0000200000000080 RDI: 00007fb98d325eb0
RBP: 0000200000024c80 R08: 00007fb98d325ef0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000080
R13: 00007fb98d325eb0 R14: 0000000000024c70 R15: 00002000000000c0
 </TASK>
