INFO: task syz-executor:9002 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:17496 pid:9002  tgid:9002  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: 0033:0x7f81a858ff17
RSP: 002b:00007fff2d74fdd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f81a8611c05 RCX: 00007f81a858ff17
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff2d74fe90
RBP: 00007fff2d74fe90 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fff2d750f20
R13: 00007f81a8611c05 R14: 0000000000038646 R15: 00007fff2d750f60
 </TASK>
INFO: lockdep is turned off.
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: 5848 Comm: udevd 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:entry_SYSCALL_64+0xf/0x2b
Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc f3 0f 1e fa 0f 01 f8 65 48 89 25 85 df 9e 11 <66> 90 0f 20 dc 0f 1f 44 00 00 48 81 e4 ff e7 ff ff 0f 22 dc 65 48
RSP: 0018:00007ffd3855a910 EFLAGS: 00000002
RAX: 0000000000000101 RBX: 000055afb227e870 RCX: 00007efd6a1169a4
RDX: 0000000000080000 RSI: 000055afb2260140 RDI: 00000000ffffff9c
RBP: 000055afb2260140 R08: 000055afb2260140 R09: 0000000000000020
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000080000
R13: 0000000000000707 R14: 0000000000000000 R15: 0000000000000001
FS:  00007efd6a57fc80(0000) GS:ffff8881a3c1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8494df6fe0 CR3: 0000000028468000 CR4: 00000000000006f0
Call Trace:
