INFO: task syz.4.1147:10739 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.1147      state:D stack:25256 pid:10739 tgid:10738 ppid:9092   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x5fd/0x8f0
 down_read+0x98/0x2e0
 super_lock+0x2a9/0x3b0
 __iterate_supers+0x126/0x290
 ksys_sync+0x94/0x150
 __ia32_sys_sync+0xe/0x20
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7e8738ebe9
RSP: 002b:00007f7e88287038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f7e875b5fa0 RCX: 00007f7e8738ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f7e875b5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7e875b6038 R14: 00007f7e875b5fa0 R15: 00007ffe93602e68
 </TASK>
INFO: lockdep is turned off.
NMI backtrace for cpu 1
CPU: 1 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 6706 Comm: syz-executor 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:_raw_spin_unlock+0x2f/0x50
Code: 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 6a 5e 21 f6 48 89 df e8 c2 f5 21 f6 bf 01 00 00 00 e8 28 f0 13 f6 65 8b 05 f1 42 24 07 <85> c0 74 07 5b e9 d7 4d 00 00 cc e8 a1 b9 b7 f5 5b e9 cb 4d 00 00
RSP: 0018:ffffc90002fdf6c0 EFLAGS: 00000297
RAX: 0000000080000000 RBX: ffff88811aa0ec20 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 00000000ffffffff
RBP: 0000000000000000 R08: ffff88811aa0ec23 R09: 1ffff11023541d84
R10: dffffc0000000000 R11: ffffed1023541d85 R12: 0000000000000000
R13: ffff88811aa0ec20 R14: ffff88811aa0eba0 R15: 1ffff11023541d8e
FS:  000055558948b500(0000) GS:ffff8880b861b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055556d922608 CR3: 000000010f08a000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 writeback_single_inode+0x43e/0x6a0
 sync_inode_metadata+0xb9/0x110
 f2fs_write_checkpoint+0xb06/0x1df0
 kill_f2fs_super+0x2c3/0x6c0
 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: 0033:0x7ff036b8ff17
Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffe5bb3fee8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007ff036c11c05 RCX: 00007ff036b8ff17
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe5bb3ffa0
RBP: 00007ffe5bb3ffa0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe5bb41030
R13: 00007ff036c11c05 R14: 000000000004e6b5 R15: 00007ffe5bb41070
 </TASK>
