INFO: task syz.6.887:13345 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.887       state:D stack:25128 pid:13345 tgid:13344 ppid:12680  task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_write_slowpath+0x872/0xfe0
 down_write+0x1ab/0x1f0
 super_lock+0x25c/0x3b0
 user_get_super+0xc8/0x120
 __se_sys_quotactl+0x4da/0x950
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7dff78eba9
RSP: 002b:00007f7e00621038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f7dff9d5fa0 RCX: 00007f7dff78eba9
RDX: 0000000000000000 RSI: 0000200000000080 RDI: ffffffff80000201
RBP: 00007f7dff811e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7dff9d6038 R14: 00007f7dff9d5fa0 R15: 00007ffcdf2325a8
 </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 getty/5675:
 #0: ffff888107cab0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900028282f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
3 locks held by syz-executor/8987:
1 lock held by syz.6.887/13345:
 #0: ffff88811f3f20e0 (&type->s_umount_key#81){++++}-{4:4}, at: super_lock+0x25c/0x3b0
1 lock held by syz.7.987/14355:
 #0: ffff88811f3f20e0 (&type->s_umount_key#81){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.8.1046/14819:
 #0: ffff88811f3f20e0 (&type->s_umount_key#81){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
4 locks held by syz-executor/15187:
1 lock held by syz.6.1150/15965:
 #0: ffff88811f3f20e0 (&type->s_umount_key#81){++++}-{4:4}, at: super_lock+0x25c/0x3b0
7 locks held by syz.1.1169/16077:
1 lock held by dhcpcd-run-hook/16094:

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

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: 8987 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:__lock_acquire+0x855/0xd20
Code: 06 44 31 fe 01 ca 89 f0 c1 c0 08 29 f1 31 c8 01 d6 29 c2 89 c1 c1 c1 10 31 d1 01 f0 41 89 cf 41 c1 c7 13 29 ce 41 31 f7 01 c1 <44> 29 f8 44 01 f9 41 c1 c7 04 41 31 c7 49 c1 e7 20 49 09 cf 83 3d
RSP: 0018:ffffc900031bf590 EFLAGS: 00000093
RAX: 00000000e8f3114d RBX: 0000000000000002 RCX: 00000000e0ebc680
RDX: 000000002b58d1a4 RSI: 000000008c627f7a RDI: ffff888022ca0000
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff824205e4
R10: ffffc900031bf740 R11: fffff52000637f16 R12: 00000000346e684b
R13: ffff888022ca0af0 R14: ffff888022ca0b40 R15: 0000000025fdc0bf
FS:  0000555557e2c500(0000) GS:ffff8881a3c15000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556cad358950 CR3: 000000003186e000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x120/0x360
 _raw_spin_lock+0x2e/0x40
 writeback_single_inode+0x34/0x6a0
 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: 0033:0x7f6facd8fed7
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:00007ffe9d71f848 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f6face11c05 RCX: 00007f6facd8fed7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe9d71f900
RBP: 00007ffe9d71f900 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe9d720990
R13: 00007f6face11c05 R14: 000000000003fcd5 R15: 00007ffe9d7209d0
 </TASK>
