INFO: task syz.5.1429:10996 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.1429      state:D stack:25896 pid:10996 tgid:10995 ppid:7400   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: 0033:0x7f3354f8ebe9
RSP: 002b:00007f3355df5038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f33551c5fa0 RCX: 00007f3354f8ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f33551c5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f33551c6038 R14: 00007f33551c5fa0 R15: 00007ffe463ddae8
 </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/5673:
 #0: ffff888020d500a0 (&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
3 locks held by syz-executor/7268:
1 lock held by syz.5.1429/10996:
 #0: ffff88802a3500e0 (&type->s_umount_key#78){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
2 locks held by syz-executor/11310:
 #0: ffffffff8e88e5c8 (bio_slab_lock){+.+.}-{4:4}, at: bioset_exit+0x44a/0x690
 #1: ffffffff8e13f880 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570
3 locks held by udevd/11992:
3 locks held by syz.7.2209/14191:
 #0: ffffffff8f59e270 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8e418648 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x2cb/0x960
 #2: ffffffff8e13f880 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570
2 locks held by syz.8.2211/14199:
 #0: ffff888032e400e0 (&type->s_umount_key#91/1){+.+.}-{4:4}, at: alloc_super+0x204/0x970
 #1: ffffffff8dfe16a8 (wq_pool_mutex){+.+.}-{4:4}, at: __alloc_workqueue+0x9eb/0x1b70

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

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: 7268 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:do_raw_spin_unlock+0x11d/0x240
Code: fa 8d 48 c1 e8 03 42 80 3c 20 00 74 0c 48 c7 c7 18 71 fa 8d e8 a4 15 85 00 48 83 3d 84 6a 5c 0c 00 0f 84 14 01 00 00 48 89 df <c6> 07 00 0f 1f 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc
RSP: 0018:ffffc90002faf628 EFLAGS: 00000286
RAX: 1ffffffff1bf4e23 RBX: ffff88802bac9b68 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88802bac9b68
RBP: 1ffff1100575936e R08: ffff88802bac9b6b R09: 1ffff1100575936d
R10: dffffc0000000000 R11: ffffed100575936e R12: dffffc0000000000
R13: 1ffff1100575936f R14: ffff88802bac9b78 R15: ffff88802bac9b70
FS:  0000555568052500(0000) GS:ffff8881a3c18000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c38df7a CR3: 000000003779e000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 _raw_spin_unlock+0x1e/0x50
 __writeback_single_inode+0x480/0xff0
 writeback_single_inode+0x1f3/0x6a0
 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: 0033:0x7f68e9d8ff17
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:00007fffd00833b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f68e9e11c05 RCX: 00007f68e9d8ff17
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fffd0083470
RBP: 00007fffd0083470 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fffd0084500
R13: 00007f68e9e11c05 R14: 000000000003c355 R15: 00007fffd0084540
 </TASK>
