INFO: task syz-executor:6410 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:18856 pid:6410  tgid:6410  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: 0033:0x7f05e278ff17
RSP: 002b:00007fffb52dcae8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f05e2811c05 RCX: 00007f05e278ff17
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fffb52dcba0
RBP: 00007fffb52dcba0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fffb52ddc30
R13: 00007f05e2811c05 R14: 0000000000024787 R15: 00007fffb52ddc70
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/u10:0/27:
 #0: ffff888136639f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140
 #1: ffff888136624008 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880
 #2: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0xa5/0x2390
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/u10:2/40:
 #0: ffff8881001a4948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900006efbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
2 locks held by getty/5674:
 #0: ffff88810d7df0a0 (&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
1 lock held by syz-executor/6410:
 #0: ffff888109c100e0 (&type->s_umount_key#55){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
1 lock held by syz.0.281/7747:
 #0: ffff888109c100e0 (&type->s_umount_key#55){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.3.526/9524:
 #0: ffff888109c100e0 (&type->s_umount_key#55){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.2.604/10080:
 #0: ffffffff8e13f9b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730

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

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: 10080 Comm: syz.2.604 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_is_held_type+0x0/0x190
Code: 7f 09 f6 90 0f 0b 90 90 90 eb b5 e8 1a fc ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 55 41 57 41 56 41 55 41 54 53 48 83 ec 10 65 48 8b 05
RSP: 0000:ffffc9000479fd90 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff888122fbc000 RCX: 6417b35666879900
RDX: ffffc90008bb1000 RSI: 00000000ffffffff RDI: ffffffff8e1713a8
RBP: 0000000000000017 R08: 0000000000000000 R09: ffffffff820a6361
R10: dffffc0000000000 R11: ffffed1004f1dea9 R12: 0000000000001254
R13: ffff88810658b980 R14: ffff888104eb1cc0 R15: dffffc0000000000
FS:  00007fc6554ad6c0(0000) GS:ffff8881a3c18000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc64a2ec000 CR3: 0000000106ba0000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 mem_cgroup_from_task+0x62/0x120
 count_memcg_event_mm+0x12c/0x260
 handle_mm_fault+0x50f/0x8e0
 do_user_addr_fault+0xa81/0x1390
 exc_page_fault+0x76/0xf0
 asm_exc_page_fault+0x26/0x30
RIP: 0033:0x7fc654450c46
Code: f0 72 6e 48 63 cd 48 01 c1 49 39 4f 08 72 4c 8d 4d ff 85 ed 74 33 66 0f 1f 44 00 00 48 39 f0 72 1b 4d 8b 07 49 89 c1 49 29 f1 <47> 0f b6 0c 08 45 84 c9 74 08 45 88 0c 00 49 8b 47 10 48 83 c0 01
RSP: 002b:00007fc6554ac4a0 EFLAGS: 00010206
RAX: 00000000000ec001 RBX: 00007fc6554ac540 RCX: 000000000000006f
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00007fc6554ac5e0
RBP: 0000000000000102 R08: 00007fc64a200000 R09: 00000000000ec000
R10: 0000000000000000 R11: 00007fc6554ac550 R12: 0000000000000001
R13: 00007fc65462da20 R14: 0000000000000000 R15: 00007fc6554ac5e0
 </TASK>
