INFO: task syz-executor:6964 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:21224 pid:6964  tgid:6964  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: 0033:0x7f356f98ff17
RSP: 002b:00007ffd479329d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f356fa11c05 RCX: 00007f356f98ff17
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd47932a90
RBP: 00007ffd47932a90 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd47933b20
R13: 00007f356fa11c05 R14: 000000000001f142 R15: 00007ffd47933b60
 </TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
 #0: ffffffff8e13f9f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730
2 locks held by kworker/u9:1/28:
 #0: ffff88801afef948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000061fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
1 lock held by khungtaskd/34:
 #0: ffffffff8e139f60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5675:
 #0: ffff88810f3210a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900025182f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
1 lock held by syz-executor/6964:
 #0: ffff88802409e0e0 (&type->s_umount_key#62){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
1 lock held by syz.9.314/8783:
 #0: ffff88802409e0e0 (&type->s_umount_key#62){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
2 locks held by syz-executor/9716:
 #0: ffff888038be60e0 (&type->s_umount_key#62){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
 #1: ffff88811e980278 (&c->state_lock){++++}-{4:4}, at: __bch2_fs_stop+0xf8/0x900
1 lock held by syz.7.520/10832:
 #0: ffff88802409e0e0 (&type->s_umount_key#62){++++}-{4:4}, at: super_lock+0x2a9/0x3b0

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

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: 12 Comm: kworker/u8:0 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
Workqueue: bat_events batadv_nc_worker
RIP: 0010:check_preemption_disabled+0x35/0x120
Code: 48 8b 05 be 7e 26 07 48 89 44 24 08 65 8b 05 c6 7e 26 07 65 8b 0d bb 7e 26 07 f7 c1 ff ff ff 7f 74 23 65 48 8b 0d 9b 7e 26 07 <48> 3b 4c 24 08 0f 85 cc 00 00 00 48 83 c4 10 5b 41 5e 41 5f 5d e9
RSP: 0018:ffffc900000f7958 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffffff8b47e050 RCX: db3cf94ccc69d000
RDX: ffff88801c685640 RSI: ffffffff8be339e0 RDI: ffffffff8be339a0
RBP: ffff8880393598c0 R08: 0000000000000000 R09: ffffffff8b47dd5a
R10: dffffc0000000000 R11: fffffbfff1f47227 R12: dffffc0000000000
R13: 1ffff110023ab313 R14: 0000000000000001 R15: ffff888011d58d80
FS:  0000000000000000(0000) GS:ffff8880b8618000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffea7436e28 CR3: 000000010e0de000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 rcu_is_watching+0x15/0xb0
 batadv_nc_process_nc_paths+0xfa/0x3a0
 batadv_nc_worker+0x429/0x610
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
