INFO: task syz-executor:9769 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:9769  tgid:9769  ppid:1      task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 wb_wait_for_completion+0x15f/0x260
 sync_inodes_sb+0x1bb/0xa10
 sync_filesystem+0x17a/0x230
 generic_shutdown_super+0x6f/0x2c0
 kill_block_super+0x44/0x90
 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: 0033:0x7f797b58fed7
RSP: 002b:00007fff95339578 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000064 RCX: 00007f797b58fed7
RDX: 0000000000000200 RSI: 0000000000000009 RDI: 00007fff9533a720
RBP: 00007f797b611c05 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000206 R12: 00007fff9533a720
R13: 00007f797b611c05 R14: 00005555569384a8 R15: 00007fff9533b7f0
 </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 kworker/u10:4/1091:
 #0: ffff88801b38c148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90006d67bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
2 locks held by getty/5681:
 #0: ffff888022dbc0a0 (&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
2 locks held by syz-executor/9769:
 #0: ffff888112d920e0 (&type->s_umount_key#82){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0
 #1: ffff888106e3c7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10
1 lock held by segctord/18282:

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

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: 5887 Comm: kworker/u8:4 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:debug_lockdep_rcu_enabled+0x2a/0x40
Code: f3 0f 1e fa 31 c0 83 3d 57 72 29 04 00 74 1e 83 3d 6a a2 29 04 00 74 15 65 48 8b 0c 25 08 b0 a0 92 31 c0 83 b9 ec 0a 00 00 00 <0f> 94 c0 e9 ce dc 02 00 cc cc cc cc cc cc cc cc cc cc cc cc cc cc
RSP: 0018:ffffc900035dfa18 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff888021d10000
RDX: 0000000000000000 RSI: ffffffff8be33960 RDI: ffffffff8be33920
RBP: fffffffffffffe38 R08: 0000000000000000 R09: ffffffff8b47aca2
R10: dffffc0000000000 R11: ffffffff8b47abd0 R12: dffffc0000000000
R13: ffffffff8b47aca2 R14: ffff88802ee5cd80 R15: 00000000000001f8
FS:  0000000000000000(0000) GS:ffff8881a3c15000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000024000 CR3: 000000003408c000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 batadv_nc_worker+0x1f4/0x610
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
