INFO: task syz-executor:5858 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:5858  tgid:5858  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: 0033:0x7f918838fed7
RSP: 002b:00007ffd655d14e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f9188411c05 RCX: 00007f918838fed7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd655d15a0
RBP: 00007ffd655d15a0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd655d2630
R13: 00007f9188411c05 R14: 000000000001426c R15: 00007ffd655d2670
 </TASK>
INFO: task syz.1.61:6278 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.61        state:D stack:24648 pid:6278  tgid:6277  ppid:5857   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
 __se_sys_quotactl+0x353/0x950
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc20738eba9
RSP: 002b:00007fc2055f6038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007fc2075d5fa0 RCX: 00007fc20738eba9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000101
RBP: 00007fc207411e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc2075d6038 R14: 00007fc2075d5fa0 R15: 00007fff64b75018
 </TASK>
INFO: task syz.3.65:6334 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.65        state:D stack:25128 pid:6334  tgid:6333  ppid:6282   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
 __se_sys_quotactl+0x353/0x950
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1ce958eba9
RSP: 002b:00007f1cea44c038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f1ce97d5fa0 RCX: 00007f1ce958eba9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000100
RBP: 00007f1ce9611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1ce97d6038 R14: 00007f1ce97d5fa0 R15: 00007ffc85fae248
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by kworker/u10:5/1090:
7 locks held by kworker/u9:4/1385:
2 locks held by getty/5679:
 #0: ffff888106a910a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029032f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
2 locks held by kworker/u8:2/5722:
3 locks held by kworker/0:3/5849:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900030ffbc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff888072963240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x26b/0x3180
1 lock held by syz-executor/5858:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
1 lock held by syz.1.61/6278:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.3.65/6334:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.5.83/6584:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.6.85/6603:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.4.87/6610:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.8.89/6699:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.9.102/6841:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.0.114/6992:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.2.127/7081:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.1.143/7135:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.3.153/7177:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.6.176/7458:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.5.191/7542:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.7.225/7786:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.8.231/7811:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.9.242/7928:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.0.258/8040:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.2.265/8065:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.2.265/8066:
 #0: ffff8881112ce0e0 (&type->s_umount_key#67){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.1.269/8096:

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

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+0x439/0x7d0
 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: 0 Comm: swapper/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
RIP: 0010:pv_native_safe_halt+0x13/0x20
Code: 53 e8 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d b3 d9 0d 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8de07d80 EFLAGS: 00000282
RAX: b05c452b1c9f1e00 RBX: ffffffff819693f8 RCX: b05c452b1c9f1e00
RDX: 0000000000000001 RSI: ffffffff8d9b9e62 RDI: ffffffff8be33e80
RBP: ffffffff8de07eb8 R08: ffff88804b032f9b R09: 1ffff110096065f3
R10: dffffc0000000000 R11: ffffed10096065f4 R12: ffffffff8fa3a530
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1bd2a20
FS:  0000000000000000(0000) GS:ffff8880b8615000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556b6bc34280 CR3: 000000000df36000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 default_idle+0x13/0x20
 default_idle_call+0x74/0xb0
 do_idle+0x1e8/0x510
 cpu_startup_entry+0x44/0x60
 rest_init+0x2de/0x300
 start_kernel+0x3a9/0x410
 x86_64_start_reservations+0x24/0x30
 x86_64_start_kernel+0x143/0x1c0
 common_startup_64+0x13e/0x147
 </TASK>
