INFO: task syz.2.1145:12160 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.1145      state:D stack:24696 pid:12160 tgid:12159 ppid:11627  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x1821/0x5740
 schedule+0x164/0x360
 schedule_preempt_disabled+0x73/0xa0
 rwsem_down_read_slowpath+0x6d9/0x940
 down_read+0x99/0x2e0
 super_lock+0x2d6/0x3d0
 bdev_super_lock+0x1db/0x370
 fs_bdev_sync+0x17/0x50
 blkdev_common_ioctl+0x12e1/0x3240
 blkdev_ioctl+0x528/0x740
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f264159cdd9
RSP: 002b:00007f2642538028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2641815fa0 RCX: 00007f264159cdd9
RDX: 0000000000000000 RSI: 0000000000001261 RDI: 0000000000000006
RBP: 00007f2641632d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2641816038 R14: 00007f2641815fa0 R15: 00007ffc0b5e2b38
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5436:
 #0: ffff8881710030a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034732e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0
2 locks held by syz-executor/5611:
5 locks held by kworker/1:8/10283:
1 lock held by syz.2.1145/12160:
 #0: ffff8881164dc0d8 (&type->s_umount_key#65){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.5.1251/12891:
 #0: ffff8881164dc0d8 (&type->s_umount_key#65){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.6.1390/13753:
 #0: ffff8881164dc0d8 (&type->s_umount_key#65){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz-executor/13975:
 #0: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770
1 lock held by syz.0.1451/14282:
 #0: ffff8881164dc0d8 (&type->s_umount_key#65){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.0.1451/14291:
 #0: ffff8881164dc0d8 (&type->s_umount_key#65){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.1.1566/15171:
3 locks held by dhcpcd-run-hook/15199:

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

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+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xfd3/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 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: 1112 Comm: kworker/u10:5 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: events_unbound call_usermodehelper_exec_work
RIP: 0010:unwind_next_frame+0x132/0x2550
Code: 2b 00 4c 89 64 24 78 48 89 5c 24 70 49 8d 5e 50 48 89 d8 48 c1 e8 03 48 89 44 24 40 80 3c 28 00 74 08 48 89 df e8 8e 0c ba 00 <48> 89 5c 24 28 48 8b 1b 48 85 db 74 23 48 81 c3 88 00 00 00 48 89
RSP: 0018:ffffc900075b7078 EFLAGS: 00000246
RAX: 1ffff92000eb6e3f RBX: ffffc900075b71f8 RCX: 0000000080000001
RDX: 000000006da6d180 RSI: ffffffff8c28af40 RDI: ffffffff8c28af00
RBP: dffffc0000000000 R08: ffffffff8176f256 R09: ffffffff8e95cd60
R10: ffffc900075b71f8 R11: fffff52000eb6e41 R12: ffffc900075b71e0
R13: 1ffff92000eb6e35 R14: ffffc900075b71a8 R15: ffffffff8176f256
FS:  0000000000000000(0000) GS:ffff8882a928d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555594fa6a68 CR3: 0000000116dd8000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 __unwind_start+0x5b8/0x760
 arch_stack_walk+0xe3/0x150
 stack_trace_save+0xa9/0x100
 kasan_save_track+0x3e/0x80
 __kasan_slab_alloc+0x6c/0x80
 kmem_cache_alloc_noprof+0x2bc/0x650
 copy_signal+0x50/0x650
 copy_process+0x1eae/0x4440
 kernel_clone+0x284/0x8f0
 user_mode_thread+0x110/0x180
 call_usermodehelper_exec_work+0x5c/0x230
 process_scheduled_works+0xb5d/0x1860
 worker_thread+0xa53/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
