INFO: task syz.1.553:10067 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.553       state:D stack:25128 pid:10067 tgid:10066 ppid:9167   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_write_slowpath+0x872/0xfe0
 down_write+0x1ab/0x1f0
 super_lock+0x25c/0x3b0
 user_get_super+0xc8/0x120
 __se_sys_quotactl+0x4da/0x950
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc96d38ebe9
RSP: 002b:00007fc96e289038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007fc96d5c5fa0 RCX: 00007fc96d38ebe9
RDX: 0000000000000000 RSI: 0000200000000300 RDI: ffffffff80000300
RBP: 00007fc96d411e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc96d5c6038 R14: 00007fc96d5c5fa0 R15: 00007fffb7481ad8
 </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 getty/5682:
 #0: ffff88810e96d0a0 (&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 syz-executor/5860:
4 locks held by udevd/6022:
2 locks held by syz-executor/9055:
1 lock held by syz.1.553/10067:
 #0: ffff888022a6a0e0 (&type->s_umount_key#61){++++}-{4:4}, at: super_lock+0x25c/0x3b0
2 locks held by syz-executor/11358:
 #0: ffffffff8e88ed08 (bio_slab_lock){+.+.}-{4:4}, at: bioset_exit+0x44a/0x690
 #1: ffffffff8e13f880 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570
2 locks held by syz.0.816/12458:
 #0: ffff8881288280e0 (&type->s_umount_key#51/1){+.+.}-{4:4}, at: alloc_super+0x204/0x970
 #1: ffffffff8dfe16a8 (wq_pool_mutex){+.+.}-{4:4}, at: __alloc_workqueue+0x9eb/0x1b70
1 lock held by syz.7.819/12482:
 #0: ffffffff8e13f9b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730
1 lock held by udevadm/12487:

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

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: 3 Comm: pool_workqueue_ 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:zap_class+0xc2/0x360
Code: 49 81 fc 00 00 08 00 0f 84 a5 01 00 00 4e 8b 2c e5 40 73 64 93 4d 85 ed 0f 94 c0 49 83 c5 f8 0f 94 c1 08 c1 75 d7 45 8b 7d 00 <41> f6 c7 fc 0f 84 e2 00 00 00 41 c1 ef 08 4e 8d 34 7d 10 73 a9 92
RSP: 0018:ffffc90000067bc0 EFLAGS: 00000046
RAX: 000000000001ef00 RBX: 0000000000000cfa RCX: 000000000001ef00
RDX: ffffffff93a47358 RSI: ffffffff93a47358 RDI: ffffffff93539670
RBP: ffffffff93a877b0 R08: 0000000000000000 R09: ffffffff81aa8528
R10: dffffc0000000000 R11: fffffbfff1f47407 R12: 000000000000e80e
R13: ffffffff93d8c4b0 R14: ffffffff92ad51ca R15: 00000000061d1c1c
FS:  0000000000000000(0000) GS:ffff8880b8615000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a5454f2008 CR3: 0000000132026000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lockdep_unregister_key+0x1a6/0x310
 pwq_release_workfn+0x6d5/0x870
 kthread_worker_fn+0x507/0xb60
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
