INFO: task syz.8.3344:18648 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.3344      state:D stack:25352 pid:18648 tgid:18647 ppid:18563  task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17d9/0x56c0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x6ba/0x920
 down_read+0x9c/0x330
 super_lock+0x2d6/0x3d0
 user_get_super+0xc8/0x120
 __se_sys_quotactl+0x538/0x9a0
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd6ba39e0d9
RSP: 002b:00007fd6bb2b2028 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007fd6ba625fa0 RCX: 00007fd6ba39e0d9
RDX: 0000000000000000 RSI: 0000200000000340 RDI: ffffffff80000800
RBP: 00007fd6ba435024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000080 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd6ba626038 R14: 00007fd6ba625fa0 R15: 00007fff26646308
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/31:
 #0: ffffffff8eb5a608 (rcu_tasks.tasks_gp_mutex){+.+.}-{4:4}, at: rcu_tasks_one_gp+0xb2a/0xe20
1 lock held by khungtaskd/35:
 #0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5427:
 #0: ffff88816efe10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034762e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
3 locks held by syz-executor/7387:
1 lock held by syz.8.3344/18648:
 #0: ffff8881137660d8 (&type->s_umount_key#56){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.5.3529/19333:
 #0: ffff8881137660d8 (&type->s_umount_key#56){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by udevd/20890:
5 locks held by syz.4.3857/21129:
2 locks held by syz.4.3865/21150:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 35 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
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/0x380
 sys_info+0x135/0x170
 watchdog+0xfd7/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
