INFO: task syz.6.2369:18815 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.2369      state:D stack:24680 pid:18815 tgid:18814 ppid:14976  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: 0033:0x7f280658ebe9
RSP: 002b:00007f28073d8038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f28067b5fa0 RCX: 00007f280658ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000102
RBP: 00007f2806611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f28067b6038 R14: 00007f28067b5fa0 R15: 00007fffef5493c8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e139ee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5675:
 #0: ffff8881030450a0 (&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/15433:
1 lock held by syz.6.2369/18815:
 #0: ffff88810bd8e0e0 (&type->s_umount_key#69){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.0.2683/24937:
 #0: ffff88810bd8e0e0 (&type->s_umount_key#69){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.9.2726/25323:

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

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: 19215 Comm: kworker/0:0H 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: kblockd blk_mq_requeue_work
RIP: 0010:validate_chain+0x2ae/0x2140
Code: 0a 14 73 53 e8 e3 09 27 03 89 c3 e8 dc 9a ff ff 85 db 0f 85 56 02 00 00 83 3d 7d 17 06 0e 00 0f 84 a2 17 00 00 b8 01 00 00 00 <65> 48 8b 0d 2a ac 02 11 48 3b 8c 24 d8 00 00 00 0f 85 43 1c 00 00
RSP: 0018:ffffc90003c7ebb0 EFLAGS: 00000002
RAX: 0000000000000001 RBX: 0000000000000006 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff88801eb14560 RDI: ffff88801eb13980
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8172c195
R10: ffffc90003c7ef28 R11: fffff5200078fdf1 R12: 00000000fd170782
R13: ffff88801eb14470 R14: ffff88801eb14560 R15: 333b1b050c741b42
FS:  0000000000000000(0000) GS:ffff8880b861b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555628cc5c8 CR3: 000000001283a000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 __lock_acquire+0xab9/0xd20
 lock_acquire+0x120/0x360
 unwind_next_frame+0xc2/0x2390
 __unwind_start+0x5b9/0x760
 arch_stack_walk+0xe4/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_stack+0x3e/0x60
 kasan_record_aux_stack+0xbd/0xd0
 insert_work+0x3d/0x330
 __queue_work+0xcd2/0xfb0
 queue_work_on+0x181/0x270
 loop_queue_rq+0x9f0/0xb00
 blk_mq_dispatch_rq_list+0x4c0/0x1900
 __blk_mq_sched_dispatch_requests+0x350/0x1570
 blk_mq_sched_dispatch_requests+0xd7/0x190
 blk_mq_run_hw_queue+0x404/0x4f0
 blk_mq_run_hw_queues+0x33e/0x430
 blk_mq_requeue_work+0x717/0x760
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
