INFO: task syz.3.853:9417 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.3.853       state:D stack:26208 pid:9417  tgid:9416  ppid:5873   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x1821/0x5740
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x6d9/0x940
 down_read+0x99/0x2e0
 super_lock+0x2d6/0x3d0
 __iterate_supers+0x126/0x250
 __se_sys_quotactl+0x3a7/0x9e0
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0070b9ce59
RSP: 002b:00007f00719b2028 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f0070e15fa0 RCX: 00007f0070b9ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000101
RBP: 00007f0070c32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0070e16038 R14: 00007f0070e15fa0 R15: 00007fff7f890d48
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/0:1/10:
1 lock held by khungtaskd/34:
 #0: ffffffff8e95cce0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5449:
 #0: ffff8881125430a0 (&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
4 locks held by udevd/5618:
 #0: ffff88819e7a9638 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10
 #1: ffff8881bbe6fc80 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420
 #2: ffff888111dcaf08 (kn->active#29){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x420
 #3: ffff888120d661d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0
2 locks held by syz-executor/5619:
6 locks held by kworker/0:7/5958:
 #0: ffff8881052be140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc900042b7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffff88810be3b1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x17f/0x4f30
 #3: ffff888120d661d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450
 #4: ffff88802ddd71a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450
 #5: ffff88801b5f00c8 (&d->usb_mutex){+.+.}-{4:4}, at: rtl28xxu_ctrl_msg+0x59/0x690
3 locks held by kworker/u9:27/9022:
 #0: ffff88812103aee0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150
 #1: ffff888121024588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880
 #2: ffff888121026118 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x1ae/0xf30
3 locks held by kworker/u9:31/9026:
 #0: ffff88812103aee0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150
 #1: ffff888121024588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880
 #2: ffff888121026118 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x1ae/0xf30
1 lock held by syz.3.853/9417:
 #0: ffff8881122c60d8 (&type->s_umount_key#71){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.4.1386/11923:
 #0: ffff8881122c60d8 (&type->s_umount_key#71){++++}-{4:4}, at: super_lock+0x2d6/0x3d0

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 34 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/0x300
 sys_info+0x135/0x170
 watchdog+0xfd3/0x1030
 kthread+0x389/0x470
 ret_from_fork+0x514/0xb70
 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: 5681 Comm: kworker/0:5 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
Workqueue: events legacy_dvb_usb_read_remote_control
RIP: 0010:io_serial_out+0x7c/0xc0
Code: ef 80 fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 3c 47 ec fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d e9 17 52 65 06 cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc900048b7470 EFLAGS: 00000006
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 00000000000003f9 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f9 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff8544c7c0 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff9a78dac0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88818dc9f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f25f75ea540 CR3: 00000001150dc000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 serial8250_console_write+0x5ae/0x1ba0
 console_flush_all+0x718/0xb20
 console_unlock+0xd1/0x1c0
 vprintk_emit+0x485/0x560
 _printk+0xdd/0x130
 m920x_rc_query+0x2f6/0x830
 legacy_dvb_usb_read_remote_control+0x107/0x450
 process_scheduled_works+0xb5d/0x1860
 worker_thread+0xa53/0xfc0
 kthread+0x389/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
