INFO: task syz.1.745:9243 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.1.745       state:D stack:26304 pid:9243  tgid:9240  ppid:5826   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x14bc/0x5000
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x5fd/0x8f0
 down_read+0x99/0x2e0
 super_lock+0x2a9/0x3b0
 __iterate_supers+0x126/0x290
 __se_sys_quotactl+0x353/0x950
 do_syscall_64+0xfa/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8fb2b8f7c9
RSP: 002b:00007f8fb3a4c038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f8fb2de6090 RCX: 00007f8fb2b8f7c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000102
RBP: 00007f8fb2bf297f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8fb2de6128 R14: 00007f8fb2de6090 R15: 00007fff512ec2f8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8df419a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
6 locks held by kworker/0:2/842:
 #0: ffff88816810d148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770
 #1: ffffc90007307b80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770
 #2: ffff88816cd79198 (&dev->mutex){....}-{4:4}, at: hub_event+0x187/0x4ef0
 #3: ffff88816cd7c518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x215a/0x4ef0
 #4: ffff88816c171068 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x2182/0x4ef0
 #5: ffffffff8ebd0bf0 (ehci_cf_port_reset_rwsem){.+.+}-{4:4}, at: hub_port_reset+0x14e/0x1850
2 locks held by kworker/u9:12/3626:
 #0: ffff888100089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770
 #1: ffffffff8df419a0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run4+0x19c/0x4b0
6 locks held by kworker/1:3/5291:
 #0: ffff88816810d148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770
 #1: ffffc90004027b80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770
 #2: ffff88816cd61198 (&dev->mutex){....}-{4:4}, at: hub_event+0x187/0x4ef0
 #3: ffff88816cd64518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x215a/0x4ef0
 #4: ffff88816c167768 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x2182/0x4ef0
 #5: ffffffff8ebd0bf0 (ehci_cf_port_reset_rwsem){.+.+}-{4:4}, at: hub_port_reset+0x14e/0x1850
2 locks held by getty/5646:
 #0: ffff8881144fa0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000356b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x449/0x1460
3 locks held by kworker/0:5/5892:
 #0: ffff888100075948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770
 #1: ffffc90005b27b80 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770
 #2: ffff88816bde2240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x1f7/0x3b0
2 locks held by syz.5.705/9117:
1 lock held by syz.1.745/9243:
 #0: ffff888175f020e0 (&type->s_umount_key#102){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.9.1102/10734:
 #0: ffff888175f020e0 (&type->s_umount_key#102){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.3.1165/10990:
 #0: ffff888175f020e0 (&type->s_umount_key#102){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.2.1196/11113:
 #0: ffff888175f020e0 (&type->s_umount_key#102){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
3 locks held by syz.1.1244/11364:
 #0: ffff8881b8df9408 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: sock_close+0x9b/0x240
 #1: ffff88811e5188e0 (sk_lock-AF_QIPCRTR){+.+.}-{0:0}, at: qrtr_release+0x52/0x2d0
 #2: ffffffff8df474f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730

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

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+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xf95/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x599/0xb30
 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: 5291 Comm: kworker/1:3 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: usb_hub_wq hub_event
RIP: 0010:io_serial_out+0x7c/0xc0
Code: cd a5 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 7c 64 0c fd 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d e9 57 2d 43 06 cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc90004026e10 EFLAGS: 00000002
RAX: 0000000000000038 RBX: 0000000000000038 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 000000000002523f RDI: 0000000000025240
RBP: 00000000000003f8 R08: ffff88816a9e8237 R09: 1ffff1102d53d046
R10: dffffc0000000000 R11: ffffffff851bedc0 R12: dffffc0000000000
R13: ffffffff998e29ad R14: ffffffff99bf72a0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8882a9e32000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8dcce28440 CR3: 00000001b337e000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 serial8250_console_write+0x1410/0x1ba0
 console_flush_all+0x745/0xb60
 console_unlock+0xbb/0x190
 vprintk_emit+0x4f8/0x5f0
 dev_vprintk_emit+0x337/0x3f0
 dev_printk_emit+0xe0/0x130
 _dev_warn+0x10a/0x160
 hub_port_init+0x1e70/0x28e0
 hub_event+0x2573/0x4ef0
 process_scheduled_works+0xad1/0x1770
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x599/0xb30
 ret_from_fork_asm+0x1a/0x30
 </TASK>
