INFO: task syz.7.698:9984 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.698       state:D stack:23272 pid:9984  tgid:9982  ppid:8559   task_flags:0x400140 flags:0x00080006
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/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1bec38efc9
RSP: 002b:00007f1bed1b6038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f1bec5e5fa0 RCX: 00007f1bec38efc9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000100
RBP: 00007f1bec411f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1bec5e6038 R14: 00007f1bec5e5fa0 R15: 00007ffd4d195018
 </TASK>

Showing all locks held in the system:
6 locks held by kworker/1:1/33:
 #0: ffff8881607b2948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90000a97ba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff88816b4c9198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20
 #3: ffff8881bc1f9198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400
 #4: ffff8881b7b19160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400
 #5: ffffffff8f23af68 (register_mutex#6){+.+.}-{4:4}, at: usb_audio_probe+0x7f8/0x22f0
1 lock held by khungtaskd/35:
 #0: ffffffff8df3d620 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by kworker/u10:4/1090:
 #0: ffff8881037c0948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90007bffba0 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
2 locks held by getty/5645:
 #0: ffff88810c1cb0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000357b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
2 locks held by syz-executor/5814:
4 locks held by udevd/5910:
 #0: ffff888113caf2f0 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe20
 #1: ffff88811f368888 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420
 #2: ffff8881aee6c0f8 (kn->active#31){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x420
 #3: ffff8881bc1f9198 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0
1 lock held by syz.7.698/9984:
 #0: ffff88811fe780e0 (&type->s_umount_key#74){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
2 locks held by syz.0.1310/13108:
 #0: ffff88816ae56e08 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: sock_close+0x9b/0x240
 #1: ffffffff8df430b8 (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 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+0xf60/0xfa0
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 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: 11952 Comm: kworker/u10:16 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: iou_exit io_ring_exit_work
RIP: 0010:__lock_acquire+0x88b/0xd20
Code: c7 49 c1 e7 20 49 09 cf 83 3d 64 d5 df 0d 00 0f 85 36 02 00 00 48 83 7c 24 28 00 0f 84 bc 01 00 00 41 8b 46 f8 25 ff 1f 00 00 <48> 0f a3 05 6d 22 d9 11 0f 83 5a 01 00 00 48 69 c0 c8 00 00 00 48
RSP: 0018:ffffc900052ff028 EFLAGS: 00000002
RAX: 0000000000000a20 RBX: 0000000000000003 RCX: 00000000fde829c0
RDX: 000000004bae3f17 RSI: 000000002f1e26c9 RDI: ffff88819f210000
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff81739d25
R10: ffffc900052ff278 R11: ffffffff81ac42f0 R12: 0000000078641692
R13: ffff88819f210b30 R14: ffff88819f210ba8 R15: cb259665fde829c0
FS:  0000000000000000(0000) GS:ffff8882a9f32000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcd5c0c2723 CR3: 000000010daba000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x120/0x360
 unwind_next_frame+0xc2/0x2390
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_stack+0x3e/0x60
 kasan_record_aux_stack+0xbd/0xd0
 task_work_add+0xb1/0x420
 __io_req_task_work_add+0x37c/0x950
 io_poll_remove_all+0x27e/0x360
 io_uring_try_cancel_requests+0x3a8/0x4d0
 io_ring_exit_work+0x296/0x930
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 ret_from_fork_asm+0x1a/0x30
 </TASK>
