INFO: task syz.9.2965:30581 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.2965      state:D stack:24296 pid:30581 tgid:30580 ppid:9728   task_flags:0x400040 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
 ksys_sync+0x94/0x150
 __ia32_sys_sync+0xe/0x20
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f431318ebe9
RSP: 002b:00007f4313f30038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f43133b5fa0 RCX: 00007f431318ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f43133b5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f43133b6038 R14: 00007f43133b5fa0 R15: 00007ffe29b476f8
 </TASK>
INFO: lockdep is turned off.
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: 10 Comm: kworker/0:1 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: usb_hub_wq hub_event
RIP: 0010:io_serial_out+0x7c/0xc0
Code: 8e 70 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 8c f7 d3 fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d e9 17 3e 2d 06 cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc900000d6630 EFLAGS: 00000002
RAX: 0000000000000020 RBX: 0000000000000020 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 000000000007535a RDI: 000000000007535b
RBP: 00000000000003f8 R08: ffff888021630237 R09: 1ffff110042c6046
R10: dffffc0000000000 R11: ffffffff854f1c80 R12: dffffc0000000000
R13: ffffffff99afa8c3 R14: ffffffff99def3e0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b861b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000000c0 CR3: 0000000126762000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 serial8250_console_write+0x1410/0x1ba0
 console_flush_all+0x728/0xc40
 console_unlock+0xc4/0x270
 vprintk_emit+0x5b7/0x7a0
 _printk+0xcf/0x120
 sensor_read_8+0x41d/0x640
 sensor_write_mask+0xac/0x1e0
 stk1135_camera_disable+0x2c4/0xa70
 sd_init+0x253/0x1260
 gspca_dev_probe2+0x855/0x1440
 usb_probe_interface+0x668/0xc30
 really_probe+0x26d/0x9e0
 __driver_probe_device+0x18c/0x2f0
 driver_probe_device+0x4f/0x430
 __device_attach_driver+0x2ce/0x530
 bus_for_each_drv+0x251/0x2e0
 __device_attach+0x2b8/0x400
 bus_probe_device+0x185/0x260
 device_add+0x7b6/0xb50
 usb_set_configuration+0x1a87/0x20e0
 usb_generic_driver_probe+0x8d/0x150
 usb_probe_device+0x1c4/0x390
 really_probe+0x26d/0x9e0
 __driver_probe_device+0x18c/0x2f0
 driver_probe_device+0x4f/0x430
 __device_attach_driver+0x2ce/0x530
 bus_for_each_drv+0x251/0x2e0
 __device_attach+0x2b8/0x400
 bus_probe_device+0x185/0x260
 device_add+0x7b6/0xb50
 usb_new_device+0xa39/0x16f0
 hub_event+0x2958/0x4a20
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
