usb 1-1: Manufacturer: syz
usb 1-1: SerialNumber: syz
usb 1-1: config 0 descriptor??
usbtv 1-1:0.0: Fushicai USBTV007 Audio-Video Grabber
usb 1-1: USB disconnect, device number 2
============================================
WARNING: possible recursive locking detected
6.8.0-rc6-syzkaller-00139-g19e7b35d8a71 #0 Not tainted
--------------------------------------------
kworker/0:2/725 is trying to acquire lock:
ffff88811e446b70 (&usbtv->vb2q_lock){+.+.}-{3:3}, at: vb2_video_unregister_device drivers/media/common/videobuf2/videobuf2-v4l2.c:1269 [inline]
ffff88811e446b70 (&usbtv->vb2q_lock){+.+.}-{3:3}, at: vb2_video_unregister_device+0x12b/0x2d0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1245

but task is already holding lock:
ffff88811e446b70 (&usbtv->vb2q_lock){+.+.}-{3:3}, at: usbtv_video_free+0x28/0x70 drivers/media/usb/usbtv/usbtv-video.c:966

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&usbtv->vb2q_lock);
  lock(&usbtv->vb2q_lock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

7 locks held by kworker/0:2/725:
 #0: ffff888106296938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x789/0x15d0 kernel/workqueue.c:2608
 #1: ffffc90001cefd80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7eb/0x15d0 kernel/workqueue.c:2609
 #2: ffff88810b3c0190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:990 [inline]
 #2: ffff88810b3c0190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1be/0x4f40 drivers/usb/core/hub.c:5840
 #3: ffff888105abb190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:990 [inline]
 #3: ffff888105abb190 (&dev->mutex){....}-{3:3}, at: usb_disconnect+0x10a/0x910 drivers/usb/core/hub.c:2287
 #4: ffff888108281160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:990 [inline]
 #4: ffff888108281160 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1095 [inline]
 #4: ffff888108281160 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xa4/0x610 drivers/base/dd.c:1292
 #5: ffff88811e446b70 (&usbtv->vb2q_lock){+.+.}-{3:3}, at: usbtv_video_free+0x28/0x70 drivers/media/usb/usbtv/usbtv-video.c:966
 #6: ffff88811e446ae0 (&usbtv->v4l2_lock){+.+.}-{3:3}, at: usbtv_video_free+0x32/0x70 drivers/media/usb/usbtv/usbtv-video.c:967

stack backtrace:
CPU: 0 PID: 725 Comm: kworker/0:2 Not tainted 6.8.0-rc6-syzkaller-00139-g19e7b35d8a71 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 check_deadlock kernel/locking/lockdep.c:3062 [inline]
 validate_chain kernel/locking/lockdep.c:3856 [inline]
 __lock_acquire+0x210a/0x3b30 kernel/locking/lockdep.c:5137
 lock_acquire kernel/locking/lockdep.c:5754 [inline]
 lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5719
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x175/0x9d0 kernel/locking/mutex.c:752
 vb2_video_unregister_device drivers/media/common/videobuf2/videobuf2-v4l2.c:1269 [inline]
 vb2_video_unregister_device+0x12b/0x2d0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1245
 usbtv_video_free+0x4a/0x70 drivers/media/usb/usbtv/usbtv-video.c:970
 usbtv_disconnect+0x5c/0xd0 drivers/media/usb/usbtv/usbtv-core.c:138
 usb_unbind_interface+0x1e5/0x960 drivers/usb/core/driver.c:461
 device_remove drivers/base/dd.c:569 [inline]
 device_remove+0x11f/0x170 drivers/base/dd.c:561
 __device_release_driver drivers/base/dd.c:1272 [inline]
 device_release_driver_internal+0x44a/0x610 drivers/base/dd.c:1295
 bus_remove_device+0x22c/0x420 drivers/base/bus.c:574
 device_del+0x39a/0xa50 drivers/base/core.c:3828
 usb_disable_device+0x36c/0x7f0 drivers/usb/core/message.c:1418
 usb_disconnect+0x2e1/0x910 drivers/usb/core/hub.c:2296
 hub_port_connect drivers/usb/core/hub.c:5352 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5652 [inline]
 port_event drivers/usb/core/hub.c:5812 [inline]
 hub_event+0x1be0/0x4f40 drivers/usb/core/hub.c:5894
 process_one_work+0x886/0x15d0 kernel/workqueue.c:2633
 process_scheduled_works kernel/workqueue.c:2706 [inline]
 worker_thread+0x8b9/0x1290 kernel/workqueue.c:2787
 kthread+0x2c6/0x3a0 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:243
 </TASK>