============================================
WARNING: possible recursive locking detected
6.8.0-rc5-syzkaller #0 Not tainted
--------------------------------------------
kworker/0:0/8 is trying to acquire lock:
ffff888022964b78 (&usbtv->vb2q_lock){+.+.}-{3:3}, at: vb2_video_unregister_device+0x15f/0x230 drivers/media/common/videobuf2/videobuf2-v4l2.c:1269
but task is already holding lock:
ffff888022964b78 (&usbtv->vb2q_lock){+.+.}-{3:3}, at: usbtv_video_free+0x22/0x70 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/0:0/8:
#0: ffff88801bad1d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2608 [inline]
#0: ffff88801bad1d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x825/0x1420 kernel/workqueue.c:2706
#1: ffffc900000d7d20 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2608 [inline]
#1: ffffc900000d7d20 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x825/0x1420 kernel/workqueue.c:2706
#2: ffff888023c22190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:990 [inline]
#2: ffff888023c22190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1fe/0x50f0 drivers/usb/core/hub.c:5811
#3: ffff88802955d190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:990 [inline]
#3: ffff88802955d190 (&dev->mutex){....}-{3:3}, at: usb_disconnect+0x103/0x950 drivers/usb/core/hub.c:2258
#4: ffff88807a3cc160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:990 [inline]
#4: ffff88807a3cc160 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1095 [inline]
#4: ffff88807a3cc160 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xce/0x7c0 drivers/base/dd.c:1292
#5: ffff888022964b78 (&usbtv->vb2q_lock){+.+.}-{3:3}, at: usbtv_video_free+0x22/0x70 drivers/media/usb/usbtv/usbtv-video.c:966
#6: ffff888022964ae8 (&usbtv->v4l2_lock){+.+.}-{3:3}, at: usbtv_video_free+0x33/0x70 drivers/media/usb/usbtv/usbtv-video.c:967
stack backtrace:
CPU: 0 PID: 8 Comm: kworker/0:0 Not tainted 6.8.0-rc5-syzkaller #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+0x1e7/0x2e0 lib/dump_stack.c:106
check_deadlock kernel/locking/lockdep.c:3062 [inline]
validate_chain+0x15c0/0x58e0 kernel/locking/lockdep.c:3856
__lock_acquire+0x1345/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
vb2_video_unregister_device+0x15f/0x230 drivers/media/common/videobuf2/videobuf2-v4l2.c:1269
usbtv_video_free+0x47/0x70 drivers/media/usb/usbtv/usbtv-video.c:970
usbtv_disconnect+0x6d/0xd0 drivers/media/usb/usbtv/usbtv-core.c:138
usb_unbind_interface+0x1d4/0x850 drivers/usb/core/driver.c:461
device_remove drivers/base/dd.c:569 [inline]
__device_release_driver drivers/base/dd.c:1272 [inline]
device_release_driver_internal+0x503/0x7c0 drivers/base/dd.c:1295
bus_remove_device+0x34f/0x420 drivers/base/bus.c:574
device_del+0x580/0xa30 drivers/base/core.c:3828
usb_disable_device+0x3bf/0x850 drivers/usb/core/message.c:1416
usb_disconnect+0x340/0x950 drivers/usb/core/hub.c:2267
hub_port_connect drivers/usb/core/hub.c:5323 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5623 [inline]
port_event drivers/usb/core/hub.c:5783 [inline]
hub_event+0x1e62/0x50f0 drivers/usb/core/hub.c:5865
process_one_work kernel/workqueue.c:2633 [inline]
process_scheduled_works+0x913/0x1420 kernel/workqueue.c:2706
worker_thread+0xa5f/0x1000 kernel/workqueue.c:2787
kthread+0x2ef/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242
</TASK>