uvc_unregister_video() can be called asynchronously from uvc_disconnect(). If the device is still streaming when that happens, a plethora of race conditions can happen. Make sure that the device has stopped streaming before exiting this function. If the user still holds handles to the driver's file descriptors, any ioctl will return -ENODEV from the v4l2 core. This change make uvc more consistent with the rest of the v4l2 drivers using the vb2_fop_* and vb2_ioctl_* helpers. Suggested-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx> Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx> --- drivers/media/usb/uvc/uvc_driver.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index bbd90123a4e76..17fc945c8deb6 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -1911,8 +1911,19 @@ static void uvc_unregister_video(struct uvc_device *dev) if (!video_is_registered(&stream->vdev)) continue; + /* + * Serialize other access to the stream. + */ + mutex_lock(&stream->mutex); + uvc_queue_streamoff(&stream->queue, stream->type); video_unregister_device(&stream->vdev); video_unregister_device(&stream->meta.vdev); + mutex_unlock(&stream->mutex); + + /* + * Now the vdev is not streaming and all the ioctls will + * return -ENODEV + */ uvc_debugfs_cleanup_stream(stream); } -- 2.44.0.396.g6e790dbe36-goog
