Back in 2020 Guenter published a set of patches to fix some race conditions on UVC. https://lore.kernel.org/all/20200917022547.198090-5-linux@xxxxxxxxxxxx/ That kind of race conditions are not only seen on UVC, but are a common sin on almost all the kernel, so this is what it was decided back then that we should try to fix them at higher levels. After that. A lot of video_is_registered() were added to the core: ``` ribalda@alco:~/work/linux$ git grep is_registered drivers/media/v4l2-core/ drivers/media/v4l2-core/v4l2-compat-ioctl32.c: if (!video_is_registered(vdev)) drivers/media/v4l2-core/v4l2-dev.c: if (video_is_registered(vdev)) drivers/media/v4l2-core/v4l2-dev.c: if (video_is_registered(vdev)) drivers/media/v4l2-core/v4l2-dev.c: if (video_is_registered(vdev)) { drivers/media/v4l2-core/v4l2-dev.c: if (video_is_registered(vdev)) drivers/media/v4l2-core/v4l2-dev.c: if (!video_is_registered(vdev)) drivers/media/v4l2-core/v4l2-dev.c: if (video_is_registered(vdev)) drivers/media/v4l2-core/v4l2-dev.c: if (vdev == NULL || !video_is_registered(vdev)) { drivers/media/v4l2-core/v4l2-dev.c: if (video_is_registered(vdev)) drivers/media/v4l2-core/v4l2-dev.c: if (!vdev || !video_is_registered(vdev)) drivers/media/v4l2-core/v4l2-ioctl.c: if (!video_is_registered(vfd)) { drivers/media/v4l2-core/v4l2-subdev.c: if (video_is_registered(vdev)) { ``` And recently Sakari is trying to land: https://lore.kernel.org/linux-media/20230201214535.347075-1-sakari.ailus@xxxxxxxxxxxxxxx/ Which will make obsolete a lot of (all?) of the video_is_registered() checks on Guenter's patches. Besides those checks, there were some other valid races fixed on his patches. This series is just a rebase of what I think is missing on UVC even if we fixed v4l2/core with all the video_is_register() checks removed. Thanks! Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx> --- Changes in v3: - Introduce media: uvcvideo: Do not halt the device after disconnect - Introduce media: uvcvideo: Always use uvc_status_stop() - Link to v2: https://lore.kernel.org/r/20230309-guenter-mini-v2-0-e6410d590d43@xxxxxxxxxxxx Changes in v2: - Actually send the series to the ML an not only to individuals. - Link to v1: https://lore.kernel.org/r/20230309-guenter-mini-v1-0-627d10cf6e96@xxxxxxxxxxxx --- Guenter Roeck (1): media: uvcvideo: Lock video streams and queues while unregistering Ricardo Ribalda (2): media: uvcvideo: Always use uvc_status_stop() media: uvcvideo: Do not halt the device after disconnect drivers/media/usb/uvc/uvc_ctrl.c | 4 ---- drivers/media/usb/uvc/uvc_driver.c | 11 ++++++++++ drivers/media/usb/uvc/uvc_status.c | 2 +- drivers/media/usb/uvc/uvc_video.c | 45 ++++++++++++++++++++++++-------------- drivers/media/usb/uvc/uvcvideo.h | 2 ++ 5 files changed, 42 insertions(+), 22 deletions(-) --- base-commit: 98b1cc82c4affc16f5598d4fa14b1858671b2263 change-id: 20230309-guenter-mini-89861b084ef1 Best regards, -- Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
