| Message ID | 20241127-uvc-fix-async-v2-2-510aab9570dd@chromium.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | media: uvcvideo: Two fixes for async controls | expand |
diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c index b6af4ff92cbd..3f8ae35cb3bc 100644 --- a/drivers/media/usb/uvc/uvc_ctrl.c +++ b/drivers/media/usb/uvc/uvc_ctrl.c @@ -1955,6 +1955,10 @@ int uvc_ctrl_set(struct uvc_fh *handle, if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR)) return -EACCES; + /* Other file handle is waiting a response from this async control. */ + if (ctrl->handle && ctrl->handle != handle) + return -EBUSY; + /* Clamp out of range values. */ switch (mapping->v4l2_type) { case V4L2_CTRL_TYPE_INTEGER:
If a file handle is waiting for a response from an async control, avoid that other file handle operate with it. Without this patch, the first file handle will never get the event associated with that operation, which can lead to endless loops in applications. Eg: If an application A wants to change the zoom and to know when the operation has completed: it will open the video node, subscribe to the zoom event, change the control and wait for zoom to finish. If before the zoom operation finishes, another application B changes the zoom, the first app A will loop forever. Cc: stable@vger.kernel.org Fixes: e5225c820c05 ("media: uvcvideo: Send a control event when a Control Change interrupt arrives") Signed-off-by: Ricardo Ribalda <ribalda@chromium.org> --- drivers/media/usb/uvc/uvc_ctrl.c | 4 ++++ 1 file changed, 4 insertions(+)