On Mon, 2020-12-28 at 09:21 -0300, Ezequiel Garcia wrote:
> The csc/scaler device private struct is released by
> ipu_csc_scaler_video_device_release(), which can be called
> by video_unregister_device() if there are no users
> of the underlying struct video device.
>
> Therefore, the mutex can't be held when calling
> video_unregister_device() as its memory may be freed
> by it, leading to a kernel oops.
>
> Fortunately, the fix is quite simple as no locking
> is needed when calling video_unregister_device(): v4l2-core
> already has its own internal locking, and the structures
> are also properly refcounted.
>
> Fixes: a8ef0488cc59 ("media: imx: add csc/scaler mem2mem device")
> Signed-off-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx>
> ---
> drivers/staging/media/imx/imx-media-csc-scaler.c | 4 ----
> 1 file changed, 4 deletions(-)
>
> diff --git a/drivers/staging/media/imx/imx-media-csc-scaler.c b/drivers/staging/media/imx/imx-media-csc-scaler.c
> index fab1155a5958..63a0204502a8 100644
> --- a/drivers/staging/media/imx/imx-media-csc-scaler.c
> +++ b/drivers/staging/media/imx/imx-media-csc-scaler.c
> @@ -869,11 +869,7 @@ void imx_media_csc_scaler_device_unregister(struct imx_media_video_dev *vdev)
> struct ipu_csc_scaler_priv *priv = vdev_to_priv(vdev);
> struct video_device *vfd = priv->vdev.vfd;
>
> - mutex_lock(&priv->mutex);
> -
> video_unregister_device(vfd);
> -
> - mutex_unlock(&priv->mutex);
> }
>
> struct imx_media_video_dev *
Reviewed-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
regards
Philipp
