Re: [PATCH] drm, video: fix use-before-NULL-check

[Jesse Barnes]

On Fri, 27 Aug 2010 14:07:19 -0700
Kees Cook <kees.cook@xxxxxxxxxxxxx> wrote:

> Fix potential crashes due to use-before-NULL situations.
> 
> Signed-off-by: Kees Cook <kees.cook@xxxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/drm_fb_helper.c           |    3 ++-
>  drivers/media/video/em28xx/em28xx-video.c |    3 ++-
>  2 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index de82e20..8dd7e6f 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -94,10 +94,11 @@ static bool drm_fb_helper_connector_parse_command_line(struct drm_fb_helper_conn
>  	int i;
>  	enum drm_connector_force force = DRM_FORCE_UNSPECIFIED;
>  	struct drm_fb_helper_cmdline_mode *cmdline_mode;
> -	struct drm_connector *connector = fb_helper_conn->connector;
> +	struct drm_connector *connector;
>  
>  	if (!fb_helper_conn)
>  		return false;
> +	connector = fb_helper_conn->connector;
>  
>  	cmdline_mode = &fb_helper_conn->cmdline_mode;
>  	if (!mode_option)
> diff --git a/drivers/media/video/em28xx/em28xx-video.c b/drivers/media/video/em28xx/em28xx-video.c
> index 7b9ec6e..95a4b60 100644
> --- a/drivers/media/video/em28xx/em28xx-video.c
> +++ b/drivers/media/video/em28xx/em28xx-video.c
> @@ -277,12 +277,13 @@ static void em28xx_copy_vbi(struct em28xx *dev,
>  {
>  	void *startwrite, *startread;
>  	int  offset;
> -	int bytesperline = dev->vbi_width;
> +	int bytesperline;
>  
>  	if (dev == NULL) {
>  		em28xx_isocdbg("dev is null\n");
>  		return;
>  	}
> +	bytesperline = dev->vbi_width;
>  
>  	if (dma_q == NULL) {
>  		em28xx_isocdbg("dma_q is null\n");

Look fine to me.

Reviewed-by: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>


-- 
Jesse Barnes, Intel Open Source Technology Center
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