[PATCH] drm/fsl-dcu: Fix no fb check bug

[PATCH] drm/fsl-dcu: Fix no fb check bug

[Jianwei Wang]

For state->fb may be NULL in fsl_dcu_drm_plane_atomic_check function,
if so, return -EINVAL. No need check in fsl_dcu_drm_plane_atomic_update
anymore.

Signed-off-by: Jianwei Wang <jianwei.wang.chn@gmail.com>
---
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c
index 82be6b8..8787920 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c
@@ -41,6 +41,9 @@ static int fsl_dcu_drm_plane_atomic_check(struct drm_plane *plane,
 {
 	struct drm_framebuffer *fb = state->fb;
 
+	if (!fb)
+		return -EINVAL;
+
 	switch (fb->pixel_format) {
 	case DRM_FORMAT_RGB565:
 	case DRM_FORMAT_RGB888:
@@ -84,9 +87,6 @@ static void fsl_dcu_drm_plane_atomic_update(struct drm_plane *plane,
 	unsigned int alpha, bpp;
 	int index, ret;
 
-	if (!fb)
-		return;
-
 	index = fsl_dcu_drm_plane_index(plane);
 	if (index < 0)
 		return;
-- 
2.1.0.27.g96db324

Re: [PATCH] drm/fsl-dcu: Fix no fb check bug

[Stefan Agner]

Hi,

This avoids a NULL pointer dereference when no crtc is available (e.g.
the fsl,panel not assigned).

Any chance to get this into 4.4?

Tested-by: Stefan Agner <stefan@agner.ch>

--
Stefan

On 2015-08-30 20:39, Jianwei Wang wrote:
> For state->fb may be NULL in fsl_dcu_drm_plane_atomic_check function,
> if so, return -EINVAL. No need check in fsl_dcu_drm_plane_atomic_update
> anymore.
> 
> Signed-off-by: Jianwei Wang <jianwei.wang.chn@gmail.com>
> ---
>  drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c
> b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c
> index 82be6b8..8787920 100644
> --- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c
> +++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c
> @@ -41,6 +41,9 @@ static int fsl_dcu_drm_plane_atomic_check(struct
> drm_plane *plane,
>  {
>  	struct drm_framebuffer *fb = state->fb;
>  
> +	if (!fb)
> +		return -EINVAL;
> +
>  	switch (fb->pixel_format) {
>  	case DRM_FORMAT_RGB565:
>  	case DRM_FORMAT_RGB888:
> @@ -84,9 +87,6 @@ static void fsl_dcu_drm_plane_atomic_update(struct
> drm_plane *plane,
>  	unsigned int alpha, bpp;
>  	int index, ret;
>  
> -	if (!fb)
> -		return;
> -
>  	index = fsl_dcu_drm_plane_index(plane);
>  	if (index < 0)
>  		return;