drm/komeda: Potential error pointer dereference

[james qian wang (Arm Technology China)]

Hi Dan 

On Fri, May 03, 2019 at 03:25:25PM +0300, Dan Carpenter wrote:
> We need to check whether drm_atomic_get_crtc_state() returns an error
> pointer before dereferencing "crtc_st".
> 
> Fixes: 7d31b9e7a550 ("drm/komeda: Add komeda_plane/plane_helper_funcs")
> Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>
> Acked-by: Liviu Dudau <liviu.dudau at arm.com>
> ---
>  drivers/gpu/drm/arm/display/komeda/komeda_plane.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_plane.c b/drivers/gpu/drm/arm/display/komeda/komeda_plane.c
> index 07ed0cc1bc44..c7e5fc6e5500 100644
> --- a/drivers/gpu/drm/arm/display/komeda/komeda_plane.c
> +++ b/drivers/gpu/drm/arm/display/komeda/komeda_plane.c
> @@ -64,7 +64,7 @@ komeda_plane_atomic_check(struct drm_plane *plane,
>  		return 0;
>  
>  	crtc_st = drm_atomic_get_crtc_state(state->state, state->crtc);
> -	if (!crtc_st->enable) {
> +	if (IS_ERR(crtc_st) || !crtc_st->enable) {
>  		DRM_DEBUG_ATOMIC("Cannot update plane on a disabled CRTC.\n");
>  		return -EINVAL;
>  	}

Thank you for the fixing.
-- 
Reviewed-by: James Qian Wang (Arm Technology China) <james.qian.wang at arm.com>