Re: [PATCH v2] drm/amd/display: Fix null check for pipe_ctx->plane_state in resource_build_scaling_params

[Alex Hung <alex.hung@amd.com>]

Reviewed-by: Alex Hung <alex.hung@amd.com>

On 2/26/25 01:37, Ma Ke wrote:
> Null pointer dereference issue could occur when pipe_ctx->plane_state
> is null. The fix adds a check to ensure 'pipe_ctx->plane_state' is not
> null before accessing. This prevents a null pointer dereference.
> 
> Found by code review.
> 
> Cc: stable@vger.kernel.org
> Fixes: 3be5262e353b ("drm/amd/display: Rename more dc_surface stuff to plane_state")
> Signed-off-by: Ma Ke <make24@iscas.ac.cn>
> ---
> Changes in v2:
> - modified the patch as suggestions.
> ---
>   drivers/gpu/drm/amd/display/dc/core/dc_resource.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
> index 520a34a42827..a45037cb4cc0 100644
> --- a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
> +++ b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
> @@ -1455,7 +1455,8 @@ bool resource_build_scaling_params(struct pipe_ctx *pipe_ctx)
>   	DC_LOGGER_INIT(pipe_ctx->stream->ctx->logger);
>   
>   	/* Invalid input */
> -	if (!plane_state->dst_rect.width ||
> +	if (!plane_state ||
> +			!plane_state->dst_rect.width ||
>   			!plane_state->dst_rect.height ||
>   			!plane_state->src_rect.width ||
>   			!plane_state->src_rect.height) {