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

[Ma Ke]

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 at vger.kernel.org
Fixes: 3be5262e353b ("drm/amd/display: Rename more dc_surface stuff to plane_state")
Signed-off-by: Ma Ke <make24 at 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) {
-- 
2.25.1