drm/amd/display: Check stream before comparing them

[WHAT & HOW]
amdgpu_dm can pass a null stream to dc_is_stream_unchanged. It is
necessary to check for null before dereferencing them.

This fixes 1 FORWARD_NULL issue reported by Coverity.

Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Jerry Zuo <jerry.zuo@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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 bcb5267b5a6bc22573eb9b9164e87a7d38eadaff..83aa3d8a997a01c4da25ae1fa0c883ce0aa20c72 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
@@ -3241,6 +3241,8 @@ static bool are_stream_backends_same(
 bool dc_is_stream_unchanged(
        struct dc_stream_state *old_stream, struct dc_stream_state *stream)
 {
+       if (!old_stream || !stream)
+               return false;
 
        if (!are_stream_backends_same(old_stream, stream))
                return false;