drm/amd/display: Check stream before comparing them

[ Upstream commit 35ff747c86767937ee1e0ca987545b7eed7a0810 ]

[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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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 0a13c06eea4472cdb5ed902bb4aaf1ac3f71121b..3af9591baa767e17e12401a60344d8967064aa9e 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
@@ -1697,6 +1697,8 @@ 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;