drm/amd/display: fix dereference before NULL check

The "plane_state" pointer was access before checking if it was NULL.

Avoid a possible NULL pointer dereference by accessing the plane
address after the check.

Addresses-Coverity-ID: 1493892 ("Dereference before null check")
Fixes: 3f68c01be9a22 ("drm/amd/display: add cyan_skillfish display support")
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/dcn201/dcn201_hwseq.c b/drivers/gpu/drm/amd/display/dc/dcn201/dcn201_hwseq.c
index cfd09b3f705e9319224a2f0c3544970197cda198..fe22530242d2ecd126ba62cea0815266c262bce2 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dcn201/dcn201_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn201/dcn201_hwseq.c
@@ -134,11 +134,12 @@ void dcn201_update_plane_addr(const struct dc *dc, struct pipe_ctx *pipe_ctx)
        PHYSICAL_ADDRESS_LOC addr;
        struct dc_plane_state *plane_state = pipe_ctx->plane_state;
        struct dce_hwseq *hws = dc->hwseq;
-       struct dc_plane_address uma = plane_state->address;
+       struct dc_plane_address uma;
 
        if (plane_state == NULL)
                return;
 
+       uma = plane_state->address;
        addr_patched = patch_address_for_sbs_tb_stereo(pipe_ctx, &addr);
 
        plane_address_in_gpu_space_to_uma(hws, &uma);