[lvc-project] [PATCH 6.1] drm/amd/display: Check null pointers before multiple uses

[Aleksandr Burakov]

From: Alex Hung <alex.hung at amd.com>

commit fdd5ecbbff751c3b9061d8ebb08e5c96119915b4 upstream.

[WHAT & HOW]
Poniters, such as stream_enc and dc->bw_vbios, are null checked previously
in the same function, so Coverity warns "implies that stream_enc and
dc->bw_vbios might be null". They are used multiple times in the
subsequent code and need to be checked.

This fixes 10 FORWARD_NULL issues reported by Coverity.

Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira at amd.com>
Signed-off-by: Jerry Zuo <jerry.zuo at amd.com>
Signed-off-by: Alex Hung <alex.hung at amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
[ Aleksandr Burakov: Introducing only the NULL check in
  dcn32_enable_phantom_plane() resolves the bug while minimizing risk
  and preserving stability in the 6.1.y codebase. ]
Signed-off-by: Aleksandr Burakov <a.burakov at rosa.ru>
---
 drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c b/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c
index 1b1534ffee9f..2e95b48439ca 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c
@@ -1664,6 +1664,9 @@ static void dcn32_enable_phantom_plane(struct dc *dc,
 		else
 			phantom_plane = dc_create_plane_state(dc);
 
+		if !(phantom_plane)
+			continue;
+
 		memcpy(&phantom_plane->address, &curr_pipe->plane_state->address, sizeof(phantom_plane->address));
 		memcpy(&phantom_plane->scaling_quality, &curr_pipe->plane_state->scaling_quality,
 				sizeof(phantom_plane->scaling_quality));
-- 
2.40.1