[PATCH AUTOSEL 6.10 009/121] drm/amd/display: Ensure array index tg_inst won't be -1

Sasha Levin
2024-08-01T00:09:19Z

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

[ Upstream commit 687fe329f18ab0ab0496b20ed2cb003d4879d931 ]

[WHY & HOW]
tg_inst will be a negative if timing_generator_count equals 0, which
should be checked before used.

This fixes 2 OVERRUN issues reported by Coverity.

Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@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>
---
drivers/gpu/drm/amd/display/dc/core/dc_resource.c | 2 +-
1 file changed, 1 insertion(+), 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 15819416a2f36..693d05a98c6fb 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
@@ -3492,7 +3492,7 @@ static bool acquire_otg_master_pipe_for_stream(
if (pool->dpps[pipe_idx])
pipe_ctx->plane_res.mpcc_inst = pool->dpps[pipe_idx]->inst;

- if (pipe_idx >= pool->timing_generator_count) {
+ if (pipe_idx >= pool->timing_generator_count && pool->timing_generator_count != 0) {
int tg_inst = pool->timing_generator_count - 1;

pipe_ctx->stream_res.tg = pool->timing_generators[tg_inst];
--
2.43.0