[PATCH AUTOSEL 6.6 18/83] drm/amd/display: Fix Coverity INTEGER_OVERFLOW within decide_fallback_link_setting_max_bw_policy

Sasha Levin sashal at kernel.org
Thu Aug 1 00:17:33 UTC 2024


From: Hersen Wu <hersenxs.wu at amd.com>

[ Upstream commit 83c0c8361347cf43937348e8ca0a487679c003ae ]

[Why]
For addtion (uint8_t) variable + constant 1,
coverity generates message below:
Truncation due to cast operation on "cur_idx + 1" from
32 to 8 bits.

Then Coverity assume result is 32 bits value be saved into
8 bits variable. When result is used as index to access
array, Coverity suspects index invalid.

[How]
Change varaible type to uint32_t.

Reviewed-by: Alex Hung <alex.hung at amd.com>
Reviewed-by: Harry Wentland <harry.wentland at amd.com>
Acked-by: Tom Chung <chiahsuan.chung at amd.com>
Signed-off-by: Hersen Wu <hersenxs.wu at amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 .../gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c  | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
index 9a0beaf601f87..16f4865e4246d 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
@@ -528,7 +528,7 @@ static bool decide_fallback_link_setting_max_bw_policy(
 		struct dc_link_settings *cur,
 		enum link_training_result training_result)
 {
-	uint8_t cur_idx = 0, next_idx;
+	uint32_t cur_idx = 0, next_idx;
 	bool found = false;
 
 	if (training_result == LINK_TRAINING_ABORT)
-- 
2.43.0



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