[PATCH 6.6.y] drm/amd/display: Stop amdgpu_dm initialize when link nums greater than max_links - Linux-stable-mirror

16 Apr 2025

From: Hersen Wu hersenxs.wu@amd.com
[ Upstream commit cf8b16857db702ceb8d52f9219a4613363e2b1cf ]
[Why]
Coverity report OVERRUN warning. There are
only max_links elements within dc->links. link
count could up to AMDGPU_DM_MAX_DISPLAY_INDEX 31.
[How]
Make sure link count less than max_links.
Reviewed-by: Harry Wentland harry.wentland@amd.com
Acked-by: Tom Chung chiahsuan.chung@amd.com
Signed-off-by: Hersen Wu hersenxs.wu@amd.com
Tested-by: Daniel Wheeler daniel.wheeler@amd.com
Signed-off-by: Alex Deucher alexander.deucher@amd.com
[Minor conflict resolved due to code context change. And the macro MAX_LINKS
 is introduced by Commit 60df5628144b ("drm/amd/display: handle invalid
 connector indices") after 6.10. So here we still use the original array
 length MAX_PIPES * 2]
Signed-off-by: Jianqi Ren jianqi.ren.cn@windriver.com
Signed-off-by: He Zhe zhe.he@windriver.com
---
Verified the build test
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 3696b9112c74..28f2b4022d34 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -4484,17 +4484,17 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
    	}
    }
+	if (link_cnt > (MAX_PIPES * 2)) {
+		DRM_ERROR(
+			"KMS: Cannot support more than %d display indexes\n",
+				MAX_PIPES * 2);
+		goto fail;
+	}
+
    /* loops over all connectors on the board */
    for (i = 0; i < link_cnt; i++) {
    	struct dc_link *link = NULL;
-		if (i > AMDGPU_DM_MAX_DISPLAY_INDEX) {
-			DRM_ERROR(
-				"KMS: Cannot support more than %d display indexes\n",
-					AMDGPU_DM_MAX_DISPLAY_INDEX);
-			continue;
-		}
-
    	aconnector = kzalloc(sizeof(*aconnector), GFP_KERNEL);
    	if (!aconnector)
    		goto fail;
-- 
2.34.1



    