drm/amd/display: Stop amdgpu_dm initialize when link nums greater than max_links

commit cf8b16857db702ceb8d52f9219a4613363e2b1cf upstream.

[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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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 3696b9112c74e3f61b9eff826c7f7f1bca3178ba..28f2b4022d34e3cd6ede15e0fd6dcdb20dd9c7d3 100644 (file)
--- 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;