diff --git a/routers/api/v1/repo/repo.go b/routers/api/v1/repo/repo.go
index 2e551ef83..3faadd6fd 100644
--- a/routers/api/v1/repo/repo.go
+++ b/routers/api/v1/repo/repo.go
@@ -1144,6 +1144,7 @@ func PrepareCompareDiff(
 
 	// gitRepo, _ := git.OpenRepository(repoPath)
 	gitRepo, _ := git.OpenRepository(repoPath)
+	defer gitRepo.Close()
 
 	diff, err := gitdiff.GetDiffRange(gitRepo,
 		compareInfo.MergeBase, headCommitID, setting.Git.MaxGitDiffLines,