diff --git a/src/diff.c b/src/diff.c
index 375520e04..7a0051ae3 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -448,7 +448,11 @@ static int oid_for_workdir_item(
 		return -1;
 
 	/* calculate OID for file if possible*/
-	if (S_ISLNK(item->mode))
+	if (S_ISGITLINK(item->mode)) {
+		/* Don't bother to figure out an oid for a submodule. We won't use it anyway. */
+		memset(oid, 0, sizeof(*oid));
+		result = 0;
+	} else if (S_ISLNK(item->mode))
 		result = git_odb__hashlink(oid, full_path.ptr);
 	else if (!git__is_sizet(item->file_size)) {
 		giterr_set(GITERR_OS, "File size overflow for 32-bit systems");