diff --git a/tools/testing/selftests/safesetid/safesetid-test.c b/tools/testing/selftests/safesetid/safesetid-test.c
index 4b809c93ba36..111dcbcc0491 100644
--- a/tools/testing/selftests/safesetid/safesetid-test.c
+++ b/tools/testing/selftests/safesetid/safesetid-test.c
@@ -194,7 +194,7 @@ static bool test_userns(bool expect_success)
 			printf("preparing file name string failed");
 			return false;
 		}
-		success = write_file(map_file_name, "0 0 1", uid);
+		success = write_file(map_file_name, "0 %d 1", uid);
 		return success == expect_success;
 	}