diff --git a/tools/testing/selftests/bpf/prog_tests/tcp_rtt.c b/tools/testing/selftests/bpf/prog_tests/tcp_rtt.c
index dee68ef97..d207e968e 100755
--- a/tools/testing/selftests/bpf/prog_tests/tcp_rtt.c
+++ b/tools/testing/selftests/bpf/prog_tests/tcp_rtt.c
@@ -1,5 +1,4 @@
 // SPDX-License-Identifier: GPL-2.0
-#define _GNU_SOURCE
 #include <test_progs.h>
 #include "cgroup_helpers.h"
 #include "network_helpers.h"