diff --git a/tools/testing/selftests/bpf/cgroup_helpers.c b/tools/testing/selftests/bpf/cgroup_helpers.c
index e95c33e333a4..4d74f3c4619b 100644
--- a/tools/testing/selftests/bpf/cgroup_helpers.c
+++ b/tools/testing/selftests/bpf/cgroup_helpers.c
@@ -41,7 +41,7 @@
  *
  * If successful, 0 is returned.
  */
-int enable_all_controllers(char *cgroup_path)
+static int enable_all_controllers(char *cgroup_path)
 {
 	char path[PATH_MAX + 1];
 	char buf[PATH_MAX];