tools/testing/selftests/bpf/progs/test_global_func15.c

// SPDX-License-Identifier: GPL-2.0-only
#include <stddef.h>
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>

__noinline int foo(unsigned int *v)
{
	if (v)
		*v = bpf_get_prandom_u32();

	return 0;
}

SEC("cgroup_skb/ingress")
int test_cls(struct __sk_buff *skb)
{
	unsigned int v = 1;

	foo(&v);

	return v;
}