1// SPDX-License-Identifier: GPL-2.0
2// Copyright (c) 2019 Facebook
3#include <linux/sched.h>
4#include <linux/ptrace.h>
5#include <stdint.h>
6#include <stddef.h>
7#include <stdbool.h>
8#include <linux/bpf.h>
9#include <bpf/bpf_helpers.h>
10#include <bpf/bpf_tracing.h>
11
12char _license[] SEC("license") = "GPL";
13
14SEC("raw_tracepoint/kfree_skb")
15int nested_loops(volatile struct pt_regs* ctx)
16{
17 int i, j, sum = 0, m;
18
19 for (j = 0; j < 300; j++)
20 for (i = 0; i < j; i++) {
21 if (j & 1)
22 m = PT_REGS_RC(ctx);
23 else
24 m = j;
25 sum += i * m;
26 }
27
28 return sum;
29}
30

source code of linux/tools/testing/selftests/bpf/progs/loop1.c