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1// SPDX-License-Identifier: GPL-2.0-only2/* Copyright (c) 2020 Facebook */3#include <stddef.h>4#include <linux/bpf.h>5#include <bpf/bpf_helpers.h>6#include "bpf_misc.h"7 8#define MAX_STACK 2609 10static __attribute__ ((noinline))11int f0(int var, struct __sk_buff *skb)12{13 asm volatile ("");14 15 return skb->len;16}17 18__attribute__ ((noinline))19int f1(struct __sk_buff *skb)20{21 volatile char buf[MAX_STACK] = {};22 23 __sink(buf[MAX_STACK - 1]);24 25 return f0(0, skb) + skb->len;26}27 28int f3(int, struct __sk_buff *skb, int);29 30__attribute__ ((noinline))31int f2(int val, struct __sk_buff *skb)32{33 volatile char buf[MAX_STACK] = {};34 35 __sink(buf[MAX_STACK - 1]);36 37 return f1(skb) + f3(val, skb, 1);38}39 40__attribute__ ((noinline))41int f3(int val, struct __sk_buff *skb, int var)42{43 volatile char buf[MAX_STACK] = {};44 45 __sink(buf[MAX_STACK - 1]);46 47 return skb->ifindex * val * var;48}49 50SEC("tc")51__failure __msg("combined stack size of 3 calls is")52int global_func1(struct __sk_buff *skb)53{54 return f0(1, skb) + f1(skb) + f2(2, skb) + f3(3, skb, 4);55}56