1 // SPDX-License-Identifier: GPL-2.0-only
2 /* 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 260
9
10 static __attribute__ ((noinline))
11 int f0(int var, struct __sk_buff *skb)
12 {
13 asm volatile ("");
14
15 return skb->len;
16 }
17
18 __attribute__ ((noinline))
19 int 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
28 int f3(int, struct __sk_buff *skb, int);
29
30 __attribute__ ((noinline))
31 int 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))
41 int 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
50 SEC("tc")
51 __failure __msg("combined stack size of 3 calls is")
52 int global_func1(struct __sk_buff *skb)
53 {
54 return f0(1, skb) + f1(skb) + f2(2, skb) + f3(3, skb, 4);
55 }
56
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