1 /* Copyright (c) 2015 PLUMgrid, http://plumgrid.com
2 *
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software Foundation.
6 */
7 #include "vmlinux.h"
8 #include <linux/version.h>
9 #include <bpf/bpf_helpers.h>
10 #include <bpf/bpf_tracing.h>
11
12 struct pair {
13 u64 val;
14 u64 ip;
15 };
16
17 struct {
18 __uint(type, BPF_MAP_TYPE_HASH);
19 __type(key, long);
20 __type(value, struct pair);
21 __uint(max_entries, 1000000);
22 } my_map SEC(".maps");
23
24 /* kprobe is NOT a stable ABI. If kernel internals change this bpf+kprobe
25 * example will no longer be meaningful
26 */
27 SEC("kprobe/kmem_cache_free")
28 int bpf_prog1(struct pt_regs *ctx)
29 {
30 long ptr = PT_REGS_PARM2(ctx);
31
32 bpf_map_delete_elem(&my_map, &ptr);
33 return 0;
34 }
35
36 SEC("kretprobe/kmem_cache_alloc_node")
37 int bpf_prog2(struct pt_regs *ctx)
38 {
39 long ptr = PT_REGS_RC(ctx);
40 long ip = 0;
41
42 /* get ip address of kmem_cache_alloc_node() caller */
43 BPF_KRETPROBE_READ_RET_IP(ip, ctx);
44
45 struct pair v = {
46 .val = bpf_ktime_get_ns(),
47 .ip = ip,
48 };
49
50 bpf_map_update_elem(&my_map, &ptr, &v, BPF_ANY);
51 return 0;
52 }
53 char _license[] SEC("license") = "GPL";
54 u32 _version SEC("version") = LINUX_VERSION_CODE;
55
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.