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 <linux/ptrace.h>
8 #include <linux/version.h>
9 #include <uapi/linux/bpf.h>
10 #include <bpf/bpf_helpers.h>
11 #include <bpf/bpf_tracing.h>
12
13 struct pair {
14 u64 val;
15 u64 ip;
16 };
17
18 struct {
19 __uint(type, BPF_MAP_TYPE_HASH);
20 __type(key, long);
21 __type(value, struct pair);
22 __uint(max_entries, 1000000);
23 } my_map SEC(".maps");
24
25 /* kprobe is NOT a stable ABI. If kernel internals change this bpf+kprobe
26 * example will no longer be meaningful
27 */
28 SEC("kprobe/kmem_cache_free")
bpf_prog1(struct pt_regs * ctx)29 int bpf_prog1(struct pt_regs *ctx)
30 {
31 long ptr = PT_REGS_PARM2(ctx);
32
33 bpf_map_delete_elem(&my_map, &ptr);
34 return 0;
35 }
36
37 SEC("kretprobe/kmem_cache_alloc_node")
bpf_prog2(struct pt_regs * ctx)38 int bpf_prog2(struct pt_regs *ctx)
39 {
40 long ptr = PT_REGS_RC(ctx);
41 long ip = 0;
42
43 /* get ip address of kmem_cache_alloc_node() caller */
44 BPF_KRETPROBE_READ_RET_IP(ip, ctx);
45
46 struct pair v = {
47 .val = bpf_ktime_get_ns(),
48 .ip = ip,
49 };
50
51 bpf_map_update_elem(&my_map, &ptr, &v, BPF_ANY);
52 return 0;
53 }
54 char _license[] SEC("license") = "GPL";
55 u32 _version SEC("version") = LINUX_VERSION_CODE;
56