tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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_helpers.h"
11#include "bpf_tracing.h"
12
13struct pair {
14 u64 val;
15 u64 ip;
16};
17
18struct bpf_map_def SEC("maps") my_map = {
19 .type = BPF_MAP_TYPE_HASH,
20 .key_size = sizeof(long),
21 .value_size = sizeof(struct pair),
22 .max_entries = 1000000,
23};
24
25/* kprobe is NOT a stable ABI. If kernel internals change this bpf+kprobe
26 * example will no longer be meaningful
27 */
28SEC("kprobe/kmem_cache_free")
29int 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
37SEC("kretprobe/kmem_cache_alloc_node")
38int 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}
54char _license[] SEC("license") = "GPL";
55u32 _version SEC("version") = LINUX_VERSION_CODE;