LXR linux/samples/bpf/test_overhead_kprobe

   1/* Copyright (c) 2016 Facebook
   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/version.h>
   8#include <linux/ptrace.h>
   9#include <uapi/linux/bpf.h>
  10#include <bpf/bpf_helpers.h>
  11#include <bpf/bpf_tracing.h>
  12
  13#define _(P)                                                                   \
  14        ({                                                                     \
  15                typeof(P) val = 0;                                             \
  16                bpf_probe_read_kernel(&val, sizeof(val), &(P));                \
  17                val;                                                           \
  18        })
  19
  20SEC("kprobe/__set_task_comm")
  21int prog(struct pt_regs *ctx)
  22{
  23        struct signal_struct *signal;
  24        struct task_struct *tsk;
  25        char oldcomm[16] = {};
  26        char newcomm[16] = {};
  27        u16 oom_score_adj;
  28        u32 pid;
  29
  30        tsk = (void *)PT_REGS_PARM1(ctx);
  31
  32        pid = _(tsk->pid);
  33        bpf_probe_read_kernel(oldcomm, sizeof(oldcomm), &tsk->comm);
  34        bpf_probe_read_kernel(newcomm, sizeof(newcomm),
  35                              (void *)PT_REGS_PARM2(ctx));
  36        signal = _(tsk->signal);
  37        oom_score_adj = _(signal->oom_score_adj);
  38        return 0;
  39}
  40
  41SEC("kprobe/urandom_read")
  42int prog2(struct pt_regs *ctx)
  43{
  44        return 0;
  45}
  46
  47char _license[] SEC("license") = "GPL";
  48u32 _version SEC("version") = LINUX_VERSION_CODE;
  49