linux-stable/samples/bpf/test_overhead_kprobe.bpf.c
Daniel T. Lee 11430421b4 samples/bpf: make tracing programs to be more CO-RE centric
The existing tracing programs have been developed for a considerable
period of time and, as a result, do not properly incorporate the
features of the current libbpf, such as CO-RE. This is evident in
frequent usage of functions like PT_REGS* and the persistence of "hack"
methods using underscore-style bpf_probe_read_kernel from the past.

These programs are far behind the current level of libbpf and can
potentially confuse users. Therefore, this commit aims to convert the
outdated BPF programs to be more CO-RE centric.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20230818090119.477441-6-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-08-21 15:39:09 -07:00

41 lines
1 KiB
C

/* Copyright (c) 2016 Facebook
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
#include "vmlinux.h"
#include <linux/version.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_core_read.h>
SEC("kprobe/__set_task_comm")
int prog(struct pt_regs *ctx)
{
struct signal_struct *signal;
struct task_struct *tsk;
char oldcomm[TASK_COMM_LEN] = {};
char newcomm[TASK_COMM_LEN] = {};
u16 oom_score_adj;
u32 pid;
tsk = (void *)PT_REGS_PARM1_CORE(ctx);
pid = BPF_CORE_READ(tsk, pid);
bpf_core_read_str(oldcomm, sizeof(oldcomm), &tsk->comm);
bpf_core_read_str(newcomm, sizeof(newcomm),
(void *)PT_REGS_PARM2(ctx));
signal = BPF_CORE_READ(tsk, signal);
oom_score_adj = BPF_CORE_READ(signal, oom_score_adj);
return 0;
}
SEC("kprobe/fib_table_lookup")
int prog2(struct pt_regs *ctx)
{
return 0;
}
char _license[] SEC("license") = "GPL";
u32 _version SEC("version") = LINUX_VERSION_CODE;