linux/samples/bpf/test_overhead_kprobe_kern.c
Yafang Shao d068144d3b samples/bpf/test_overhead_kprobe_kern: replace bpf_probe_read_kernel with bpf_probe_read_kernel_str to get task comm
bpf_probe_read_kernel_str() will add a nul terminator to the dst, then
we don't care about if the dst size is big enough.  This patch also
replaces the hard-coded 16 with TASK_COMM_LEN to make it grepable.

Link: https://lkml.kernel.org/r/20211120112738.45980-6-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-20 08:52:53 +02:00

50 lines
1.4 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 <linux/version.h>
#include <linux/ptrace.h>
#include <linux/sched.h>
#include <uapi/linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#define _(P) \
({ \
typeof(P) val = 0; \
bpf_probe_read_kernel(&val, sizeof(val), &(P)); \
val; \
})
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(ctx);
pid = _(tsk->pid);
bpf_probe_read_kernel_str(oldcomm, sizeof(oldcomm), &tsk->comm);
bpf_probe_read_kernel_str(newcomm, sizeof(newcomm),
(void *)PT_REGS_PARM2(ctx));
signal = _(tsk->signal);
oom_score_adj = _(signal->oom_score_adj);
return 0;
}
SEC("kprobe/urandom_read")
int prog2(struct pt_regs *ctx)
{
return 0;
}
char _license[] SEC("license") = "GPL";
u32 _version SEC("version") = LINUX_VERSION_CODE;