Linux run kernel probe systemtap script failed with semantic error: no match"

Linux run kernel probe systemtap script failed with semantic error: no match"

我有 2 个实验环境:CentOS 6.8 和 Ubuntu16.04 都在 Virtualbox VM 中 运行。

我在 CentOS 上安装

yum install kernel-devel kernel-debug

在 Ubuntu 我安装了:

sudo apt-get install linux-headers-$(uname -r)
sudo apt-get install fakeroot build-essential crash kexec-tools makedumpfile kernel-wedge

在两个系统上我都可以运行成功:

stap -ve 'probe begin { log("hello world") exit() }'

我尝试了这个 .stp 来自 systemtap 指南的脚本:

#!/usr/bin/stap
probe begin
{
    log("begin probe")
}
probe syscall.open
{
    printf("%s(%d) open (%s)\n",execname(),pid(),argstr)
}
probe timer.ms(4000)#4s later
{
    exit()
}
probe end
{
    log("end probe")
}

chmod +x ... 脚本和 运行 作为 root 用户。两个系统都报告如下错误:

./test2.stp -v
Pass 1: parsed user script and 124 library script(s) using 217780virt/45168res/3204shr/42664data kb, in 210usr/20sys/238real ms.
semantic error: while resolving probe point: identifier 'kernel' at /usr/share/systemtap/tapset/linux/syscalls2.stp:197:24
        source: probe __syscall.open = kernel.function("sys_open").call
                                       ^

semantic error: missing x86_64 kernel/module debuginfo [man warning::debuginfo] under '/lib/modules/2.6.32-642.el6.x86_64/build'

semantic error: while resolving probe point: identifier '__syscall' at :177:47
        source: probe syscall.open = __syscall.compat_open ?, __syscall.open
                                                              ^

semantic error: no match

semantic error: while resolving probe point: identifier 'syscall' at ./test2.stp:6:7
        source: probe syscall.open
                      ^

semantic error: no match

Pass 2: analyzed script: 3 probe(s), 6 function(s), 0 embed(s), 0 global(s) using 230172virt/57516res/5204shr/52952data kb, in 120usr/150sys/270real ms.
Pass 2: analysis failed.  [man error::pass2]

这个错误是关于什么的?是安装问题吗?我的脚本有语法错误吗?

非常感谢。

tl;dr 安装内核映像调试符号,例如包裹 linux-image-$(uname -r)-dbgsym.

问题背景

我遇到了类似的错误

$ sudo stap -v udp_detect_exec.stp
...
semantic error: while resolving probe point: identifier 'kernel' at /usr/share/systemtap/tapset/linux/udp.stp:39:21
        source: probe udp.sendmsg = kernel.function("udp_sendmsg") {

systemtap 脚本到 track DNS requests

#! /usr/bin/env stap
probe udp.sendmsg (
  if ( dport == 53 && ( daddr == "8.8.8.8" || daddr == "8.8.4.4" ) ) {
    printf ("PID %5d (%s) sent UDP to %15s 53\n", pid(), execname(), daddr)
  }
}

this blog.jeffli.me post 之后,一个 hello world systemtap 脚本成功了。

sudo stap -e 'probe kernel.function("sys_open") {log("hello world") exit()}'

解决方法(安装内核调试符号)

在此 wiki.ubuntu.com entry 之后,我的 Ubuntu 16.04 系统缺少内核调试符号。我运行安装步骤:

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys C8CAB6595FDFF622
codename=$(lsb_release -c | awk  '{print }')
sudo tee /etc/apt/sources.list.d/ddebs.list << EOF
  deb http://ddebs.ubuntu.com/ ${codename}      main restricted universe multiverse
  deb http://ddebs.ubuntu.com/ ${codename}-security main restricted universe multiverse
  deb http://ddebs.ubuntu.com/ ${codename}-updates  main restricted universe multiverse
  deb http://ddebs.ubuntu.com/ ${codename}-proposed main restricted universe multiverse
EOF
sudo apt-get update
sudo apt-get install linux-image-$(uname -r)-dbgsym

脚本udp_detect_exec.stp成功运行。

我建议在 wiki.ubuntu.com 条目中检查更新的 apt-get install 步骤。