linux 内核模块调试


 1. 开启虚拟机,虚拟机运行到 kgdb: Waiting for connection from remote gdb

  2. 在Host机上运行: socat tcp-listen:8888 /tmp/vbox2, 其中/tmp/vbox2为管道文件,它是目标机串口的重定向目的文件,socat将这个管道文件又重定向到tcp socket的8888端口。

  3. 开启一个新的虚拟终端,cd path/to/kernel/source/tree, 然后执行gdb ./vmlinux

  输出

  GNU gdb 6.8-debian

  Copyright (C) 2008 Free Software Foundation, Inc.

  License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

  This is free software: you are free to change and redistribute it.

  There is NO WARRANTY, to the extent permitted by law.  Type "show copying"

  and "show warranty" for details.

  This GDB was configured as "i486-linux-gnu"...

  (gdb) set-remote

  set remote baud rate to 115200c/s

  set remote target to local tcp socket

  kgdb_breakpoint () at kernel/kgdb.c:1721

  1721        wmb(); /* Sync point after breakpoint */

  (gdb) c

  Continuing.

  目标机会一直启动,直到提示输入用户名密码。

  4. 进入目标机,输入用户名密码(推荐使用字符界面下的root用户),输入g命令,目标机被断下,控制移交到Host机中的gdb中。(目标机root的用户目录中的.bashrc中添加一行alias g='echo g>/proc/sysrq-trigger')

  5. 在Host机中的gdb中

  (gdb) set-mod-break

  set breakpoint in system module init function

  Breakpoint 1 at 0xc014bac5: file kernel/module.c, line 2288.

  (gdb) c

  Continuing.

  6. 在目标机中

  insmod klogger2.ko

  目标机再次断下,控制权移交Host机中的gdb

  7. 在Host机中的gdb中

  [New Thread 4693]

  [Switching to Thread 4693]

  Breakpoint 1, sys_init_module (umod=0x0, len=0, uargs=0x0)

  at kernel/module.c:2288

  2288        if (mod->init != NULL)

  (gdb) print-mod-segment

  Name:.note.gnu.build-id Address:0xdf977058

  Name:.text Address:0xdf975000

  Name:.rodata Address:0xdf977080

  Name:.rodata.str1.4 Address:0xdf9774b4

  Name:.rodata.str1.1 Address:0xdf977522

  Name:.parainstructions Address:0xdf977a00

  Name:.data Address:0xdf978440

  Name:.gnu.linkonce.this_module Address:0xdf978480

  Name:.bss Address:0xdf978a00

  Name:.symtab Address:0xdf977a08

  Name:.strtab Address:0xdf978078

  (gdb) add-symbol-file /home/done/programs/linux-kernel/vlogger/klogger2.ko 0xdf975000 -s .data 0xdf978440 -s .bss 0xdf978a00

  add symbol table from file "/home/done/programs/linux-kernel/vlogger/klogger2.ko" at

  .text_addr = 0xdf975000

  .data_addr = 0xdf978440

  .bss_addr = 0xdf978a00

  (y or n) y

  Reading symbols from /home/done/programs/linux-kernel/vlogger/klogger2.ko...done.

  (gdb) b hook_init

  Breakpoint 2 at 0xdf976d19: file /home/done/programs/linux-kernel/vlogger/hook.c, line 255.

  (gdb)

  你可以调试自己些的LKM模块了

  附gdb的初始化配置文件~/.gdbinit

  define set-remote

  echo set remote baud rate to 115200c/s\n

  set remotebaud 115200

  echo set remote target to local tcp socket\n

  target remote tcp:localhost:8888

  end

  define set-mod-break

  echo set breakpoint in system module init function\n

  break kernel/module.c:2288

  end

  define print-mod-segment

  set $sect_num=mod->sect_attrs->nsections

  set $cur=0

  while $cur < $sect_num

  printf "Name:%-s Address:0x%x\n",mod->sect_attrs->attrs[$cur]->name,mod->sect_attrs->attrs[$cur]->address

  set $cur=$cur+1

  end

  end

  后记:gdb的调试脚本真难写,简单的字符串变量连接和等价判断都显得十分困难,不知道是我水平太差还是gdb的脚本功能太弱,总之比起Windbg来说,内核调试困难程度上了个等级



相关阅读:
菜鸟课堂:Linux操作系统下进行C程序编译
php cookie的操作实现代码(登录)
Oracle的初学者入门心得
ASP.NET开发网站程序常见错误汇总
Linux+Apache+PHP+JSP 的Resin解决方案
Ubuntu 7.04到Ubuntu 8.10越来越慢了吗?
jQuery Jcrop插件实现图片选取功能
JS 单击连接保存图片的函数
Asp.net 通用万级数据分页代码
AJAX实现web页面中级联菜单的设计
VBS访问剪贴板的几种方法小结
PHP的七大优势
Linux系统下如何转换文本文件的内码
linux下几种通过重写硬盘实现擦除数据的办法共享
快速导航

Copyright © 2016 phpStudy | 皖ICP备18014864号-4