kgtp linux内核调试

作者：朱辉

开源网址：https://github.com/teawater

http://teawater.github.io/kgtp/      有中文版说明

内核编绎：

General setup  --->

     [ * ] Prompt for development and/or incomplete code/drivers

     [ * ] Kprobe

Kernel hacking  --->

     [ * ] Compile the kernel with debug info

     [ * ] Compile the kernel with frame pointers

 

 

gdb版本:

 

 KGTP_NEED_GDB_VERSION = 7.6

KGTP_INSTALL_GDB = "gdb-7.7"

1.编绎

tar -zxvf kgtp-20140510.tar.gz

[root@localhost kgtp-]# ls
add-ons                   gtp_2..20_to_2.6.32.patch  gtp_rb.c      plugin_example.c
dkms.conf                 gtp_2..33_to_2.6.38.patch  kgtpcn.odt    putgtprsp.c
dkms_others_install.sh    gtp_2.6.39.patch            kgtpcn.pdf    README.md
dkms_others_uninstall.sh  gtp_3.0_to_3..patch        kgtp.odt      ring_buffer.c
getframe.c                gtp_3.7_to_upstream.patch   kgtp.pdf      ring_buffer.h
getgtprsp.pl              gtp.c                       kgtp.py       UPDATE
getmod.c                  gtp.h                       Makefile
getmod.py                 gtp_older_to_2.6.19.patch   perf_event.c
[root@localhost kgtp-]# make
make CROSS_COMPILE= -C /lib/modules/2.6./build/ M=/root/kgtp- modules
make[]: Entering directory `/usr/src/kernels/linux-2.6.'
  CC [M]  /root/kgtp-/gtp.o
/root/kgtp-/gtp.c::: warning: #warning "Current Kernel is too old.  Function of performance counters is not available."
/root/kgtp-/gtp.c::: warning: #warning "Cannot trace user program because the Linux Kernel that older than 3.9 doesn't support UPROBES."
/root/kgtp-/gtp_rb.c: In function ‘gtp_rb_walk’:
/root/kgtp-/gtp_rb.c:: warning: ‘step’ may be used uninitialized in this function
/root/kgtp-/gtp.c::: warning: #warning "Current Kernel is too old.  Function of performance counters is not available."
/root/kgtp-/gtp.c::: warning: #warning "Cannot trace user program because the Linux Kernel that older than 3.9 doesn't support UPROBES."
  Building modules, stage .
  MODPOST  modules
  CC      /root/kgtp-/gtp.mod.o
  LD [M]  /root/kgtp-/gtp.ko
make[]: Leaving directory `/usr/src/kernels/linux-2.6.'
gcc -O2 -static -o getmod getmod.c
gcc -O2 -static -o getframe getframe.c
gcc -O2 -static -o putgtprsp putgtprsp.c

2.insmod   gtp.ko

3.  mount -t sysfs none /sys/

mount   -t  debugfs none  /sys/kernel/debug/

 

4. cd  /usr/src/kernels/linux-2.6.32    进入源代码目录

5.gdb vmlinux

6.(gdb) target remote /sys/kernel/debug/gtp

7. 调试内核

(gdb) trace vfs_readdir     跟踪涵数名
Tracepoint  at 0xffffffff810d751f: file fs/readdir.c, line .
--------------------------------------------------------------------
(gdb) actions   设轩预到跟踪点进行收集信息
Enter actions for tracepoint , one per line.
End with a line saying just "end".
> collect jiffies_64
> collect file->f_path.dentry->d_iname
> end
-------------------------------------------------------------------------------------------
(gdb) tstart        开始跟踪
--------------------------------------------------------------------------------------------
(gdb) shell ls   ：跟踪ls
arch     Documentation  init    MAINTAINERS     net             security    virt
block    drivers        ipc     Makefile        README          sound       vmlinux
COPYING  firmware       Kbuild  mm              REPORTING-BUGS  System.map  vmlinux.o
CREDITS  fs             kernel  modules.order   samples         tools
crypto   include        lib     Module.symvers  scripts         usr
----------------------------------------------------------------------------------------------
(gdb) tstop       停止跟踪
-------------------------------------------------------------------------------------------------
(gdb) tfind
#  vfs_readdir (file=0xffff88003c087480, filler=0xffffffff810d7468 <filldir>,
    buf=0xffff88004884df38) at fs/readdir.c:
      {
(gdb) p jiffies_64
$ =
(gdb) p file->f_path.dentry->d_iname
$ = "/\000r", '\000' <repeats  times>

(gdb) list vfs_readdir
      #include <linux/unistd.h>

      #include <asm/uaccess.h>

      int vfs_readdir(struct file *file, filldir_t filler, void *buf)
      {
              struct inode *inode = file->f_path.dentry->d_inode;
              int res = -ENOTDIR;
              if (!file->f_op || !file->f_op->readdir)
                      goto out;

(gdb) disassemble /m vfs_readdir
Dump of assembler code for function vfs_readdir:
      {
0xffffffff810d751f <vfs_readdir+>:     push   %r15
0xffffffff810d7521 <vfs_readdir+>:     mov    %rdx,%r15
0xffffffff810d7524 <vfs_readdir+>:     push   %r14
0xffffffff810d7526 <vfs_readdir+>:     mov    %rsi,%r14
0xffffffff810d7529 <vfs_readdir+>:    push   %r13
0xffffffff810d752b <vfs_readdir+>:    push   %r12
0xffffffff810d752d <vfs_readdir+>:    push   %rbp
0xffffffff810d752e <vfs_readdir+>:    mov    %rdi,%rbp
0xffffffff810d7531 <vfs_readdir+>:    push   %rbx
0xffffffff810d7532 <vfs_readdir+>:    sub    $0x8,%rsp

              struct inode *inode = file->f_path.dentry->d_inode;
0xffffffff810d7536 <vfs_readdir+>:    mov    0x18(%rdi),%rax
0xffffffff810d753a <vfs_readdir+>:    mov    0x10(%rax),%r12

              int res = -ENOTDIR;
              if (!file->f_op || !file->f_op->readdir)
0xffffffff810d753e <vfs_readdir+>:    mov    0x20(%rdi),%rax
---Type <return> to continue, or q <return> to quit---
0xffffffff810d7542 <vfs_readdir+>:    test   %rax,%rax
0xffffffff810d7545 <vfs_readdir+>:    je     0xffffffff810d75b3 <vfs_readdir+>
0xffffffff810d7547 <vfs_readdir+>:    cmpq   $0x0,0x30(%rax)
0xffffffff810d754c <vfs_readdir+>:    je     0xffffffff810d75b3 <vfs_readdir+>

                      goto out;

              res = security_file_permission(file, MAY_READ);
0xffffffff810d754e <vfs_readdir+>:    mov    $0x4,%esi
0xffffffff810d7553 <vfs_readdir+>:    callq  0xffffffff8113848d <security_file_permission>
0xffffffff810d755a <vfs_readdir+>:    mov    %eax,%ebx

              if (res)
0xffffffff810d7558 <vfs_readdir+>:    test   %eax,%eax
0xffffffff810d755c <vfs_readdir+>:    jne    0xffffffff810d75b8 <vfs_readdir+>

                      goto out;

              res = mutex_lock_killable(&inode->i_mutex);
0xffffffff810d755e <vfs_readdir+>:    lea    0xb8(%r12),%r13
---Type <return> to continue, or q <return> to quit---
0xffffffff810d7566 <vfs_readdir+>:    mov    %r13,%rdi
0xffffffff810d7569 <vfs_readdir+>:    callq  0xffffffff812f4bff <mutex_lock_killable>
0xffffffff810d7570 <vfs_readdir+>:    mov    %eax,%ebx

              if (res)
0xffffffff810d756e <vfs_readdir+>:    test   %eax,%eax
0xffffffff810d7572 <vfs_readdir+>:    jne    0xffffffff810d75b8 <vfs_readdir+>

                      goto out;

              res = -ENOENT;
              if (!IS_DEADDIR(inode)) {
0xffffffff810d7574 <vfs_readdir+>:    testb  $0x10,0x220(%r12)
0xffffffff810d757d <vfs_readdir+>:    mov    $0xfffffffe,%ebx
0xffffffff810d7582 <vfs_readdir+>:    jne    0xffffffff810d75a9 <vfs_readdir+>

                      res = file->f_op->readdir(file, buf, filler);
0xffffffff810d7584 <vfs_readdir+>:   mov    0x20(%rbp),%rax
0xffffffff810d7588 <vfs_readdir+>:   mov    %r14,%rdx
0xffffffff810d758b <vfs_readdir+>:   mov    %r15,%rsi
---Type <return> to continue, or q <return> to quit---
0xffffffff810d758e <vfs_readdir+>:   mov    %rbp,%rdi
0xffffffff810d7591 <vfs_readdir+>:   callq  *0x30(%rax)
0xffffffff810d7598 <vfs_readdir+>:   mov    %eax,%ebx

                      file_accessed(file);
              }
              mutex_unlock(&inode->i_mutex);
0xffffffff810d75a9 <vfs_readdir+>:   mov    %r13,%rdi
0xffffffff810d75ac <vfs_readdir+>:   callq  0xffffffff812f4a35 <mutex_unlock>
0xffffffff810d75b1 <vfs_readdir+>:   jmp    0xffffffff810d75b8 <vfs_readdir+>

      out:
0xffffffff810d75b3 <vfs_readdir+>:   mov    $0xffffffec,%ebx

              return res;
      }
0xffffffff810d75b8 <vfs_readdir+>:   pop    %rcx
0xffffffff810d75b9 <vfs_readdir+>:   mov    %ebx,%eax
0xffffffff810d75bb <vfs_readdir+>:   pop    %rbx
0xffffffff810d75bc <vfs_readdir+>:   pop    %rbp
---Type <return> to continue, or q <return> to quit---
0xffffffff810d75bd <vfs_readdir+>:   pop    %r12
0xffffffff810d75bf <vfs_readdir+>:   pop    %r13
0xffffffff810d75c1 <vfs_readdir+>:   pop    %r14
0xffffffff810d75c3 <vfs_readdir+>:   pop    %r15
0xffffffff810d75c5 <vfs_readdir+>:   retq 

http://www.cnblogs.com/ahuo/archive/2012/08/10/2632227.html