2011年8月6日 星期六

core dump and debug



看ulimit預設的一些參數,注意core file size若是0,就不會產生core文件了。

brook@vista:~$ cat -n foo.c 
     1  #include 
     2
     3  static void sub(void);
     4
     5  int main(void)
     6  {
     7      sub();
     8      return 0;
     9  }
    10
    11  static void sub(void)
    12  {
    13      int *p = NULL;
    14
    15      /* derefernce a null pointer, expect core dump. */
    16      printf("%d", *p);
    17  }
    18
    19
brook@vista:~$ gcc -g -Wall foo.c 
brook@vista:~$ ./a.out 
Segmentation fault
brook@vista:~$ ls core*
ls: cannot access core*: No such file or directory
brook@vista:~$ ulimit -c 1024
brook@vista:~$ ./a.out 
Segmentation fault (core dumped)
brook@vista:~$ ls core*
core
brook@vista:~$ gdb ./a.out core 
GNU gdb (Ubuntu/Linaro 7.2-1ubuntu11) 7.2
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later
 
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 "x86_64-linux-gnu".
For bug reporting instructions, please see:
...
Reading symbols from /home/brook/a.out...done.
[New Thread 5382]

warning: Can't read pathname for load map: Input/output error.
Reading symbols from /lib/x86_64-linux-gnu/libc.so.6...
Reading symbols from /usr/lib/debug/lib/x86_64-linux-gnu/libc-2.13.so...done.
done.
Loaded symbols for /lib/x86_64-linux-gnu/libc.so.6
Reading symbols from /lib64/ld-linux-x86-64.so.2...
(no debugging symbols found)...done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
Core was generated by `./a.out'.
Program terminated with signal 11, Segmentation fault.
#0  0x0000000000400518 in sub () at foo.c:16
16          printf("%d", *p);
(gdb) 


    參考資料:
  1. http://blog.csdn.net/borefo/article/details/5029555, 在Linux下产生并调试core文件