有关free()函数的一个问题

1.源码

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(){
  char *test1;
  test1 = (char *)malloc(8);
  printf("test1 addr is 0x%lx\n",test1);
  strncpy(test1,"adbdefg",7);
  //test1 = "adbdefg";
  printf("test1 addr is 0x%lx\n",test1);
  printf("test1 addr is 0x%lx\n",test1);
  printf("test1 is %s\n",test1);
  printf("test1 size is %d\n",sizeof(*test1));
  printf("test1 addr size is %d\n",sizeof(test1));
  free(test1);
  test1 = NULL;
  return 0;
}

gcc -o test test.c
结果：

test1 addr is 0x255b010
test1 addr is 0x255b010
test1 addr is 0x255b010
test1 is adbdefg
test1 size is 1
test1 addr size is 8

如果//test1 = "adbdegf"放通，strncpy那句屏蔽；结果如下：

test1 addr is 0x11cd010
test1 addr is 0x400751
test1 addr is 0x400751
test1 is adbdefg
test1 size is 1
test1 addr size is 8
*** glibc detected *** ./testt: free(): invalid pointer: 0x0000000000400751 ***
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x7ae16)[0x7fc54434ee16]
/lib/x86_64-linux-gnu/libc.so.6(cfree+0x6c)[0x7fc5443530fc]
./testt[0x400640]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xed)[0x7fc5442f530d]
./testt[0x4004c9]
======= Memory map: ========
00400000-00401000 r-xp 00000000 08:07 21086431                           /home/lianxi/c++/testt
00600000-00601000 r--p 00000000 08:07 21086431                           /home/lianxi/c++/testt
00601000-00602000 rw-p 00001000 08:07 21086431                           /home/lianxi/c++/testt
011cd000-011ee000 rw-p 00000000 00:00 0                                  [heap]
7fc540000000-7fc540021000 rw-p 00000000 00:00 0 
7fc540021000-7fc544000000 ---p 00000000 00:00 0 
7fc5440be000-7fc5440d3000 r-xp 00000000 08:05 2050760                    /lib/x86_64-linux-gnu/libgcc_s.so.1
7fc5440d3000-7fc5442d2000 ---p 00015000 08:05 2050760                    /lib/x86_64-linux-gnu/libgcc_s.so.1
7fc5442d2000-7fc5442d3000 r--p 00014000 08:05 2050760                    /lib/x86_64-linux-gnu/libgcc_s.so.1
7fc5442d3000-7fc5442d4000 rw-p 00015000 08:05 2050760                    /lib/x86_64-linux-gnu/libgcc_s.so.1
7fc5442d4000-7fc54446d000 r-xp 00000000 08:05 2048322                    /lib/x86_64-linux-gnu/libc-2.13.so
7fc54446d000-7fc54466c000 ---p 00199000 08:05 2048322                    /lib/x86_64-linux-gnu/libc-2.13.so
7fc54466c000-7fc544670000 r--p 00198000 08:05 2048322                    /lib/x86_64-linux-gnu/libc-2.13.so
7fc544670000-7fc544671000 rw-p 0019c000 08:05 2048322                    /lib/x86_64-linux-gnu/libc-2.13.so
7fc544671000-7fc544677000 rw-p 00000000 00:00 0 
7fc544677000-7fc544698000 r-xp 00000000 08:05 2048320                    /lib/x86_64-linux-gnu/ld-2.13.so
7fc54486f000-7fc544872000 rw-p 00000000 00:00 0 
7fc544894000-7fc544897000 rw-p 00000000 00:00 0 
7fc544897000-7fc544898000 r--p 00020000 08:05 2048320                    /lib/x86_64-linux-gnu/ld-2.13.so
7fc544898000-7fc54489a000 rw-p 00021000 08:05 2048320                    /lib/x86_64-linux-gnu/ld-2.13.so
7fffd2e0f000-7fffd2e30000 rw-p 00000000 00:00 0                          [stack]
7fffd2f54000-7fffd2f55000 r-xp 00000000 00:00 0                          [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]
已放弃

2.分析原因

char *test1;

test1 = (char *)malloc(8);//在堆中分配动态内存

test1 = "adbdefg";//"adbdefg"为常量，存储在TEXT存储区域；试图释放该内存会导致异常

free(test1);//使用free函数去释放一个TEXT只读区域内存，程序肯定异常