「free（）：invalid pointer」錯誤和核心轉儲

Question

我在程序成功執行結束時得到了這個不需要的輸出，同時釋放了動態分配的動態內存。

*** glibc detected *** /home/ahor/Desktop/Project Work/node: free(): invalid pointer: 0xb7fda000 *** 
======= Backtrace: ========= 
/lib/i386-linux-gnu/libc.so.6(+0x75ee2)[0xb7e93ee2] 
/home/ahor/Desktop/Project Work/node[0x8048cf9] 
/lib/i386-linux-gnu/libc.so.6(__libc_start_main+0xf3)[0xb7e374d3] 
/home/ahor/Desktop/Project Work/node[0x8048561] 
======= Memory map: ======== 
08048000-0804a000 r-xp 00000000 08:06 786473  /home/ahor/Desktop/Project Work/node 
0804a000-0804b000 r--p 00001000 08:06 786473  /home/ahor/Desktop/Project Work/node 
0804b000-0804c000 rw-p 00002000 08:06 786473  /home/ahor/Desktop/Project Work/node 
0804c000-0806d000 rw-p 00000000 00:00 0   [heap] 
b7deb000-b7e07000 r-xp 00000000 08:06 2228253 /lib/i386-linux-gnu/libgcc_s.so.1 
b7e07000-b7e08000 r--p 0001b000 08:06 2228253 /lib/i386-linux-gnu/libgcc_s.so.1 
b7e08000-b7e09000 rw-p 0001c000 08:06 2228253 /lib/i386-linux-gnu/libgcc_s.so.1 
b7e1d000-b7e1e000 rw-p 00000000 00:00 0 
b7e1e000-b7fc1000 r-xp 00000000 08:06 2228351 /lib/i386-linux-gnu/libc-2.15.so 
b7fc1000-b7fc3000 r--p 001a3000 08:06 2228351 /lib/i386-linux-gnu/libc-2.15.so 
b7fc3000-b7fc4000 rw-p 001a5000 08:06 2228351 /lib/i386-linux-gnu/libc-2.15.so 
b7fc4000-b7fc7000 rw-p 00000000 00:00 0 
b7fd7000-b7fd8000 rw-p 00000000 00:00 0 
b7fd8000-b7fd9000 rw-s 00000000 00:04 12517386 /SYSV001120bd (deleted) 
b7fd9000-b7fda000 rw-p 00000000 00:00 0 
b7fda000-b7fdb000 rw-s 00000000 00:04 12484617 /SYSV00307eff (deleted) 
b7fdb000-b7fdd000 rw-p 00000000 00:00 0 
b7fdd000-b7fde000 r-xp 00000000 00:00 0   [vdso] 
b7fde000-b7ffe000 r-xp 00000000 08:06 2228363 /lib/i386-linux-gnu/ld-2.15.so 
b7ffe000-b7fff000 r--p 0001f000 08:06 2228363 /lib/i386-linux-gnu/ld-2.15.so 
b7fff000-b8000000 rw-p 00020000 08:06 2228363 /lib/i386-linux-gnu/ld-2.15.so 
bffdf000-c0000000 rw-p 00000000 00:00 0   [stack] 

...... 
...... 
...... 

我使用gdb返回跟蹤時收到此消息。

Program received signal SIGABRT, Aborted. 
0xb7fdd424 in __kernel_vsyscall() 
(gdb) bt 
#0 0xb7fdd424 in __kernel_vsyscall() 
#1 0xb7e4c1df in raise() from /lib/i386-linux-gnu/libc.so.6 
#2 0xb7e4f825 in abort() from /lib/i386-linux-gnu/libc.so.6 
#3 0xb7e8939a in ??() from /lib/i386-linux-gnu/libc.so.6 
#4 0xb7e93ee2 in ??() from /lib/i386-linux-gnu/libc.so.6 
#5 0x08048cf9 in main (argc=6, argv=0xbffff214) at node.c:180 

...... ...... 下面是這是影響這個我的代碼段？我無法檢測到原因，如果能幫助我，我將非常感激。

// creating the dynamic memory for net 
    if((net = (struct dot **)malloc(v * sizeof(struct dot))) == NULL) { 
     perror("struct dot malloc() failed\n"); 
     exit(1); 
    } 
    for(i = 0 ; i < v; i++) 
     if((net[i] = (struct dot *)malloc(v * sizeof(struct dot))) == NULL) { 
     perror("net[i] malloc() failed.\n"); 
     for(j = 0; j < i; j++) 
      free(net[j]); 
     free(net);  
     } 
..... 
..... 
// creating the dynamic memory for link_status 
    if((link_status = (struct link **)malloc(v * sizeof(struct link))) == NULL) { 
     perror("struct link malloc() failed\n"); 
     exit(1); 
    } 
    for(i = 0 ; i < v; i++) 
     if((link_status[i] = (struct link *)malloc(v * sizeof(struct link))) == NULL) { 
     perror("link_status[i] malloc() failed.\n"); 
     for(j = 0; j < i; j++) 
      free(link_status[j]); 
     free(link_status);  
     } 
...... 

檢測到的glibc來自下面使用的free（）函數。

// free the allocated dynamic memories 
    for(i = 0; i < v; i++) { 
     free(net[i]); 
     free(link_status[i]); 
    } 
    free(net); 
    free(link_status); 

請幫幫我！

Answer 1

你正在覆蓋一些不屬於你的內存。您可以使用valgrind來查找負責寫入錯誤的代碼。