ढेर अतिप्रवाहcorrupted double-linked list
, malloc(): memory corruption
, double free or corruption (!prev)
तरह glibc चेतावनी के लिए दोष (लेकिन हमेशा नहीं) होना चाहिए।
यह निम्न कोड से reproduced किया जाना चाहिए:
#include <vector>
using std::vector;
int main(int argc, const char *argv[])
{
int *p = new int[3];
vector<int> vec;
vec.resize(100);
p[6] = 1024;
delete[] p;
return 0;
}
अगर जी ++ (4.5.4) का उपयोग कर संकलित:
$ ./heapoverflow
*** glibc detected *** ./heapoverflow: double free or corruption (!prev): 0x0000000001263030 ***
======= Backtrace: =========
/lib64/libc.so.6(+0x7af26)[0x7f853f5d3f26]
./heapoverflow[0x40138e]
./heapoverflow[0x400d9c]
./heapoverflow[0x400bd9]
./heapoverflow[0x400aa6]
./heapoverflow[0x400a26]
/lib64/libc.so.6(__libc_start_main+0xfd)[0x7f853f57b4bd]
./heapoverflow[0x4008f9]
======= Memory map: ========
00400000-00403000 r-xp 00000000 08:02 2150398851 /data1/home/mckelvin/heapoverflow
00602000-00603000 r--p 00002000 08:02 2150398851 /data1/home/mckelvin/heapoverflow
00603000-00604000 rw-p 00003000 08:02 2150398851 /data1/home/mckelvin/heapoverflow
01263000-01284000 rw-p 00000000 00:00 0 [heap]
7f853f559000-7f853f6fa000 r-xp 00000000 09:01 201329536 /lib64/libc-2.15.so
7f853f6fa000-7f853f8fa000 ---p 001a1000 09:01 201329536 /lib64/libc-2.15.so
7f853f8fa000-7f853f8fe000 r--p 001a1000 09:01 201329536 /lib64/libc-2.15.so
7f853f8fe000-7f853f900000 rw-p 001a5000 09:01 201329536 /lib64/libc-2.15.so
7f853f900000-7f853f904000 rw-p 00000000 00:00 0
7f853f904000-7f853f919000 r-xp 00000000 09:01 74726670 /usr/lib64/gcc/x86_64-pc-linux-gnu/4.8.1/libgcc_s.so.1
7f853f919000-7f853fb19000 ---p 00015000 09:01 74726670 /usr/lib64/gcc/x86_64-pc-linux-gnu/4.8.1/libgcc_s.so.1
7f853fb19000-7f853fb1a000 r--p 00015000 09:01 74726670 /usr/lib64/gcc/x86_64-pc-linux-gnu/4.8.1/libgcc_s.so.1
7f853fb1a000-7f853fb1b000 rw-p 00016000 09:01 74726670 /usr/lib64/gcc/x86_64-pc-linux-gnu/4.8.1/libgcc_s.so.1
7f853fb1b000-7f853fc11000 r-xp 00000000 09:01 201329538 /lib64/libm-2.15.so
7f853fc11000-7f853fe10000 ---p 000f6000 09:01 201329538 /lib64/libm-2.15.so
7f853fe10000-7f853fe11000 r--p 000f5000 09:01 201329538 /lib64/libm-2.15.so
7f853fe11000-7f853fe12000 rw-p 000f6000 09:01 201329538 /lib64/libm-2.15.so
7f853fe12000-7f853fefc000 r-xp 00000000 09:01 74726678 /usr/lib64/gcc/x86_64-pc-linux-gnu/4.8.1/libstdc++.so.6.0.18
7f853fefc000-7f85400fb000 ---p 000ea000 09:01 74726678 /usr/lib64/gcc/x86_64-pc-linux-gnu/4.8.1/libstdc++.so.6.0.18
7f85400fb000-7f8540103000 r--p 000e9000 09:01 74726678 /usr/lib64/gcc/x86_64-pc-linux-gnu/4.8.1/libstdc++.so.6.0.18
7f8540103000-7f8540105000 rw-p 000f1000 09:01 74726678 /usr/lib64/gcc/x86_64-pc-linux-gnu/4.8.1/libstdc++.so.6.0.18
7f8540105000-7f854011a000 rw-p 00000000 00:00 0
7f854011a000-7f854013c000 r-xp 00000000 09:01 201328977 /lib64/ld-2.15.so
7f854031c000-7f00 rw-p 00000000 00:00 0
7f8540339000-7f854033b000 rw-p 00000000 00:00 0
7f854033b000-7f854033c000 r--p 00021000 09:01 201328977 /lib64/ld-2.15.so
7f854033c000-7f854033d000 rw-p 00022000 09:01 201328977 /lib64/ld-2.15.so
7f854033d000-7f854033e000 rw-p 00000000 00:00 0
7fff92922000-7fff92943000 rw-p 00000000 00:00 0 [stack]
7fff929ff000-7fff92a00000 r-xp 00000000 00:00 0 [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]
[1] 18379 abort ./heapoverflow
और यदि का उपयोग कर बजना संकलित ++ (6.0 (बजना-600.0.56)):
$ ./heapoverflow
[1] 96277 segmentation fault ./heapoverflow
यदि आप सोचा हो सकता है कि आपने इस तरह की एक बग लिखी हो, यहां कुछ पता लगाने के लिए कुछ संकेत दिए गए हैं।
पहले, डिबग ध्वज के साथ कोड (-g
) संकलन:
g++ -g foo.cpp
और फिर, यह valgrind का उपयोग कर चलाएँ:
$ valgrind ./a.out
==12693== Memcheck, a memory error detector
==12693== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==12693== Using Valgrind-3.10.1 and LibVEX; rerun with -h for copyright info
==12693== Command: ./a.out
==12693==
==12693== Invalid write of size 4
==12693== at 0x400A25: main (foo.cpp:11)
==12693== Address 0x5a1c058 is 12 bytes after a block of size 12 alloc'd
==12693== at 0x4C2B800: operator new[](unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==12693== by 0x4009F6: main (foo.cpp:8)
==12693==
==12693==
==12693== HEAP SUMMARY:
==12693== in use at exit: 0 bytes in 0 blocks
==12693== total heap usage: 2 allocs, 2 frees, 412 bytes allocated
==12693==
==12693== All heap blocks were freed -- no leaks are possible
==12693==
==12693== For counts of detected and suppressed errors, rerun with: -v
==12693== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
बग 12,693 == पर == में स्थित है 0x400A25: मुख्य (foo.cpp: 11)
हास्यास्पद होगा;) "बैड प्रोग्राम डिजाइन" -> * दुर्घटना * – mlvljr