为什么会报错 malloc(): invalid size (unsorted)?
问题:为什么会报错 malloc(): invalid size (unsorted)?
我在https://github.com/JamesRead5737/webcrawler/blob/master/crawler.c有一个网络爬虫代码,它产生了一些我无法解释的奇怪错误。最常见的是它中止并出现错误malloc(): invalid size (unsorted)
回溯显示:
(gdb) bt
#0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
#1 0x00007ffff760e859 in __GI_abort () at abort.c:79
#2 0x00007ffff76793ee in __libc_message (action=action@entry=do_abort, fmt=fmt@entry=0x7ffff77a3285 "%sn") at ../sysdeps/posix/libc_fatal.c:155
#3 0x00007ffff768147c in malloc_printerr (str=str@entry=0x7ffff77a5a50 "malloc(): invalid size (unsorted)") at malloc.c:5347
#4 0x00007ffff7684234 in _int_malloc (av=av@entry=0x7ffff77d4b80 <main_arena>, bytes=bytes@entry=8200) at malloc.c:3736
#5 0x00007ffff7686419 in __GI___libc_malloc (bytes=8200) at malloc.c:3066
#6 0x00005555555578b3 in html_link_find (url=0x55555d0f8b08 "https://www.android.com/intl/en_us//security-center/",
html=0x55555f9e6c00 "<!DOCTYPE html>n<html lang="en" dir="ltr">n <head>n <meta charset="utf-8">n <title>Android Security Center</title>n <meta content="initial-scale=1, minimum-scale=1, width=device-width" name="...) at crawler.c:455
#7 0x0000555555557d70 in html_parse (url=0x55555d0f8b08 "https://www.android.com/intl/en_us//security-center/",
html=0x55555f9e6c00 "<!DOCTYPE html>n<html lang="en" dir="ltr">n <head>n <meta charset="utf-8">n <title>Android Security Center</title>n <meta content="initial-scale=1, minimum-scale=1, width=device-width" name="...) at crawler.c:536
#8 0x00005555555582cc in check_multi_info (g=0x7ffffffe0970) at crawler.c:678
#9 0x00005555555583db in event_cb (g=0x7ffffffe0970, fd=1164, revents=1) at crawler.c:706
#10 0x0000555555559829 in crawler_init () at crawler.c:1154
#11 0x0000555555559ae9 in main (argc=1, argv=0x7fffffffe018) at crawler.c:1207
这将我带到写着sql_current->next = (SqlNode *)malloc(sizeof(SqlNode));的代码行,据我所知,这应该不会导致任何错误。
谷歌搜索错误表明问题可能出现在代码中的任何位置,并且与所讨论的行完全无关。那正确吗?
MySQL数据库设置如下:
USE crawl;
CREATE TABLE IF NOT EXISTS `crawled` (`id` int NOT NULL AUTO_INCREMENT, `url` varchar(768) DEFAULT NULL, `title` varchar(768) DEFAULT NULL, `date` varchar(128) DEFAULT NULL, `links` int DEFAULT 0, `backlinks` int DEFAULT 0, `frontier` int DEFAULT 1, PRIMARY KEY (`id`), UNIQUE KEY `url` (`url`), KEY `title` (`title`), KEY `frontier` (`frontier`)) ENGINE=InnoDB AUTO_INCREMENT=1;
CREATE TABLE IF NOT EXISTS `emails` (`email` varchar(2084) NOT NULL, `id` int NOT NULL AUTO_INCREMENT, PRIMARY KEY (`id`), UNIQUE KEY `email` (`email`)) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=latin1;
INSERT INTO crawled (url) VALUES ('http://www.bing.com'),('http://www.yahoo.com'),('http://www.google.com');
如果有问题的线路很好,我怎么能找到真正的问题?
编辑
这是一些 valgrind 输出:
==318618== Memcheck, a memory error detector ==318618== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al. ==318618== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info ==318618== Command: ./a.out ==318618== Parent PID: 2591 ==318618== ==318618== Warning: ignored attempt to set SIGKILL handler in sigaction(); ==318618== the SIGKILL signal is uncatchable ==318618== Syscall param epoll_ctl(event) points to uninitialised byte(s) ==318618== at 0x515AACE: epoll_ctl (syscall-template.S:78) ==318618== by 0x10D052: crawler_init (crawler.c:987) ==318618== by 0x10DAE8: main (crawler.c:1207) ==318618== Address 0x1ffefe28ac is on thread 1's stack ==318618== in frame #1, created by crawler_init (crawler.c:956) ==318618== ==318618== Syscall param epoll_ctl(event) points to uninitialised byte(s) ==318618== at 0x515AACE: epoll_ctl (syscall-template.S:78) ==318618== by 0x10C61C: setsock (crawler.c:769) ==318618== by 0x10C6BC: addsock (crawler.c:782) ==318618== by 0x10CE70: sock_cb (crawler.c:921) ==318618== by 0x48B70B1: singlesocket (multi.c:2593) ==318618== by 0x48B7878: multi_socket (multi.c:2839) ==318618== by 0x48B8053: curl_multi_socket_action (multi.c:2956) ==318618== by 0x10C4E8: timer_cb (crawler.c:741) ==318618== by 0x10D7C7: crawler_init (crawler.c:1152) ==318618== by 0x10DAE8: main (crawler.c:1207) ==318618== Address 0x1ffefe2584 is on thread 1's stack ==318618== in frame #1, created by setsock (crawler.c:749) ==318618== ==318618== Syscall param epoll_ctl(event) points to uninitialised byte(s) ==318618== at 0x515AACE: epoll_ctl (syscall-template.S:78) ==318618== by 0x10C61C: setsock (crawler.c:769) ==318618== by 0x10CE8F: sock_cb (crawler.c:923) ==318618== by 0x48B70B1: singlesocket (multi.c:2593) ==318618== by 0x48B7878: multi_socket (multi.c:2839) ==318618== by 0x48B8053: curl_multi_socket_action (multi.c:2956) ==318618== by 0x10C3BA: event_cb (crawler.c:703) ==318618== by 0x10D828: crawler_init (crawler.c:1154) ==318618== by 0x10DAE8: main (crawler.c:1207) ==318618== Address 0x1ffefe25a4 is on thread 1's stack ==318618== in frame #1, created by setsock (crawler.c:749) ==318618== ==318618== ==318618== HEAP SUMMARY: ==318618== in use at exit: 149,695,831 bytes in 27,400 blocks ==318618== total heap usage: 2,198,504 allocs, 2,171,104 frees, 3,507,931,785 bytes allocated ==318618== ==318618== LEAK SUMMARY: ==318618== definitely lost: 1,889,627 bytes in 9,067 blocks ==318618== indirectly lost: 0 bytes in 0 blocks ==318618== possibly lost: 2,137,116 bytes in 27 blocks ==318618== still reachable: 145,669,088 bytes in 18,306 blocks ==318618== suppressed: 0 bytes in 0 blocks ==318618== Rerun with --leak-check=full to see details of leaked memory ==318618== ==318618== Use --track-origins=yes to see where uninitialised values come from ==318618== ERROR SUMMARY: 295 errors from 3 contexts (suppressed: 0 from 0) ==318618== ==318618== 1 errors in context 1 of 3: ==318618== Syscall param epoll_ctl(event) points to uninitialised byte(s) ==318618== at 0x515AACE: epoll_ctl (syscall-template.S:78) ==318618== by 0x10D052: crawler_init (crawler.c:987) ==318618== by 0x10DAE8: main (crawler.c:1207) ==318618== Address 0x1ffefe28ac is on thread 1's stack ==318618== in frame #1, created by crawler_init (crawler.c:956) ==318618== ==318618== ==318618== 79 errors in context 2 of 3: ==318618== Syscall param epoll_ctl(event) points to uninitialised byte(s) ==318618== at 0x515AACE: epoll_ctl (syscall-template.S:78) ==318618== by 0x10C61C: setsock (crawler.c:769) ==318618== by 0x10CE8F: sock_cb (crawler.c:923) ==318618== by 0x48B70B1: singlesocket (multi.c:2593) ==318618== by 0x48B7878: multi_socket (multi.c:2839) ==318618== by 0x48B8053: curl_multi_socket_action (multi.c:2956) ==318618== by 0x10C3BA: event_cb (crawler.c:703) ==318618== by 0x10D828: crawler_init (crawler.c:1154) ==318618== by 0x10DAE8: main (crawler.c:1207) ==318618== Address 0x1ffefe25a4 is on thread 1's stack ==318618== in frame #1, created by setsock (crawler.c:749) ==318618== ==318618== ==318618== 215 errors in context 3 of 3: ==318618== Syscall param epoll_ctl(event) points to uninitialised byte(s) ==318618== at 0x515AACE: epoll_ctl (syscall-template.S:78) ==318618== by 0x10C61C: setsock (crawler.c:769) ==318618== by 0x10C6BC: addsock (crawler.c:782) ==318618== by 0x10CE70: sock_cb (crawler.c:921) ==318618== by 0x48B70B1: singlesocket (multi.c:2593) ==318618== by 0x48B7878: multi_socket (multi.c:2839) ==318618== by 0x48B8053: curl_multi_socket_action (multi.c:2956) ==318618== by 0x10C4E8: timer_cb (crawler.c:741) ==318618== by 0x10D7C7: crawler_init (crawler.c:1152) ==318618== by 0x10DAE8: main (crawler.c:1207) ==318618== Address 0x1ffefe2584 is on thread 1's stack ==318618== in frame #1, created by setsock (crawler.c:749) ==318618== ==318618== ERROR SUMMARY: 295 errors from 3 contexts (suppressed: 0 from 0)
编辑
这是崩溃的一些 valgrind 输出:
==319842== Memcheck, a memory error detector ==319842== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al. ==319842== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info ==319842== Command: ./a.out ==319842== Parent PID: 2591 ==319842== ==319842== Warning: ignored attempt to set SIGKILL handler in sigaction(); ==319842== the SIGKILL signal is uncatchable ==319842== Syscall param epoll_ctl(event) points to uninitialised byte(s) ==319842== at 0x515AACE: epoll_ctl (syscall-template.S:78) ==319842== by 0x10D052: crawler_init (crawler.c:987) ==319842== by 0x10DAE8: main (crawler.c:1207) ==319842== Address 0x1ffefe28ac is on thread 1's stack ==319842== in frame #1, created by crawler_init (crawler.c:956) ==319842== ==319842== Syscall param epoll_ctl(event) points to uninitialised byte(s) ==319842== at 0x515AACE: epoll_ctl (syscall-template.S:78) ==319842== by 0x10C61C: setsock (crawler.c:769) ==319842== by 0x10C6BC: addsock (crawler.c:782) ==319842== by 0x10CE70: sock_cb (crawler.c:921) ==319842== by 0x48B70B1: singlesocket (multi.c:2593) ==319842== by 0x48B7878: multi_socket (multi.c:2839) ==319842== by 0x48B8053: curl_multi_socket_action (multi.c:2956) ==319842== by 0x10C4E8: timer_cb (crawler.c:741) ==319842== by 0x10D7C7: crawler_init (crawler.c:1152) ==319842== by 0x10DAE8: main (crawler.c:1207) ==319842== Address 0x1ffefe2584 is on thread 1's stack ==319842== in frame #1, created by setsock (crawler.c:749) ==319842== ==319842== Syscall param epoll_ctl(event) points to uninitialised byte(s) ==319842== at 0x515AACE: epoll_ctl (syscall-template.S:78) ==319842== by 0x10C61C: setsock (crawler.c:769) ==319842== by 0x10CE8F: sock_cb (crawler.c:923) ==319842== by 0x48B70B1: singlesocket (multi.c:2593) ==319842== by 0x48B7878: multi_socket (multi.c:2839) ==319842== by 0x48B8053: curl_multi_socket_action (multi.c:2956) ==319842== by 0x10C3BA: event_cb (crawler.c:703) ==319842== by 0x10D828: crawler_init (crawler.c:1154) ==319842== by 0x10DAE8: main (crawler.c:1207) ==319842== Address 0x1ffefe25a4 is on thread 1's stack ==319842== in frame #1, created by setsock (crawler.c:749) ==319842== ==319842== Invalid write of size 1 ==319842== at 0x48436E4: mempcpy (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) ==319842== by 0x50CD1D8: _IO_default_xsputn (genops.c:386) ==319842== by 0x50CD1D8: _IO_default_xsputn (genops.c:370) ==319842== by 0x50B227B: __vfprintf_internal (vfprintf-internal.c:1688) ==319842== by 0x50C0278: __vsprintf_internal (iovsprintf.c:95) ==319842== by 0x509D047: sprintf (sprintf.c:30) ==319842== by 0x10B88F: html_link_find (crawler.c:452) ==319842== by 0x10BD6F: html_parse (crawler.c:536) ==319842== by 0x10C2CB: check_multi_info (crawler.c:678) ==319842== by 0x10C3DA: event_cb (crawler.c:706) ==319842== by 0x10D828: crawler_init (crawler.c:1154) ==319842== by 0x10DAE8: main (crawler.c:1207) ==319842== Address 0xf107d18 is 0 bytes after a block of size 8,200 alloc'd ==319842== at 0x483B7F3: malloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) ==319842== by 0x10B736: html_link_find (crawler.c:440) ==319842== by 0x10BD6F: html_parse (crawler.c:536) ==319842== by 0x10C2CB: check_multi_info (crawler.c:678) ==319842== by 0x10C3DA: event_cb (crawler.c:706) ==319842== by 0x10D828: crawler_init (crawler.c:1154) ==319842== by 0x10DAE8: main (crawler.c:1207) ==319842== valgrind: m_mallocfree.c:305 (get_bszB_as_is): Assertion 'bszB_lo == bszB_hi' failed. valgrind: Heap block lo/hi size mismatch: lo = 8272, hi = 3625731377157460067. This is probably caused by your program erroneously writing past the end of a heap block and corrupting heap metadata. If you fix any invalid writes reported by Memcheck, this assertion failure will probably go away. Please try that before reporting this as a bug. host stacktrace: ==319842== at 0x58046FFA: ??? (in /usr/lib/x86_64-linux-gnu/valgrind/memcheck-amd64-linux) ==319842== by 0x58047127: ??? (in /usr/lib/x86_64-linux-gnu/valgrind/memcheck-amd64-linux) ==319842== by 0x580472CB: ??? (in /usr/lib/x86_64-linux-gnu/valgrind/memcheck-amd64-linux) ==319842== by 0x580514B4: ??? (in /usr/lib/x86_64-linux-gnu/valgrind/memcheck-amd64-linux) ==319842== by 0x5803DE9A: ??? (in /usr/lib/x86_64-linux-gnu/valgrind/memcheck-amd64-linux) ==319842== by 0x5803CD9F: ??? (in /usr/lib/x86_64-linux-gnu/valgrind/memcheck-amd64-linux) ==319842== by 0x58041F04: ??? (in /usr/lib/x86_64-linux-gnu/valgrind/memcheck-amd64-linux) ==319842== by 0x5803C1D8: ??? (in /usr/lib/x86_64-linux-gnu/valgrind/memcheck-amd64-linux) ==319842== by 0x1002EC6B18: ??? ==319842== by 0x1002CADF2F: ??? ==319842== by 0x1002CADF17: ??? ==319842== by 0x1002CADF2F: ??? ==319842== by 0x1002CADF3F: ??? sched status: running_tid=1 Thread 1: status = VgTs_Runnable (lwpid 319842) ==319842== at 0x50CD2B4: _IO_default_xsputn (genops.c:394) ==319842== by 0x50CD2B4: _IO_default_xsputn (genops.c:370) ==319842== by 0x50B2165: __vfprintf_internal (vfprintf-internal.c:1719) ==319842== by 0x50C0278: __vsprintf_internal (iovsprintf.c:95) ==319842== by 0x509D047: sprintf (sprintf.c:30) ==319842== by 0x10B88F: html_link_find (crawler.c:452) ==319842== by 0x10BD6F: html_parse (crawler.c:536) ==319842== by 0x10C2CB: check_multi_info (crawler.c:678) ==319842== by 0x10C3DA: event_cb (crawler.c:706) ==319842== by 0x10D828: crawler_init (crawler.c:1154) ==319842== by 0x10DAE8: main (crawler.c:1207) client stack range: [0x1FFEFDB000 0x1FFF000FFF] client SP: 0x1FFEFDB600 valgrind stack range: [0x1002BAE000 0x1002CADFFF] top usage: 10344 of 1048576 Note: see also the FAQ in the source distribution. It contains workarounds to several common problems. In particular, if Valgrind aborted or crashed after identifying problems in your program, there's a good chance that fixing those problems will prevent Valgrind aborting or crashing, especially if it happened in m_mallocfree.c. If that doesn't help, please report this bug to: www.valgrind.org In the bug report, send all the above text, the valgrind version, and what OS and version you are using. Thanks.
解答
将评论转移到答案。
似乎函数html_link_find()在第 440 行分配了内存,然后在第 452 行调用了sprintf()来格式化某些东西,并且它将分配的内存的末尾覆盖了 1 个字节,这足以杀死malloc()。
一种部分解决方法是使用snprintf()而不是sprintf()— 但您还需要测试返回值以避免数据截断。有可能某些应该以空值终止的数据不是,这可能导致部分溢出。
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