但是，最近重启了一下apache，结果报错：

/etc/init.d/httpd: line 81: 27835 Segmentation fault $HTTPD "$@"

如何定位问题？我们需要把coredump搞出来，用gdb进行调试，看能不能把问题定位出来。

关于coredump：

coredump又叫核心转储, 当程序运行过程中发生异常, 程序异常退出时, 由操作系统把程序当前的内存状况存储在一个core文件中, 叫coredump。

产生coredump的条件：

ulimit -c unlimited

/lnmp/apache/bin/httpd -k start

就会在当前的目录下生成一个”core+进程id“的dump包

实际上，在Apache的配置文件中有个配置选项，可以用来控制Apache使用的内核转储目录：

CoreDumpDirectory "/tmp/apache-gdb-dump"

但是，我设置了以后，不起作用，求大神解惑啊。

然后，用gdb进行调试：

gdb /lnamp/apache/bin/httpd core.28051

GNU gdb (GDB) Red Hat Enterprise Linux (7.2-60.el6_4.1)

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-redhat-linux-gnu".

For bug reporting instructions, please see:

...

Reading symbols from /lnmp/apache/bin/httpd...done.

[New Thread 28051]

.......

warning: no loadable sections found in added symbol-file system-supplied DSO at 0x7ffee7794000

Core was generated by `/lnmp/apache/bin/httpd -k start'.

Program terminated with signal 11, Segmentation fault.

#0 memcpy () at ../sysdeps/x86_64/memcpy.S:267

267 rep

Missing separate debuginfos, use: debuginfo-install libidn-1.18-2.el6.x86_64

报了一个Missin separate debuginfos, use: debuginfo-install libidn-1.18-2.el6.x86_64的错误，但是没有找到解决方法。

接着执行：

(gdb) bt full #调用栈信息

......

#6 0x00007f52c4e6651a in zend_startup_modules () at /software/git_download/php-7.0.0/Zend/zend_API.c:1967

No locals.

#7 0x00007f52c4df016d in php_module_startup (sf=, additional_modules=, num_additional_modules=)

at /software/git_download/php-7.0.0/main/main.c:2194

zuf = {error_function = 0x7f52c4aaffd6 , printf_function = 0x7f52c4def8e0 , write_function = 0x7f52c4dedff0 ,

fopen_function = 0x7f52c4dee370 , message_handler = 0x7f52c4aafbf3 , block_interruptions = 0, unblock_interruptions = 0,

get_configuration_directive = 0x7f52c4dee360 , ticks_function = 0x7f52c4dffd50 , on_timeout = 0x7f52c4def420 ,

stream_open_function = 0x7f52c4def650 , vspprintf_function = 0x7f52c4df4120 , vstrpprintf_function = 0x7f52c4df3fe0 ,

getenv_function = 0x7f52c4df7830 , resolve_path_function = 0x7f52c4dee300 }

zuv = {import_use_extension = 0x7f52c53fc770 ".php", import_use_extension_length = 4, html_errors = 1 '\001'}

retval = 0

php_os = 0x7f52c541c6f7 "Linux"

module = 

#8 0x00007f52c2621be5 in php_apache2_startup (sapi_module=) at /software/php-5.6.5/sapi/apache2handler/sapi_apache2.c:348

No locals.

从上面的信息中可以看出调用了两个php扩展，一个是php-7的，一个是php-5.6.5的，然后看了httpd的配置文件，结果配置了两个php模块：

LoadModule php7_module modules/libphp7.so

LoadModule php5_module modules/libphp5.so

，去掉一个扩展后，apache启动正常。

应该是安装了php7后，又往httpd的配置文件中加入了php7的扩展。

另外在Apache主配置文件中/usr/local/apache/conf/httpd.conf里的php_modules栏里也会有两个，需要注销掉一个。

出处：https://www.bhqb.org/blog/post-695.html