CentOS7.9下Apache+PHP+Engintron Nginx报AH00052段错误的原因是什么

环境&故障现象 #

服务器运行环境为 CentOS 7.9，使用搭载 PHP 的 Apache2 服务器，配合 Engintron Nginx 运行。目前服务频繁抛出段错误，导致站点持续卡顿，甚至频繁停止服务。

报错日志 #

[Sat Oct 02 16:54:14.334779 2021] [core:notice] [pid 797] AH00052: child pid 3314 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:14.334820 2021] [core:notice] [pid 797] AH00052: child pid 3315 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:14.334828 2021] [core:notice] [pid 797] AH00052: child pid 3316 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:14.334835 2021] [core:notice] [pid 797] AH00052: child pid 3317 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:14.334843 2021] [core:notice] [pid 797] AH00052: child pid 3318 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:14.334849 2021] [core:notice] [pid 797] AH00052: child pid 3319 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:14.334856 2021] [core:notice] [pid 797] AH00052: child pid 3320 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:14.335007 2021] [core:notice] [pid 797] AH00052: child pid 3321 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:15.336067 2021] [core:notice] [pid 797] AH00052: child pid 3330 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:15.336102 2021] [core:notice] [pid 797] AH00052: child pid 3331 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:15.336112 2021] [core:notice] [pid 797] AH00052: child pid 3332 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:15.336118 2021] [core:notice] [pid 797] AH00052: child pid 3333 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:15.336124 2021] [core:notice] [pid 797] AH00052: child pid 3334 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:15.336129 2021] [core:notice] [pid 797] AH00052: child pid 3335 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:15.336134 2021] [core:notice] [pid 797] AH00052: child pid 3336 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:15.336141 2021] [core:notice] [pid 797] AH00052: child pid 3337 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:15.336314 2021] [core:notice] [pid 797] AH00052: child pid 3340 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:16.337893 2021] [core:notice] [pid 797] AH00052: child pid 3339 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:16.337940 2021] [core:notice] [pid 797] AH00052: child pid 3341 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:16.337946 2021] [core:notice] [pid 797] AH00052: child pid 3342 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:17.340298 2021] [core:notice] [pid 797] AH00052: child pid 3343 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:17.340343 2021] [core:notice] [pid 797] AH00052: child pid 3344 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:17.340353 2021] [core:notice] [pid 797] AH00052: child pid 3345 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:17.340362 2021] [core:notice] [pid 797] AH00052: child pid 3346 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:18.347122 2021] [core:notice] [pid 797] AH00052: child pid 3362 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:18.347227 2021] [core:notice] [pid 797] AH00052: child pid 3367 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:18.347252 2021] [core:notice] [pid 797] AH00052: child pid 3368 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:19.352435 2021] [core:notice] [pid 797] AH00052: child pid 3371 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:19.352485 2021] [core:notice] [pid 797] AH00052: child pid 3372 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:19.352494 2021] [core:notice] [pid 797] AH00052: child pid 3373 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:19.352502 2021] [core:notice] [pid 797] AH00052: child pid 3374 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:20.360845 2021] [core:notice] [pid 797] AH00052: child pid 3379 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:20.360877 2021] [core:notice] [pid 797] AH00052: child pid 3380 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:20.360883 2021] [core:notice] [pid 797] AH00052: child pid 3381 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:20.360890 2021] [core:notice] [pid 797] AH00052: child pid 3382 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:20.360896 2021] [core:notice] [pid 797] AH00052: child pid 3383 exit signal Segmentation fault (11)
[Sat Oct 02 16:54:20.360901 2021] [core:notice] [pid 797] AH00052: child pid 3384 exit signal Segmentation fault (11)

故障原因 #

• PHP扩展兼容问题：这是该场景下最高发的诱因，使用第三方编译扩展、过时扩展（例如旧版本ionCube、imagick、redis、opcache），或扩展版本与当前PHP、Apache版本不匹配，会触发非法内存访问导致段错误。可先临时禁用所有非系统默认PHP扩展，再逐个开启复现定位问题扩展。
• Apache模块冲突：配合Engintron Nginx反向代理使用时，Apache的mod_rpaf、mod_remoteip这类客户端IP获取模块配置错误，或和mod_security、mod_cgi等其他模块冲突，也会触发子进程内存越界。
• PHP代码内存错误：业务代码存在非法内存操作逻辑，例如调用未初始化指针、数组越界访问、无限递归导致栈溢出，或大量加载大文件未释放内存，PHP解析执行时会触发段错误。可开启PHP慢日志、配置core dump规则定位触发问题的具体代码行。
• Engintron配置异常：Engintron反向代理规则配置错误，例如转发请求头长度超限、缓冲区配置不合理，导致Apache接收异常请求时触发内存访问错误。可临时关闭Engintron直接访问Apache，验证是否还会抛出该报错，排除Nginx侧的影响。
• 系统依赖库版本问题：CentOS 7.9底层依赖库（例如glibc、libcurl、libxml2）版本过低，或升级了不兼容的依赖库版本，导致Apache、PHP调用系统库时触发段错误。

内容的提问来源于stack exchange，提问作者Mohamed Manshy