 <p>Process exited with singal 11 (segmentation fault). Typically, it means process unexpectedly crashed because of some error in memory usage, and php just can't handle that error in any way. You will get same error using apache+mod_php, apache+mod_fcgid or any other configuration.</p> <p>In my practice, segfault gives you no useful error message in all cofigurations. The only real way to debug it is <strong>strace</strong>. One-liner to attach strace to all php processes running:</p> <pre><code>strace -f -F -s1000 -t -T `ps aux | grep -E 'apache|php|httpd' | awk '{print "-p" $2}' | xargs` </code></pre> <p>If the error is hard to reproduce, you can use <strong>xdebug</strong> php-module. You need to install it like that:</p> <pre><code>apt-get install php5-xdebug </code></pre> <p>or</p> <pre><code>yum install php-pecl-xdebug </code></pre> <p>for CentOS. For automatic tracing of all processes add to config:</p> <pre><code>xdebug.auto_trace=On </code></pre> <p>And you'll get traces, default path is:</p> <pre><code>xdebug.trace_output_dir =&gt; /tmp =&gt; /tmp xdebug.trace_output_name =&gt; trace.%c =&gt; trace.%c </code></pre> <p>So your trace will have name /tmp/trace.$PID.xt</p> <p>There you should be able to see last called fuction before process crash.</p>