PHP Causing Segmentation Fault & Apache Blank Response
- by Joe
I recently updated a Debian Lenny server to php 5.3,5 using the dotdeb source. Soon after doing so certain (but not all) sites on the server stopped responding to requests. A blank response would be returned - no headers, no content, nothing.
I found this related question on stackoverflow which seems to describe something similar and used the same code the user had in their answer to see if I could replicate the issue:
<?php
class A {
public function __construct()
{
new B;
}
}
class B {
public function __construct()
{
new A;
}
}
new A;
print 'Loaded Class A';
?>
This triggered the problem - the page returned absolutely nothing despite the original question stating this was fixed in PHP 5.5.0. No CPU block as you'd expect, no wait, just an almost instant zero response.
I then ran this same code from the cli (php -f test.php) and the only output I got was 'Segmentation fault'.
Tailing the kernel log I've spotted:
Feb 16 07:04:06 creature kernel: [192203.269037] php[17710] general protection ip:76ef37 sp:7fff155e9bb0 error:0 in php5[400000+870000]
Feb 16 08:57:31 creature kernel: [199639.699854] apache2[31136]: segfault at 7fff13a84fe0 ip 7f730514ea40 sp 7fff13a85008 error 6 in libphp5.so[7f7304ce8000+915000]
All extremely odd and I'm not sure what it's pointing to/what I should do to debug this further. As I said some sites work but code such as the above definitely trigger it. Not that the sites I want to server have code like that - it's just an example.
Any help is much appreciated!
