Why Do I Get This Segmentation Fault In This PHP Command Line Script?

Question

It's just a quick script to a message to what I call a 'mental log file'. Just to keep track of my thoughts when I drift off and get myself back to work. Anyway, it works alright most of the time, but every so often I get a segmentation fault. Heard of them in C, but never had them before in PHP. Here's the script:

#!/usr/bin/php 
<?php 

    $mental_log_file = "/home/ali/mental-log"; 
    array_shift($argv);      //get rid of the initial arg (name of the command) 
    $log_entry = date('j-n-y H:i') . ' ' . implode(' ', $argv) . "\n";

    file_put_contents($mental_log_file, $log_entry, FILE_APPEND);

Here's what I get on a few runs:

ali@oem-desktop:~$ mlog blah
ali@oem-desktop:~$ mlog blah
Segmentation fault
ali@oem-desktop:~$ mlog blah
ali@oem-desktop:~$ mlog blah
Segmentation fault
ali@oem-desktop:~$ mlog blah
ali@oem-desktop:~$ mlog blah
ali@oem-desktop:~$ mlog blah
Segmentation fault
ali@oem-desktop:~$ mlog blah
ali@oem-desktop:~$ mlog blah
Segmentation fault
ali@oem-desktop:~$ mlog blah
Segmentation fault

Any idea of what I could be doing wrong here? The file seems to be updating correctly as expected even on the runs that produce segmentation faults. I'm running Ubuntu 9.04 Jaunty.

ali@oem-desktop:~$ php --version
PHP 5.2.6-3ubuntu4.1 with Suhosin-Patch 0.9.6.2 (cli) (built: Apr 23 2009 14:37:14) 
Copyright (c) 1997-2008 The PHP Group
Zend Engine v2.2.0, Copyright (c) 1998-2008 Zend Technologies

Thanks in advance.

Answer 1

Try

strace mlog blah

and see if that gives some clues as what it is doing when it dies. For what it's worth, I couldn't reproduce that on a 64 bit Jaunty install with the same php build you report.

Answer 2

It's very likely that you have an extension which somehow messes up. That can happen if the extension was built for a different version of php or of an external library. Try to disable all extensions in php.ini and see if it solves the problem. If it does, then re-enable each extension, one at a time, until you find the offender.