PHP and Apache Segmentation Fault with large variable size

I seem to be having a really weird problem. I have a single variable (string) where I am storing some data. As soon as the data stored in that variable exceeds 2KB, Apache Seg faults and PHP returns an error 324.

I am saving this in my session variable (ie. $_SESSION["my_index"]) and can't change that due to the nature of the script.

Environment:

CentOS 5 64bit. PHP 5.2.16 (Can't upgrade since 5.3 is not supported by ZendOptimizer). Zend Version 2.2.0. Apache 2.2.3`

The only thing httpd logs mention is: [Thu Apr 14 01:57:00 2011] [notice] child pid 22493 exit s开发者_开发知识库ignal Segmentation fault (11)

Thanks

EDIT: It seems like $_SESSION is not the culprit. I have tried using another variable name that is not predefined by PHP and the same error occurs

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Try making a test case so you can crash PHP when running in CLI mode. You can then compile PHP and run the script in GDB to create a backtrace.