In a new post to his blog, Paul Jones anout a small issue when working with the PHP 5.2.5 command line functionality - a segfault if you extend the Exception class.

When executing code at the command line using php -r and PHP 5.2.5, be sure not to extend the Exception class. It will cause a segmentation fault.

He includes examples of the issue that would cause the problem and the bug he's filed in an effort to get it fixed.