My MediaWiki installation all of a sudden started returning "500 Internal Server Error". I tried to run the wiki's index.php file from the command line, and found that php is dying with a segmentation fault:
~/sustainableballard.org/cgi-bin/> ./php.cgi ../wiki/index.php title=Press_Kit
Segmentation fault (core dumped)
Some pages still work, e.g. all of those in the "Special" namespace:
php.cgi ../wiki/index.php title=Special:RecentChanges
works fine, and I can even open them in the browser.
Why would PHP start dumping core all of a sudden?