I just recently ran into some issues with my Linode virtual private server after my last PHP (Nginx/Php-Fpm) update. I started getting the following error:
PHP Warning: PHP Startup: Unable to load dynamic library ‘/usr/lib/php/modules/apc.so’ – /usr/lib/php/modules/apc.so: undefined symbol: pcre_exec in Unknown on line 0
I also received the same error on my other Linode in Japan last month before I shut it down. It seems that there was an issue with the APC module in PHP-5.3.
The solution, turns out that you can fix this error by a simple update of PHP 5.3 to PHP 5.4. I use the CentOS REMI repository but you will need to enable the REMI-TEST repository to get the latest PHP 5.4 update. Go to this website for more information on how to do this:
http://tuxawy.wordpress.com/2012/07/21/install-nginxphp-fpm-on-fedora-1716-centosrhel-6-25-8/
After the upgrade, everything seems to be resolved. Hopefully my server will not need a reboot every 18-20 hours now.