Nginx error: 502 Bad Gateway. ZF2, APC and segmentation fault.

I tried Zend Framework 2 for my last project. When everything was done with development I moved project to production server but every time I tried to open project url in bowser Nginx returned an error:

502 bad gateway

Server is running under Debian, also I have installed Nginx(1.2.6) + PHP(5.3.20) and PHP-FPM.

Increasing buffer size and read timeout value in Nginx config had no results, still 502 error. I've looked into Nginx logs and found next entries:

… recv() failed (104: Connection reset by peer) while reading response header from upstream ...

So, it seems that problem is not in Nginx config. Something is wrong with backend. PHP-FPM log contains plenty of entries like next:

php5-fpm.log:
WARNING: [pool www] child 7050 exited on signal 11 (SIGSEGV) after 14.101753 seconds from start

Well, something is causing segmentation fault. I'm hosting a lot of projects on this server and everything was fine, problem appeared only for the last project that was developed using ZF2.

Googling a little bit, I found that some of PHP extensions can cause segmentation fault. One by one I started disabling PHP-extensions. After I disabled APC extension problem disappeared and everything started working fine. So, disabling APC extension helped to solve the problem and seems that ZF2 has some problems with APC, or APC has some problems with ZF2 :)

Will try to make some research what exactly was the reason of this problem and post here if I'll find something interesting.