I use PHP on FreeBSD servers, compiled from the ports system. It works very well, except that sometimes… well… sometimes… segfaults happen. Yes random, bizarre, “how did this working system suddenly become non-working wtf” errors happen.
Here’s an example of what happened to me today. This is a snip from my lighttpd error log
(mod_fastcgi.c.2722) child signaled: 11
(mod_fastcgi.c.1051) the fastcgi-backend /usr/local/bin/php-cgi failed to start:
(mod_fastcgi.c.1065) terminated by signal: 11
(mod_fastcgi.c.1070) to be exact: it segfaulted, crashed, died, … you get the idea.
(mod_fastcgi.c.1072) If this is PHP, try removing the bytecode caches for now and try again.
(mod_fastcgi.c.2759) ERROR: spawning fcgi failed.
Well in a nutshell, php-cgi is failing to start. When I attempt to run /usr/local/bin/php-cgi from the command line, it causes a segmentation fault. If you’ve seen this before, you might have thought “oh no… sig11! signal 11 could mean my hardware is fried!” At least I thought so. The truth of the matter, in this case, is that the php-cgi executable is not happy. Why isn’t it happy? I’m glad you asked. We all want our executeables to be happy, right?
This wasn’t easy for me to figure out the first time it happened to me last year. I was going nuts trying to figure out what went wrong, I even put in a request for new hardware (yes a new development server, which I actually got). This didn’t solve my problem either. I began to panic. I’m not sure what made me think of it, but after a while I decided to try minimalizing my PHP installation, by commenting out extensions from my extensions.ini file (on my sys it’s /usr/local/etc/php/extensions.ini)
With everything commented out, php-cgi was happy again, but of course I need at least a few of the extensions (specifically mysqli), and so I started adding extensions back in one at a time to find the problem. It turns out that the problem is with the recode extension.
With the recode extension out of the picture, things went along fine for quite a while and I was able to develop my small web application with Zend Framework (1.5 at the time, I think). PHP was happy, Lighttpd was happy, I was happy. There was a lot of happiness to be found! And then it happened. I updated my PHP port with portmaster. A dark cloud (a cloud named sig11) loomed over the server and the happiness turned to confusion once again. Then I remembered… “didn’t this happen last year?” Yes. Yes it did. Same problem. This time I didn’t panic though, I went straight for the extensions file.
Now I’m not sure what about the recode extension my system doesn’t like, but it doesn’t like it. It didn’t like it last year, and it doesn’t like it now. The PHP port installed a new copy of extensions.ini which includes the recode extension and so that’s why the error reoccured after updating the port. If you are experiencing weird segmentation faults with PHP, I highly recommend you start commenting out your extensions. Also, you may want to check the order of the extensions. If they are in alphabetical order, something is wrong. Some extensions rely on others to be loaded first, so be careful.
That’s it for now… PHP is happy once again, and I’m working on a new dev project, this time with Zend Framework 1.7 I’d tell you more about it… but it’s a secret. No, really, it’s a secret.