Apache :: A weird behaviour I'd like to understand.

romangoro

Hi all, I found what I consider a weird behaviour and I'd like to "un-weird" it, to understand why apache behaves the way it did.

I had a site running PHP that was wrongly installed, so when I tried to open the site, the apache subprocess segfaulted. I don't know the specifics of the problem, it "solved itself" by rerunning composer on the site's directory, and that problem itself is (I believe) irrelevant to this post. The relevant part is how apache reacted to this problem.

This was on a desktop PC running linux mint 17, apache 2.4 and php 5.5.9, installed via apt, nothing fancy, and accesing the sites with both chromium and firefox. I had two sites deployed, one to port 8000, that works fine, and the one that failed on port 8100, and this is what was happening:

1: $ service apache2 restart
2: load site on port 8100 --> empty result, apache's error.log shows a segfault on a subprocess.
3: load site on port 8000 --> also empty result and segfault logged.
4: $ service apache2 restart
5: load site on port 8000 --> runs fine.
6: load site on port 8100 --> (Tries to) run the site on port 8000, by which I mean it runs the dynamic (PHP) part of the site deployed on port 8000 and fails to load the static files, which are not deployed on port 8100

A third, php free site, deployed to the same server runs fine in all conditions.

So I'd like to ask to people with more knowledge of the apache server why did that happen. Of course, this may not be an issue with apache, but with mod_php, but since I don't know anything about the innards of both apache and mod_php I couldn't tell.

My guess is that once the faulty site on port 8100 segfaults it "poisons" all php sites if it runs first, but if a different site runs first it ... remains in a buffer or something? As I said, I don't really know how the server works, that's why I'm asking.

Thanks for your time,
Román.

James Blond

You may post our vhost config with the redirection at http://apaste.info/ (recommended) or http://pastebin.com/

Also you may post there the error log with the complete segfault stuff.