[Dovecot] fd leak in 1.0rc7?

[Quentin Garnier]

On Mon, Oct 09, 2006 at 01:40:10AM +0300, Timo Sirainen wrote:
> On Mon, 2006-09-04 at 01:23 +0200, Quentin Garnier wrote:
> > Hi,
> > 
> > I just upgraded a 0.99 installation to 1.0rc7 (going from mbox to
> > maildir along the way, but that's another story), and I'm seeing a
> > rather fast fd quick;  I already had to restart dovecot once, after a
> > few hours.
> > 
> > What is leaked are pipes, left open on the master dovecot process while
> > the other end is long gone.  I can't tell right now if it happens for
> > every single login process spawned (either pop3 or imap), but at least
> > a lot of them.
> > 
> > FWIW, I'm running dovecot 1.0rc7 on NetBSD 2.0.3_STABLE.  I'll try
> > debugging tomorrow, but if anyone has an idea what happens in the
> > meantime, I'm all hears.
> 
> Have you figured out anything yet?
> 
> Pipes are created for logging. I haven't been able to reproduce this fd
> leak myself, but since several people have ran into "too many open
> files" problems I guess it could be because of fd leaks..
> 
> I don't really see how it could leak though. Or maybe there are problems
> with noticing that the other end of the pipe died with non-Linux OSes?
> For example are you using kqueue? I haven't tested it with that.

Yes, I have identified the culprit as the kqueue code.

> Also do you see any "Sending log messages too fast, throttling.."
> messages in your logs? That part of the code is a bit weird, so it might
> have caused them.

Nope, no such thing in the logs.

I haven't gone much further with the investigation;  not using kqueue
made the problem go away, so I moved on.  However, I can tell that I was
mostly able to reproduce the issue on a test server, but somehow it was
harder (and the kernel was a different version of NetBSD).

-- 
Quentin Garnier - cube at cubidou.net - cube at NetBSD.org
"You could have made it, spitting out benchmarks
Owe it to yourself not to fail"
Amplifico, Spitting Out Benchmarks, Hometakes Vol. 2, 2005.
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