[syslog-ng] Memory leak reintroduced in 3.3.3.

[Jakub Jankowski]

On Friday 30 of March 2012, Gergely Nagy wrote:
> Jakub Jankowski <shasta at toxcorp.com> writes:
> > I'm pretty sure this particular memory leak was fixed in 3.3.2,
> > but then got reintroduced in this commit:
> > http://git.balabit.hu/?p=bazsi/syslog-ng-3.3.git;a=commitdiff;h=c7070e2a6
> > f1c3a312260bcecf49d62028fef27ce which was done to fix tcp() destination
> > related crash after 3.3.2 was released.
> > 
> > So, Bazsi, yes - it does reintroduce the leak :) (in reply to your
> > comment in
> > https://lists.balabit.hu/pipermail/syslog-ng/2011-November/017697.html )
> 
> I think I found the solution: the reason for the crash in afsocket,
> which Bazsi fixed with killing the log_queue_unref in lib/driver.h was
> that it was missing a log_queue_ref. We didn't unref more than we
> should, we reffed less!
> 
> While I don't entirely understand the call chain, comparing how affile
> and afsocket did their queue magic, I prepared a patch that does not
> crash afsocket on reload, and stops the leak aswell. It also looks
> sane-ish to me, so I'm reasonably sure it's fine.
> 
> The patch is attached, I tested it as much as I could: no crash, no
> leak, no empty files. If you could test it too, it would be most
> appreciated!

Thanks!

With this patch I can no longer trigger this memory leak, indeed.
I've forwarded it to my ex-coworkers who suffer from this on production 
servers (I'm not there anymore), so I hope to hear from them if it makes the 
leak go away there as well.
I also hope others will test it too (especially Patrick H., who reported the 
tcp() crash).
Ack from me on the memleak fix, though.

As for the missing files - don't bother. It was a PEBKAC, and a completely 
unrelated issue. I needed to setup a testbed from scratch for this, and forgot 
to raise maximum fd limit before testing.

So now fingers crossed for this patch to make it's way into 3.3 tree :) Thanks 
again, Gergely!


Regards,

-- 
Jakub Jankowski|shasta at toxcorp.com|http://toxcorp.com/
GPG: FCBF F03D 9ADB B768 8B92 BB52 0341 9037 A875 942D