[syslog-ng] Possible memleak in 3.3 HEAD

[Balazs Scheidler]

On Fri, 2011-10-14 at 01:39 +0200, Jakub Jankowski wrote:
> On Thu, 13 Oct 2011 15:32:27 +0200, Balazs Scheidler wrote:
> > 
> > > Anything else looks interesting?
> > > 
> > > During this run, VmRSS kept rising, from:
> > > Sun Oct  9 21:44:51 CEST 2011; VmRSS:	    3804 kB
> > > (...)
> > > to:
> > > Sun Oct  9 23:07:44 CEST 2011; VmRSS:	  445332 kB
> > 
> > Valgrind itself allocates memory to store the errors and warnings. Do
> > you see this increase of memory usage without valgrind too?
> 
> I did, that graph I sent here earlier was exactly the VmRSS of syslog-ng
> running, and as you've seen, it was rising. And it was running without
> valgrind :) I wanted to test this some more, but today I've noticed something
> odd.
> 
> Since upgrading to 3.3.1, there is a strange behaviour of my system: if I
> reload syslog-ng, it spits out *tons* of similar messages:
> Internal error, duplicate configuration elements refer to the same persistent config; name='dd_queue(d_mesg,d_mesg#0)'
> 
> As far as I can tell, this happens for every destination that was open:
> $ grep '^Oct 14 00:00:03' /var/log/messages | grep -c 'dd_queue(d_mesg,d_mesg#0)' 
> 186 
> $ grep '^Oct 14 00:00:03' /var/log/messages | grep -c 'dd_queue(d_cron,d_cron#0)'
> 164
> $ grep '^Oct 14 00:00:03' /var/log/messages | grep -c '_errorlog#0'
> 62435
> 
> I'm pretty sure there are no duplicate configuration elements in my config,
> especially for those "standard" ones like d_mesg or d_cron:
> 
> $ grep d_mesg /etc/syslog-ng/syslog-ng.conf
> destination d_mesg { file("/var/log/messages" group("root") flush_lines(1)); };
> log { source(s_sys); filter(f_default); destination(d_mesg); };
> $ grep messages /etc/syslog-ng/syslog-ng.conf
> destination d_mesg { file("/var/log/messages" group("root") flush_lines(1)); };
> $
> 
> If there were, I'd get some errors at startup, right? Well, I don't.
> 
> But what's most peculiar, is that after such reload, VmRSS stays roughly the
> same (at least it's not climbing like crazy).
> 
> > I've also read the complete log and I've found two minor leaks, both of
> > which leak memory when processing SIGHUPs, I've fixed these:
> 
> I've built a package with these two patches applied, and run it on my test
> system, to confirm this weird behaviour above. It still manifests.
> After a clean start, until there are logs to process, I can reload syslog-ng
> and there are no "Internal error" messages. As soon as I make my log relays
> send some messages to this test system, and try to reload it: boom, internal
> errors again.
> 
> This is very weird, I don't recall this behaviour before. I know this
> description isn't the most precise one, but at this moment I had no time to
> investigate more. I promise I'll dig some more during next few days.
> But maybe even this much will help someone debug it.

Ops, I've missed this email until now. I'm trying to fix this issue
before releasing 3.3.2.


-- 
Bazsi