Re: [Libevent-users] Infinite Loop in libevent.

[Mark Ellzey <mthomas@xxxxxxxxxx>]

On Sat, Jun 06, 2015 at 04:22:06AM +0000, Tomer Heber wrote:
> Hi Mark,
> 
> 
> Thanks for your reply. I agree about increasing the limit/or that I have a descriptor leak. What worries me is the infinite loop.
> 
> 
> I'll have a look in my code and in libevents code. If I find anything intresting or manage to reproduce it, I'll update.

General debugging should easily point out the problem here: lsof,
sudo netstat -anp (look for ESTAB, rx/tx queue len), try A really
really really old program I wrote that I still useful for quick
network statistics (https://github.com/ellzey/trafan), ls -la /proc/<pid>/fd,
htop (configure your bars for ioin/ioout), atop. Try lsof, do you have a
bunch of sock/fdpairs/af_unix descriptors open you don't need?

If your program is being spawned by another program, make sure the
parent fd's are setup with FD_CLOEXEC, (I've encountered this with older
versions of nodejs). 

The big question: are you using LEV_OPT_CLOSE_ON_FREE? If you're not,
you have to close sockets manually.

I don't see the infinite loop in your gdb output; I see something trying
to make a connection, the accept fails due to fd resource limits, and
defaults to sending an "event_sock_warn".

I would suggest setting read/write timeouts on your accepted connections
(if you are resource limited); or setting the evconnlistener's errorcb,
and adding some logic to log various stats about the process.

One other thing you could do (after setting the errorcb) is to
evconnlistener_disable(), and wait (timer event or a client to
disconnect/timeout/error/whatever (eventcb)), check your resources, and
if all is good, call evconnlistener_enable().
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