[Freeswitch-users] mod_event_zmq thread safety

Alex Massover alex at jajah.com
Thu Aug 16 23:50:48 MSD 2012


This is what I understood as well. I'm not able to get a core for some reason, but provided that event callback is called by different threads, it strongly suggests that current implementation of mod_event_zmq is unsafe as sharing zmq context is not thread-safe.

What is the process of creating a ticket, please? Should I sing-up to JIRA?

From: freeswitch-users-bounces at lists.freeswitch.org [freeswitch-users-bounces at lists.freeswitch.org] On Behalf Of João Mesquita [jmesquita at freeswitch.org]
Sent: Thursday, August 16, 2012 10:27 PM
To: FreeSWITCH Users Help
Subject: Re: [Freeswitch-users] mod_event_zmq thread safety

I do *think* that events are dispatched by different workers on the core indeed which might be the cause of your problem. ZMQ also has a few asserts on the core that can be quite disruptive and they were working on getting it working more properly. Dunno what's the status of that right now.

A core dump would help a lot on any case tho.

João Mesquita

On Thu, Aug 16, 2012 at 4:23 PM, Alex Massover <alex at jajah.com<mailto:alex at jajah.com>> wrote:

We're using mod_event_zmq module (slightly modified, we use different socket type and IPC instead of TCP), and experience crashes.

As far as I understood the module it creates ZMQ context and all event sent by using same context.

Events callback is called from different threads, isn't it? And can be a situation when different threads access send() api on this context simultaneously.

ZMQ guide strongly prohibits doing that: " You MUST NOT share ØMQ sockets between threads."

And when I do a mutex around send() there're no more crashes (at least today).

Am I missing something or mod_event_zmq is potentially dangerous?

Best Regards,
Alex Massover
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