[Freeswitch-dev] Possible deadlock in src/switch_event.c ?

[Anthony Minessale]

you're probably right but I wonder what you are doing that is binding and
unbinding so much?
The bind and unbind was designed to be called once when the module is
loaded and called again when it exits.

My fear is you are using the embedded scripting event handers in some quick
repeating fashion.

I did a commit to flip that case around but I don't encourage you to use
embedded scripts for heavy event traffic, that's what event socket is for
and if you have the C skills to debug this, you might want to try a C app ;)


2011/11/28 Brian West <brian at freeswitch.org>

> Please post it to jira.freeswitch.org
>
> /b
>
> On Nov 28, 2011, at 2:31 AM, Karol Golab wrote:
>
>
>   Hi!
>
>   I've noticed some strange code in src/switch_event.c - could someone
> smarter (& knowing the mentioned code) please take a look?
>
>   The problem is in the order of calls to locks BLOCK & RWLOCK - it
> differs between functions:
>
> switch_event_bind_removable
>         switch_mutex_lock(BLOCK);
>         switch_thread_rwlock_wrlock(RWLOCK);
>
> switch_event_unbind_callback
>     switch_thread_rwlock_wrlock(RWLOCK);
>     switch_mutex_lock(BLOCK);
>
> switch_event_unbind
>     switch_thread_rwlock_wrlock(RWLOCK);
>     switch_mutex_lock(BLOCK);
>
>   As I understand this may lead to an outright deadlock between bind
> and unbind.
>
>   I stumbled upon this code while debugging what seems like deadlocks
> in our test FS installation put under some heavy load. The load is about
> 25 new event subscribers per second (destroyed few seconds later) and
> about 700 events per second.
>
>   Regards,
>   Karol
>
>
>
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-- 
Anthony Minessale II

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