[reSIProcate] Threading issues in DUM

[Richard Stellingwerff]

Hi,

I may have found some threading issues in the Dialog Usage Manager. I've
written a little application that stress tests my VOIP server. It dials a
SIP user, then when it rings it hangs up. Once it's hung up, it calls again,
and so forth, endlessly.

Inside a worker thread, I call _uacDum->process() etc. to handle the
incoming data.

>From the main thread, I create and send requests (invite, etc.) using
_uacDum->send(_uacDum->makeInviteSession(...)).

With this stress-test application, I get random crashes. Sometimes after a
minute, sometimes after 10 minutes. The crashes seem to happen most often in
DialogUsageManager::makeUacDialogSet. More specifically, it crashes at this
code:

    mDialogSetMap[ds->getId()] = ds;

My guess is that this crash happens because inside the worker thread, DUM is
removing DialogSets from that hashmap, while the main thread is
simultaneously adding them. Looking at the DUM code, I see no sort
synchronization whatsoever, which could confirm my suspicion.

I know this email is short on details, but I was wondering if I could be on
the right track here. Maybe I should be calling _uacDum->makeInviteSession()
etc. from the same thread that's calling _uacDum->process() ?

I really hope someone could give me a clue here. Thanks in advance.

Kind regards,
Richard.
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