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OPAL: SIP Transports deletion, when STUN enabled

Hi again...
 
I'm testing new release of OPAL intensively, as you can observe:>
 
Environment: Windows XP, VS.NET 2003
 
There is a problem with SIPEndPoint::TransportThreadMain method. When I set STUN, and during exit delete OPALManager, program crashes (access violation reading location 0xXXXXXXXX) at:
 
(sipep.cxx, v2.97, line 664)
 
if (stunTransport) {
natTransportMutex.Wait();    ------> here....
natTransports.Remove(transport);
natTransportMutex.Signal();
}
 
This code is after main loop of transport thread, so it runs during deletion of it.
 
Well, I've started to debug the code, and after some time I have some conclusions:
1) this problem is connected with NAT binding which Damien implemented recently. Because previous versions do not have this piece of code at all.
2) It seems that there is some kind of race situation between thread that deletes SIPEndpoint and transport threads.
I've observed that when I'm deleting manager (and implicitly all classes connected to it), sometimes:
A) this code from TransportThreadMain is called before destructor of SIPEndpoint (in MY machine very rare situation),
B) this code runs AFTER destructor of endpoint (most of the cases).
 
When A occurs - all is clear, when B: the code use memory which is already free (becuase class is already deleted)  -> this is the cause of the crash and access violation exception. I don't have neccesary knowledge of library threading model to be able to correct this (but I'm understanding it better and better....:).
 
When I disable STUN, this piece of code is skipped, and program exits with no problems.
 
In my opinion this is very serious problem, but I must point that I didn't test this code on other machines - maybe mine is not typical....
 
Regards:
Jacek Stobnicki