[Mono-dev] Trying to reproduce _wapi_handle_unref bug

[Brian Crowell]

I'm trying to reproduce a situation seen in my program involving the following 
message:

-------------------------------
   ** (process:2655): WARNING **: _wapi_handle_unref: Attempting to unref nused 
handle 0x18
-------------------------------

...where 0x18 may be any low hex number. This happens on mono-1.1.16.1 on Linux. 
Nearby error messages suggest a handle allocation problem:

-------------------------------
   ** (process:2655): WARNING **: CreateThread: error creating thread handle

   Unhandled Exception: System.ExecutionEngineException: Couldn't create thread
     at <0x00000> <unknown method>
     at (wrapper managed-to-native) 
System.Object:__icall_wrapper_mono_delegate_begin_invoke (object,intptr)
     at (wrapper delegate-begin-invoke) 
System.MulticastDelegate:begin_invoke_IAsyncResult_object_AsyncCallback_object 
(object,System.AsyncCallback,object)
     at System.Threading.ThreadPool.QueueUserWorkItem 
(System.Threading.WaitCallback callback, System.Object state) [0x00000]
     at System.Timers.Timer.StartTimer () [0x00000]
     at (wrapper delegate-invoke) System.MulticastDelegate::invoke_void ()
-------------------------------

So far, I've been able to make the mono internals SIGSEGV and deadlock from 
managed code (and I will file these as bugs later) but I'm having trouble 
reproducing this particular error except with the original application. So far, 
I'm pretty sure this is something that only comes up with a long-running 
application.

Can anyone give me some guidance as to what, in general, could cause this error? 
Handle exhaustion? Leaked handles?

Any help would be appreciated.

--Brian