Mdbg Stack Frame,

Hi,


I need some help with cordbg. I try to do some search on google, but
don't find any answer.
I try to use MDBGEngine to analyse the trace stack frame of an
appplication which have deadlocks.
For this, I use the following code:

proc = debugger.Attach(processId);
DrainAttach(debugger, proc);
MDbgThreadCollection threads = proc.Threads;
Console.WriteLine("Attached to pid:{0}", processId);
foreach (MDbgThread thread in threads)
{
Console.WriteLine("Callstack for Thread {0}",
thread.Id.ToString());
foreach (MDbgFrame frame in thread.Frames)
{
Console.WriteLine(" " + frame);
}
}

It's work well, and output something like this:
...
System.Web.HttpRuntime.ProcessRequestInternal (source line
information unavailable)
System.Web.HttpRuntime.ProcessRequestNoDemand (source line
information unavailable)
System.Web.Hosting.ISAPIRuntime.ProcessRequest (source line
information unavailable)
[Internal Frame, 'AD Switch']
[Internal Frame, 'U-->M']

My question is about the last two lines "Internal Frame". I don't
understand what is it ?
Somes of the stacks have the U-->M flags, other don't have. Is this
related to lock waiting ?


Thanks,
Laurent.