I've been working with the DEBUG build of EDK2, and thought I had changed the configuration to be 'proper' for a single core, and it ran fine on a single core simulation.  As I started removing debug prints, I started getting simulator seg faults.  I confirmed that the difference between running and crashing versions were simply debug prints.

Changing the simulation to simulator 2 cores resolved the problem.  I suspect that there may be a race condition or some other multi-core detection bug that causes this crash.

I don't plan to investigate this further at this point - just wanted to report this as I was surprised to find that a debug print being removed would cause the simulator to crash.

Roy