> I have a very simple question. Can a thread's stack (RVMThread.stack) move?
> If so, can it be disabled?

In the current system, a stack will only be moved if we have a stackoverflow exception and grow the stack.  On linux, we start with really big stacks so this is very unlikely to happen.  I've been meaning to remove this functionality for years as it is complex and rarely tested.  As we move to native threads (instead of green threads) the functionality will almost certainly be removed.

For experimental purposes, just set the initial and max stack size to the same (large) constant and then the stacks should never be moved.