double fault

[Roland McGrath]

The stack overflow notion sounds plausible.  To investigate that angle, one
thing to try comes to mind off hand.  In each probe that might be hitting,
stick some %{ ... %} code to do a "stack getting small" check.  It can do
something like:

	unsigned left = (unsigned)regs & 0xfff;
	if (left < 256) panic("stack getting close");

That might manage to print out a full oops with backtrace details that show
the cascade of page fault frames or whatever the situation actually is.


Thanks,
Roland