// the stack (in theory VirtualQuery isn't supposed to include
	// that, but it does). Add an additional 8K of slop for
	// calling C functions that don't have stack checks and for
	// lastcontinuehandler. We shouldn't be anywhere near this
	// bound anyway.
	base := mbi.allocationBase + 16<<10
	// Sanity check the stack bounds.
	g0 := getg()
	if base > g0.stack.hi || g0.stack.hi-base > 64<<20 {