Even worse anything that monkey's with the CPU's cache logic on a multiprocessor machine will corrupt memory. From a post by Bruce Dawson where he was working w

Even worse anything that monkey's with the CPU's cache logic on a multiprocessor machine will corrupt memory. From a post by Bruce Dawson where he was working with a machine that had an instruction to bypass the cache. It was bad news, doubly so because the machine also did speculative execution.