On Thu, Dec 14, 2017 at 2:02 PM, Peter Zijlstra <pet...@infradead.org> wrote: > > _Should_ being the operative word, because I cannot currently see it > DTRT. But maybe I'm missing the obvious -- I tend to do that at times.
At least the old get_user_pages_fast() code used to check the USER bit: unsigned long need_pte_bits = _PAGE_PRESENT|_PAGE_USER; if (write) need_pte_bits |= _PAGE_RW; but that may have been lost when we converted over to the generic code. It shouldn't actually _matter_, since we'd need to change access_ok() anyway (and gup had better check that!) Linus