On Thu, Jun 3, 2021 at 12:12 PM Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > Yeah, if that's sufficient, then that original patch should just work as-is. To clarify: it obviously needs the VM_xyz flags things, but the VM_SHARED check in do_anonymous_page() is fine, and the whole issue with VM_MAYWRITE is entirely moot. MAP_PRIVATE works fine with zero pages even when writable - they get COW'ed properly, of course. Linus