Re: [PATCH 2/2] mm: adds NOSIGBUS extension for out-of-band shmem read

From: Linus Torvalds
Date: Thu Jun 03 2021 - 15:16:16 EST

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.