Re: [PATCH v1 0/2] mremap refactor: check src address for vma boundaries first.

[Jeff Xu <jeffxu@chromium.org>]

On Wed, Aug 14, 2024 at 7:40 AM Liam R. Howlett <Liam.Howlett@oracle.com> wrote:
>
> * jeffxu@chromium.org <jeffxu@chromium.org> [240814 03:14]:
> > From: Jeff Xu <jeffxu@chromium.org>
> >
> > mremap doesn't allow relocate, expand, shrink across VMA boundaries,
> > refactor the code to check src address range before doing anything on
> > the destination, i.e. destination won't be unmapped, if src address
> > failed the boundaries check.
> >
> > This also allows us to remove can_modify_mm from mremap.c, since
> > the src address must be single VMA, can_modify_vma is used.
>
> I don't think sending out a separate patch to address the same thing as
> the patch you said you were testing [1] is the correct approach.  You
> had already sent suggestions on mremap changes - why send this patch set
> instead of making another suggestion?
>
As indicated in the cover letter, this patch aims to improve mremap
performance while preserving existing mseal's semantics. And this
patch can go in-dependantly regardless of in-loop out-loop discussion.

[1] link in your email is broken, but I assume you meant Pedro's V1/V2
of in-loop change. In-loop change has a semantic/regression risk to
mseal, and will take longer time to review/test/prove and bake.

We can leave in-loop discussion in Pedro's thread, I hope the V3 of
Pedro's patch adds more testing coverage and addresses existing
comments in V2.

Thanks
-Jeff

-Jeff