Re: [PATCH] mm/gup: stop leaking pinned pages in low memory conditions

Andrew Morton
2024-10-16T22:41:28Z

On Wed, 16 Oct 2024 15:05:28 -0700 John Hubbard <jhubbard@nvidia.com> wrote:

> On 10/16/24 2:57 PM, Andrew Morton wrote:
> > On Wed, 16 Oct 2024 13:22:42 -0700 John Hubbard <jhubbard@nvidia.com> wrote:
> ...
> >> Fix this by unpinning the pages that __get_user_pages_locked() has
> >> pinned, in such error cases.
> >
> > Thanks.
> >
> >> Fixes: 24a95998e9ba ("mm/gup.c: simplify and fix check_and_migrate_movable_pages() return codes")
> >
> > I'll add this to the -stable backport pile, although this seems a bit
> > marginal?
>
> I'm on the fence about that. It is marginal: you have to
> exhaust memory. On the other hand, a real user reported
> this bug to us.
>
> I guess I'd lean toward "correctness in -stable", and
> add it to the pile, in the end.

Thanks. It's a super-simple patch, which helps the decision.