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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Tue, 9 Aug 2022 12:07:31 -0700
Message-ID: <CAHk-=wjh3wkhQWN8BHFUT6t52kfNMcRd+1JczD4Sgp_q11w8eA@mail.gmail.com>
Subject: Re: [PATCH v1] mm/gup: fix FOLL_FORCE COW security issue and remove FOLL_COW
To:     Jason Gunthorpe <jgg@nvidia.com>
Cc:     David Hildenbrand <david@redhat.com>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, stable@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Axel Rasmussen <axelrasmussen@google.com>,
        Peter Xu <peterx@redhat.com>, Hugh Dickins <hughd@google.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Matthew Wilcox <willy@infradead.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        John Hubbard <jhubbard@nvidia.com>
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On Tue, Aug 9, 2022 at 11:48 AM Jason Gunthorpe <jgg@nvidia.com> wrote:
>
> It is because of all this madness with COW.

Yes, yes, but we have the proper long-term pinning now with
PG_anon_exclusive, and it actually gets the pinning right not just
over COW, but even over a fork - which that early write never did.

David, I thought all of that got properly merged? Is there something
still missing?

                     Linus