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Date:   Thu, 15 Dec 2022 14:37:00 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Mike Kravetz <mike.kravetz@oracle.com>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Muchun Song <songmuchun@bytedance.com>,
        Miaohe Lin <linmiaohe@huawei.com>,
        David Hildenbrand <david@redhat.com>,
        Peter Xu <peterx@redhat.com>,
        Naoya Horiguchi <naoya.horiguchi@linux.dev>,
        "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>,
        James Houghton <jthoughton@google.com>,
        Mina Almasry <almasrymina@google.com>
Subject: Re: [PATCH 1/2] hugetlb: really allocate vma lock for all sharable
 vmas
Message-Id: <20221215143700.232f7ef0084167269f7068df@linux-foundation.org>
In-Reply-To: <20221212235042.178355-1-mike.kravetz@oracle.com>
References: <20221212235042.178355-1-mike.kravetz@oracle.com>
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On Mon, 12 Dec 2022 15:50:41 -0800 Mike Kravetz <mike.kravetz@oracle.com> wrote:

> Commit bbff39cc6cbc ("hugetlb: allocate vma lock for all sharable vmas")
> removed the pmd sharable checks in the vma lock helper routines.
> However, it left the functional version of helper routines behind #ifdef
> CONFIG_ARCH_WANT_HUGE_PMD_SHARE.  Therefore, the vma lock is not being
> used for sharable vmas on architectures that do not support pmd sharing.
> On these architectures, a potential fault/truncation race is exposed
> that could leave pages in a hugetlb file past i_size until the file is
> removed.
> 
> Move the functional vma lock helpers outside the ifdef, and remove the
> non-functional stubs.  Since the vma lock is not just for pmd sharing,
> rename the routine __vma_shareable_flags_pmd.
> 
> Fixes: bbff39cc6cbc ("hugetlb: allocate vma lock for all sharable vmas")

So I assume we want this backported to 6.1?  I added a cc:stable.

The [2/2] patch is, I think, 6.3-rc1 material?