From: Muchun Song <songmuchun@bytedance.com>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Linux Memory Management List <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Oscar Salvador <osalvador@suse.de>,
Michal Hocko <mhocko@suse.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
David Hildenbrand <david@redhat.com>,
Matthew Wilcox <willy@infradead.org>,
Miaohe Lin <linmiaohe@huawei.com>,
Mina Almasry <almasrymina@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux- stable <stable@vger.kernel.org>
Subject: Re: [External] [PATCH] userfaultfd: hugetlbfs: fix new flag usage in error path
Date: Sun, 23 May 2021 10:45:11 +0800 [thread overview]
Message-ID: <CAMZfGtVnGMu9SU8U+aXp6YKz0p1pBxcYy4OMpNftpkxTbJBM8w@mail.gmail.com> (raw)
In-Reply-To: <20210521233952.236434-1-mike.kravetz@oracle.com>
On Sat, May 22, 2021 at 7:40 AM Mike Kravetz <mike.kravetz@oracle.com> wrote:
>
> In commit d6995da31122 ("hugetlb: use page.private for hugetlb specific
> page flags") the use of PagePrivate to indicate a reservation count
> should be restored at free time was changed to the hugetlb specific flag
> HPageRestoreReserve. Changes to a userfaultfd error path as well as a
> VM_BUG_ON() in remove_inode_hugepages() were overlooked.
>
> Users could see incorrect hugetlb reserve counts if they experience an
> error with a UFFDIO_COPY operation. Specifically, this would be the
> result of an unlikely copy_huge_page_from_user error. There is not an
> increased chance of hitting the VM_BUG_ON.
>
> Fixes: d6995da31122 ("hugetlb: use page.private for hugetlb specific page flags")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Thanks Mike.
prev parent reply other threads:[~2021-05-23 2:45 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-21 23:39 Mike Kravetz
2021-05-22 19:41 ` Mina Almasry
2021-05-23 2:45 ` Muchun Song [this message]
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