From: Muchun Song <songmuchun@bytedance.com>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
zi.yan@cs.rutgers.edu,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
David Rientjes <rientjes@google.com>,
Lars Persson <lars.persson@axis.com>, Zi Yan <ziy@nvidia.com>,
Linux Memory Management List <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Xiongchun duan <duanxiongchun@bytedance.com>,
Fam Zheng <fam.zheng@bytedance.com>
Subject: Re: [PATCH v4 3/5] mm: hugetlb: fix missing cache flush in copy_huge_page_from_user()
Date: Thu, 10 Feb 2022 15:19:57 +0800 [thread overview]
Message-ID: <CAMZfGtUTj-r-sO3YRfyEhvR1mKYxi6kXx+ZZPVYjV3AhAMdh1g@mail.gmail.com> (raw)
In-Reply-To: <d78d6e56-1879-94c8-dc28-06431e583a77@oracle.com>
On Thu, Feb 10, 2022 at 3:07 AM Mike Kravetz <mike.kravetz@oracle.com> wrote:
>
> On 2/7/22 23:36, Muchun Song wrote:
> > The userfaultfd calls copy_huge_page_from_user() which does not do
> > any cache flushing for the target page. Then the target page will
> > be mapped to the user space with a different address (user address),
> > which might have an alias issue with the kernel address used to copy
> > the data from the user to. Fix this issue by flushing dcache in
> > copy_huge_page_from_user().
>
> Quick question.
>
> Should this also be done for the non-hugetlb case? Take a look at the
> routines __mcopy_atomic() and mcopy_atomic_pte(). Or, is that somehow
> handled?
Actually, you are right. __mcopy_atomic() and mcopy_atomic_pte()
should also be fixed. And shmem_mfill_atomic_pte() also should
be fixed. I'll fix those places in the next version. Thanks.
>
> For this change,
> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Thanks Mike.
next prev parent reply other threads:[~2022-02-10 7:20 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-08 7:36 [PATCH v4 0/5] Fix some cache flush bugs Muchun Song
2022-02-08 7:36 ` [PATCH v4 1/5] mm: thp: fix wrong cache flush in remove_migration_pmd() Muchun Song
2022-02-08 7:36 ` [PATCH v4 2/5] mm: fix missing cache flush for all tail pages of compound page Muchun Song
2022-02-08 7:36 ` [PATCH v4 3/5] mm: hugetlb: fix missing cache flush in copy_huge_page_from_user() Muchun Song
2022-02-09 19:07 ` Mike Kravetz
2022-02-10 7:19 ` Muchun Song [this message]
2022-02-08 7:36 ` [PATCH v4 4/5] mm: hugetlb: fix missing cache flush in hugetlb_mcopy_atomic_pte() Muchun Song
2022-02-09 18:59 ` Mike Kravetz
2022-02-08 7:36 ` [PATCH v4 5/5] mm: replace multiple dcache flush with flush_dcache_folio() Muchun Song
2022-02-09 19:10 ` Mike Kravetz
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