Re: + mm-sanitize-page-mapping-for-tail-pages.patch added to -mm tree

[Kirill A. Shutemov]

On Fri, Mar 20, 2015 at 01:36:30PM -0700, akpm@xxxxxxxxxxxxxxxxxxxx wrote:
> 
> The patch titled
>      Subject: mm: sanitize page->mapping for tail pages
> has been added to the -mm tree.  Its filename is
>      mm-sanitize-page-mapping-for-tail-pages.patch
> 
> This patch should soon appear at
>     http://ozlabs.org/~akpm/mmots/broken-out/mm-sanitize-page-mapping-for-tail-pages.patch
> and later at
>     http://ozlabs.org/~akpm/mmotm/broken-out/mm-sanitize-page-mapping-for-tail-pages.patch
> 
> Before you just go and hit "reply", please:
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>    b) Prefer to cc a suitable mailing list as well
>    c) Ideally: find the original patch on the mailing list and do a
>       reply-to-all to that, adding suitable additional cc's
> 
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> 
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> 
> ------------------------------------------------------
> From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
> Subject: mm: sanitize page->mapping for tail pages
> 
> We don't define meaning of page->mapping for tail pages.  Currently it's
> always NULL, which can be inconsistent with head page and potentially lead
> to problems.
> 
> Let's poison the pointer to catch all illigal uses.
> 
> page_rmapping() and page_mapping() are changed to look on head page.


Could you replace the patch with the patch below. It also takes care about
page_anon_vma().