Re: [PATCH] hugetlb: ensure we do not reference a surplus pageafter handing it to buddy

From: Adam Litke
Date: Tue Feb 19 2008 - 13:35:27 EST


Indeed. I'll take credit for this thinko...

On Tue, 2008-02-19 at 18:28 +0000, Andy Whitcroft wrote:
> When we free a page via free_huge_page and we detect that we are in
> surplus the page will be returned to the buddy. After this we no longer
> own the page. However at the end free_huge_page we clear out our mapping
> pointer from page private. Even where the page is not a surplus we
> free the page to the hugepage pool, drop the pool locks and then clear
> page private. In either case the page may have been reallocated. BAD.
>
> Make sure we clear out page private before we free the page.
>
> Signed-off-by: Andy Whitcroft <apw@xxxxxxxxxxxx>

Acked-by: Adam Litke <agl@xxxxxxxxxx>

--
Adam Litke - (agl at us.ibm.com)
IBM Linux Technology Center

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