Re: [PATCH v2 1/6] mm/balloon_compaction: ignore anonymous pages

[Rafael Aquini]

On Sat, Aug 30, 2014 at 08:41:09PM +0400, Konstantin Khlebnikov wrote:
> From: Konstantin Khlebnikov <k.khlebnikov@xxxxxxxxxxx>
> 
> Sasha Levin reported KASAN splash inside isolate_migratepages_range().
> Problem is in function __is_movable_balloon_page() which tests AS_BALLOON_MAP
> in page->mapping->flags. This function has no protection against anonymous
> pages. As result it tried to check address space flags in inside anon-vma.
> 
> Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@xxxxxxxxxxx>
> Reported-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
> Link: http://lkml.kernel.org/p/53E6CEAA.9020105@xxxxxxxxxx
> Cc: stable <stable@xxxxxxxxxxxxxxx> # v3.8
> ---
>  include/linux/balloon_compaction.h |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h
> index 089743a..53d482e 100644
> --- a/include/linux/balloon_compaction.h
> +++ b/include/linux/balloon_compaction.h
> @@ -128,7 +128,7 @@ static inline bool page_flags_cleared(struct page *page)
>  static inline bool __is_movable_balloon_page(struct page *page)
>  {
>  	struct address_space *mapping = page->mapping;
> -	return mapping_balloon(mapping);
> +	return !PageAnon(page) && mapping_balloon(mapping);
>  }
>  
>  /*
> 
Acked-by: Rafael Aquini <aquini@xxxxxxxxxx>

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