Re: [PATCH 2/2 mmotm] mm/page-writeback: check-before-clear PageReclaim

["Kirill A. Shutemov" <kirill@shutemov.name>]

On Mon, Apr 06, 2015 at 08:13:25AM +0000, Naoya Horiguchi wrote:
> With page flag sanitization patchset, an invalid usage of ClearPageReclaim()
> is detected in set_page_dirty().
> This can be called from __unmap_hugepage_range(), so let's check PageReclaim
> flag before trying to clear it to avoid the misuse.
> 
> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>

Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

> ---
>  mm/page-writeback.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index 22f3714d35e6..38aa0d8f19d3 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -2225,7 +2225,8 @@ int set_page_dirty(struct page *page)
>  		 * it will confuse readahead and make it restart the size rampup
>  		 * process. But it's a trivial problem.
>  		 */
> -		ClearPageReclaim(page);
> +		if (PageReclaim(page))
> +			ClearPageReclaim(page);
>  #ifdef CONFIG_BLOCK
>  		if (!spd)
>  			spd = __set_page_dirty_buffers;
> -- 
> 2.1.0

-- 
 Kirill A. Shutemov

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