Re: [PATCH 02/13] mm: Revalidate anon_vma in page_lock_anon_vma()

[Peter Zijlstra]

On Fri, 2010-04-09 at 16:29 +0900, KOSAKI Motohiro wrote:
> 
> 
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 8b088f0..b4a0b5b 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -295,7 +295,7 @@ struct anon_vma *page_lock_anon_vma(struct page
> *page)
>         unsigned long anon_mapping;
>  
>         rcu_read_lock();
> -       anon_mapping = (unsigned long) ACCESS_ONCE(page->mapping);
> +       anon_mapping = (unsigned long) rcu_dereference(page->mapping);
>         if ((anon_mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON)
>                 goto out;
>         if (!page_mapped(page)) 

Yes, I think this is indeed required.

I'll do a new version of the patch that includes the comment updates
requested by Andrew.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/