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

[Andrew Morton]

On Fri, 09 Apr 2010 10:44:53 +0200
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> 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.

Either this didn't happen or I lost the patch.

I parked mm-revalidate-anon_vma-in-page_lock_anon_vma.patch for now. 
Hopefully everything still works without it..

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