> On 04/02/2010 02:37 PM, Linus Torvalds wrote:
> > On Fri, 2 Apr 2010, Andrew Morton wrote:
> >> On Fri, 2 Apr 2010 11:09:14 -0700 (PDT) Linus Torvalds<torvalds@linux-foundation.org> wrote:
> >>
> >>>
> >>> I think this is likely due to the new scalable anon_vma linking by Rik.
> >>
> >> Similar to
https://bugzilla.kernel.org/show_bug.cgi?id=15680
> >
> > Yup, looks like the same thing, except that bugzilla entry was due to
> > swapping rather than hibernation and memory shrinking. But same end
> > result, just different reasons for why we were trying to shrink the page
> > lists.
>
> Interesting that it is a null pointer dereference, given
> that we do not zero out the anon_vma_chain structs before
> freeing them.
>
> Page_referenced_anon() takes the anon_vma->lock before
> walking the list. The three places where we modify the
> anon_vma_chain->same_anon_vma list, we also hold the
> lock.
>
> No doubt something in mm/ is doing something silly, but
> I have not found anything yet :(
>
> If I had to guess, I'd say maybe we got one of the
> mprotect & vma_adjust cases wrong. Maybe a page stayed
> around in the LRU (and in a process?) after its anon_vma
> already got freed?
