On Wed 11-01-12 14:34:39, Andrew Morton wrote:
> On Tue, 10 Jan 2012 17:30:22 +0100
> Michal Hocko <mhocko@xxxxxxx> wrote:
>
> > This patch fixes the following NULL ptr dereference caused by
> > cat /sys/devices/system/memory/memory0/removable:
>
> Which is world-readable, I assume?
Right. But considering that we haven't seen any report like that it
seems that the HW is rather rare
>
> > ...
> > --- a/mm/page_alloc.c
> > +++ b/mm/page_alloc.c
> > @@ -5608,6 +5608,17 @@ __count_immobile_pages(struct zone *zone, struct page *page, int count)
> > bool is_pageblock_removable_nolock(struct page *page)
> > {
> > struct zone *zone = page_zone(page);
> > + unsigned long pfn = page_to_pfn(page);
> > +
> > + /*
> > + * We have to be careful here because we are iterating over memory
> > + * sections which are not zone aware so we might end up outside of
> > + * the zone but still within the section.
> > + */
> > + if (!zone || zone->zone_start_pfn > pfn ||
> > + zone->zone_start_pfn + zone->spanned_pages <= pfn)
> > + return false;
> > +
> > return __count_immobile_pages(zone, page, 0);
> > }
>
> So I propose that we backport it into -stable?
Agreed.
--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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