[PATCH] powerpc/mm: Recompute hash value after a failed update

[Michael Ellerman]

On Wed, 2015-09-16 at 08:53 +0530, Aneesh Kumar K.V wrote:
> "Aneesh Kumar K.V" <aneesh.kumar at linux.vnet.ibm.com> writes:
> 
> > If we had secondary hash flag set, we ended up modifying hash value in
> > the updatepp code path. Hence with a failed updatepp we will be using
> > a wrong hash value for the following hash insert. Fix this by
> > recomputing hash before insert.
> 
> Without this patch we can end up with using wrong slot number in linux
> pte. That can result in us missing an hash pte update or invalidate
> which can cause memory corruption or even machine check ?

Thanks. When did this break? Always? If so this should go to stable?

cheers