Re: Patch "x86/kexec: Allocate 8k PGDs for PTI" has been added to the 3.18-stable tree

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Sep 17, 2018 at 12:33:47PM -0700, Hugh Dickins wrote:
> On Mon, 17 Sep 2018, gregkh@linuxfoundation.org wrote:
> > 
> > This is a note to let you know that I've just added the patch titled
> > 
> >     x86/kexec: Allocate 8k PGDs for PTI
> > 
> > to the 3.18-stable tree which can be found at:
> >     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> > 
> > The filename of the patch is:
> >      x86-kexec-allocate-8k-pgds-for-pti.patch
> > and it can be found in the queue-3.18 subdirectory.
> > 
> > If you, or anyone else, feels it should not be added to the stable tree,
> > please let <stable@vger.kernel.org> know about it.
> 
> I believe this commit is an example of the auto-selector being too
> eager, and this should not be in *any* of the stable trees.  As the
> commit message indicates, it's a fix by Joerg for his PTI-x86-32
> implementation - which has not been backported to any of the stable
> trees (yet), has it?
> 
> In several of the recent stable trees, I think this will not do any
> actual harm; but it looks as if it will prevent relevant x86-32 configs
> from building on 3.18 (I see no definition of PGD_ALLOCATION_ORDER in
> linux-3.18.y - you preferred not to have any PTI in that tree), and I
> haven't checked whether its definition in older backports will build
> correctly here or not.

Ah, you are right, I just got a build failure report from the 4.4.y tree
with this exact error.

Thanks for letting me know, I'll go drop this from all of the stable
tree queues right now.

greg k-h