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* DO NOT APPLY: x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stack
@ 2014-07-15 23:21 Andrew Lutomirski
  2014-07-15 23:52 ` Greg KH
  2014-07-16  0:56 ` Kamal Mostafa
  0 siblings, 2 replies; 5+ messages in thread
From: Andrew Lutomirski @ 2014-07-15 23:21 UTC (permalink / raw)
  To: Kamal Mostafa
  Cc: linux-kernel@vger.kernel.org, stable, kernel-team, H. Peter Anvin,
	Konrad Rzeszutek Wilk, Borislav Petkov, Linus Torvalds,
	Dirk Hohndel, Arjan van de Ven, comex, Alexander van Heukelum,
	Boris Ostrovsky

On Tue, Jul 15, 2014 at 2:28 PM, Kamal Mostafa <kamal@canonical.com> wrote:
> 3.13.11.5 -stable review patch.  If anyone has any objections, please let me know.
>
> ------------------
>
> From: "H. Peter Anvin" <hpa@linux.intel.com>
>
> commit 3891a04aafd668686239349ea58f3314ea2af86b upstream.

Do not apply to any -stable release yet.  This causes nasty regressions on Xen.

--Andy

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: DO NOT APPLY: x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stack
  2014-07-15 23:21 DO NOT APPLY: x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stack Andrew Lutomirski
@ 2014-07-15 23:52 ` Greg KH
  2014-07-15 23:56   ` Andrew Lutomirski
  2014-07-16  0:56 ` Kamal Mostafa
  1 sibling, 1 reply; 5+ messages in thread
From: Greg KH @ 2014-07-15 23:52 UTC (permalink / raw)
  To: Andrew Lutomirski
  Cc: Kamal Mostafa, linux-kernel@vger.kernel.org, stable, kernel-team,
	H. Peter Anvin, Konrad Rzeszutek Wilk, Borislav Petkov,
	Linus Torvalds, Dirk Hohndel, Arjan van de Ven, comex,
	Alexander van Heukelum, Boris Ostrovsky

On Tue, Jul 15, 2014 at 04:21:46PM -0700, Andrew Lutomirski wrote:
> On Tue, Jul 15, 2014 at 2:28 PM, Kamal Mostafa <kamal@canonical.com> wrote:
> > 3.13.11.5 -stable review patch.  If anyone has any objections, please let me know.
> >
> > ------------------
> >
> > From: "H. Peter Anvin" <hpa@linux.intel.com>
> >
> > commit 3891a04aafd668686239349ea58f3314ea2af86b upstream.
> 
> Do not apply to any -stable release yet.  This causes nasty regressions on Xen.

I thought you all found the Xen-regression-fix patch a few hours ago,
right?

This means that Linus's tree is also broken?

thanks,

greg k-h

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: DO NOT APPLY: x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stack
  2014-07-15 23:52 ` Greg KH
@ 2014-07-15 23:56   ` Andrew Lutomirski
  2014-07-16  0:49     ` Greg KH
  0 siblings, 1 reply; 5+ messages in thread
From: Andrew Lutomirski @ 2014-07-15 23:56 UTC (permalink / raw)
  To: Greg KH
  Cc: Kamal Mostafa, linux-kernel@vger.kernel.org, stable, kernel-team,
	H. Peter Anvin, Konrad Rzeszutek Wilk, Borislav Petkov,
	Linus Torvalds, Dirk Hohndel, Arjan van de Ven, comex,
	Alexander van Heukelum, Boris Ostrovsky

On Tue, Jul 15, 2014 at 4:52 PM, Greg KH <greg@kroah.com> wrote:
> On Tue, Jul 15, 2014 at 04:21:46PM -0700, Andrew Lutomirski wrote:
>> On Tue, Jul 15, 2014 at 2:28 PM, Kamal Mostafa <kamal@canonical.com> wrote:
>> > 3.13.11.5 -stable review patch.  If anyone has any objections, please let me know.
>> >
>> > ------------------
>> >
>> > From: "H. Peter Anvin" <hpa@linux.intel.com>
>> >
>> > commit 3891a04aafd668686239349ea58f3314ea2af86b upstream.
>>
>> Do not apply to any -stable release yet.  This causes nasty regressions on Xen.
>
> I thought you all found the Xen-regression-fix patch a few hours ago,
> right?

That patch is insufficient: Xen guests still fail to initialize
espfix64 correctly on SMP.  It's currently unclear that espfix64 can
work at all on Xen -- it's may be rather fundamentally incompatible
with the Xen hypercall IRET mechanism.  So it might need to be
disabled entirely on Xen (and maybe Xen will fix the info leak in the
hypervisor).

>
> This means that Linus's tree is also broken?

Yes.

--Andy

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: DO NOT APPLY: x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stack
  2014-07-15 23:56   ` Andrew Lutomirski
@ 2014-07-16  0:49     ` Greg KH
  0 siblings, 0 replies; 5+ messages in thread
From: Greg KH @ 2014-07-16  0:49 UTC (permalink / raw)
  To: Andrew Lutomirski
  Cc: Kamal Mostafa, linux-kernel@vger.kernel.org, stable, kernel-team,
	H. Peter Anvin, Konrad Rzeszutek Wilk, Borislav Petkov,
	Linus Torvalds, Dirk Hohndel, Arjan van de Ven, comex,
	Alexander van Heukelum, Boris Ostrovsky

On Tue, Jul 15, 2014 at 04:56:36PM -0700, Andrew Lutomirski wrote:
> On Tue, Jul 15, 2014 at 4:52 PM, Greg KH <greg@kroah.com> wrote:
> > On Tue, Jul 15, 2014 at 04:21:46PM -0700, Andrew Lutomirski wrote:
> >> On Tue, Jul 15, 2014 at 2:28 PM, Kamal Mostafa <kamal@canonical.com> wrote:
> >> > 3.13.11.5 -stable review patch.  If anyone has any objections, please let me know.
> >> >
> >> > ------------------
> >> >
> >> > From: "H. Peter Anvin" <hpa@linux.intel.com>
> >> >
> >> > commit 3891a04aafd668686239349ea58f3314ea2af86b upstream.
> >>
> >> Do not apply to any -stable release yet.  This causes nasty regressions on Xen.
> >
> > I thought you all found the Xen-regression-fix patch a few hours ago,
> > right?
> 
> That patch is insufficient: Xen guests still fail to initialize
> espfix64 correctly on SMP.  It's currently unclear that espfix64 can
> work at all on Xen -- it's may be rather fundamentally incompatible
> with the Xen hypercall IRET mechanism.  So it might need to be
> disabled entirely on Xen (and maybe Xen will fix the info leak in the
> hypervisor).

Ok, I'll pospone these all until the next round of stable releases next
week, Linus's tree should be fixed by then.

thanks,

greg k-h

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: DO NOT APPLY: x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stack
  2014-07-15 23:21 DO NOT APPLY: x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stack Andrew Lutomirski
  2014-07-15 23:52 ` Greg KH
@ 2014-07-16  0:56 ` Kamal Mostafa
  1 sibling, 0 replies; 5+ messages in thread
From: Kamal Mostafa @ 2014-07-16  0:56 UTC (permalink / raw)
  To: Andrew Lutomirski
  Cc: linux-kernel@vger.kernel.org, stable, kernel-team, H. Peter Anvin,
	Konrad Rzeszutek Wilk, Borislav Petkov, Linus Torvalds,
	Dirk Hohndel, Arjan van de Ven, comex, Alexander van Heukelum,
	Boris Ostrovsky

On Tue, 2014-07-15 at 16:21 -0700, Andrew Lutomirski wrote:
> On Tue, Jul 15, 2014 at 2:28 PM, Kamal Mostafa <kamal@canonical.com> wrote:
> > 3.13.11.5 -stable review patch.  If anyone has any objections, please let me know.
> >
> > ------------------
> >
> > From: "H. Peter Anvin" <hpa@linux.intel.com>
> >
> > commit 3891a04aafd668686239349ea58f3314ea2af86b upstream.
> 
> Do not apply to any -stable release yet.  This causes nasty regressions on Xen.
> 
> --Andy
> 


Thanks very much Andy.  I've dropped it from the 3.13-stable queue.

 -Kamal



^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2014-07-16  0:57 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2014-07-15 23:21 DO NOT APPLY: x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stack Andrew Lutomirski
2014-07-15 23:52 ` Greg KH
2014-07-15 23:56   ` Andrew Lutomirski
2014-07-16  0:49     ` Greg KH
2014-07-16  0:56 ` Kamal Mostafa

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