Bug#1043585: Update on this issue

[Martin Johnson <martin.d.johnson@outlook.com>]

Hi Salvatore,

As I was unfortunately not successful to apply the suggested patch to 
the Debian sources, however I since have tried to apply it to 6.4.11 
vanilla stable kernel.

That patch has applied fine, and the emulated TPM in KVM is also back 
into a working state :-)

So if you back-ported to the Debian kernel, it should hopefully fix 
things there too.

If you need me to test a patch for the back-port against the Debian 
kernel, and you can provide one, please let me know :-)

Kind Regards,

Martin.


On 17/08/2023 08:38, Salvatore Bonaccorso wrote:
> Control: tags -1 + moreinfo upstream
>
> Hi Martin,
>
> On Wed, Aug 16, 2023 at 07:16:58PM +0100, Martin Johnson wrote:
> > Package: linux-image-amd64
> >
> > Version: 6.1.0-11-amd64
> >
> > Update of this recent issue - I might not have specified the package
> > correctly, sorry for that - its the first bug I tried to report on Debian -
> > hey Debian really is that good :-)
> >
> > I found some sort of workaround too, but its far from ideal at present.
> >
> > To avoid this issue you can set the kernel boot parameter:
> > spec_rstack_overflow=off
> >
> > Then the problem no longer exists, obviously with an additional and quite
> > serious AMD Zen processor security issue.
> >
> > So the cause is also related to the recent AMD Zen security patch.
> >
> > The problem seems related to these posts on bugzilla.kernel.org, but is
> > manifesting in a different way for me:
> >
> > https://bugzilla.kernel.org/show_bug.cgi?id=217796
> >
> > and this:
> >
> > https://bugzilla.kernel.org/show_bug.cgi?id=217796
> Did you meant to reference here two different bugzilla enties?
>
> > Hope this information is of assistance for anyone who is lucky enough to
> > find this information :-)
> Thanks for providing that. Would it be possible for you to test a
> custom kernel built with the following commit applied on top and see
> if this resolved the issue you are seeing?
>
> https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=ba5ca5e5e6a1d55923e88b4a83da452166f5560e
>
> See
> https://kernel-team.pages.debian.net/kernel-handbook/ch-common-tasks.html#id-1.6.6.4
> for instructions.
>
> Regards,
> Salvatore