[Pkg-xen-devel] Bug#994870: Bug#994870: Bug#994870: Bug#994870: Memory allocation problem for VM after xen security update

[Hans van Kranenburg]

Hi!

On 9/30/21 12:45 AM, Andy Smith wrote:
> Hi Alex,
> 
> On Thu, Sep 30, 2021 at 12:10:32AM +0200, Alexander Dahl wrote:
>> Am 22.09.21 um 20:54 schrieb Hans van Kranenburg:
>>> At this point I would really recommend to not wait for a fix to arrive
>>> which makes it start again, but change your VM to use a 64-bit kernel.
>>
>> How?
> 
> This was answered in earlier comments on this bug; please see:
> 
>     https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=994870#15
>     https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=994870#20
> 
> The brief summary is, "start out like a crossgrade, but only do the
> kernel". Very simple and quite safe.
> 
> You haven't said how you boot your guest though (show us your
> /etc/xen/guest.cfg file). If it's pvgrub, that has a 32-bit and a
> 64-bit version so you'll need to change those as well. If it's
> pygrub you probably don't need to do anything, though pygrub has its
> own issues outside the scope of this bug.
> 
>> FWIW, Debian 10 VMs with 32 bit running with PVH work fine. My important VM
>> is still Debian 9 however due to a software I can not simply upgrade.
> 
> I've found PVH needs at least 4.19 guest kernel to work, which can
> be achieved in Debian 9 (stretch) today by using kernel from
> stretch-backports, so perhaps that is an option for you.

You can certainly do that and then run PVH.

Since stretch-backports is not used any more since stretch became
oldoldstable, new 4.19 backports kernels for Stretch are released
through the security updates channel. Be aware of this.

https://lists.debian.org/debian-lts-announce/2020/08/msg00019.html

Latest in stretch-backports (frozen) is 4.19.118, and stretch security
is now at 4.19.194. So double check you end up following the right one.

Hans