Regression warning about 4.4.17+18 / 4.6.7 / 4.7+ and Xen

[Tim Gardner]

On 08/22/2016 04:07 AM, Stefan Bader wrote:
> There has been a recent (maybe not that recent, it was in 4.7) kernel regression
> for Xen which made its way back to several stable trees[1]:
> 
>   xenbus: don't BUG() on user mode induced condition
> 
> It appears there is a fix on patchworks[2] but as of today was not included, yet
> in upstream Linux.
> 
> For Yakkety the regression is part of the 4.6.0-11 unstable package. For Xenial
> it is part of the pending next SRU cycle (master-next). I did a quick test with
> the proposed patch on top of 4.6 in yakkety/master-next and it allowed me to
> starts VMs again. Not sure whether we want to pick that additional patch or back
> out the stable change introducing the problem. But either way the master-next
> branches of both Xenial and Yakkety will cause a Xen regression as they are now.
> 
> The effect is that tools like xenstore-ls or xenstore-write no longer work and
> it is no longer possible to start any VMs.
> 
> -Stefan
> 
> [1] https://lists.xenproject.org/archives/html/xen-devel/2016-08/msg02496.html
> [2] https://patchwork.kernel.org/patch/9281193/
> 
> 
> 

Looks like we should apply the one liner patchworks patch.

-- 
Tim Gardner tim.gardner at canonical.com