On Fri, Jan 26, 2018 at 8:08 AM, Andreas Manschke
<[log in to unmask]> wrote:
> Dear colleagues,
>
> just to inform you about a problem I have/had:
>
> Xen host: SL5 kernel-xen-2.6.18-419.el5.x86_64 ,xen-3.0.3-148.el5_11.x86_64, libvirt-0.8.2-29.el5_9.1.x86_64
> Xen guest: SL6 kernel 2.6.32-696.16.1.el6.x86_64, kernel-firmware-2.6.32-696.18.7.el6
>
> Guest runs fine. yum update -> kernel-2.6.32-696.18.7.el6.x86_64
> Guest does not boot. Using the graphical virt-manager display you don't see anything. Only machine crashed.
>
> Workaround:
> Add
>  extra = "(hd0)/boot/grub/menu.lst"
> to /etc/xen/guest
>
> xm create -c guest
>
> Select older kernel, boot, yum remove kernel-2.6.32-696.18.7.el6.x86_64
>
> Perhaps a problem with Spectre/Meltdown handling?

This is not unlikely. Why are you continuing with SL 5? RHEL 5 is now
over 10 years old and is no longer getting ordinary maintenance
updates. Sounds like time to upgrade.