## Kernel Updates Today, Downtime – VirtualBox Maybe Affected

I take the unusual approach, of hosting my Web-site, and this blog, on my personal computer at home. This implies that the visibility of this blog on the Web, is only as good the reliability of my PC, which I name ‘Phoenix’. Along with the computer I name ‘Plato’, Phoenix received a kernel-update today, which required a reboot.

The kernel-update took place uneventfully.

But, my site and blog would not have remained visible, from 20h20 until about 20h30 this evening.

I apologize for any inconvenience to my readers.

(Update 05/02/2018 … )

Contrarily to first appearances, this kernel-update did seem to have a side-effect: On one of my computers, it prevented the VirtualBox kernel-modules from being built…

## Kernel Update Today, Downtime

A fact about mys site which some people may not know, is that I take the unusual approach of hosting it on one of my PCs at home. The computer which acts as my Web-server, is also the one I named ‘Phoenix’, and which is still running Debian / Jessie. What this piece of trivia means in practice, is that any downtime of this one PC, also causes the site not to be accessible on the Internet. This is very different from how it would be, if I was to pay a professional hosting service.

Today, ‘Phoenix’ received a long-awaited kernel update, With which the package maintainers hope to be mitigating the ‘Meltdown’ vulnerability. What this does, is complete the work that some of the System Programmers have been doing, on the ‘Meltdown’ vulnerability, since as it stands, all the kernels on the list here have been patched now.

The fact is somewhat ironic, that ‘Phoenix’ has an AMD processor, and was therefore never directly susceptible to this form of attack. However, the computer which I name ‘Plato’ has an Intel CPU, and received its kernel update on January 5.

I congratulate the kernel-programmers on a milestone in their work.

Now an unanswered question remains, as to what will be done – if anything – about ‘Spectre’, which is a related vulnerability, in which a hypothetical attacker would ‘attack’ other processes running on the same machine, but not the kernel. The problem with ‘Spectre’, as far as I think I understand it, is that it involves “Speculative Execution” of code, but does not involve ‘system calls’ per se. What that means is that, unless somebody comes up with something brilliant, the only ways to patch that would either be to disable Speculative Execution entirely, or, switch to new chips, which have been designed with ‘Spectre’ taken into account, but which haven’t been designed yet in fact.

‘Spectre’ may also affect some AMD CPUs.

In any case, my site was unavailable from about 15h30 until 15h45.

Dirk

## Routine Kernel Update Today, Downtime

I host this site on a Debian / Jessie (Linux) computer, which I name ‘Phoenix’. Through the package manager, it receives routine kernel updates, and today was a day on which it received one.

Even on a Linux computer, a kernel update generally requires a reboot, which I carried out.

But, because This computer is also my Web-server, and the host to my blog, that means that for a few minutes my site and blog were offline – i.e., unavailable to readers. This was happening from approximately 19h45 until 19h55.

I apologize for any inconvenience.

For what it’s worth, I consider this to have been one of the least-troublesome reboots, that I’ve had to carry out over the years.

Dirk

## Routine Kernel Update Today, Downtime

Today, the Debian Package Maintainers pushed through a routine kernel update, to version ‘3.16.0-4-amd64‘ . Even though this machine is a Linux computer, this update required a reboot. Further, I take the unusual step of hosting my Web-site and blog on my own server at home.

This implies that the Web-site was offline briefly, more specifically from about 13h05 until 13h15. I cannot display a Maintenance Mode Page during such an event, because doing so would still require that my Web-server be online.

However, because everything about this update went smoothly, the interruption to the system processes had a duration closer to 5 minutes than to 10 minutes. I did not notice any malfunctions.

Oh yes, this also caused my local cache to get flushed (‘memcached‘), for which reason access to the favorite postings of the readers will remain a bit sluggish for the next day or so.

Dirk