[CentOS-devel] Broken hyperthreading on Intel Skylake and Kaby Lake processors

[Phil Perry]

On 27/06/17 10:08, Laurentiu Pancescu wrote:
> Hi there,
> 
> I stumbled upon a thread on debian-devel, regarding hyperthreading 
> problems on Intel Skylake and Kaby Lake processors (discovered in Q2 
> 2016 by the OCaml developers, fixed by Intel in microcode updates in May 
> 2017 - for some, but not all processors [1]).  The "safe" solution is to 
> disable hyperthreading in the BIOS, but there's a Perl script telling 
> you if you CPU is affected, or affected and patched in microcode. [2]
> 
> Considering that (probably) not all processors are fixed, would this 
> warrant notifying our users via the centos-announce mailing list?
> 
> Best regards,
> Laurențiu
> 
> [1] https://lists.debian.org/debian-devel/2017/06/msg00308.html
> [2] https://lists.debian.org/debian-user/2017/06/msg01011.html


I have a potentially affected system. I've filed a bug with Red Hat to 
request microcode_ctl be updated to include the latest microcode:

https://bugzilla.redhat.com/show_bug.cgi?id=1465631

I can confirm the issue is not fixed in the current RHEL7.4beta 
microcode_ctl package.

In the meantime I've manually applied the microcode update on my 
affected system.

phil