CPU Bug on Intel Skylake and Kabylake

I had two or three system crashes on my Linux workstation after upgrading to a new mother board and CPU within some months. This is very unusual for me because stability is the main objective when I build a new a workstation. So I tried to find the reason.

Some weeks ago I found this bug report: https://lists.debian.org/debian-devel/2017/06/msg00308.html

Hyperthreading on Skylake and Kabylake CPUs is buggy!

If your processor model (listed in /proc/cpuinfo) is 78 or 94, and the stepping is 3 you are lucky because Intel already provides a microcode update. My workstation is processor level 94 which is Intel Core i5 6500. So I installed the debian packages intel-microcode 3.20170511.1 from jessie-backports.

Since this update I had no System crash and hang up.