Comment # 25 on bug 1129428 from J. Daniel Schmidt

I investigated a bit more:

I found a similar workstation (very same hardware) which does not show that
bug.
It was running with kernel 4.20.13-1-default (tumbleweed).
But it had a BIOS version from before the spectre patches (my workstation had a
BIOS version from after that).

So I downgraded to the same BIOS version, then UNinstalled the package
ucode-intel, created a new initrd and booted again with the initial Leap kernel
4.12.14-lp150.11-default.
With this the segfaults still happen on CPU 3 and 7.

Today I additionally disabled hyperthreading in the BIOS and booted the same
old Leap kernel. Still segfaults happen to processes on CPU 3.

Is there anything else I can check/change/do?
Or can I safely assume, that it is a hardware issue, that popped up suddenly?
Is something like this possible? See also comment #19 in this regard.

Is it possible that an update (anomalies started after an update on Feb 27th,
see comment #19) changed something on the CPU that can not be undone? ... or
that I did not yet undo during my investigation?