On Tue, Mar 31, 2020 at 4:06 PM Brandon Nielsen <nielsenb@jetfuse.net> wrote:
Recently I've had cause to run memtest on some relatively modern systems
(Haswell, Haswell refresh, and Kaby Lake R). On all three systems the
memtest86+ provided with the Fedora Workstation Live media failed.

On the Haswell and Haswell refresh machines it froze shortly after
starting. It didn't matter if the test was run in 'Safe Mode', or with SMP.

I can confirm the issues. I have Haswell (i5 4570):
* With F32 Workstation Beta, memtest freezes at 35% (of the first test) reliably if I keep the defaults (which defaults to SMP:disabled) or force safe mode with F1. When I force SMP using F2, it reboots quickly.
* With F31 Workstation, memtest reboots at 35% (of the first test) reliably if I keep the defaults (SMP: disabled) or force safe mode. When I force SMP, it reboots quickly.
* With F30 Workstation, memtest seems to work fine (I waited only a few minutes) in all configurations.

With a libvirt VM, memtest seems to work fine (I waited only a few minutes) with safe mode with F30-F32, but reboots immediately in default configuration or SMP (F30-F32).

I used to have problems with memtest when I forced SMP in the past, but never with the default or safe mode configuration. Something changed recently (F31) for the worse. Interestingly, memtest always reports the same version (5.01) so I wonder what affects this.