[Bug 1876157] Re: Memtest86+ in Ubuntu 20.04 doesn't work, switch to Coreboot branch or package new release v5.31b is available since 12/04/2020

[Phil Marsh]

Ubuntu maintainers,
Thanks for your software and service to us all!
Please, Please, Please stop shipping Memtest86+ version 5.31b with Ubuntu.
>From my experience, this software IS NOT threadsafe and will falsely report RAM errors when RAM is OK. I think this happens because, in mult-core (multithread) mode, i.e. use all CPU cores in parallel, the software allows simultaneous reads and writes to a RAM location which corrupts the RAM, causing indeterminate values to be read. These are of course, interpreted as RAM errors, even though the RAM is sound.

I verified this by running Memtest86+ version 5.31b in multicore mode (default that shipped with Xubuntu 22.04) on my E5-2690v4 and E5-2697v3 based servers with DDR4 RAM. The Xubuntu Memtest86+ showed several RAM errors after 30min to 5hrs of running. Memtest86+ running one CPU round-robin showed no errors. Also, Memtest86 version 10.0 (a different vendor than Memtest86+) showed no errors in multicore mode running for 24hrs on both machines.
To users: DO NOT trust Memtest86+ multi-core mode. Use single-core mode only OR better use Memtest86 version 10.0 (latest version) and run that in parallel, multicore mode.

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https://bugs.launchpad.net/bugs/1876157

Title:
  Memtest86+ in Ubuntu 20.04 doesn't work, switch to Coreboot branch or
  package new release v5.31b is available since 12/04/2020

Status in memtest86+ package in Ubuntu:
  Fix Released
Status in memtest86+ source package in Focal:
  Confirmed
Status in memtest86+ package in Baltix:
  Triaged
Status in memtest86+ package in Debian:
  Fix Released

Bug description:
  Memtest in Ubuntu is very old, not updated since 2013, new Memtest86+
  release v5.31b is available at http://memtest.org , dated 12/04/2020

  *** Enhancements in v5.31b : ***
  I've started compiling many codes branches to release public builds again! Here is Memtest86+ 5.31b, with many bug fixes in the core functions.

  Also there is updated Memtest86+ branch at https://www.coreboot.org/Memtest86%2B - several people told, that this branch does work, where original Memtest 5.01 doesn't, see
  https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=943752

  ---- Original bugreport ----
  I ran it twice, and both times it hung at exactly 79% in the first test. Even fail safe mode hung exactly at that point.

  Then I booted with the floppy image from memtest86+-4.10.floppy.zip
  and it worked fine.

  Today I installed memtest86+_5.01-3ubuntu2_amd64.deb from Ubuntu 19.10
  and that worked fine too.

  The failing version is 5.01-3.1ubuntu1.

  Memory configuration is 2 * 2 GB (F2-6400CL5-2GBPQ) and 2 * 1 GB
  (OCZ2G8001G) working in dual channel mode. CPU is Harpertown Xeon
  X5470 running at stock speed (3.33 GHz).

  ProblemType: Bug
  DistroRelease: Ubuntu 20.04
  Package: memtest86+ 5.01-3.1ubuntu1
  ProcVersionSignature: Ubuntu 5.4.0-28.32-generic 5.4.30
  Uname: Linux 5.4.0-28-generic x86_64
  Architecture: amd64
  CasperMD5CheckResult: skip
  CurrentDesktop: XFCE
  Date: Thu Apr 30 13:51:01 2020
  SourcePackage: memtest86+
  UpgradeStatus: Upgraded to focal on 2020-04-06 (24 days ago)

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