[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

[Bernd Edlinger]

Hi,

I am also affected by this problem.  It is an overflow check
using undefined behavior in an overflow check in test.c
that looks like "if (pe + SPINSZ > pe && pe != 0)"
but with >4G memory pe + SIINSZ wraps around.

I think the most simple fix would be the following:

2020-12-15  Bernd Edlinger  <bernd.edlinger at hotmail.de>

        * Makefile: Use -fwrapv-pointer for test.c.

diff -u memtest86+-5.01.orig/Makefile memtest86+-5.01/Makefile
--- memtest86+-5.01.orig/Makefile	2020-12-15 06:50:42.000000000 +0100
+++ memtest86+-5.01/Makefile	2020-12-15 06:54:08.941390803 +0100
@@ -58,7 +58,8 @@
 	$(CC) -c $(CFLAGS) -fno-strict-aliasing reloc.c
 
 test.o: test.c
-	$(CC) -c -Wall -march=i486 -m32 -O0 -fomit-frame-pointer -fno-builtin -ffreestanding test.c
+	$(CC) -c -Wall -march=i486 -m32 -O0 -fomit-frame-pointer -fno-builtin \
+	-ffreestanding -fwrapv-pointer test.c
 
 random.o: random.c
 	$(CC) -c -Wall -march=i486 -m32 -O3 -fomit-frame-pointer -fno-builtin -ffreestanding random.c


** Patch added: "bug-fix for >4G memory"
   https://bugs.launchpad.net/ubuntu/+source/memtest86+/+bug/1876157/+attachment/5443714/+files/memtest.diff

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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:
  Confirmed
Status in memtest86+ package in Baltix:
  Triaged
Status in memtest86+ package in Debian:
  Confirmed

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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