On Wed, Jul 15, 2020 at 2:55 PM Przemek Klosowski via devel <devel@xxxxxxxxxxxxxxxxxxxxxxx> wrote: > > On 7/15/20 1:11 PM, Chris Murphy wrote: > > Hi, > > > > While bad RAM is uncommon, it comes up with some regularity to cause > > folks a lot of grief. I'm wondering if there's a way to make it easier > > to get bad news :-\ In particular there are cases where RAM defects > > just don't show up with a few hours of memtest86+, it can take days of > > contiguous testing, which is so inconvenient the test itself seems > > worse. > > > > Here's what I've got so far: > > > > 1. Fedora includes /boot/memtest86+-5.01 on every installation. But this is a legacy/BIOS program. [..] > > 2. The kernel has a built-in memory tester. [..] > > 3. "memory interface test" used at Google,[..] > > 4. "multiple concurrent kernel compiles" > > There's also 5. memtester, http://pyropus.ca/software/memtester/ , > packaged in Fedora. It runs in userland, so obvously isn't as thorough > but I'd think it has got to better than gcc and other userland > utilities, because it tries the 'known-tricky' access patterns rather > than hoping to see them in compiler output. > > I remember the beginnings of memtest86+: its predecessor was written at > the SGI hardware division by folks who understood how e.g specific > access paterns appear on the physical traces on the memory modules, and > can lead to crosstalk, but only if you simulataneously and repeatedly > toggle very specific bits. This type of knowledge was essential to > writing good tests, and probably also to discovering vulnerabilites like > rowhammer. > > Have you looked at memtester? What do you think of it? I haven't. It might be useful to know what Michael Catanzaro thinks of it, before he goes off to buy and install ECC RAM! -- Chris Murphy _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx
