Bug 1432562
| Summary: | Memtest86+ reports false positive memory errors | ||||||||||
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| Product: | [Fedora] Fedora | Reporter: | Marc Muehlfeld <rh> | ||||||||
| Component: | memtest86+ | Assignee: | Jaroslav Škarvada <jskarvad> | ||||||||
| Status: | CLOSED EOL | QA Contact: | Fedora Extras Quality Assurance <extras-qa> | ||||||||
| Severity: | unspecified | Docs Contact: | |||||||||
| Priority: | unspecified | ||||||||||
| Version: | 25 | CC: | jskarvad, mmuehlfe | ||||||||
| Target Milestone: | --- | ||||||||||
| Target Release: | --- | ||||||||||
| Hardware: | x86_64 | ||||||||||
| OS: | Linux | ||||||||||
| Whiteboard: | |||||||||||
| Fixed In Version: | Doc Type: | If docs needed, set a value | |||||||||
| Doc Text: | Story Points: | --- | |||||||||
| Clone Of: | Environment: | ||||||||||
| Last Closed: | 2017-12-12 10:45:06 UTC | Type: | Bug | ||||||||
| Regression: | --- | Mount Type: | --- | ||||||||
| Documentation: | --- | CRM: | |||||||||
| Verified Versions: | Category: | --- | |||||||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||||||
| Embargoed: | |||||||||||
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Description
Marc Muehlfeld
2017-03-15 16:58:09 UTC
Created attachment 1263399 [details]
Screenshot
This is how it looks if I only run "test 7" and only on the reported area (0 - 1MB) for more than 10000 loops.
Created attachment 1263400 [details]
Screenshot with SMP disabled
If I disable SMP, no errors are reported (not even after 6400 passes).
This sounds like the same problem that was fixed in Passmark Memtest86. See #c0.
Thanks for info, but it seems like HW problem, from the Passmark release notes: --- It turned out the problem was more elusive that we expected. Basically when multiple threads are running the CPU registers get corrupted. They appear to spontaneously become corrupted during the test. Causing a flood of errors. People generally encountered the problem at Test #3 as this was the first test to use multi-threading. But the other tests had similar problems. We don't know if this is a CPU errata, a bug in the way multi-threading is setup, non maskable hardware interrupts messing up the CPU's state or something more subtle. Part of the problem is also that the available debugging techniques (as MemTest86 runs without having an operating system being loaded) are extremely basic. Debugging the code probably even worse than it was in the DOS3.3 days. So the work-around implemented was to change the default CPU selection mode to round robin. In this mode only one CPU is used at a time, but after each test the CPU in use is rotated. So all CPUs will still get used, but only after a longer period of time. --- If I understand it correctly the workaround consists in effectively turning multi-threaded test to single-threaded? Too bad. Unfortunately I do not have the affected HW so I cannot look onto it myself. Also if I am not mistaken the default running mode in Fedora is single core, so you shouldn't encounter the problem if you use the default mode. The SMP mode is still experimental and needs to be explicitly selected. This message is a reminder that Fedora 25 is nearing its end of life. Approximately 4 (four) weeks from now Fedora will stop maintaining and issuing updates for Fedora 25. It is Fedora's policy to close all bug reports from releases that are no longer maintained. At that time this bug will be closed as EOL if it remains open with a Fedora 'version' of '25'. Package Maintainer: If you wish for this bug to remain open because you plan to fix it in a currently maintained version, simply change the 'version' to a later Fedora version. Thank you for reporting this issue and we are sorry that we were not able to fix it before Fedora 25 is end of life. If you would still like to see this bug fixed and are able to reproduce it against a later version of Fedora, you are encouraged change the 'version' to a later Fedora version prior this bug is closed as described in the policy above. Although we aim to fix as many bugs as possible during every release's lifetime, sometimes those efforts are overtaken by events. Often a more recent Fedora release includes newer upstream software that fixes bugs or makes them obsolete. Fedora 25 changed to end-of-life (EOL) status on 2017-12-12. Fedora 25 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. If you are unable to reopen this bug, please file a new report against the current release. If you experience problems, please add a comment to this bug. Thank you for reporting this bug and we are sorry it could not be fixed. |