Bug 1907082

Summary: msr: Write to unrecognized MSR 0x49 by perl
Product: [Fedora] Fedora Reporter: Knut J BJuland <knutjbj>
Component: kernelAssignee: Kernel Maintainer List <kernel-maint>
Status: CLOSED NOTABUG QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: urgent Docs Contact:
Priority: unspecified    
Version: 33CC: acaringi, adscvr, airlied, bskeggs, georgios, hdegoede, itamar, jarodwilson, jeremy, jglisse, jonathan, josef, kernel-maint, lgoncalv, linville, masami256, mchehab, ptalbert, redhat, steved
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Target Release: ---   
Hardware: x86_64   
OS: Linux   
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Last Closed: 2021-04-20 21:07:21 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Knut J BJuland 2020-12-12 21:17:01 UTC
Description of problem:
 msr: Write to unrecognized MSR 0x49 by perl




Version-Release number of selected component (if applicable):
Linux knut 5.9.13-200.fc33.x86_64 #1 SMP Tue Dec 8 15:42:52 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux


How reproducible:
every time 

Steps to Reproduce:
1. start system
2. se in dmesg
3.

Actual results:

 Please report to x86
[24388.843824] msr: Write to unrecognized MSR 0x49 by perl
               Please report to x86
[24388.846210] msr: Write to unrecognized MSR 0x49 by perl
               Please report to x86
[24388.848557] msr: Write to unrecognized MSR 0x49 by perl
               Please report to x86
[24388.850886] msr: Write to unrecognized MSR 0x49 by perl
               Please report to x86
[24388.853237] msr: Write to unrecognized MSR 0x49 by perl
               Please report to x86
[24388.855569] msr: Write to unrecognized MSR 0x49 by perl
               Please report to x86
[24388.857872] msr: Write to unrecognized MSR 0x49 by perl
               Please report to x86
[24388.860237] msr: Write to unrecognized MSR 0x49 by perl
               Please report to x86
[24388.862585] msr: Write to unrecognized MSR 0x49 by perl
               Please report to x86


Expected results:
It should not be there

Additional info:

Comment 1 George B. Magklaras 2020-12-20 07:29:55 UTC
Yeah, I see this in my Fedora 33 (Linux 5.9 kernel) with Perl. I think the Linux 5.9 kernel is trying to filter now all the direct access to Machine Specific Registers (MSRs) from userland. Have not straced exactly what the Perl interpreter is doing in the background, in my case it's cruncing mostly a MariaDB database with DBI. You should be able to regulate dmesg noise by using the kernel msr.allow_writes=on/off/default boot time parameter. Does it work for you?

GM

Comment 2 Knut J BJuland 2021-04-20 21:07:21 UTC
Close it is not a a bug it cause by spectre-meltdown-checker