Bug 472523 - AMD: Panic if cpu_khz is incorrect
AMD: Panic if cpu_khz is incorrect
Product: Red Hat Enterprise Linux 5
Classification: Red Hat
Component: kernel (Show other bugs)
x86_64 Linux
high Severity medium
: rc
: ---
Assigned To: Prarit Bhargava
Red Hat Kernel QE team
Depends On:
Blocks: 483701 485920
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Reported: 2008-11-21 09:22 EST by Prarit Bhargava
Modified: 2009-09-03 09:46 EDT (History)
6 users (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2009-09-02 04:33:53 EDT
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
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oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)
RHEL5 fix for this issue (990 bytes, patch)
2008-11-24 08:50 EST, Prarit Bhargava
no flags Details | Diff

  None (edit)
Description Prarit Bhargava 2008-11-21 09:22:19 EST
Description of problem:

After code inspection it was discovered that new(ish) AMD processors could boot with an incorrect value for cpu_khz.  This in turn leads to an incorrect value for tsc_khz which then leads to significant problems on the system.

Version-Release number of selected component (if applicable): -124.el5

How reproducible: > 1% of the time

Additional info: The code in question was modified in 467782.  With the new code if a perfctr cannot be reserved the code simply uses PERFCTR3 -- even if it is busy.

If it is busy, the result for cpu_khz is questionable.

In this case we should simply panic() and output a message to the user to reboot because of a HW error.

I have pushed a patch upstream http://marc.info/?l=linux-kernel&m=122651496115998&w=2
which outputs a printk warning to the user.

In the Enterprise space, however, I think we should panic.
Comment 1 Prarit Bhargava 2008-11-24 08:50:05 EST
Created attachment 324472 [details]
RHEL5 fix for this issue
Comment 2 RHEL Product and Program Management 2009-02-11 05:10:09 EST
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update
Comment 3 RHEL Product and Program Management 2009-02-16 10:06:03 EST
Updating PM score.
Comment 5 Don Zickus 2009-04-06 17:16:54 EDT
in kernel-2.6.18-138.el5
You can download this test kernel from http://people.redhat.com/dzickus/el5

Please do NOT transition this bugzilla state to VERIFIED until our QE team
has sent specific instructions indicating when to do so.  However feel free
to provide a comment indicating that this fix has been verified.
Comment 10 Caspar Zhang 2009-08-06 01:18:15 EDT
I've tested it in the old kernel, I record the bogomips value of cpuinfo, then restart the machine. I tested for 314 times and all of the bogomips value are between 4400 to 4500 except one(it's 4332).

Then I tested it in the new kernel(160.el5), I tested for 334 times and no abnormal bogomips value appeared. I'll keep the machine running to try to produce an incorrect value.

I leave this bug ON_QA and do code review to the patch.
Comment 12 errata-xmlrpc 2009-09-02 04:33:53 EDT
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.


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