Note: This bug is displayed in read-only format because the product is no longer active in Red Hat Bugzilla.
For bugs related to Red Hat Enterprise Linux 5 product line. The current stable release is 5.10. For Red Hat Enterprise Linux 6 and above, please visit Red Hat JIRA https://issues.redhat.com/secure/CreateIssue!default.jspa?pid=12332745 to report new issues.

Bug 472523

Summary: AMD: Panic if cpu_khz is incorrect
Product: Red Hat Enterprise Linux 5 Reporter: Prarit Bhargava <prarit>
Component: kernelAssignee: Prarit Bhargava <prarit>
Status: CLOSED ERRATA QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: medium Docs Contact:
Priority: high    
Version: 5.4CC: czhang, dzickus, hdong, kzhang, peterm, woodard
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2009-09-02 08:33:53 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 483701, 485920    
Attachments:
Description Flags
RHEL5 fix for this issue none

Description Prarit Bhargava 2008-11-21 14:22:19 UTC 
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 13:50:05 UTC 
Created attachment 324472 [details]
RHEL5 fix for this issue
Comment 2 RHEL Program Management 2009-02-11 10:10:09 UTC 
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
release.
Comment 3 RHEL Program Management 2009-02-16 15:06:03 UTC 
Updating PM score.
Comment 5 Don Zickus 2009-04-06 21:16:54 UTC 
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 05:18:15 UTC 
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 08:33:53 UTC 
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.

http://rhn.redhat.com/errata/RHSA-2009-1243.html