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.
Created attachment 324472 [details] RHEL5 fix for this issue
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.
Updating PM score.
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.
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.
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