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Bug 601090

Summary: time drift due to incorrect accounting of lost ticks with VXTIME_PMTMR mode and VXTIME_TSC mode if 'tick_divider' > 1 [rhel-5.5.z]
Product: Red Hat Enterprise Linux 5 Reporter: RHEL Program Management <pm-rhel>
Component: kernelAssignee: Jiri Pirko <jpirko>
Status: CLOSED ERRATA QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: medium Docs Contact:
Priority: urgent    
Version: 5.4.zCC: dhoward, gcosta, jpirko, jwest, mjenner, pm-eus, rkhan, tburke, uobergfe, wquan
Target Milestone: rcKeywords: ZStream
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
The timer_interrupt() routine did not scale lost real ticks to logical ticks correctly. This could have caused time drift for 64-bit Red Hat Enterprise Linux 5: KVM (Kernel-based Virtual Machine) guests that were booted with the "divider=x" kernel parameter set to a value greater than 1. "warning: many lost ticks" messages may have been logged on the affected guest systems.
Story Points: ---
Clone Of: Environment:
Last Closed: 2010-07-01 18:29:00 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: 579711    
Bug Blocks:    

Description RHEL Program Management 2010-06-07 08:00:43 UTC
This bug has been copied from bug #579711 and has been proposed
to be backported to 5.5 z-stream (EUS).

Comment 3 Jiri Pirko 2010-06-07 13:31:30 UTC
in 2.6.18-194.6.1.el5

Comment 8 Douglas Silas 2010-06-28 20:53:45 UTC
Technical note added. If any revisions are required, please edit the "Technical Notes" field
accordingly. All revisions will be proofread by the Engineering Content Services team.

New Contents:
The timer_interrupt() routine did not scale lost real ticks to logical ticks correctly. This could have caused time drift for 64-bit Red Hat Enterprise Linux 5: KVM (Kernel-based Virtual Machine) guests that were booted with the "divider=x" kernel parameter set to a value greater than 1. "warning: many lost ticks" messages may have been logged on the affected guest systems.

Comment 10 errata-xmlrpc 2010-07-01 18:29:00 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-2010-0504.html