Bug 592021 - race condition in pvclock wallclock calculation
race condition in pvclock wallclock calculation
Status: CLOSED ERRATA
Product: Red Hat Enterprise Linux 5
Classification: Red Hat
Component: kvm (Show other bugs)
5.5
All Linux
urgent Severity urgent
: rc
: ---
Assigned To: Glauber Costa
Virtualization Bugs
: ZStream
Depends On:
Blocks: Rhel5KvmTier2 592033 596623 596625
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Reported: 2010-05-13 13:31 EDT by Glauber Costa
Modified: 2013-01-09 17:34 EST (History)
6 users (show)

See Also:
Fixed In Version: kvm-83-182.el5
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
: 592033 (view as bug list)
Environment:
Last Closed: 2011-01-13 18:35:32 EST
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
CRM:
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---


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Description Glauber Costa 2010-05-13 13:31:33 EDT
The hypervisor code for wallclock setting in pvclock is subject to race, since the version variable is static, and thus, shared among all guests.

This means that theoretically, one guest can mess up with the others view of version, causing it to be different among reads, which can lead to a livelock.
Comment 12 Mike Cao 2010-11-03 22:57:30 EDT
Verify this issue on :
# uname -r
2.6.18-229.el5
# rpm -q kvm
kvm-83-207.el5

steps:,start 7 guest on 8cores host with -no-kvm-pit-reinjection  -rtc-td-hack -startdate now

actual results:all guests didn't observe large offset(all less than 3s) after boot,pass.

this issue has already been fixed.
Comment 15 errata-xmlrpc 2011-01-13 18:35:32 EST
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-2011-0028.html

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