Bug 222520

Summary: PIT handler wrongly registered to dom0
Product: Red Hat Enterprise Linux 5 Reporter: Herbert Xu <herbert.xu>
Component: kernel-xenAssignee: Rik van Riel <riel>
Status: CLOSED CURRENTRELEASE QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: 5.0CC: dzickus, lawrence.newitt, xen-maint
Target Milestone: ---Keywords: Regression
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: 5.0.0 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2007-01-26 21:32:00 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:
Attachments:
Description Flags
Register PIT handlers to the correct domain none

Description Herbert Xu 2007-01-13 04:15:04 UTC 
Due to an early patch (backport of upstream changeset 13028), the PIT handlers
for HVM guests ended up getting registered to dom0.  This causes two problems:

1) The HVM guest doesn't work because there is no PIT IO handler.
2) dom0 eventually dies because all its IO handler slots are consumed (there are
only 8 to start with).

This is a reduced version of upstream changeset 12243 that fixes the problem.
Comment 1 Herbert Xu 2007-01-13 04:15:04 UTC 
Created attachment 145517 [details]
Register PIT handlers to the correct domain
Comment 4 Jay Turner 2007-01-15 15:25:22 UTC 
QE ack for RHEL5 and setting the proposed blocker flags, as there's really no
way to ship without fixing this.
Comment 6 Don Zickus 2007-01-16 21:38:31 UTC 
in 2.6.18-2.el5
Comment 7 Jan Pazdziora 2007-01-17 10:49:42 UTC 
Is this patch supposed to have some effect on paravirtualized guests? I've seen
my dom0 reboot occasionally since upgrading to 2.6.18-1.3002.el5xen, and with
2.6.18-2.el5xen I had no crashes yet, but I wonder if it's just luck or if the
code could have fixed paravirt as well.
Comment 8 Herbert Xu 2007-01-17 11:24:48 UTC 
Yes it does affect PV as well, albeit partially.  It doesn't prevent PV guests
from functioning (although the PIT handler won't be completely functional).  The
part where dom0's IO handlers fill up definitely will occur for all guests
regardless of whether they're PV or FV.
Comment 9 Daniel Berrangé 2007-01-18 21:47:38 UTC 
*** Bug 223264 has been marked as a duplicate of this bug. ***
Comment 10 Jan Pazdziora 2007-01-22 10:52:59 UTC 
Herbert, thanks. The 2.6.18-2.el5xen is definitely more stable for PV then
2.6.18-1.3002.el5xen.
Comment 11 Jay Turner 2007-01-26 21:32:00 UTC 
2.6.18-7.el5 included in 20070125.0.