Bug 725519

Summary:	revert of bug 716498 that causes x86_64 xen pv guest boot failure
Product:	Red Hat Enterprise Linux 6	Reporter:	Igor Mammedov <imammedo>
Component:	kernel	Assignee:	Andrew Jones <drjones>
Status:	CLOSED ERRATA	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	6.2	CC:	drjones, jzheng, leiwang, pbonzini, qwan, xen-maint
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	kernel-2.6.32-176.el6	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-12-06 13:54:15 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Bug Depends On:
Bug Blocks:	523122, 653816

Description Igor Mammedov 2011-07-25 18:37:24 UTC

Description of problem:

bug 716498 introduced a regression when booting x86_64 pv guest with
following xm config
-------------
maxmem = 4096
memory = 512
vcpus = 1
kernel = "mp2mkernel"
extra = "ignore_loglevel console=hvc0 "
on_poweroff = "destroy"
on_reboot = "restart"
on_crash = "preserve"
------------


Problem started to appear with usage of extend_brk in this patch-set.
In RHEL6 there is another commit that fixes guest boot failure by removing
usage of extend_brk 2d5f59f50.

Bisecting upstream doesn't help, a crash magically disappears on with unrelated
commit. Failing address is always the same however after adding extra debugging
code failing address changes to another constant. Looks like crash point
depends on the kernel size.

So far no know fix. Thus reopening this bug.
Version-Release number of selected component (if applicable):


How reproducible:
always

Additional info:
guest kernel 2.6.32-169

Comment 1 Igor Mammedov 2011-07-25 18:39:05 UTC

Patch range 1382eec..c5b979d for reverting.

Comment 3 Igor Mammedov 2011-07-25 18:48:01 UTC

If interested in crash logs check bug 716498.

Comment 4 Andrew Jones 2011-07-26 10:03:41 UTC

(In reply to comment #1)
> Patch range 1382eec..c5b979d for reverting.

We can keep

91ceeef [virt] Unset CONFIG_DEBUG_FORCE_WEAK_PER_CPU on x86/x86_64 platforms
8d641fc [virt] xen: bump memory limit for x86 domU PV guest to 128Gb

Which fix the incorrect config and bumps 32-bit PV guest memory.

Comment 5 RHEL Program Management 2011-07-26 10:20:14 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 6 Igor Mammedov 2011-07-26 13:59:40 UTC

(In reply to comment #4)
> (In reply to comment #1)
> > Patch range 1382eec..c5b979d for reverting.
> 
> We can keep
> 
> 91ceeef [virt] Unset CONFIG_DEBUG_FORCE_WEAK_PER_CPU on x86/x86_64 platforms
> 8d641fc [virt] xen: bump memory limit for x86 domU PV guest to 128Gb
> 
> Which fix the incorrect config and bumps 32-bit PV guest memory.

Yes sure, these patches shouldn't hurt.

Comment 7 Aristeu Rozanski 2011-08-02 13:59:08 UTC

Patch(es) available on kernel-2.6.32-176.el6

Comment 11 Jinxin Zheng 2011-09-02 08:01:09 UTC

Reproduced on kernel-2.6.32-169.el6.

The test step is simply xm create with the config in comment 0, with kernel replaced with "vmlinuz-2.6.32-169.el6.x86_64". xm console has nothing output. xm dmesg has the same crash info as comment 28 of bug 716498.

Verified on kernel -176 and -194, that the same crash info does not occur. They can output messages on the console, until crashed at 

VFS: Cannot open root device "(null)" or unknown-block(0,0)

which is expected.

Putting this to VERIFIED.

Comment 12 errata-xmlrpc 2011-12-06 13:54:15 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHSA-2011-1530.html