WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] pv 2.6.31 (kernel.org) and save/migrate fails, domU BUG

To: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
Subject: Re: [Xen-devel] pv 2.6.31 (kernel.org) and save/migrate fails, domU BUG
From: Pasi Kärkkäinen <pasik@xxxxxx>
Date: Tue, 10 Nov 2009 12:08:06 +0200
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>, "Xen-Devel \(E-mail\)" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Tue, 10 Nov 2009 02:08:28 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <20091108172747.GR1434@xxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <20091108154153.GM1434@xxxxxxxxxxx> <693ea516-aa5b-4f82-ad48-1bd51cfa3480@default> <20091108172747.GR1434@xxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.13 (2006-08-11)
Hello,

Jeremy: Here's summary about these save/restore problems
using upstream Linux 2.6.31.5 PV guest.

For me:
        - I can "xm save" + "xm restore" UP guest, but I get non-fatal
          BUG in the guest kernel, see [1].
        - "xm save" fails for SMP guest with "failed to get the suspend evtchn 
port", see [2].

For Dan:
        - "xm save" works for UP guest, but "xm restore" doesn't, giving
          infinite xen_sched_clock related dumps in the guest kernel, see [3].
        - "xm save" for SMP guest fails, it never ends. I suspect this
          is the same problem I'm seeing.


[1] non-fatal BUG on the guest kernel after "xm restore":
http://pasik.reaktio.net/xen/debug/dmesg-2.6.31.5-122.fc12.x86_64-saverestore.txt

[2] "xm log" contains:
[2009-11-09 23:44:38 1353] DEBUG (XendCheckpoint:110) [xc_save]: 
/usr/lib64/xen/bin/xc_save 28 2 0 0 0
[2009-11-09 23:44:38 1353] INFO (XendCheckpoint:417) xc_save: failed to get the 
suspend evtchn port

[3] See the attachment in this email:
http://lists.xensource.com/archives/html/xen-devel/2009-11/msg00391.html


Any tips how to debug these? 

-- Pasi


On Sun, Nov 08, 2009 at 07:27:47PM +0200, Pasi Kärkkäinen wrote:
> On Sun, Nov 08, 2009 at 08:54:23AM -0800, Dan Magenheimer wrote:
> > > > Ok, so it appears there is something problematic with
> > > > saving an upstream kernel.  It might be (partially) fixed
> > > > in Fedora 12 or maybe there is some other environmental
> > > > difference which makes save fail entirely on my system.
> > > > 
> > > 
> > > Yeah, fedora kernel has some patches, but it should be pretty 
> > > close to upstream kernel..
> > > 
> > > btw was your guest UP or SMP? Mine was UP..
> > 
> > Mine was SMP... switching to UP I can now save.  BUT...
> > restore doesn't seem to quite work.  The restore completes
> > but I get no response from the VNC console.  When I
> > use a tty console, after restore, I am getting
> > an infinite dump of
> > 
> > WARNING: at arch/x86/time.c:180 xen_sched_clock+0x2b
> > 
> > (see attached).
> > 
> > Did you try restore on Fedora 12?
> >  
> 
> Yeah. save+restore for UP F12 guest works for me 
> (except I get that non-fatal BUG on the guest).
> 
> SMP guest doesn't work.. save crashes it.
> 
> > > > > > The results explain why I can get it to run on
> > > > > > one machine (an older laptop) and not run on another
> > > > > > machine (a Nehalem system)... looks like this is maybe
> > > > > > related to the cpuid-extended-topology-leaf bug that Jeremy
> > > > > > sent a fix for upstream recently.
> > > > > 
> > > > > Did you try with that patch applied? 
> > > > 
> > > > No, the patch wasn't posted, just a pull request to Linus,
> > > > so I don't have the patch (and am not a git expert so
> > > > am not sure how to get it).
> > > > 
> > > > http://lists.xensource.com/archives/html/xen-devel/2009-11/msg00182.html
> > > >
> > > > So I'll try it again when .6 or .7 is available.
> > > 
> > > See here for changelog:
> > > http://git.kernel.org/?p=linux/kernel/git/jeremy/xen.git;a=shortlog;h=bugfix
> > > 
> > > You can get the diffs/patches from there using the links..
> > 
> > Thanks.  Yes, Jeremy's patch allows 2.6.31.5 (in a PV domain)
> > to completely boot on my Nehalem box.
> 
> Ok. But I guess those doesn't help for the save+restore problem..
> 
> -- Pasi
> 


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>