From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Jones Subject: Re: Re: [PATCH] blkfront: Move blkif_interrupt into a tasklet. Date: Fri, 24 Sep 2010 09:14:34 +0200 Message-ID: <4C9C4FDA.1070907@redhat.com> References: <1282546470-5547-1-git-send-email-daniel.stodden@citrix.com> <1282546470-5547-2-git-send-email-daniel.stodden@citrix.com> <4C802934.2000305@goop.org> <4C9B7B69.7080705@redhat.com> <4C9B7F1A.2040302@goop.org> <4C9B826B.10302@redhat.com> <4C9B9E1D.2040501@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4C9B9E1D.2040501@goop.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Jeremy Fitzhardinge Cc: Paolo Bonzini , Xen , Tom Kopec , Daniel Stodden List-Id: xen-devel@lists.xenproject.org On 09/23/2010 08:36 PM, Jeremy Fitzhardinge wrote: > On 09/23/2010 09:38 AM, Paolo Bonzini wrote: >> On 09/23/2010 06:23 PM, Jeremy Fitzhardinge wrote: >>>> Any developments with this? I've got a report of the exact same >>>> warnings >>>> on RHEL6 guest. See >>>> >>>> https://bugzilla.redhat.com/show_bug.cgi?id=632802 >>>> >>>> RHEL6 doesn't have the 'Move blkif_interrupt into a tasklet' patch, so >>>> that can be ruled out. Unfortunately I don't have this reproducing on a >>>> test machine, so it's difficult to debug. The report I have showed >>>> that >>>> in at least one case it occurred on boot up, right after initting the >>>> block device. I'm trying to get confirmation if that's always the case. >>>> >>>> Thanks in advance for any pointers you might have. >>> >>> Yes, I see it even after reverting that change as well. However I only >>> see it on my domain with an XFS filesystem, but I haven't dug any deeper >>> to see if that's relevant. >>> >>> Do you know when this appeared? Is it recent? What changes are in the >>> rhel6 kernel in question? >> >> It's got pretty much everything in stable-2.6.32.x, up to the 16 patch >> blkfront series you posted last July. There are some RHEL-specific >> workarounds for PV-on-HVM, but for PV domains everything matches >> upstream. > > Have you tried bisecting to see when this particular problem appeared? > It looks to me like something is accidentally re-enabling interrupts - > perhaps a stack overrun is corrupting the "flags" argument between a > spin_lock_irqsave()/restore pair. > Unfortunately I don't have a test machine where I can do a bisection (yet). I'm looking for one. I only have this one report so far, and it's on a production machine. > Is it only on 32-bit kernels? > This one report I have is a 32b guest on a 64b host. Drew