From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: [PATCH] blkfront: Move blkif_interrupt into a tasklet. Date: Thu, 23 Sep 2010 11:36:13 -0700 Message-ID: <4C9B9E1D.2040501@goop.org> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4C9B826B.10302@redhat.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Paolo Bonzini Cc: Andrew Jones , Xen , Tom Kopec , Daniel Stodden List-Id: xen-devel@lists.xenproject.org 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. Is it only on 32-bit kernels? J