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] Domain 0 stop response on frequently reboot VMS

On Sun, 2010-10-24 at 01:48 -0400, MaoXiaoyun wrote:
> Hi Daniel:
>  
>      Sorry for tht late response, and really thanks for your kindly
> suggestion.
>      Well, I believe we will upgrade to the lastest kernel in the
> coming future, but currently 
> we perfer to maintain for stable reason.
>  
>     Our kernel version is 2.6.31. Now I am going through the change
> set of blktap to get 
> more detail info. 

NP. Let me know if you have questions.

Daniel

>    thanks.
>  
> > Subject: RE: [Xen-devel] Domain 0 stop response on frequently reboot
> VMS
> > From: daniel.stodden@xxxxxxxxxx
> > To: tinnycloud@xxxxxxxxxxx; jeremy@xxxxxxxx
> > CC: keir@xxxxxxx; xen-devel@xxxxxxxxxxxxxxxxxxx
> > Date: Mon, 18 Oct 2010 14:17:50 -0700
> > 
> > 
> > I'd strongly suggest to try upgrading your kernel, or at least the
> > blktap component. The condition below is new to me, but that
> wait_queue
> > file and some related code was known to be buggy and has long since
> been
> > removed.
> > 
> > If you choose to only upgrade blktap from tip, let me know what
> kernel
> > version you're dealing with, you might need to backport some of the
> > device queue macros to match your version's needs.
> > 
> > Daniel
> > 
> > 
> > On Sat, 2010-10-16 at 01:39 -0400, MaoXiaoyun wrote:
> > > Well, Thanks Keir.
> > > Fortunately we caught the bug, it turned out to be a tapdisk
> problem. 
> > > A brief explaination for other guys might confront this issue.
> > > 
> > > Clear BLKTAP_DEFERRED on line 19 will lead to the concurrent
> access
> > > of 
> > > tap->deferred_queue between line 24 and 37, which will finally
> cause
> > > bad 
> > > pointer of tap->deferred_queue, and infinte loop in while clause
> in
> > > line 22.
> > > Lock line 24 will be a simple fix. 
> > > 
> > > /linux-2.6-pvops.git/drivers/xen/blktap/wait_queue.c
> > > 9 void
> > > 10 blktap_run_deferred(void)
> > > 11 {
> > > 12 LIST_HEAD(queue);
> > > 13 struct blktap *tap;
> > > 14 unsigned long flags;
> > > 15 
> > > 16 spin_lock_irqsave(&deferred_work_lock, flags);
> > > 17 list_splice_init(&deferred_work_queue, &queue);
> > > 18 list_for_each_entry(tap, &queue, deferred_queue)
> > > 19 clear_bit(BLKTAP_DEFERRED, &tap->dev_inuse);
> > > 20 spin_unlock_irqrestore(&deferred_work_lock, flags);
> > > 21 
> > > 22 while (!list_empty(&queue)) {
> > > 23 tap = list_entry(queue.next, struct blktap,
> > > deferred_queue);
> > > 24 &nb sp; list_del_init(&tap->deferred_queue);
> > > 25 blktap_device_restart(tap);
> > > 26 } 
> > > 27 } 
> > > 28 
> > > 29 void
> > > 30 blktap_defer(struct blktap *tap)
> > > 31 {
> > > 32 unsigned long flags;
> > > 33 
> > > 34 spin_lock_irqsave(&deferred_work_lock, flags);
> > > 35 if (!test_bit(BLKTAP_DEFERRED, &tap->dev_inuse)) {
> > > 36 set_bit(BLKTAP_DEFERRED, &tap->dev_inuse);
> > > 37 list_add_tail(&tap->deferred_queue, &deferred_work_queue);
> > > 38 } 
> > > 39 spin_unlock_irqrestore(&deferred_work_lock, f lags);
> > > 40 } 
> > > 
> > > 
> > > > Date: Fri, 15 Oct 2010 13:57:09 +0100
> > > > Subject: Re: [Xen-devel] Domain 0 stop response on frequently
> reboot
> > > VMS
> > > > From: keir@xxxxxxx
> > > > To: tinnycloud@xxxxxxxxxxx; xen-devel@xxxxxxxxxxxxxxxxxxx
> > > > 
> > > > You'll probably want to see if you can get SysRq output from
> dom0
> > > via serial
> > > > line. It's likely you can if it is alive enough to respond to
> ping.
> > > This
> > > > might tell you things like what all processes are getting
> blocked
> > > on, and
> > > > thus indicate what is stopping dom0 from making progress.
> > > > 
> > > > -- Keir
> > > > 
> > > > On 15/10/2010 13:43, "MaoXiaoyun" <tinnycloud@xxxxxxxxxxx>
> wrote:
> > > > 
> > > > > 
> > > > > Hi Keir:
> > > > > 
> > > > > First, I'd like to express my appreciation for the help your
> > > offered
> > > > > before.
> > > > > Well, recently we confront a rather nasty domain 0 no response
> > > > > problem.
> > > > > 
> > > > > We still have 12 HVMs almost continuously and con currently
> reboot
> > > > > test on a physical server.
> > > > > A few hours later, the server looks like dead. We only can
> ping to
> > > > > the server and get right response,
> > > > > the Xen works fine since we can get debug info from serial
> port.
> > > Attached is
> > > > > the full debug output.
> > > > > After decode the domain 0 CPU stack, I find the CPU still
> works
> > > for domain 0
> > > > > since the stack changed
> > > > > info changed every time I dumped.
> > > > > 
> > > > > Could help to take a look at the attentchment to see whether
> there
> > > are
> > > > > some hints for debugging this
> > > > > problem. Thanks in advance.
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > _______________________________________________
> > > > > Xen-devel mailing list
> > > > > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > > > > http://lists.xensource.com/xen-devel
> > > > 
> > > > 
> > 
> > 



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