Re: [Xen-devel] Instability with Xen, interrupt routing frozen, HPET broadcast

[Andreas Kinzler <ml-xen-devel@xxxxxx>]

On 21.09.2010 13:56, Pasi Kärkkäinen wrote:
> >   I am talking a while (via email) with Jan now to track the following
> > problem and he suggested that I report the problem on xen-devel:
> >
> > Jul  9 01:48:04 virt kernel: aacraid: Host adapter reset request. SCSI
> > hang ?
> > Jul  9 01:49:05 virt kernel: aacraid: SCSI bus appears hung
> > Jul  9 01:49:10 virt kernel: Calling adapter init
> > Jul  9 01:49:49 virt kernel: IRQ 16/aacraid: IRQF_DISABLED is not
> > guaranteed on shared IRQs
> > Jul  9 01:49:49 virt kernel: Acquiring adapter information
> > Jul  9 01:49:49 virt kernel: update_interval=30:00 check_interval=86400s
> > Jul  9 01:53:13 virt kernel: aacraid: aac_fib_send: first asynchronous
> > command timed out.
> > Jul  9 01:53:13 virt kernel: Usually a result of a PCI interrupt routing
> > problem;
> > Jul  9 01:53:13 virt kernel: update mother board BIOS or consider
> > utilizing one of
> > Jul  9 01:53:13 virt kernel: the SAFE mode kernel options (acpi, apic etc)
> >
> > After the VMs have been running a while the aacraid driver reports a
> > non-responding RAID controller. Most of the time the NIC is also no
> > longer working.
> > I nearly tried every combination of dom0 kernel (pvops0, xenfied suse
> > 2.6.31.x, xenfied suse 2.6.32.x, xenfied suse 2.6.34.x) with Xen
> > hypervisor 3.4.2, 3.4.4-cs19986, 4.0.1, unstable.
> > No success in two month. Every combination earlier or later had the
> > problem shown above. I did extensive tests to make sure that the
> > hardware is OK. And it is - I am sure it is a Xen/dom0 problem.
> >
> > Jan suggested to try the fix in c/s 22051 but it did not help. My answer
> > to him:
> >
> > > In the meantime I did try xen-unstable c/s 22068 (contains staging c/s
> > 22051) and
> > > it did not fix the problem at all. I was able to fix a problem with
> > the serial console
> > > and so I got some debug info that is attached to this email. The
> > following line looks
> > > suspicious to me (irr=1, delivery_status=1):
> > > (XEN)     IRQ 16 Vec216:
> > > (XEN)       Apic 0x00, Pin 16: vector=216, delivery_mode=1,
> > dest_mode=logical,
> > >              delivery_status=1, polarity=1, irr=1, trigger=level,
> > mask=0, dest_id:1
> >
> > > IRQ 16 is the aacraid controller which after some while seems to be
> > enable to receive
> > > interrupts. Can you see from the debug info what is going on?
> > I also applied a small patch which disables HPET broadcast. The machine
> > is now running
> > for 110 hours without a crash while normally it crashes within a few
> > minutes. Is there
> > something wrong (race, deadlock) with HPET broadcasts in relation to
> > blocked interrupt
> > reception (see above)?
> What kind of hardware does this happen on?
It is a Supermicro X8SIL-F, Intel Xeon 3450 system.

> Should this patch be merged?
Not easy to answer. I spend more than 10 weeks searching nearly full 
time for the reason of the stability issues. Finally I was able to track 
it down to the HPET broadcast code.
We need to find the developer of the HPET broadcast code. Then, he 
should try to fix the code. I consider it a quite severe bug as it 
renders Xen nearly useless on affected systems. That is why I (and my 
boss who pays me) spend so much time (developing/fixing Xen is not 
really my core job) and money (buying a E5620 machine just for testing Xen).
I think many people on affected systems are having problems. See 
http://lists.xensource.com/archives/html/xen-users/2010-09/msg00370.html
Regards Andreas

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