Re: [Xen-devel] xenconsoled needs restart after long dom0 uptime otherwise domU console output hangs and domU doesn't come up

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Thu, Aug 14, 2008 at 02:22:10PM +0300, Pasi Kärkkäinen wrote:
> Hello list!
> 
> I've noticed this problem a couple of times now.. so I'm wondering if it's a
> known bug? 
> 
> Symptoms:
> 
> After "long" dom0 uptime (174 days when it happened now, was something
> similar on previous times too) cannot start new pv domUs anymore.. 
> pygrub runs and boots the kernel, but kernel newer gets to actually running 
> initrd
> and the console output hangs/stalls..
> 
> "xm console" output might look like this:
> 
> checking if image is initramfs... it is
> Freeing initrd memory: 12028k freed
> Grant table initialized
> NET: Registered protocol family 16
> SMP alternatives: switching to SMP code
> <hangs here, nothing happens anymore>
> 
> The point where it hangs might be a couple of lines earlier or later.. seems
> to change on almost every run..
> 
> "xm list" in dom0 shows the domU as "-b----" and the Time(s) stays at 1.9..
> after 8 hours of being hanged/stalled Time(s) was at 5.0 for that domU, but
> the console output had not changed, and the domU was still non-functional.
> 
> Already running domUs keep running fine when this happens.. 
> 
> Solution:
> 
> This problem gets fixed when you kill xenconsoled in dom0, and restart it. 
> After
> this new domUs can be started just fine, and everything works normally
> again. "xm console" works, initrd is executed, domU comes up OK, and you see
> the full console output.
> 
> I've seen this happening on dom0s running RHEL/CentOS 5.0 (Xen 3.0.3) and 
> RHEL/CentOS 5.1 (Xen 3.1.0). 
> 
> I just upgraded to 5.2 so can't tell (yet) if it happens with Xen 3.1.2.
> 
> I'm running 32bit x86 PAE, and the domU kernels in question are Debian etch
> 2.6.18-6-xen-686. I think it also happens RHEL/CentOS 5.x kernel-xen, but
> not totally sure about that. I think I also saw it with Fedora 8/9
> domU kernel-xen once.
> 
> Looks like a bug in xenconsoled.. 
> 

Oh, and I forgot to mention there's nothing unusual in "xm log", "xm dmesg" or
in dom0 /var/log/*. 

xenconsoled doesn't take 100% CPU or anything like that.. so it just
silently goes bad somehow. 

-- Pasi

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