[Pkg-xen-devel] Bug#617421: Bug#617421: xen-hypervisor-4.0-i386: can't migrate (or save/resume) lenny guests: BUG: recent printk recursion

[Thomas Goirand]

On 03/09/2011 03:41 AM, Ferenc Wagner wrote:
> Hi,
> 
> Take the following config file (standard lenny kernel and initrd, with
> some customization for iSCSI root):
> 
> name = "lenny3"
> kernel = "vmlinuz-2.6.26-2-686-bigmem"
> ramdisk = "initrd.img-2.6.26-2-686-bigmem"
> memory = 100
> vcpus = 1
> vif = [ 'mac=00:16:3e:00:00:17, bridge=br695, vifname=lenny3.alma-g' ]
> extra = "break=top"
> on_poweroff = 'destroy'
> on_reboot   = 'restart'
> on_crash    = 'restart'
> 
> Start the domain:
> 
> xm create -c lenny3.conf
> [...]
> (initramfs)
> 
>>From another terminal, save the guest:
> 
> xm save lenny3 /tmp/lenny3.save
> 
> The guest console says: Suspending xenbus... and detaches.
> 
> Restore the guest (paused to attach its console before continuing):
> 
> xm restore -p /tmp/lenny3.save
> xm console lenny3
> xm unpause lenny3
> 
> The console starts spewing out "BUG: recent printk recursion" and the
> domain spins until destroyed.  The same thing happens on (live or not)
> migration.  The very same domains could be migrated without issues under
> Xen 3.2 (more precisely, before I upgraded my dom0 to squeeze --
> previously it was running lenny with the etch dom0 kernel for stability).
> 
> Migrating squeeze guests isn't a problem in the same setup (just replace
> 26-2 with 32-5 in the above config).
> 
> This looks like a regression.  On the other hand, it doesn't seem to
> affect a lot of people, because I couldn't find anything relevant on the
> web.  Please tell me if I can help debugging the issue further.

Kernel 2.6.26 are designed for Xen 3, and 2.6.32 are for Xen 4. I'm not
really surprised with the result you have here, and I don't think you
can expect to have it fixed. Why don't you simply use kernel 2.6.32 for
your Lenny VMs? It does work well, even with a Lenny userland.

Thomas