libvirt users - Jan 2015 - Re: ubuntu virsh snapshot-create-as gives Error -22 while writing VM

Hello all, I'm trying to create an online internal snapshot to work with
Cuckoo Sandbox.
I keep receiving this -22 error below on my Ubuntu system and I'm out of
ideas, been at it for a while so any help is appreciated.

root@cuckoo-sec:~# virsh snapshot-create-as cuckoo cuckoo-snap1 "Cuckoo
Snapshot"
error: operation failed: Error -22 while writing VM

$ uname -a
Linux cuckoo-sec 3.13.0-24-generic #46-Ubuntu SMP Thu Apr 10 19:11:08 UTC
2014 x86_64 x86_64 x86_64 GNU/Linux

$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=14.04
DISTRIB_CODENAME=trusty
DISTRIB_DESCRIPTION="Ubuntu 14.04 LTS"

$ kvm --version
QEMU emulator version 2.0.0 (Debian 2.0.0+dfsg-2ubuntu1.9), Copyright (c)
2003-2008 Fabrice Bellard

$ libvirtd --version
libvirtd (libvirt) 1.2.2

$ qemu-img info /opt/kvm/Windows7-64.qcow2
image: /opt/kvm/Windows7-64.qcow2
file format: qcow2
virtual size: 25G (26843545600 bytes)
disk size: 12G
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false

$ virsh list
 Id    Name                           State
----------------------------------------------------
 17    cuckoo                         running

$ apt-get install apparmor-utils
$ aa-status
$ aa-complain /usr/sbin/libvirtd
$ aa-complain /etc/apparmor.d/libvirt/libvirt-bdfcd0d8-b032-6870-
79bf-c77e0a3c8590

$ strace virsh snapshot-create-as cuckoo cuckoo-snap1 "Cuckoo
Snapshot"
...
gettid()                                = 10168
futex(0x7f4726ab8240, FUTEX_WAKE_PRIVATE, 1) = 0
futex(0x7f4726ab8240, FUTEX_WAIT_PRIVATE, 2, NULL) = -1 EAGAIN (Resource
temporarily unavailable)
futex(0x7f4726ab8240, FUTEX_WAKE_PRIVATE, 1) = 0
gettid()                                = 10168
Thanks
-- 
Jon Schipp,
jonschipp.com, sickbits.net, opennsm.ncsa.illinois.edu

On 01/06/2015 02:03 PM, Jon Schipp wrote:
> Hello all, I'm trying to create an online internal snapshot to work
with
> Cuckoo Sandbox.
> I keep receiving this -22 error below on my Ubuntu system and I'm out
of
> ideas, been at it for a while so any help is appreciated.
> 
> root@cuckoo-sec:~# virsh snapshot-create-as cuckoo cuckoo-snap1
"Cuckoo
> Snapshot"
> error: operation failed: Error -22 while writing VM
That message comes from qemu (file a bug report with them for
poor-quality error message; looks like someone forgot to convert a
negative value back into a positive EINVAL errno value).

As for why qemu is seeing an EINVAL, I have to wonder if it is a case of
AppArmor blocking access to a file.  But that's weird, as internal
snapshots don't normally need to open any additional files.  At any
rate, it's more likely to be a qemu bug than a libvirt one.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

There was no entry in kern.log for AppArmor. Thanks I'll look at the qemu
lists.

On Tue, Jan 6, 2015 at 3:27 PM, Eric Blake <eblake@redhat.com> wrote:
> On 01/06/2015 02:03 PM, Jon Schipp wrote:
> > Hello all, I'm trying to create an online internal snapshot to
work with
> > Cuckoo Sandbox.
> > I keep receiving this -22 error below on my Ubuntu system and I'm
out of
> > ideas, been at it for a while so any help is appreciated.
> >
> > root@cuckoo-sec:~# virsh snapshot-create-as cuckoo cuckoo-snap1
"Cuckoo
> > Snapshot"
> > error: operation failed: Error -22 while writing VM
>
> That message comes from qemu (file a bug report with them for
> poor-quality error message; looks like someone forgot to convert a
> negative value back into a positive EINVAL errno value).
>
> As for why qemu is seeing an EINVAL, I have to wonder if it is a case of
> AppArmor blocking access to a file.  But that's weird, as internal
> snapshots don't normally need to open any additional files.  At any
> rate, it's more likely to be a qemu bug than a libvirt one.
>
> --
> Eric Blake   eblake redhat com    +1-919-301-3266
> Libvirt virtualization library http://libvirt.org
>
>

-- 
Jon Schipp,
jonschipp.com, sickbits.net, opennsm.ncsa.illinois.edu