Comment 1 for bug 1845506

Hi Dominique,
isn't that the same as I outlined on [1] ?

In case you think it is related could you for a check open /etc/apparmor.d/usr.lib.libvirt.virt-aa-helper and remove the deny lines from /dev/sd to /dev/mapper; then reload via `sudo apparmor_parser -r /etc/apparmor.d/usr.lib.libvirt.virt-aa-helper` and try again.

And if it is not the same, there I definitely did "snapshot of one disk with guests having multiple disks" there. So you might take a look what differs.
From a glimpse at your command I did none,none,none,snap,none while you try to snapshot two at once.

In case the above didn't help, could you attach a guest XML so that I can recreate a similar case?

[1]: https://bugs.launchpad.net/ubuntu/+source/apparmor/+bug/1525310/comments/2