Comment 4 for bug 436253

(Right, do not know why I filed it on n-m). FYI, I tried rerunning /etc/init.d/apparmor but it did not help. It also seems like the /etc/network/if-pre-up/dhclient-apparmor script runs fine. I suspect problems dealing with union file systems. I remember seeing a workaround for something sounding similar in a changelog.