Comment 0 for bug 1222407

With the following 2 packages installed on a precise base

ii linux-image-3.11.0-5-generic 3.11.0-5.11 Linux kernel image for version 3.11.0 on 64 bit x86 SMP
ii linux-image-extra-3.11.0-5-generic 3.11.0-5.11 Linux kernel extra modules for version 3.11.0 on 64 bit x86 SMP

Trying to "modprobe aufs", results in the following error
[ 92.358229] aufs au_loopback_init:136:modprobe[2104]: loop_backing_file() is not defined

The aufs dev team replied here. This is probably fixed by now in the aufs patchset
http://<email address hidden>/msg04337.html

Kindly rebuild with a working aufs module