Comment 12 for bug 1173372

This is a bug in the package bcmwl-kernel-source (6.30.223.141+bdcom-0ubuntu2)
It still affects the latest Ubuntu. It causes an endless loop where the package won't complete installation and apt won't do anything without the package completing. The solution is as follows(credit goes to another poster)

The command that appears to be hanging is:
"modprobe -wl"
If you open another terminal and do:
"ps aux | grep modprobe"
you will see the hung process and can eliminate it using
kill -9 <processid>

Anyway, the offending package should have a timeout tied to that modprobe command.