Comment 5 for bug 1615021

I've thought about this some more, and while the /bin/readlink /usr/bin/readlink in busybox is a bug, fixing this is definitely not going to fix the problem in the installer. In the installer, /etc/udev/rules.d/80-net-setup-link.rules will never exist since this is an admin override; so the readlink command - if it existed - would still return false. I'm reasonably sure the lack of /bin/readlink is not causing the udev rule to behave differently; so it's sufficient to fix this particular issue for 16.10 and later and not SRU it.

What is *more* of an issue is that the structure of /lib/udev/rules.d/73-usb-net-by-mac.rules causes a separate call out to readlink for every single udev event, because the readlink check happens *before* checking the ACTION/SUBSYSTEM/SUBSYSTEMS attributes of the event, unless net.ifnames=0 is set.

So regardless of whether this is the root cause of the install failure, this udev rule is causing hundreds of thousands of extra calls out to /bin/readlink on boot, which should definitely be fixed by reordering these checks.

Martin, can you please look into fixing this for xenial+yakkety?