In Docker version 17.12.0-ce when using --device=/dev/snd in docker run the devices are mounted owned by root but in group audio - this can be seen by doing ls -al /dev/snd in a container that uses --device=/dev/snd.

I've just upgraded to Docker version 17.12.1-ce via my distro updater and my application has stopped working, upon investigation I noticed that when doing ls -al /dev/snd the devices have both owner and group as root, which is the most likely culprit. This was proved by execing into the container as uid 0 and manually doing chown root:audio * in /dev/snd

Don't know if other devices are affected by this though I'd be surprised if it was just /dev/snd