Comment 3 for bug 1659087

Interesting, I tried to reproduce with a Debian strech 4.8.0-2-amd64 (Debian 4.8.15-2) and 4.9.0-1-amd64 (Debian 4.9.2-2) and didn't hit the error.

This seems to be specific to tmpfs though, touching the file anywhere else yields the nobody:nogroup mapping.

Regarding my use-case, I'm creating the file in order to bind-mount on top of it. Container runtimes usually expose host files (e.g. char device) within containers similarly.