title: Docker bind mount directory in /tmp not working
body: <p>I'm trying to mount a directory in /tmp to a directory in a container, namely /test. To do this, I've run:</p>
  <p><code>docker run --rm -it -v /tmp/tmpl42ydir5/:/test alpine:latest ls /test</code></p>
  <p>I expect to see a few files when I do this, but instead I see nothing at all.</p>
  <p>I tried moving the folder into my home directory and running again:</p>
  <p><code>docker run --rm -it -v /home/theolodus/tmpl42ydir5/:/test alpine:latest ls /test</code></p>
  <p>at which point I see the expected output. This makes me thing I have mis-configured something and/or the permissions have bitten me. Have I missed a step in installing docker? I did it via <code>sudo snap install docker</code>, and then configured docker to let me run as non-root by adding myself to the docker group. Running as root doesn't help...</p>
  <p>Host machine is Ubuntu 20.04, docker version is 19.03.11</p>