title: Docker on CentOS 7.2: kernel:unregister_netdevice: waiting for lo to become free. Usage count = 1
body: <p>I'm running Docker on CentOS 7, from time to time there's the following message displayed:</p>
  
  <pre><code>Message from syslogd@dev-master at Mar 29 17:23:03 ...
    kernel:unregister_netdevice: waiting for lo to become free. Usage count = 1
  </code></pre>
  
  <p>I've googled a lot, read a lot of resources found and tried many ways like keeping my system updated, upgrading kernel etc, but the message still keeps showing up, it's not too often but sooner or later I'll see it. Also I found <a href="https://github.com/docker/docker/issues/5618" rel="noreferrer">issue for this problem on docker github</a> is still open, then my questions are:</p>
  
  <ol>
  <li>What does this message mean? Could somebody give me a simple explanation why docker causes it?</li>
  <li>Is there any workaround for this?</li>
  <li>If it could not be fixed yet(the issue is still open), will it affect the server or services running inside docker container? Will it be a serious performance issue because it also happens on our production servers? </li>
  </ol>
  
  <p>Docker version:</p>
  
  <pre><code>Client:
   Version:      1.11.1
   API version:  1.23
   Go version:   go1.5.4
   Git commit:   5604cbe
   Built:        Wed Apr 27 00:34:42 2016
   OS/Arch:      linux/amd64
  
  Server:
   Version:      1.11.1
   API version:  1.23
   Go version:   go1.5.4
   Git commit:   5604cbe
   Built:        Wed Apr 27 00:34:42 2016
   OS/Arch:      linux/amd64
  </code></pre>
  
  <p>OS info: </p>
  
  <pre><code>CentOS 7, with kernel version: 4.6.0-1.el7.elrepo.x86_64
  </code></pre>
  
  <p>I really appreciate for any info/tips or resources, thanks a lot. </p>