maybe related to #32827 (comment)

Occasionally a specific container gets stuck and can't be killed, or anything. I have no idea how I could further debug it. My setup is a docker (18.06.1-ce) + docker-stack (with only a single node) running inside a KVM guest. (all with linux 4.9.0-8-amd64, debian 9.5).

I have created a gist with:

1. docker info
2. stack trace produced with curl --unix-socket /var/run/docker.sock http://./debug/pprof/goroutine?debug=2
3. what I found in the system logs by search for the container ID:
   https://gist.github.com/hpoul/36409758905057bd3e44ede787291050

Unfortunately I have not yet figured out in which condition this happens. It is very sporadic (every week or so) - since it's "kind of" a production server for me, I can't keep it stuck but have to restart it. So for debugging the "stuck" state I can only do so every few days. - The only reliable way to "fix" it is to restart the whole server. Just restarting the docker daemon doesn't do anything either.

@cpuguy83 if you could let me know if there is anything more I could provide. let me know, thanks