[lxc-users] debugging lxcfs?

[Serge Hallyn]

Quoting Fajar A. Nugraha (list at fajar.net):
> I'm having intermittent problem with lxcfs, used by vivid (with
> systemd-sysv installed) container. For example, just now "lxc-start -n
> -v" and "lxc-console -n v -t console" stuck on
> 
> [  OK  ] Reached target Basic System.
>          Starting System Logging Service...
> 
> "lxc-stop -k -n v" (from another terminal) hangs, and only returns
> after I run "pkill lxcfs".
> 
> After that "lxc-start -n -v" followed by "lxc-console -n v -t console"
> works normally (lxcfs was restarted automatically by upstart).
> 
> This has happened several times, although the point of hang is
> different each time. Sometimes it occurs during container start,
> sometimes it's during container shutdown. In all cases killing both
> lxcfs and the container allows the container to be restarted
> correctly.
> 
> Host is ubuntu 14.10, lxc 1.1.0+master~20150224-0137-0ubuntu1~utopic,
> lxcfs 0.6-0ubuntu1~ubuntu14.10.1~ppa1 from ppa:ubuntu-lxc/daily
> 
> Any ideas how to debug this problem?

Hi Fajar,

I'd stop the lxcfs upstart job and run it by hand under gdb.  Then
you should be able to debug it a bit when it next crashes.

-serge