I tried  fc3c7f7f6e9d8adfc4be943160e4ef902436a25d but the problem is still there. When I mount cgroups to /cgroup/lxc I just get an extra lxc in the path:

Mounted on /cgroup:
lxc-attach: No such file or directory - failed to open '/cgroup//lxc/lxc/imunes/tasks'

Mounted on /cgroup/lxc
lxc-attach: No such file or directory - failed to open '/cgroup/lxc//lxc/lxc/imunes/tasks

On Fri, Mar 16, 2012 at 10:33 AM, Goran Cetusic <goran.cetusic@gmail.com> wrote:
f9d0d2cbbf401ffb74c251e75581174d91a02cfc

This should be the latest from git://lxc.git.sourceforge.net/gitroot/lxc/lxc

On Thu, Mar 15, 2012 at 8:38 PM, Serge Hallyn <serge.hallyn@canonical.com> wrote:
Quoting Goran Cetusic (goran.cetusic@gmail.com):
> Where does lxc-attach get its path for the tasks file?
> I created a rootfs and configfile with the lxc-debian script in /lxc/imunes
> and started the container with lxc-start -n imunes -f /lxc/imunes/config.
> It works but I can't execute anything because of a wrong filepath:
>
> # lxc-attach -n imunes /bin/bash
> lxc-attach: No such file or directory - failed to open
> '/cgroup//lxc/lxc/imunes/tasks'
>
> The tasks file is in /cgroup/lxc/imunes/tasks - there's an extra /lxc
> there, how do i remove it?
> I applied the patches to enable lxc-attach but am unable to test it.

Which source are you using?

Can you confirm that you have commit fc3c7f7f6e9d8adfc4be943160e4ef902436a25d?
This sounds like the same thing it was fixing, and AFAICS lxc-attach doesn't
do it's own cgroup parsing, so it should've fixed that.

thanks,
-serge