[CRIU] lxc - cgroup related restore error

[Tycho Andersen]

On Wed, Jul 13, 2016 at 05:17:24PM +0200, Adrian Reber wrote:
> On Wed, Jul 13, 2016 at 08:27:42AM -0600, Tycho Andersen wrote:
> > On Wed, Jul 13, 2016 at 12:49:07PM +0200, Adrian Reber wrote:
> > > On Wed, Jul 13, 2016 at 01:41:34PM +0300, Cyrill Gorcunov wrote:
> > > > On Wed, Jul 13, 2016 at 12:29:01PM +0200, Adrian Reber wrote:
> > > > > 
> > > > > If I am trying to migrate a process while a LXC container is running on
> > > > > the source system the migration fails during restore on the destination
> > > > > system with:
> > > > > 
> > > > > Error (cgroup.c:1193): cg: Failed writing 0-3 to cpuset//lxc/c7/cpuset.cpus: Numerical result out of range
> > > > > Error (cgroup.c:1470): cg: Restoring special cpuset props failed!
> > > > > 
> > > > > This happens with CRIU 2.3 and latest GIT.
> > > > > 
> > > > > If I am running a LXC container on the destination system I still get
> > > > > this error. If I am stopping the LXC container on the source system the
> > > > > error disappears. This is again on a RHEL7 system with a 3.10.something
> > > > > kernel.
> > > > 
> > > > Looks like you're migratin into machine with less number of cpus?
> > > 
> > > Yes, that's true. Haven't checked that before. I am using two virtual
> > > machines and it seems like I have forgotten that I changed the specs.
> > > 
> > > But as the migration works when LXC is stopped it would be nice to have
> > > it working with LXC running. Migrating the container from one system to
> > > another also works without errors. Only migrating a process unrelated to
> > > the LXC container does not work.
> > 
> > Sorry, I'm not sure I understand this paragraph. What does it mean to
> > migrate when LXC is stopped?
> 
> I meant, I cannot migrate a process when a LXC container is running as I
> get the cgroup error from above. When no LXC container is running the
> cgroup error does not happen. More understandable now?

Hmm. So is the LXC container contained in the process's subtree? What
cpuset cgroup is it in (cat /proc/pid/cgroup for the task you're
trying to migrate)?

Tycho