Re: [PATCH 1/1] cr: define CHECKPOINT_SUBTREE flag and sysctl

[Nathan Lynch <ntl-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>]

"Serge E. Hallyn" <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org> writes:
> Quoting Nathan Lynch (ntl-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org):
>> "Serge E. Hallyn" <serge-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org> writes:
>> > Now it's possible that at the *start* of the checkpoint there was
>> > another task, not being checkpointed and not frozen, in the utsns,
>> > and it exited before the leaks check took place.
>> 
>> [Please excuse the obtuse queries below]
>> 
>> In which case the check would fail, yes?  Can this scenario actually
>> occur?  I'm of the understanding that a container must be frozen before
>> proceeding with checkpoint.  If that's correct, how could a task in the
>> container exit in the meantime?
>
> Heh, because there is no such thing as a 'container'.  There is a set of
> tasks in the same freezer control group, and it's possible that there is
> a task not in that cgroup which is in the same utsname as the rest of
> the tasks in that freezer cgroup.

Sigh, I had somehow forgotten these basic facts temporarily.  Sorry for
the noise; thanks for your patient explanations.