Re: [RFC][PATCH 7/7][v2] Define clone_with_pids syscall

[Sukadev Bhattiprolu <sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>]

Oren Laadan [orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org] wrote:
| 
| 
| Sukadev Bhattiprolu wrote:
| > Sukadev Bhattiprolu [sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org] wrote:
| > | Oren Laadan [orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org] wrote:
| > 
| > I am not sure what the semantics should be for this case:
| > 
| > 	- checkpoint a process that is in level-3 pid namespace
| > 	- restart in a level-2 or level-1 pid namespace
| > 
| 
| Meaning: a container root was at level-3, so tasks in the container
| were level-3 through level-(3+N), where N is the in-container depth
| so to speak. Then it was restarted such that the base became level-2
| or level-1.
| 
| I think we already covered this.
| 

Sorry, I meant level3 not 'level minus 3' :-) Restating, suppose
init_pid_ns is L0, and L3 is a pid namespace 3 levels deep (i.e the
process has 4 pids at checkpoint time). When restarting, if the
process only needs 2 pids bc it is L1, current behavior is to return
-EINVAL. 

I have this check in copy_target_pids():

+       if (num_pids < 0 || num_pids > nesting)
+               return ERR_PTR(-EINVAL);

Is it ok to return -EINVAL when num_pids > nesting ?