[Devel] [RFC][PATCH] Add child reaper to struct pspace

[Eric W. Biederman]

Sukadev Bhattiprolu <sukadev at us.ibm.com> writes:

> Cedric Le Goater [clg at fr.ibm.com] wrote:
> | 
> | <snip>
> | 
> | >   */
> | >  static void
> | > forget_original_parent(struct task_struct *father, struct list_head
> *to_release)
> | > @@ -669,7 +670,7 @@ forget_original_parent(struct task_struc
> | >  	do {
> | >  		reaper = next_thread(reaper);
> | >  		if (reaper == father) {
> | > -			reaper = child_reaper;
> | > +			reaper = father->pspace->child_reaper;
> | >  			break;
> | >  		}
> | >  	} while (reaper->exit_state);
> | > @@ -857,7 +858,7 @@ fastcall NORET_TYPE void do_exit(long co
> | 
> | what about killing all the task in that pid space if child_reaper == init
> | dies ?
> | 
>
> We probably need that for instance when a process in the parent pspace 
> kills the init of a child pspace, we should destroy the child pspace
> by killing all the tasks in the child pspace including the child reaper.
>
> I guess we need to maintain a list of task_structs in the pspace and walk
> that list. Will work on that as a separate patch.

Yes.  We all so need something like that list to support kill -1.
Although walking the list of all processes may be sufficient for a first
pass.

The real trick is handing nested pid namespaces, properly.

Eric