Messages in this thread Patch in this message | | | Date | Fri, 13 Jan 2012 16:35:58 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] prctl: add PR_{SET,GET}_CHILD_SUBREAPER to allow simple process supervision |
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On Mon, 9 Jan 2012 16:07:01 +0100 Oleg Nesterov <oleg@redhat.com> wrote:
> > > + /* find the first ancestor marked as child_subreaper */ > > > + for (reaper = father->real_parent; > > > + reaper != &init_task; > > > + reaper = reaper->real_parent) { > > > > I admit being insufficiently caffienated - does this DTRT in a PID namespace? That > > &init_task looks fishy to me... > > Probably this needs a comment. Initially I was confused too. > > Note that the code below checks same_thread_group(reaper, pid_ns->child_reaper), > this is what we need to DTRT in a PID namespace. However we still need the > check above, see http://marc.info/?l=linux-kernel&m=131385460420380
In light of Kay's haughty silence, I did this:
--- a/kernel/exit.c~prctl-add-pr_setget_child_subreaper-to-allow-simple-process-supervision-fix-fix +++ a/kernel/exit.c @@ -724,7 +724,13 @@ static struct task_struct *find_new_reap } else if (father->signal->has_child_subreaper) { struct task_struct *reaper; - /* find the first ancestor marked as child_subreaper */ + /* + * Find the first ancestor marked as child_subreaper. + * Note that the code below checks same_thread_group(reaper, + * pid_ns->child_reaper). This is what we need to DTRT in a + * PID namespace. However we still need the check above, see + * http://marc.info/?l=linux-kernel&m=131385460420380 + */ for (reaper = father->real_parent; reaper != &init_task; reaper = reaper->real_parent) { _ I'm not a fan of URLs-in-comments, but that email was too gnarly to be condensed into a sane comment.
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