}
/*
- * When we die, we re-parent all our children.
- * Try to give them to another thread in our thread
- * group, and if no such member exists, give it to
- * the child reaper process (ie "init") in our pid
- * space.
+ * When we die, we re-parent all our children, and try to:
+ * 1. give them to another thread in our thread group, if such a member exists
+ * 2. give it to the first ancestor process which prctl'd itself as a
+ * child_subreaper for its children (like a service manager)
+ * 3. give it to the init process (PID 1) in our pid namespace
*/
static struct task_struct *find_new_reaper(struct task_struct *father)
__releases(&tasklist_lock)
* forget_original_parent() must move them somewhere.
*/
pid_ns->child_reaper = init_pid_ns.child_reaper;
+ } else if (father->signal->has_child_subreaper) {
+ struct task_struct *reaper;
+
+ /*
+ * 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) {
+ if (same_thread_group(reaper, pid_ns->child_reaper))
+ break;
+ if (!reaper->signal->is_child_subreaper)
+ continue;
+ thread = reaper;
+ do {
+ if (!(thread->flags & PF_EXITING))
+ return reaper;
+ } while_each_thread(reaper, thread);
+ }
}
return pid_ns->child_reaper;