+ /* Become a process group leader with the old leader's pid.
+ * Note: The old leader also uses thispid until release_task
+ * is called. Odd but simple and correct.
+ */
+ detach_pid(current, PIDTYPE_PID);
+ current->pid = leader->pid;
+ attach_pid(current, PIDTYPE_PID, current->pid);
+ attach_pid(current, PIDTYPE_PGID, current->signal->pgrp);
+ attach_pid(current, PIDTYPE_SID, current->signal->session);
+ list_add_tail_rcu(¤t->tasks, &init_task.tasks);