show_task: real_parent

The show_task function invoked by sysrq-t et al displays the
pid and parent's pid of each task.  It seems more useful to
show the actual process hierarchy here than who is using
ptrace on each process.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/sched.c

@@ -4918,7 +4918,7 @@ static void show_task(struct task_struct *p)
 	}
 #endif
 	printk(KERN_CONT "%5lu %5d %6d\n", free,
-		task_pid_nr(p), task_pid_nr(p->parent));
+		task_pid_nr(p), task_pid_nr(p->real_parent));
 
 	if (state != TASK_RUNNING)
 		show_stack(p, NULL);