[PATCH] Clean up subthread exec (CAN-2005-1913)

Make sure we re-parent itimers.  If subthread exec's with timer pending,
signal is delivered to old group-leader and can panic kernel.
Signed-off-by: Linus Torvalds <torvalds@ppc970.osdl.org>
Signed-off-by: Chris Wright <chrisw@osdl.org>

fs/exec.c

@@ -649,6 +649,7 @@ static inline int de_thread(struct task_struct *tsk)
 	}
 	sig->group_exit_task = NULL;
 	sig->notify_count = 0;
+	sig->real_timer.data = (unsigned long)current;
 	spin_unlock_irq(lock);
 
 	/*