[PATCH] fix ->signal->live leak in copy_process()

exit_signal() (called from copy_process's error path) should decrement
->signal->live, otherwise forking process will miss 'group_dead' in
do_exit().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/signal.c

@@ -406,6 +406,8 @@ void __exit_signal(struct task_struct *tsk)
 
 void exit_signal(struct task_struct *tsk)
 {
+	atomic_dec(&tsk->signal->live);
+
 	write_lock_irq(&tasklist_lock);
 	__exit_signal(tsk);
 	write_unlock_irq(&tasklist_lock);