Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762268AbYCWNDN (ORCPT ); Sun, 23 Mar 2008 09:03:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762030AbYCWNCS (ORCPT ); Sun, 23 Mar 2008 09:02:18 -0400 Received: from x346.tv-sign.ru ([89.108.83.215]:46061 "EHLO mail.screens.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761996AbYCWNCP (ORCPT ); Sun, 23 Mar 2008 09:02:15 -0400 Date: Sun, 23 Mar 2008 16:06:49 +0300 From: Oleg Nesterov To: Andrew Morton Cc: "Eric W. Biederman" , Pavel Emelyanov , Roland McGrath , linux-kernel@vger.kernel.org Subject: [PATCH 2/3] signals: de_thread: simplify the ->child_reaper switching Message-ID: <20080323130649.GA239@tv-sign.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1872 Lines: 56 Now that we rely on SIGNAL_UNKILLABLE flag, de_thread() doesn't need the nasty hack to kill the old ->child_reaper during the mt-exec. This also means we can avoid taking tasklist_lock around zap_other_threads(). Signed-off-by: Oleg Nesterov --- 25/fs/exec.c~2_EXEC_KILL_HACK 2008-03-03 17:01:36.000000000 +0300 +++ 25/fs/exec.c 2008-03-16 15:20:25.000000000 +0300 @@ -757,9 +757,7 @@ static int de_thread(struct task_struct /* * Kill all other threads in the thread group. - * We must hold tasklist_lock to call zap_other_threads. */ - read_lock(&tasklist_lock); spin_lock_irq(lock); if (signal_group_exit(sig)) { /* @@ -767,21 +765,10 @@ static int de_thread(struct task_struct * return so that the signal is processed. */ spin_unlock_irq(lock); - read_unlock(&tasklist_lock); return -EAGAIN; } - - /* - * child_reaper ignores SIGKILL, change it now. - * Reparenting needs write_lock on tasklist_lock, - * so it is safe to do it under read_lock. - */ - if (unlikely(tsk->group_leader == task_child_reaper(tsk))) - task_active_pid_ns(tsk)->child_reaper = tsk; - sig->group_exit_task = tsk; zap_other_threads(tsk); - read_unlock(&tasklist_lock); /* Account for the thread group leader hanging around: */ count = thread_group_leader(tsk) ? 1 : 2; @@ -812,6 +799,8 @@ static int de_thread(struct task_struct schedule(); } + if (unlikely(task_child_reaper(tsk) == leader)) + task_active_pid_ns(tsk)->child_reaper = tsk; /* * The only record we have of the real-time age of a * process, regardless of execs it's done, is start_time. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/