From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757124AbZECVQT (ORCPT ); Sun, 3 May 2009 17:16:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755862AbZECVQG (ORCPT ); Sun, 3 May 2009 17:16:06 -0400 Received: from mx2.redhat.com ([66.187.237.31]:33197 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754168AbZECVQD (ORCPT ); Sun, 3 May 2009 17:16:03 -0400 Date: Sun, 3 May 2009 23:11:18 +0200 From: Oleg Nesterov To: Andrew Morton , "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org Subject: [PATCH] rcu_sched_grace_period: kill the bogus flush_signals() Message-ID: <20090503211118.GA22973@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As a kernel thread, rcu_sched_grace_period() runs with all signals ignored. It can never receive a signal even if it sleeps in TASK_INTERRUPTIBLE, it needs the explicit allow_signal() to be visible for signals. Signed-off-by: Oleg Nesterov --- PTRACE/kernel/rcupreempt.c~ 2009-04-09 00:39:10.000000000 +0200 +++ PTRACE/kernel/rcupreempt.c 2009-05-03 02:17:11.000000000 +0200 @@ -1356,17 +1356,11 @@ static int rcu_sched_grace_period(void * rcu_ctrlblk.sched_sleep = rcu_sched_sleeping; spin_unlock_irqrestore(&rcu_ctrlblk.schedlock, flags); - ret = 0; + ret = 0; /* unused */ __wait_event_interruptible(rcu_ctrlblk.sched_wq, rcu_ctrlblk.sched_sleep != rcu_sched_sleeping, ret); - /* - * Signals would prevent us from sleeping, and we cannot - * do much with them in any case. So flush them. - */ - if (ret) - flush_signals(current); couldsleepnext = 0; } while (!kthread_should_stop());