From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966180Ab0CPL2f (ORCPT ); Tue, 16 Mar 2010 07:28:35 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:44162 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966133Ab0CPL2d (ORCPT ); Tue, 16 Mar 2010 07:28:33 -0400 Date: Tue, 16 Mar 2010 12:28:22 +0100 From: Ingo Molnar To: Lai Jiangshan Cc: "Paul E. McKenney" , LKML Subject: Re: [PATCH -tip] rcu: local_irq_disable() also delimits RCU_SCHED read-site critical sections Message-ID: <20100316112822.GB5337@elte.hu> References: <4B9F66E1.2060309@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4B9F66E1.2060309@cn.fujitsu.com> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: 0.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=0.0 required=5.9 tests=none autolearn=no SpamAssassin version=3.2.5 _SUMMARY_ Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Lai Jiangshan wrote: > It is documented that local_irq_disable() also delimits > RCU_SCHED read-site critical sections. > See the document of synchronize_sched() or > Documentation/RCU/whatisRCU.txt. > > So we have to test irqs_disabled() in rcu_read_lock_sched_held(). > Otherwise rcu-lockdep brings incorrect complaint. It would be useful to include the warning in question in the changelog - so that others who might be affected by it can see the fix and can track its progress. (and dont start a parallel effort debugging/reporting/fixing it) Thanks, Ingo