From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756358Ab0DOTsF (ORCPT ); Thu, 15 Apr 2010 15:48:05 -0400 Received: from e7.ny.us.ibm.com ([32.97.182.137]:35633 "EHLO e7.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756107Ab0DOTsB (ORCPT ); Thu, 15 Apr 2010 15:48:01 -0400 Date: Thu, 15 Apr 2010 12:47:58 -0700 From: "Paul E. McKenney" To: Frederic Weisbecker Cc: Lai Jiangshan , David Miller , a.p.zijlstra@chello.nl, mingo@elte.hu, sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: Weird rcu lockdep warning Message-ID: <20100415194758.GQ2471@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20100413234043.GG2538@linux.vnet.ibm.com> <20100414000226.GH5602@nowhere> <20100413.171306.25868761.davem@davemloft.net> <20100414014930.GI2538@linux.vnet.ibm.com> <4BC537C9.8050600@cn.fujitsu.com> <20100414154302.GC2516@linux.vnet.ibm.com> <20100414155110.GG5142@nowhere> <20100414160057.GD2516@linux.vnet.ibm.com> <20100415042426.GA4254@linux.vnet.ibm.com> <20100415185702.GC5069@nowhere> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100415185702.GC5069@nowhere> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 15, 2010 at 08:57:05PM +0200, Frederic Weisbecker wrote: > On Wed, Apr 14, 2010 at 09:24:26PM -0700, Paul E. McKenney wrote: > > On Wed, Apr 14, 2010 at 09:00:57AM -0700, Paul E. McKenney wrote: > > > On Wed, Apr 14, 2010 at 05:51:11PM +0200, Frederic Weisbecker wrote: > > > > [ . . .] > > > > > > Note I just tested the patch the previous one and it looks fine now. > > > > You can then safely consider the "general idea" fixes the problem :) > > > > > > Thank you, Frederic!!! > > > > And here is what I hope is the official fix. > > > > Could you please test it? > > > > Thanx, Paul > > > > ------------------------------------------------------------------------ > > > > commit 9be39c445a41e458d53cf9a57d25dbfa4b74c970 > > Author: Paul E. McKenney > > Date: Tue Apr 13 18:45:51 2010 -0700 > > > > rcu: Make RCU lockdep check the lockdep_recursion variable > > > > The lockdep facility temporarily disables lockdep checking by incrementing > > the current->lockdep_recursion variable. Such disabling happens in NMIs > > and in other situations where lockdep might expect to recurse on itself. > > This patch therefore checks current->lockdep_recursion, disabling RCU > > lockdep splats when this variable is non-zero. In addition, this patch > > removes the "likely()", as suggested by Lai Jiangshan. > > > > Reported-by: Frederic Weisbecker > > Reported-by: David Miller > > Signed-off-by: Paul E. McKenney > > Tested-by: Frederic Weisbecker Thank you, Frederic! Thanx, Paul