Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758914AbXIRTny (ORCPT ); Tue, 18 Sep 2007 15:43:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753938AbXIRTnq (ORCPT ); Tue, 18 Sep 2007 15:43:46 -0400 Received: from canuck.infradead.org ([209.217.80.40]:34629 "EHLO canuck.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755469AbXIRTnp (ORCPT ); Tue, 18 Sep 2007 15:43:45 -0400 Date: Tue, 18 Sep 2007 21:41:52 +0200 From: Peter Zijlstra To: paulmck@linux.vnet.ibm.com Cc: Andrew Morton , Nadia Derbey , Alexey Dobriyan , linux-kernel@vger.kernel.org, Ingo Molnar Subject: Re: 2.6.23-rc6-mm1: IPC: sleeping function called ... Message-ID: <20070918214152.3698a787@lappy> In-Reply-To: <20070918182924.GF8665@linux.vnet.ibm.com> References: <20070918091728.GA6766@localhost.sw.ru> <20070918031723.05689e92.akpm@linux-foundation.org> <46EFA8DC.2020909@bull.net> <20070918033400.495b02dd.akpm@linux-foundation.org> <20070918142451.418b3b51@twins> <20070918161337.GC8665@linux.vnet.ibm.com> <20070918095715.05899d12.akpm@linux-foundation.org> <20070918182924.GF8665@linux.vnet.ibm.com> X-Mailer: Claws Mail 3.0.0 (GTK+ 2.11.6; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1431 Lines: 34 On Tue, 18 Sep 2007 11:29:24 -0700 "Paul E. McKenney" wrote: > On Tue, Sep 18, 2007 at 09:57:15AM -0700, Andrew Morton wrote: > > On Tue, 18 Sep 2007 09:13:37 -0700 "Paul E. McKenney" wrote: > > > > > On Tue, Sep 18, 2007 at 02:24:51PM +0200, Peter Zijlstra wrote: > > > > On Tue, 18 Sep 2007 03:34:00 -0700 Andrew Morton > > > > wrote: > > > > > > > > > Well, it was an optimisation. spin_lock() implies rcu_read_lock(). That's > > > > > a bit dirty and we might choose to not do that. > > > > > > > > Not true for the preemptible-rcu work. All such sites should be fixed, > > > > or at the very least heavily annotated. > > > > > > What he said!!! > > > > > > > What he said! > > > > How are you going to find all such sites? > > A first step would be to look for patches in -rt that add rcu_read_lock() > or friends. A second step would be to look for rcu_dereference() without > an enclosing rcu_read_lock(), rcu_read_lock_bh(), or preempt_disable(). I could perhaps do that with that rcu_read_lock lockdep annotation. If I add a check for holding rcu_read_lock in rcu_dereference(). - 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/