From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755577Ab0CLAKG (ORCPT ); Thu, 11 Mar 2010 19:10:06 -0500 Received: from charlotte.tuxdriver.com ([70.61.120.58]:37459 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755405Ab0CLAKE (ORCPT ); Thu, 11 Mar 2010 19:10:04 -0500 From: nhorman@mail.tuxdriver.com To: "Andi Kleen" , "Neil Horman" Cc: "Mel Gorman" , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, "Andi Kleen" , "Paul E. McKenney" Date: Thu, 11 Mar 2010 19:09:35 -0500 User-Agent: LogicMail/1.0.4 Subject: Re: mmotm 2010-03-09-19-15: Lot of scheduling while atomic warnings related to RCU In-Reply-To: <20100311223048.GI20695@one.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: X-Spam-Score: -4.4 (----) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 11 Mar 2010 17:30:48 -0500, Andi Kleen wrote: > > a/lib/kobject_uevent.c~sysctl-fix-up-remaining-references-to-uevent_helper-fix > > +++ a/lib/kobject_uevent.c > > @@ -273,10 +273,11 @@ int kobject_uevent_env(struct kobject *k > > #endif > > > > /* call uevent_helper, usually only enabled during early boot */ > > + rcu_read_lock(); > > helper = rcu_dereference(uevent_helper); > > if (helper[0]) > > retval = uevent_call_helper(subsystem, env); > > - > > + rcu_read_unlock(); > > exit: > > The data actually has to be copied, there's a helper for this in rcustring. > I'll try to send a patch later. > > > loads/unloads while changing uevent_helper. Anywho, should be easy to fix, > > Mel, can you modify the code to copy helper to a private variable, then unlock > > the rcu read side prior to calling uevent_call_helper? I imagine that would be > > Yes, except rcustring already has a helper for that :) > Yes but the rcustring bits all got reverted, trashing my series :), so its all got to be rediffed anyway Neil > -Andi >