From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754620Ab0EPWUX (ORCPT ); Sun, 16 May 2010 18:20:23 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:34535 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754494Ab0EPWUV (ORCPT ); Sun, 16 May 2010 18:20:21 -0400 From: "Rafael J. Wysocki" To: markgross@thegnar.org Subject: Re: [patch] pm_qos update fixing mmotm 2010-05-11 -dies in pm_qos_update_request() Date: Mon, 17 May 2010 00:21:25 +0200 User-Agent: KMail/1.12.4 (Linux/2.6.34-rc7-rjw; KDE/4.3.5; x86_64; ; ) Cc: Valdis.Kletnieks@vt.eu, mgross@linux.intel.com, akpm@linux-foundation.org, davem@davemloft.net, linux-kernel@vger.kernel.org, e1000-devel@lists.sourceforge.net, netdev@vger.kernel.org, linux-pm@lists.linux-foundation.org References: <20100515021922.GA5041@thegnar.org> <201005152138.47178.rjw@sisk.pl> <20100515214256.GA3506@thegnar.org> In-Reply-To: <20100515214256.GA3506@thegnar.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201005170021.25427.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Saturday 15 May 2010, mgross wrote: > On Sat, May 15, 2010 at 09:38:47PM +0200, Rafael J. Wysocki wrote: > > On Saturday 15 May 2010, mgross wrote: > > > I apologize for the goofy email address. > > > > > > The following is a fix for the crash reported by Valdis. > > > > > > The problem was that the original pm_qos silently fails when a request > > > update is passed to a parameter that has not been added to the list > > > yet. It seems that the e1000e is doing this. This update restores this > > > behavior. > > > > > > I need to think about how to better handle such abuse, but for now this > > > restores the original behavior. > > > > Can you please post a signed-off incremental patch against > > > > git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6.git for-llinus > > > > that contains your original PM QOS update? > > No problem: > > Signed-off-by: markgross Thanks! Do you want to use this address for the sign-off or the Intel one? Rafael > From 487b8dcaeb66d3c226d4c06c1bd99689f93024be Mon Sep 17 00:00:00 2001 > From: mgross > Date: Sat, 15 May 2010 14:30:15 -0700 > Subject: [PATCH] Gard against pm_qos users calling API before registering a proper > request. > > This update handles a use case where pm_qos update requests need to > silently fail if the update is being sent to a handle that is null. > > The problem was that the original pm_qos silently fails when a request > update is passed to a parameter that has not been added to the list yet. > This update restores that behavior. > > Signed-off-by: markgross > > --- > kernel/pm_qos_params.c | 26 ++++++++++++++------------ > 1 files changed, 14 insertions(+), 12 deletions(-) > > diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c > index a1aea04..f42d3f7 100644 > --- a/kernel/pm_qos_params.c > +++ b/kernel/pm_qos_params.c > @@ -252,19 +252,21 @@ void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req, > int pending_update = 0; > s32 temp; > > - spin_lock_irqsave(&pm_qos_lock, flags); > - if (new_value == PM_QOS_DEFAULT_VALUE) > - temp = pm_qos_array[pm_qos_req->pm_qos_class]->default_value; > - else > - temp = new_value; > - > - if (temp != pm_qos_req->value) { > - pending_update = 1; > - pm_qos_req->value = temp; > + if (pm_qos_req) { /*guard against callers passing in null */ > + spin_lock_irqsave(&pm_qos_lock, flags); > + if (new_value == PM_QOS_DEFAULT_VALUE) > + temp = pm_qos_array[pm_qos_req->pm_qos_class]->default_value; > + else > + temp = new_value; > + > + if (temp != pm_qos_req->value) { > + pending_update = 1; > + pm_qos_req->value = temp; > + } > + spin_unlock_irqrestore(&pm_qos_lock, flags); > + if (pending_update) > + update_target(pm_qos_req->pm_qos_class); > } > - spin_unlock_irqrestore(&pm_qos_lock, flags); > - if (pending_update) > - update_target(pm_qos_req->pm_qos_class); > } > EXPORT_SYMBOL_GPL(pm_qos_update_request); > >