Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756319Ab2B1Uxx (ORCPT ); Tue, 28 Feb 2012 15:53:53 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:46881 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755033Ab2B1Uxv (ORCPT ); Tue, 28 Feb 2012 15:53:51 -0500 From: "Rafael J. Wysocki" To: paulmck@linux.vnet.ibm.com, lenb@kernel.org Subject: Re: [PATCH RFC] acpi: Fix unprotected smp_processor_id() in acpi_processor_cst_has_changed() Date: Tue, 28 Feb 2012 21:57:53 +0100 User-Agent: KMail/1.13.6 (Linux/3.3.0-rc5+; KDE/4.6.0; x86_64; ; ) Cc: Yong Zhang , deepthi@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org References: <20120223205805.GA31838@linux.vnet.ibm.com> <20120228071943.GE1112@zhy> <20120228133013.GE2465@linux.vnet.ibm.com> In-Reply-To: <20120228133013.GE2465@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201202282157.53804.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2699 Lines: 72 On Tuesday, February 28, 2012, Paul E. McKenney wrote: > On Tue, Feb 28, 2012 at 03:19:43PM +0800, Yong Zhang wrote: > > On Thu, Feb 23, 2012 at 12:58:05PM -0800, Paul E. McKenney wrote: > > > The acpi_processor_cst_has_changed() function is invoked from a > > > CPU_ONLINE or CPU_DEAD function, which might well execute on CPU 0 > > > even though the CPU being hotplugged is some other CPU. In addition, > > > acpi_processor_cst_has_changed() invokes smp_processor_id() without > > > protection, resulting in splats when onlining CPUs. > > > > > > This commit therefore changes the smp_processor_id() to pr->id, as is > > > used elsewhere in the code, for example, in acpi_processor_add(). > > > > > > This works for me, but I don't claim to understand ACPI. > > > > > > Signed-off-by: Paul E. McKenney > > > > Got the same warning. > > And the patch works on my side. > > > > Tested-by: Yong Zhang > > Thank you, I have added your Tested-by (and Srivatsa's Reviewed-by, > for that matter). > > Any takers for this, or should I just push it up the -tip tree? I think this patch is for Len, either through ACPI, or through the idle tree. Len? Anyway: Acked-by: Rafael J. Wysocki Thanks, Rafael > > > diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c > > > index 0e8e2de..9e57b06 100644 > > > --- a/drivers/acpi/processor_idle.c > > > +++ b/drivers/acpi/processor_idle.c > > > @@ -1159,8 +1159,7 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr) > > > * to make the code that updates C-States be called once. > > > */ > > > > > > - if (smp_processor_id() == 0 && > > > - cpuidle_get_driver() == &acpi_idle_driver) { > > > + if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) { > > > > > > cpuidle_pause_and_lock(); > > > /* Protect against cpu-hotplug */ > > > > > > -- > > > 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/ > > > > -- > 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/ > > -- 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/