From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 115B7C433E6 for ; Tue, 1 Sep 2020 20:58:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D3C83207D3 for ; Tue, 1 Sep 2020 20:58:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727927AbgIAU6A (ORCPT ); Tue, 1 Sep 2020 16:58:00 -0400 Received: from foss.arm.com ([217.140.110.172]:50462 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727788AbgIAU6A (ORCPT ); Tue, 1 Sep 2020 16:58:00 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 50D011063; Tue, 1 Sep 2020 13:57:59 -0700 (PDT) Received: from localhost (e108754-lin.cambridge.arm.com [10.1.199.49]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E72AA3F66F; Tue, 1 Sep 2020 13:57:58 -0700 (PDT) Date: Tue, 1 Sep 2020 21:57:57 +0100 From: Ionela Voinescu To: Viresh Kumar Cc: rjw@rjwysocki.net, dietmar.eggemann@arm.com, catalin.marinas@arm.com, sudeep.holla@arm.com, will@kernel.org, valentin.schneider@arm.com, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 1/5] arch_topology: validate input frequencies to arch_set_freq_scale() Message-ID: <20200901205757.GA31302@arm.com> References: <20200828173303.11939-1-ionela.voinescu@arm.com> <20200828173303.11939-2-ionela.voinescu@arm.com> <20200831111308.h5j652dnpgys2doe@vireshk-i7> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200831111308.h5j652dnpgys2doe@vireshk-i7> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Hi Viresh, On Monday 31 Aug 2020 at 16:43:08 (+0530), Viresh Kumar wrote: > On 28-08-20, 18:32, Ionela Voinescu wrote: > > The current frequency passed to arch_set_freq_scale() could end up > > being 0, signaling an error in setting a new frequency. Also, if the > > maximum frequency in 0, this will result in a division by 0 error. > > > > Therefore, validate these input values before using them for the > > setting of the frequency scale factor. > > > > Signed-off-by: Ionela Voinescu > > Cc: Sudeep Holla > > Cc: Rafael J. Wysocki > > --- > > drivers/base/arch_topology.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c > > index 75f72d684294..5708eb724790 100644 > > --- a/drivers/base/arch_topology.c > > +++ b/drivers/base/arch_topology.c > > @@ -33,6 +33,11 @@ void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq, > > unsigned long scale; > > int i; > > > > + if (unlikely(!cur_freq || !max_freq)) { > > + WARN_ON_ONCE(1); > > + return; > > + } > > This can be written as: > > if (WARN_ON_ONCE(!cur_freq || !max_freq)) > return; Yes, that's better. I've pushed v5 with this and your Acked-by. Thanks for all your reviews, Ionela. > > With that. > > Acked-by: Viresh Kumar > > > + > > /* > > * If the use of counters for FIE is enabled, just return as we don't > > * want to update the scale factor with information from CPUFREQ. > > -- > > 2.17.1 > > -- > viresh