From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752414AbcISSyV (ORCPT ); Mon, 19 Sep 2016 14:54:21 -0400 Received: from mail-it0-f48.google.com ([209.85.214.48]:38288 "EHLO mail-it0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751387AbcISSyT (ORCPT ); Mon, 19 Sep 2016 14:54:19 -0400 Reply-To: ahs3@redhat.com Subject: Re: [PATCH] cpufreq: CPPC: Avoid overflow when calculating desired_perf References: <1473894508-22270-1-git-send-email-hotran@apm.com> <2037077.Sk8HnobN5X@vostro.rjw.lan> To: Hoan Tran , "Rafael J. Wysocki" Cc: Viresh Kumar , Prashanth Prakash , linux-pm@vger.kernel.org, lkml , Loc Ho , Duc Dang From: Al Stone Organization: Red Hat, Inc. Message-ID: Date: Mon, 19 Sep 2016 12:54:14 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/14/2016 09:06 PM, Hoan Tran wrote: > Hi Rafael, > > On Wed, Sep 14, 2016 at 5:50 PM, Rafael J. Wysocki wrote: >> On Wednesday, September 14, 2016 04:08:28 PM Hoan Tran wrote: >>> This patch fixes overflow issue when calculating the desired_perf. >>> >>> Signed-off-by: Hoan Tran >>> --- >>> drivers/cpufreq/cppc_cpufreq.c | 3 ++- >>> 1 file changed, 2 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c >>> index 894e465..3e0961e 100644 >>> --- a/drivers/cpufreq/cppc_cpufreq.c >>> +++ b/drivers/cpufreq/cppc_cpufreq.c >>> @@ -84,7 +84,8 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy, >>> >>> cpu = all_cpu_data[policy->cpu]; >>> >>> - cpu->perf_ctrls.desired_perf = target_freq * policy->max / cppc_dmi_max_khz; >>> + cpu->perf_ctrls.desired_perf = >>> + (u64)target_freq * policy->max / cppc_dmi_max_khz; >>> freqs.old = policy->cur; >>> freqs.new = target_freq; >> >> That's on top of the CPPC material in linux-next I gather? > > Yes, it's on TOP of linux-next. > >> >> Which commit does it fix? > > This is a fix for ad38677df44b67e0f5b6c4d31e9c2734abde8ed9 (cpufreq: > CPPC: Force reporting values in KHz to fix user space interface) > http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/cpufreq/cppc_cpufreq.c?id=ad38677df44b67e0f5b6c4d31e9c2734abde8ed9 > > Thanks > Hoan > >> >> Thanks, >> Rafael >> Nice catch, Hoan. Thanks! -- ciao, al ----------------------------------- Al Stone Software Engineer Red Hat, Inc. ahs3@redhat.com -----------------------------------