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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 66025C43142 for ; Thu, 2 Aug 2018 10:55:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1A25B21502 for ; Thu, 2 Aug 2018 10:55:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1A25B21502 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731899AbeHBMqM (ORCPT ); Thu, 2 Aug 2018 08:46:12 -0400 Received: from foss.arm.com ([217.140.101.70]:55690 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727120AbeHBMqL (ORCPT ); Thu, 2 Aug 2018 08:46:11 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B86147A9; Thu, 2 Aug 2018 03:55:35 -0700 (PDT) Received: from [10.4.12.131] (e110467-lin.emea.arm.com [10.4.12.131]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C78463F5D0; Thu, 2 Aug 2018 03:55:34 -0700 (PDT) Subject: Re: [PATCH] arm_pmu: fix compiler warning in arm_pmu_device_probe To: Chris Packham , mark.rutland@arm.com, will.deacon@arm.com Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <20180801214526.24599-1-chris.packham@alliedtelesis.co.nz> From: Robin Murphy Message-ID: <449c26bb-9d31-984e-da74-73ef1bd9a674@arm.com> Date: Thu, 2 Aug 2018 11:55:29 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180801214526.24599-1-chris.packham@alliedtelesis.co.nz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Chris, On 01/08/18 22:45, Chris Packham wrote: > GCC warns > > arm_pmu_platform.c:234:5: error: 'err' may be used uninitialized in this function [-Werror=maybe-uninitialized] > > This is because we rely on the for_each_cpu loop in armpmu_request_irqs > to initialise err. The warning is a little bogus because we know if > there were 0 CPUs this code would not be running. > > Initialise err to 0 to avoid the warning. Maybe initialising to something like -EINVAL would be more appropriate, just in case we did ever manage to get here with armpmu->supported_cpus unset? Robin. > Signed-off-by: Chris Packham > --- > This has been reported before in https://lkml.org/lkml/2018/3/5/508 I'm not > sure if it was dismmissed as "meh, gcc is wrong" or if it was just wainting for > someone with some round tuits. > > > drivers/perf/arm_pmu_platform.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/perf/arm_pmu_platform.c b/drivers/perf/arm_pmu_platform.c > index 971ff336494a..96075cecb0ae 100644 > --- a/drivers/perf/arm_pmu_platform.c > +++ b/drivers/perf/arm_pmu_platform.c > @@ -160,7 +160,7 @@ static int pmu_parse_irqs(struct arm_pmu *pmu) > static int armpmu_request_irqs(struct arm_pmu *armpmu) > { > struct pmu_hw_events __percpu *hw_events = armpmu->hw_events; > - int cpu, err; > + int cpu, err = 0; > > for_each_cpu(cpu, &armpmu->supported_cpus) { > int irq = per_cpu(hw_events->irq, cpu); >