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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 DE438C433FE for ; Sat, 11 Sep 2021 12:21:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B95CC60FE3 for ; Sat, 11 Sep 2021 12:21:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235833AbhIKMWu (ORCPT ); Sat, 11 Sep 2021 08:22:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35528 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230249AbhIKMWs (ORCPT ); Sat, 11 Sep 2021 08:22:48 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1335BC061574; Sat, 11 Sep 2021 05:21:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=pIrRTaD+W3liNDOnfLn+k/tfGaQxG0Xkh6UvYgCUGCE=; b=SKQ72EcLo22dWu7sxbKE7Ff1QP UAawh8J5AABJMqYA0VWmHSVSozT+h3sAI0QmewQwHGDcD86Jk96FJzblUVyKf8Ls9giZMrh0xZ552 CfsFUI6hmQose/sv1nVRol7lQFj2NBRLxZd22PuQrd3VoV4jRBiPsM2Z27JJjnjjU0D8/O49Zzvj+ n86OyjkD8mcYuh7YR2SKC8+YoFAsyCRZ7hr1OpRw1WF9TgZoGFyj1bzgv2S9QJU8eJW/+aCoLkqFb bpvWYZArQXo2gl1YwvHKrsnHlgRkEdEKRT8Qzj4HO2rbeTxFZkddJCoAi/lqWwAVg/L2k77r7RfGb ZeXjNH5w==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mP202-00Bprv-LF; Sat, 11 Sep 2021 12:21:02 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 899B89862C9; Sat, 11 Sep 2021 14:20:49 +0200 (CEST) Date: Sat, 11 Sep 2021 14:20:49 +0200 From: Peter Zijlstra To: kernel test robot Cc: Yafang Shao , kbuild-all@lists.01.org, linux-kernel@vger.kernel.org, linux-toolchains@vger.kernel.org Subject: Re: [peterz-queue:sched/core 13/19] kernel/sched/fair.c:892:34: warning: variable 'stats' set but not used Message-ID: <20210911122049.GW4323@worktop.programming.kicks-ass.net> References: <202109110214.oh62aoIq-lkp@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202109110214.oh62aoIq-lkp@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Sep 11, 2021 at 02:21:26AM +0800, kernel test robot wrote: > compiler: m68k-linux-gcc (GCC) 11.2.0 > kernel/sched/fair.c: In function 'update_curr': > kernel/sched/fair.c:860:42: warning: unused variable 'stats' [-Wunused-variable] > 860 | struct sched_statistics *stats = __schedstats_from_se(curr); > | ^~~~~ OK, compiler guys, this code reads like: #define schedstats_enabled() (0) #define __schedstat_set(x, y) do { } while (0) if (schedstats_enabled()) { struct sched_statistics *stats = __schedstats_from_se(curr); __schedstat_set(stats->exec_max, max(delta_exec, stats->exec_max)); } So yes, we initialize a variable that then isn't used, but the whole bloody thing is inside if (0) which will not ever get ran *anyway*. This is a crap warning if ever I saw one...