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=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,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 03E1AC07E95 for ; Sun, 4 Jul 2021 17:43:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CA233613D0 for ; Sun, 4 Jul 2021 17:43:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229724AbhGDRpr (ORCPT ); Sun, 4 Jul 2021 13:45:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:52356 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229639AbhGDRpq (ORCPT ); Sun, 4 Jul 2021 13:45:46 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0BFF3611AD; Sun, 4 Jul 2021 17:43:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625420591; bh=vsZB68diUrd5nfeZ0c9PmU0Qj/RLt1a+fD+ihKVHCw0=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=k4txGoC6Wop6rpshn9r6AjMnsgGpoB4+wAZdw3g6GnVvxZa+ddjT4Voa+UL6kXp+o LkzjpmzeqGIjfPdJ4rPszzDH9kHsfpM98x90qHg+hZw+eocf+gFTRq6H/q/50RmyJi 2UyQfxafpZHePMVa42BrL+A6smRH/qX15YviL0aDw3x8Qgf3IjQN9M3GVIN/Gb5F1X b0I/2WDWj41QPezOmmu2DVfHl+T42lT0DwBdWDuifIzISK9mbaDJfLqLxfh2NdHJDt OqnLfGNhqsJh8smUvAxklZNYbJghdnL6CJYkVfTiFkLi1seweI7IxbS37tCoGX0Euw gLeQkTRuO+lXg== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id CFE875C0147; Sun, 4 Jul 2021 10:43:10 -0700 (PDT) Date: Sun, 4 Jul 2021 10:43:10 -0700 From: "Paul E. McKenney" To: kernel test robot Cc: clang-built-linux@googlegroups.com, kbuild-all@lists.01.org, linux-kernel@vger.kernel.org, Thomas Gleixner Subject: Re: kernel/time/clocksource-wdtest.c:47:22: warning: signed shift result (0x27BC86B00) requires 35 bits to represent, but 'long' only has 32 bits Message-ID: <20210704174310.GR4397@paulmck-ThinkPad-P17-Gen-1> Reply-To: paulmck@kernel.org References: <202107040532.wqL30yFp-lkp@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202107040532.wqL30yFp-lkp@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 04, 2021 at 05:42:36AM +0800, kernel test robot wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master > head: 303392fd5c160822bf778270b28ec5ea50cab2b4 > commit: 1253b9b87e42ab6a3d5c2cb27af2bdd67d7e50ff clocksource: Provide kernel module to test clocksource watchdog > date: 11 days ago > config: mips-randconfig-r015-20210702 (attached as .config) > compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 9eb613b2de3163686b1a4bd1160f15ac56a4b083) > reproduce (this is a W=1 build): > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > chmod +x ~/bin/make.cross > # install mips cross compiling tool for clang build > # apt-get install binutils-mips-linux-gnu > # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1253b9b87e42ab6a3d5c2cb27af2bdd67d7e50ff > git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > git fetch --no-tags linus master > git checkout 1253b9b87e42ab6a3d5c2cb27af2bdd67d7e50ff > # save the attached .config to linux build tree > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips > > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot > > All warnings (new ones prefixed by >>): > > >> kernel/time/clocksource-wdtest.c:47:22: warning: signed shift result (0x27BC86B00) requires 35 bits to represent, but 'long' only has 32 bits [-Wshift-overflow] > .mult = TICK_NSEC << JIFFIES_SHIFT, /* details above */ > ~~~~~~~~~ ^ ~~~~~~~~~~~~~ > 1 warning generated. You have CONFIG_HZ_24=y and this test module assumes HZ > 100, as noted just above the excerpt below: /* Assume HZ > 100. */ #define JIFFIES_SHIFT 8 So this is expected behavior. Would it help if I gave that comment some teeth, for example, as shown at the end of this email? > vim +/long +47 kernel/time/clocksource-wdtest.c > > 39 > 40 static struct clocksource clocksource_wdtest_jiffies = { > 41 .name = "wdtest-jiffies", > 42 .rating = 1, /* lowest valid rating*/ > 43 .uncertainty_margin = TICK_NSEC, > 44 .read = wdtest_jiffies_read, > 45 .mask = CLOCKSOURCE_MASK(32), > 46 .flags = CLOCK_SOURCE_MUST_VERIFY, > > 47 .mult = TICK_NSEC << JIFFIES_SHIFT, /* details above */ > 48 .shift = JIFFIES_SHIFT, > 49 .max_cycles = 10, > 50 }; > 51 ------------------------------------------------------------------------ diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index e1856030fa66..8f0ad6e4183c 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2573,6 +2573,7 @@ config TEST_FPU config TEST_CLOCKSOURCE_WATCHDOG tristate "Test clocksource watchdog in kernel space" depends on CLOCKSOURCE_WATCHDOG + depends on HZ >= 100 help Enable this option to create a kernel module that will trigger a test of the clocksource watchdog. This module may be loaded