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 4CFC8C4167B for ; Mon, 7 Dec 2020 12:10:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0FF9623380 for ; Mon, 7 Dec 2020 12:10:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727154AbgLGMKd (ORCPT ); Mon, 7 Dec 2020 07:10:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46618 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726254AbgLGMKc (ORCPT ); Mon, 7 Dec 2020 07:10:32 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 83273C0613D0 for ; Mon, 7 Dec 2020 04:09:52 -0800 (PST) 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=BbTSzr0ekrkrwUMtMIVfByGKajgzqxX+9tYinOrH+wI=; b=Ob9akebTGAMG8y7oW+eJRc4sl1 93P/BxcpZ/dtnKpq6iJQenFcW1a+fDFFbcG10H+UHcU0KUpWdYf+Qw6cPnCYqdNSS/kzkCgodzt1m nFIF7xYvbpKcWyL0Wp1agANSbPP9r/K593EJ2vLMHamXRBBNeGSBvKHKpmzyDl0Wdm4Ha7M01TYNJ SJ8+gzTIBHORQkgm7RGfC0eY6HcM9YCPn9ONonBmFaN2qXXdzGG/zglHnNTyxzbsxRhBQi3ZybeY7 tCK727rrldmksbFIi/zn8hSCGXtwO9KREMm+hKZ3jC7ud2c3KjpuJkqW++HDA1qltFY8DBmcdXshq zpTtRTCQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kmFKs-0001ZN-8N; Mon, 07 Dec 2020 12:09:46 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id D4703304D28; Mon, 7 Dec 2020 13:09:43 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id B8A1020812B4B; Mon, 7 Dec 2020 13:09:43 +0100 (CET) Date: Mon, 7 Dec 2020 13:09:43 +0100 From: Peter Zijlstra To: Thomas Gleixner Cc: LKML , Marco Elver , kasan-dev , "Paul E. McKenney" , Ingo Molnar , Frederic Weisbecker , Will Deacon , Naresh Kamboju , syzbot+23a256029191772c2f02@syzkaller.appspotmail.com, syzbot+56078ac0b9071335a745@syzkaller.appspotmail.com, syzbot+867130cb240c41f15164@syzkaller.appspotmail.com Subject: Re: [patch 3/3] tick: Annotate tick_do_timer_cpu data races Message-ID: <20201207120943.GS3021@hirez.programming.kicks-ass.net> References: <20201206211253.919834182@linutronix.de> <20201206212002.876987748@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201206212002.876987748@linutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Dec 06, 2020 at 10:12:56PM +0100, Thomas Gleixner wrote: > + if (data_race(tick_do_timer_cpu) == TICK_DO_TIMER_BOOT) { I prefer the form: if (data_race(tick_do_timer_cpu == TICK_DO_TIMER_BOOT)) { But there doesn't yet seem to be sufficient data_race() usage in the kernel to see which of the forms is preferred. Do we want to bike-shed this now and document the outcome somewhere?