Received: by 2002:a25:1506:0:0:0:0:0 with SMTP id 6csp6351230ybv; Tue, 18 Feb 2020 15:13:59 -0800 (PST) X-Google-Smtp-Source: APXvYqwgfxB8pse1tnDZcJW+MPKxffq1NkIPYn8Fk+yXod34mkjz3WHHEBGWcJPmqDvngBSxN9Qg X-Received: by 2002:aca:be57:: with SMTP id o84mr2890744oif.138.1582067639436; Tue, 18 Feb 2020 15:13:59 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1582067639; cv=none; d=google.com; s=arc-20160816; b=cvCcMnjXJ9ObJV7LeSTXccITnWN9s+hrk5vVJoIcj9AutrAN30NiYNysrY1+ZPp8cs Q36UzATbH++q4bFp1TVHrS5fHBijj5RYkirkKTUZsjztD2Ai0N3HJWMmywbVHjfpFLnc 7T0QXC97mcWRqEouH6DsZ5uKky+YJu9uLzbwfNSX/DYAVtcv0TSpkcRz1clE1NP17Ozx wsipr0ktETwebYOkc/qH8gZftflDBj2zbcDuaJ3qd68ZkWNznBzDjR/GmU4Qyg2YSlBP kJueK6aUeqpxAyTLnfI2Xq3YkRgfX0jzkJszX8U35lGKwwrBfOgdxD+8dLfSqmS2VQVn 5aCQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:subject:cc:to:from:date; bh=d0KB/yyPemcU/rqZQanr8v+Q+z3+r8TmLEigRk0op78=; b=NNBxAi5VKGSVtH5CF4Q7Hkg/ImRzx4+vf1La5NlWpLwIKz7Xepl9PyPDnLt742tPML GqRJHNdtBaWDnPyCmTgKrFHTExSgq9anEc9aX+mGxyPaC4qNDOAbfdSXOQOzFNjPzj+B RxwEAdcFKEgk0BqoG8tLf6OEhMZ6+12EOm+q8+XVC25ASlUpT7xZhkLghA+29s1a8IZ7 DekPwxa36yPcX4ByZW/Cp9h3hl7R/C9OFNQvUpWxncRK6rTIroWFtiq5C6obYvZ/7Mcj Px/8SDckw/GCx1JpBMKS+ZsHuNarpR8l46H96D/3cHa7liyWPNOmvuZ1RwvPvnsPoYbY L6Qw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id w12si131531otk.77.2020.02.18.15.13.46; Tue, 18 Feb 2020 15:13:59 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727686AbgBRXN0 (ORCPT + 99 others); Tue, 18 Feb 2020 18:13:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:38846 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727216AbgBRXN0 (ORCPT ); Tue, 18 Feb 2020 18:13:26 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9469A24125; Tue, 18 Feb 2020 23:13:24 +0000 (UTC) Date: Tue, 18 Feb 2020 18:13:23 -0500 From: Steven Rostedt To: "Paul E. McKenney" Cc: Peter Zijlstra , rcu@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org Subject: Re: [PATCH tip/core/rcu 1/3] rcu-tasks: *_ONCE() for rcu_tasks_cbs_head Message-ID: <20200218181323.4a102fe7@gandalf.local.home> In-Reply-To: <20200218225455.GN2935@paulmck-ThinkPad-P72> References: <20200215002446.GA15663@paulmck-ThinkPad-P72> <20200215002520.15746-1-paulmck@kernel.org> <20200217123851.GR14914@hirez.programming.kicks-ass.net> <20200217181615.GP2935@paulmck-ThinkPad-P72> <20200218075648.GW14914@hirez.programming.kicks-ass.net> <20200218162719.GE2935@paulmck-ThinkPad-P72> <20200218201142.GF11457@worktop.programming.kicks-ass.net> <20200218202226.GJ2935@paulmck-ThinkPad-P72> <20200218174503.3d4e4750@gandalf.local.home> <20200218225455.GN2935@paulmck-ThinkPad-P72> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 18 Feb 2020 14:54:55 -0800 "Paul E. McKenney" wrote: > This data race was reported by KCSAN. Not appropriate for backporting > due to failure being unlikely and due to the mild consequences of the > failure, namely a confusing rcutorture console message. > I've seen patches backported for less. :-/ Really, any statement that says something may go awry with the code, will be an argument to backport it. -- Steve