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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 5F8FCC3404D for ; Tue, 18 Feb 2020 23:54:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 38F28208E4 for ; Tue, 18 Feb 2020 23:54:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582070049; bh=sVFef4PzqftuGRief/QBL+AuxajuMta5Rk9EY8Z0RIg=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=sc8emasXiVzONiYiToLOqiCAxK6WgH/LvKq5A0GgVN/jtOi0B0FMiXFGg7fn+fNV0 vniunzgMHg6m7Bsr035ctJFTmRS3WAftwLlTBAHkJ5dSMd5U1FfCkZtxN74G/RqSi9 uPlMlTBee1LIeWVFRDLDTzFszB0Wcrslzx+EzEBc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727187AbgBRXyI (ORCPT ); Tue, 18 Feb 2020 18:54:08 -0500 Received: from mail.kernel.org ([198.145.29.99]:46182 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726716AbgBRXyH (ORCPT ); Tue, 18 Feb 2020 18:54:07 -0500 Received: from paulmck-ThinkPad-P72.home (50-39-105-78.bvtn.or.frontiernet.net [50.39.105.78]) (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 0F1CA2068F; Tue, 18 Feb 2020 23:54:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582070047; bh=sVFef4PzqftuGRief/QBL+AuxajuMta5Rk9EY8Z0RIg=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=ysC1+TgxWDsLsphReqqFT1BVqWJ9vnlLOGNZQt3e1XxQH4rY6Li/ezz7z0Evioru1 bDn/h6UG/J7T5F1SL3FFSpKqswxoNaCvn8qXP7KnY5Up9WAVAkNEs5KLF1ad5dhuUN v1yHV1aqaNPY34IMZoPTKF2QuGCIq0qmZT2XRdw0= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id DBF4F3520856; Tue, 18 Feb 2020 15:54:06 -0800 (PST) Date: Tue, 18 Feb 2020 15:54:06 -0800 From: "Paul E. McKenney" To: Steven Rostedt 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: <20200218235406.GO2935@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <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> <20200218181323.4a102fe7@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200218181323.4a102fe7@gandalf.local.home> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 18, 2020 at 06:13:23PM -0500, Steven Rostedt wrote: > 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. You aren't kidding! Rumor has it that someone tried backporting the RCU flavor-consolidation work, for but one example. Though I cannot help but salute the level of insanity represented by that attempt. ;-) Thanx, Paul