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 CE63AC2D0DB for ; Mon, 20 Jan 2020 16:27:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 90872217F4 for ; Mon, 20 Jan 2020 16:27:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579537647; bh=DfsQKj6JVD4yxySwTBjUqI0G1NNDS6wQtVYJpuK5oYY=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=ilzdIwub62kUDtBm7MeW2ju9bN4lqKjRcOEsiAvmY1nZdrv8maCClMzZiHNUIyQrR tNHMAugmfHGJ2DMbWK4z6opA3e468Wr13XIwOBACtiIf3jycPzPF30tfikz3TScakN 9cQ6vKtDjuFHOtDWezeoASMAKdTVymPlLnNrdLLw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729281AbgATQ10 (ORCPT ); Mon, 20 Jan 2020 11:27:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:55584 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726897AbgATQ10 (ORCPT ); Mon, 20 Jan 2020 11:27:26 -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 96FA22087E; Mon, 20 Jan 2020 16:27:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579537645; bh=DfsQKj6JVD4yxySwTBjUqI0G1NNDS6wQtVYJpuK5oYY=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=02XheXlNlUAXFFARtrvh6NVeg9iWItQyCrHq/oLCUJltrCFTWiDl7PK7sO76IYnyF tJ3zKkTCIzfQYN5l5nwIsH6W3b5LHKdbhmdgLFuceqqWsDSQo+QbvB9xVVgjbBvIat lZP2tp4yT5N88yggo/b9s6d3qIPOwQdq6h3Tzh8s= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 6A3543522745; Mon, 20 Jan 2020 08:27:25 -0800 (PST) Date: Mon, 20 Jan 2020 08:27:25 -0800 From: "Paul E. McKenney" To: Peter Zijlstra Cc: Marco Elver , andreyknvl@google.com, glider@google.com, dvyukov@google.com, kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, mark.rutland@arm.com, will@kernel.org, boqun.feng@gmail.com, arnd@arndb.de, viro@zeniv.linux.org.uk, christophe.leroy@c-s.fr, dja@axtens.net, mpe@ellerman.id.au, rostedt@goodmis.org, mhiramat@kernel.org, mingo@kernel.org, christian.brauner@ubuntu.com, daniel@iogearbox.net, cyphar@cyphar.com, keescook@chromium.org, linux-arch@vger.kernel.org Subject: Re: [PATCH 3/5] asm-generic, kcsan: Add KCSAN instrumentation for bitops Message-ID: <20200120162725.GE2935@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20200120141927.114373-1-elver@google.com> <20200120141927.114373-3-elver@google.com> <20200120144048.GB14914@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200120144048.GB14914@hirez.programming.kicks-ass.net> 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 Mon, Jan 20, 2020 at 03:40:48PM +0100, Peter Zijlstra wrote: > On Mon, Jan 20, 2020 at 03:19:25PM +0100, Marco Elver wrote: > > Add explicit KCSAN checks for bitops. > > > > Note that test_bit() is an atomic bitop, and we instrument it as such, > > Well, it is 'atomic' in the same way that atomic_read() is. Both are > very much not atomic ops, but are part of an interface that facilitates > atomic operations. True, but they all are either inline assembly or have either an implicit or explicit cast to volatile, so they could be treated the same as atomic_read(), correct? If not, what am I missing? (There is one exception, but it is in arch/x86/boot/bitops.h, which I UP-only, correct?) Thanx, Paul