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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 D6442C433DF for ; Thu, 14 May 2020 13:50:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A1D9820671 for ; Thu, 14 May 2020 13:50:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="iUT7/Jzi" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727067AbgENNuu (ORCPT ); Thu, 14 May 2020 09:50:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57552 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726067AbgENNut (ORCPT ); Thu, 14 May 2020 09:50:49 -0400 Received: from merlin.infradead.org (unknown [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 453F6C061A0C for ; Thu, 14 May 2020 06:50:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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=oUb9XRa4HSf+di+9adEfNnhbqfuLOkGDaR9A8N50SmY=; b=iUT7/JziNjm5u+tScAhcV8xfbC 1z3ZEoVhzeP2ZkB5SCAzzt+S0GOxdUUKKo7K8EherRQ4kR6Ja2j9KrCLu0BlZ4sMl6JxzPtcq9od3 +qpg+lO2Lq1reJmnkRfJ6SfoS+GP3YRxhjfWZWbMNpllNCb6j8JrGgijxpVvATOLi+flAsPqY6Qc1 yWU75AUYlRyh/S5kvLZ7QUeAyCjKc19SIHiKRsZHL0zjwdoY2yrjNsMYaQ+uObMhuEjrCVInyBYtz XvqvO8MZOa4O7DGQZmGzS/cAOasvl7Uk2nCBwhAYWVT3trNDe41xQmoLI+ozXwgT5y2QW+eTyL2ak o6GY8awA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jZEFm-0000C0-Ut; Thu, 14 May 2020 13:50:27 +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 A7B46301A66; Thu, 14 May 2020 15:50:25 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 944742B852D66; Thu, 14 May 2020 15:50:25 +0200 (CEST) Date: Thu, 14 May 2020 15:50:25 +0200 From: Peter Zijlstra To: Marco Elver Cc: Will Deacon , kasan-dev , LKML , Thomas Gleixner , "Paul E. McKenney" , Ingo Molnar , Dmitry Vyukov Subject: Re: [PATCH v5 00/18] Rework READ_ONCE() to improve codegen Message-ID: <20200514135025.GZ2978@hirez.programming.kicks-ass.net> References: <20200513124021.GB20278@willie-the-truck> <20200513165008.GA24836@willie-the-truck> <20200513174747.GB24836@willie-the-truck> <20200513212520.GC28594@willie-the-truck> <20200514110537.GC4280@willie-the-truck> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 14, 2020 at 03:35:58PM +0200, Marco Elver wrote: > 4. __no_kcsan functions should never be spuriously inlined into > instrumented functions, causing the accesses of the __no_kcsan > function to be instrumented. [Satisfied by Clang >= 7. All GCC > versions are broken.] The current noinstr annotation implies noinline, for a similar issue, we need the function to be emitted in a specific section. So while yuck, this is not an immediate issue for us.