Received: by 2002:a25:e74b:0:0:0:0:0 with SMTP id e72csp751180ybh; Tue, 21 Jul 2020 07:08:24 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyHg7MwV230d+8O/farU1CWKnDwWoE4qQeLJwmQL1meqdp+nj394M+ORKglQ0bvAkVe2dEm X-Received: by 2002:a17:906:94c6:: with SMTP id d6mr26599238ejy.389.1595340504324; Tue, 21 Jul 2020 07:08:24 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1595340504; cv=none; d=google.com; s=arc-20160816; b=TRMPJWXPnMFMxkAyPWlNZgIh5qS4u+28NjXGuH/83hOgv2QpBQQdqqx03RwnSfYKOx oIF9vtQY5w3AzsI5Gzvcx5dwOvjiCwoHyRfuXjtSFbtXXDYeNWlt2py2IwB81pVoAFPj Lf2cVKsTZl6Y9X57k+eJhFPWI05Nk9jsk0tuYCdkXl2RY0PR6rvYR2PPjTp8SrKNyDCs NX1LJldToH28lw5AVUYZS2ruSlSW2uWvoqRRbWNERgLKoEdHqBc+Yxgs8Z9Lf+HdPpMv H2GcG4O1an7YbL4TXroU1zqP8KpLVVMdAPe+CL7UAA0FIRsothGU/Y0AoBBpGUDUsmCq PSIA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:in-reply-to:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :dkim-signature; bh=ECmtTwPcomeUswGmRukW4GbqA5iIbD8q9cRC6UN4mms=; b=yX/micaoot27Q4Ntr29T4vaAa8ZpOdi8x8x/5NeIGzs6anr9thaZ1aC5jg3Rx/2Aja GjHEosnHHfTgmEpjC0W3gvk8AP3qnQz5tpUZEgcx9C3MWI25oEk1X+XHhEAYFmDDXc4A NrHqBZQENXgIMsvRa9B4YqOb25RiVT2y0dZTxG5QM4dy9/cVOx10sSzdr5jXVflZe3wy 8f7uSV8bVctYC3hyw252SP+kqHMTqOZamhHxGQfEjcsXyPxlMUEV02n78MAthK98h0P5 1Eo8BWYbVVLyHjfHDugmbGrhJ5ku2KK3mzfnoPebGf7RYbs+nwbWjTkf5+4lcHvwsXFb ecUg== ARC-Authentication-Results: i=1; mx.google.com; dkim=fail header.i=@infradead.org header.s=merlin.20170209 header.b=Kca9vB0Y; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id f20si12196287edx.189.2020.07.21.07.08.01; Tue, 21 Jul 2020 07:08:24 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=fail header.i=@infradead.org header.s=merlin.20170209 header.b=Kca9vB0Y; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728153AbgGUOFd (ORCPT + 99 others); Tue, 21 Jul 2020 10:05:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50558 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726522AbgGUOFc (ORCPT ); Tue, 21 Jul 2020 10:05:32 -0400 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 826C9C061794; Tue, 21 Jul 2020 07:05:32 -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=ECmtTwPcomeUswGmRukW4GbqA5iIbD8q9cRC6UN4mms=; b=Kca9vB0Yyw+RmCgPIuI2zi9I7K Prt45YiQPU3sC2xyS8lDgTY5ILGPwV4ZrpTCR9hkSwk6EyICV6vgJaa6Ss37sVeA8RnPbD04lprp+ CWoO13LbzUQDDaYe6okyPo26VAm5+2FGh+EQ2fYpvyLYX1hOY0et1A/xwe6AqX5xTYxFHQmRwcgMP W42tPb9t88dVFufbZ5m2FviGAAsrqJRsMoRmYbu4h5eGbcr8J2Te/Cj/KNQHFX4h5i6nBFn/8VyV5 N0LXzHPqw0cK5/ZdqmT+3bL/7FgH8RW/zjpGi/JqlUmU/gLkyrab18+qg2rhQYjZO0XGSaeKD8ozE yZgVzCxQ==; 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 1jxstY-0008M4-Ut; Tue, 21 Jul 2020 14:05:25 +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 BB6A4304E03; Tue, 21 Jul 2020 16:05:23 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 8590720DCCA0B; Tue, 21 Jul 2020 16:05:23 +0200 (CEST) Date: Tue, 21 Jul 2020 16:05:23 +0200 From: Peter Zijlstra To: Marco Elver Cc: paulmck@kernel.org, will@kernel.org, arnd@arndb.de, mark.rutland@arm.com, dvyukov@google.com, glider@google.com, kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org Subject: Re: [PATCH 3/8] kcsan: Skew delay to be longer for certain access types Message-ID: <20200721140523.GA10769@hirez.programming.kicks-ass.net> References: <20200721103016.3287832-1-elver@google.com> <20200721103016.3287832-4-elver@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200721103016.3287832-4-elver@google.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 21, 2020 at 12:30:11PM +0200, Marco Elver wrote: > For compound instrumentation and assert accesses, skew the watchpoint > delay to be longer. We still shouldn't exceed the maximum delays, but it > is safe to skew the delay for these accesses. Complete lack of actual justification.. *why* are you doing this, and *why* is it safe etc..