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=-24.8 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 DE8A7C433DB for ; Tue, 12 Jan 2021 13:35:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 91DA320771 for ; Tue, 12 Jan 2021 13:35:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733099AbhALNf3 (ORCPT ); Tue, 12 Jan 2021 08:35:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53460 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727305AbhALNf2 (ORCPT ); Tue, 12 Jan 2021 08:35:28 -0500 Received: from mail-wr1-x42d.google.com (mail-wr1-x42d.google.com [IPv6:2a00:1450:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EBA60C061575 for ; Tue, 12 Jan 2021 05:34:47 -0800 (PST) Received: by mail-wr1-x42d.google.com with SMTP id t16so2538195wra.3 for ; Tue, 12 Jan 2021 05:34:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=z9FwHUycumOs6t3SGrgS7cCKPT7xvNasenz8IWyWKdE=; b=W+nxBakCaB7ynwGYftYLRdP83y1GTuxctzs44VzPtCtmSubuMVopEKdrenyngQtkEu V7P22CcfpoY+/Gn+4UtErhSHZXc7+8zeF6bSccwaJ1VPrTpV9pzT2btHTmIDR+8MomWa yuu5VMsycC/+yIIdCfzf11BkdzD4vdiLu4uWhAXGP3YmRoTpVsuhX2hEpFWK73RAJ37l P3dNktzINSGrOdq+QJrvOu+t9lGusgUz/2+dZiOZP6eKsPvQCqK28cxb9XxfFB2e0i0X WN5K1OvfuFbjh429mqP+FXlm0TscIb3gtLKQyc8hPIDJry3r8FcZDc48D3zDDiHzmXyl rEpw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=z9FwHUycumOs6t3SGrgS7cCKPT7xvNasenz8IWyWKdE=; b=dQOCL3eSxJAXVT3ywnOmyG1I1OcphuVl5mB+9HGfQgXRbrFtRE212xQ15UPwIG5G9A 8JhtjUQxHnqUzdD8VbVlegp7FVOGyw1QkNGmem08JEXisvUKzalqEW0O/nQbLYIPCeAl btCc15ztqBmrKCj67HcLZ2N8a7vYeMwVg0XZyNBx+3gTCEjG6JlPhWwNmrwTqXGxAYEY HjKPXQjS+nTqMD6xtUMa7Xqtdsu951yqrlcVldSOLVdaRxtwKv5kuUu7z8twmiOh6fov EB3Rrj2+CrUHShnWfoGz/lMcBNybG8MNS0oClWyT3qEGkkjXBFgJL61UMOgcqe/WJcy1 glog== X-Gm-Message-State: AOAM5337b6ToO0Uqe6pYz9rrwGt8vyB+OxgB9HWO3sPGpl6Tr4LT8axT 2Gc4kcknZqCsqK8jxoObKSBnIA== X-Google-Smtp-Source: ABdhPJyKyV9ETptwrtpI2ynczocJJyRkdU4fVd84RpDQb6jfsamTI8Mh/WaitaK3csy42ynajTMGag== X-Received: by 2002:a5d:6a88:: with SMTP id s8mr4508931wru.118.1610458486541; Tue, 12 Jan 2021 05:34:46 -0800 (PST) Received: from elver.google.com ([2a00:79e0:15:13:f693:9fff:fef4:2449]) by smtp.gmail.com with ESMTPSA id h184sm4218719wmh.23.2021.01.12.05.34.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Jan 2021 05:34:45 -0800 (PST) Date: Tue, 12 Jan 2021 14:34:40 +0100 From: Marco Elver To: Andrey Konovalov Cc: Catalin Marinas , Vincenzo Frascino , Dmitry Vyukov , Alexander Potapenko , Andrew Morton , Will Deacon , Andrey Ryabinin , Evgenii Stepanov , Branislav Rankov , Kevin Brodsky , kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 07/11] kasan: add compiler barriers to KUNIT_EXPECT_KASAN_FAIL Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/2.0.2 (2020-11-20) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 05, 2021 at 07:27PM +0100, Andrey Konovalov wrote: > It might not be obvious to the compiler that the expression must be > executed between writing and reading to fail_data. In this case, the > compiler might reorder or optimize away some of the accesses, and > the tests will fail. > > Add compiler barriers around the expression in KUNIT_EXPECT_KASAN_FAIL. > > Signed-off-by: Andrey Konovalov > Link: https://linux-review.googlesource.com/id/I046079f48641a1d36fe627fc8827a9249102fd50 Reviewed-by: Marco Elver > --- > lib/test_kasan.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/lib/test_kasan.c b/lib/test_kasan.c > index dd3d2f95c24e..b5077a47b95a 100644 > --- a/lib/test_kasan.c > +++ b/lib/test_kasan.c > @@ -79,7 +79,9 @@ static void kasan_test_exit(struct kunit *test) > NULL, \ > &resource, \ > "kasan_data", &fail_data); \ > + barrier(); \ > expression; \ > + barrier(); \ > KUNIT_EXPECT_EQ(test, \ > fail_data.report_expected, \ > fail_data.report_found); \ > -- > 2.29.2.729.g45daf8777d-goog >