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=-6.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 27AE1C43444 for ; Wed, 16 Jan 2019 16:47:39 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id ECE6C205C9 for ; Wed, 16 Jan 2019 16:47:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="bp7coFWB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ECE6C205C9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=QN4NTVCUs5U14WdKvtG43KAP+hrKu6/XsN4JhhREjf8=; b=bp7coFWBzxb/eO KV+VZay48lxdoC5PcBt/6sPQ7wkw49xaPT41yoyN8jHaiFibr3NTmJgSE7GCwPwUpoXb2/l9uD1g0 WFl4HXbx7qWVzdo6WX/Os+BrVDV9MKfjf5qRaw3b1CMQPqbLejiJDhTJSRJ746MjlKfRdgnUmm8M3 0VxhL1lo3FFpDYy8ulmPv3r7Gm+XtYHwhfMQyOn1HJR0MZqzJXnUc0nCxKmmux016JGmAqzPB09i7 O8nm7798CEJZ/LZx49CHq8/CV7EcO0mEICB3c2p6ZDGRxTvopa3Y+LeI7vBl8ek+3/K+CBjoLttYM 7lkaiD7rC5BLkBXXQh5Q==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gjoLm-0007N0-UT; Wed, 16 Jan 2019 16:47:34 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gjoLX-0007EN-DL for linux-arm-kernel@lists.infradead.org; Wed, 16 Jan 2019 16:47:22 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 06095A78; Wed, 16 Jan 2019 08:47:19 -0800 (PST) Received: from brain-police (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 981C63F5AF; Wed, 16 Jan 2019 08:47:16 -0800 (PST) Date: Wed, 16 Jan 2019 16:47:13 +0000 From: Will Deacon To: Andrey Ryabinin Subject: Re: [PATCH] kasan: Remove use after scope bugs detection. Message-ID: <20190116164712.GB1910@brain-police> References: <20190111185842.13978-1-aryabinin@virtuozzo.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190111185842.13978-1-aryabinin@virtuozzo.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190116_084719_911785_5F9D7BE7 X-CRM114-Status: GOOD ( 14.03 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Catalin Marinas , linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, Qian Cai , Dmitry Vyukov , Alexander Potapenko , akpm@linux-foundation.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Jan 11, 2019 at 09:58:42PM +0300, Andrey Ryabinin wrote: > Use after scope bugs detector seems to be almost entirely useless > for the linux kernel. It exists over two years, but I've seen only > one valid bug so far [1]. And the bug was fixed before it has been > reported. There were some other use-after-scope reports, but they > were false-positives due to different reasons like incompatibility > with structleak plugin. > > This feature significantly increases stack usage, especially with > GCC < 9 version, and causes a 32K stack overflow. It probably > adds performance penalty too. > > Given all that, let's remove use-after-scope detector entirely. > > While preparing this patch I've noticed that we mistakenly enable > use-after-scope detection for clang compiler regardless of > CONFIG_KASAN_EXTRA setting. This is also fixed now. > > [1] http://lkml.kernel.org/r/<20171129052106.rhgbjhhis53hkgfn@wfg-t540p.sh.intel.com> > > Signed-off-by: Andrey Ryabinin > Cc: Qian Cai > Cc: Alexander Potapenko > Cc: Dmitry Vyukov > Cc: Catalin Marinas > Cc: Will Deacon > --- > arch/arm64/include/asm/memory.h | 4 ---- > lib/Kconfig.debug | 1 - > lib/Kconfig.kasan | 10 ---------- > lib/test_kasan.c | 24 ------------------------ > mm/kasan/generic.c | 19 ------------------- > mm/kasan/generic_report.c | 3 --- > mm/kasan/kasan.h | 3 --- > scripts/Makefile.kasan | 5 ----- > scripts/gcc-plugins/Kconfig | 4 ---- > 9 files changed, 73 deletions(-) For the arm64 part: Acked-by: Will Deacon but I defer to you and Dmitry as to whether or not you go ahead with this. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel