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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 D971FC433E1 for ; Fri, 31 Jul 2020 14:21:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A428921744 for ; Fri, 31 Jul 2020 14:21:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A428921744 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 538778D002E; Fri, 31 Jul 2020 10:21:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 510468D000B; Fri, 31 Jul 2020 10:21:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3FE508D002E; Fri, 31 Jul 2020 10:21:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0042.hostedemail.com [216.40.44.42]) by kanga.kvack.org (Postfix) with ESMTP id 289B58D000B for ; Fri, 31 Jul 2020 10:21:33 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id D4D17180AD81A for ; Fri, 31 Jul 2020 14:21:32 +0000 (UTC) X-FDA: 77098584024.20.pain28_550d39126f84 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin20.hostedemail.com (Postfix) with ESMTP id 6B167180C07AF for ; Fri, 31 Jul 2020 14:21:32 +0000 (UTC) X-HE-Tag: pain28_550d39126f84 X-Filterd-Recvd-Size: 2402 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf21.hostedemail.com (Postfix) with ESMTP for ; Fri, 31 Jul 2020 14:21:32 +0000 (UTC) Received: from gaia (unknown [95.146.230.158]) (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 66956208E4; Fri, 31 Jul 2020 14:21:29 +0000 (UTC) Date: Fri, 31 Jul 2020 15:21:27 +0100 From: Catalin Marinas To: Andrey Konovalov Cc: Andrew Morton , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Marco Elver , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Walter Wu , Elena Petrova , Vincenzo Frascino Subject: Re: [PATCH 2/4] kasan, arm64: don't instrument functions that enable kasan Message-ID: <20200731142126.GE29569@gaia> References: <55d432671a92e931ab8234b03dc36b14d4c21bfb.1596199677.git.andreyknvl@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55d432671a92e931ab8234b03dc36b14d4c21bfb.1596199677.git.andreyknvl@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Rspamd-Queue-Id: 6B167180C07AF X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Jul 31, 2020 at 03:20:39PM +0200, Andrey Konovalov wrote: > This patch prepares Software Tag-Based KASAN for stack tagging support. > > With stack tagging enabled, KASAN tags stack variable in each function > in its prologue. In start_kernel() stack variables get tagged before KASAN > is enabled via setup_arch()->kasan_init(). As the result the tags for > start_kernel()'s stack variables end up in the temporary shadow memory. > Later when KASAN gets enabled, switched to normal shadow, and starts > checking tags, this leads to false-positive reports, as proper tags are > missing in normal shadow. > > Disable KASAN instrumentation for start_kernel(). Also disable it for > arm64's setup_arch() as a precaution (it doesn't have any stack variables > right now). > > Signed-off-by: Andrey Konovalov For arm64: Acked-by: Catalin Marinas