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=-3.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 F3963C2BA1A for ; Tue, 7 Apr 2020 03:10:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BA31520716 for ; Tue, 7 Apr 2020 03:10:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="zW4DT1h4" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BA31520716 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6A9278E007C; Mon, 6 Apr 2020 23:10:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 65B3D8E0062; Mon, 6 Apr 2020 23:10:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 56EA48E007C; Mon, 6 Apr 2020 23:10:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0125.hostedemail.com [216.40.44.125]) by kanga.kvack.org (Postfix) with ESMTP id 38FCB8E0062 for ; Mon, 6 Apr 2020 23:10:21 -0400 (EDT) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 0A5BEA75D for ; Tue, 7 Apr 2020 03:10:21 +0000 (UTC) X-FDA: 76679580642.16.blood84_30498cdfcf2a X-HE-Tag: blood84_30498cdfcf2a X-Filterd-Recvd-Size: 2978 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf05.hostedemail.com (Postfix) with ESMTP for ; Tue, 7 Apr 2020 03:10:20 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (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 84187206B8; Tue, 7 Apr 2020 03:10:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586229020; bh=Iv+kN5uIt8kdks8ujrDYAUyZTbgXU1FbT1CkBsneuBk=; h=Date:From:To:Subject:In-Reply-To:From; b=zW4DT1h4RdHUhVfiAi5vt8aIkZyz/lTTg1lYl17aM8h63OCWhYqrRWvskLHw3bqCo 7G6FuBW0HJY5Dz7OWQCm8oy8+un+QlfPfasH63PVJ2yhW0KOj6kMXpvNpZlzoXn6nc fFtOfFPL/+gf0ZCy8ebeYYwpWAxatLJMRZxfjodQ= Date: Mon, 06 Apr 2020 20:10:19 -0700 From: Andrew Morton To: akpm@linux-foundation.org, andreyknvl@google.com, arnd@arndb.de, aryabinin@virtuozzo.com, dvyukov@google.com, elver@google.com, glider@google.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, sergey.senozhatsky@gmail.com, torvalds@linux-foundation.org, vegard.nossum@oracle.com Subject: [patch 118/166] lib/stackdepot.c: build with -fno-builtin Message-ID: <20200407031019.GPp46WoMb%akpm@linux-foundation.org> In-Reply-To: <20200406200254.a69ebd9e08c4074e41ddebaf@linux-foundation.org> User-Agent: s-nail v14.8.16 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: From: Alexander Potapenko Subject: lib/stackdepot.c: build with -fno-builtin Clang may replace stackdepot_memcmp() with a call to instrumented bcmp(), which is exactly what we wanted to avoid creating stackdepot_memcmp(). Building the file with -fno-builtin prevents such optimizations. This patch has been previously mailed as part of KMSAN RFC patch series. Link: http://lkml.kernel.org/r/20200220141916.55455-2-glider@google.com Signed-off-by: Alexander Potapenko Cc: Vegard Nossum Cc: Dmitry Vyukov Cc: Marco Elver Cc: Andrey Konovalov Cc: Sergey Senozhatsky Cc: Arnd Bergmann Cc: Andrey Ryabinin Signed-off-by: Andrew Morton --- lib/Makefile | 4 ++++ 1 file changed, 4 insertions(+) --- a/lib/Makefile~stackdepot-build-with-fno-builtin +++ a/lib/Makefile @@ -223,6 +223,10 @@ obj-$(CONFIG_MEMREGION) += memregion.o obj-$(CONFIG_STMP_DEVICE) += stmp_device.o obj-$(CONFIG_IRQ_POLL) += irq_poll.o +# stackdepot.c should not be instrumented or call instrumented functions. +# Prevent the compiler from calling builtins like memcmp() or bcmp() from this +# file. +CFLAGS_stackdepot.o += -fno-builtin obj-$(CONFIG_STACKDEPOT) += stackdepot.o KASAN_SANITIZE_stackdepot.o := n KCOV_INSTRUMENT_stackdepot.o := n _