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=-16.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 C882CC433E0 for ; Fri, 8 Jan 2021 20:31:13 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5529223A9C for ; Fri, 8 Jan 2021 20:31:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5529223A9C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7E6F68D01A9; Fri, 8 Jan 2021 15:31:12 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 796488D0156; Fri, 8 Jan 2021 15:31:12 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6ACBA8D01A9; Fri, 8 Jan 2021 15:31:12 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0188.hostedemail.com [216.40.44.188]) by kanga.kvack.org (Postfix) with ESMTP id 569368D0156 for ; Fri, 8 Jan 2021 15:31:12 -0500 (EST) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 1EB06180AD807 for ; Fri, 8 Jan 2021 20:31:12 +0000 (UTC) X-FDA: 77683752384.04.leg79_5c01f49274f5 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin04.hostedemail.com (Postfix) with ESMTP id F385680058F9 for ; Fri, 8 Jan 2021 20:31:11 +0000 (UTC) X-HE-Tag: leg79_5c01f49274f5 X-Filterd-Recvd-Size: 3988 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf34.hostedemail.com (Postfix) with ESMTP for ; Fri, 8 Jan 2021 20:31:11 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 7EB5E23AC9 for ; Fri, 8 Jan 2021 20:31:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610137870; bh=dN/vCuTfi01My7gqxrmbsoNneHB7mr8tZmJby3DM2Ts=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=CK8hMSmJlda2+nQd/elAbLb6PsPulkmBsfLI7uMcP/u5n2IrnaEt6BIOaRTYJxiwY LBj5ATT03OE7SXXkvjFHc+eADEWghwWQKrpuKdFN3I/CzOpVcQan+Atg0NaHa47OtK LmzxK/798PUNYHO/fGwACW0KH8Hi+652iL6SuDv9yndLXV2iiLwzJVi2Oz69n1Y4Sj N4pQqvohaveCDIzjwey5Z4V1PB75s0hXmo0GQO22OxC/+55xIxTHx9KeACIS2j/3r9 ye3R2dyzshr3vWK4ht96ESK7jnEbEUFyFgrCrJjEFGnE/hffyiVcsF/VVMJslTZ68Y 379cIu9sAq4Gw== Received: by mail-oi1-f180.google.com with SMTP id 9so12766917oiq.3 for ; Fri, 08 Jan 2021 12:31:10 -0800 (PST) X-Gm-Message-State: AOAM53120UXOaJwLf77BgOnkA+kCrKGwBqCniXj6GaSFZOOq1vn5vGS9 oGwz2t1MkBghRpVbuiQO59kcs++mAJmqrtwBc+I= X-Google-Smtp-Source: ABdhPJwYZTJvr7kFzDF/qWiLnN5DYHOF+FSG0HkLBoXAW+tr4GMnTQfrliSZqYEPhR50hYyWxogqt+5hi3LKcOotPiU= X-Received: by 2002:aca:44d:: with SMTP id 74mr3515461oie.4.1610137869802; Fri, 08 Jan 2021 12:31:09 -0800 (PST) MIME-Version: 1.0 References: <20210108040940.1138-1-walter-zh.wu@mediatek.com> In-Reply-To: From: Arnd Bergmann Date: Fri, 8 Jan 2021 21:30:53 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v3] kasan: remove redundant config option To: Andrey Konovalov Cc: Walter Wu , Arnd Bergmann , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Andrew Morton , Nathan Chancellor , kasan-dev , Linux Memory Management List , LKML , Linux ARM , wsd_upstream , "moderated list:ARM/Mediatek SoC..." Content-Type: text/plain; charset="UTF-8" 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, Jan 8, 2021 at 7:56 PM Andrey Konovalov wrote: > On Fri, Jan 8, 2021 at 5:09 AM Walter Wu wrote: > > @@ -2,6 +2,12 @@ > > CFLAGS_KASAN_NOSANITIZE := -fno-builtin > > KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET) > > > > +ifdef CONFIG_KASAN_STACK > > + stack_enable := 1 > > +else > > + stack_enable := 0 > > +endif > > + > > AFAIR, Arnd wanted to avoid having KASAN_STACK to be enabled by > default when compiling with Clang, since Clang instrumentation leads > to very large kernel stacks, which, in turn, lead to compile-time > warnings. What I don't remember is why there are two configs. > > Arnd, is that correct? What was the reason behind having two configs? I think I just considered it cleaner than defining the extra variable in the Makefile at the time, as this was the only place that referenced CONFIG_KASAN_STACK. The '#if CONFIG_KASAN_STACK' (rather than #ifdef) that got added later do make my version more confusing though, so I agree that Walter's second patch improves it. Acked-by: Arnd Bergmann On a related note: do you have any hope that clang will ever fix https://bugs.llvm.org/show_bug.cgi?id=38809 and KASAN_STACK can be enabled by default on clang without risking stack overflows? Arnd