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=-12.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,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 49AACC352A6 for ; Sat, 5 Dec 2020 00:48:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 191E0208D5 for ; Sat, 5 Dec 2020 00:48:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731181AbgLEArW (ORCPT ); Fri, 4 Dec 2020 19:47:22 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48202 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726917AbgLEArV (ORCPT ); Fri, 4 Dec 2020 19:47:21 -0500 Received: from mail-pf1-x443.google.com (mail-pf1-x443.google.com [IPv6:2607:f8b0:4864:20::443]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C4676C061A4F for ; Fri, 4 Dec 2020 16:46:18 -0800 (PST) Received: by mail-pf1-x443.google.com with SMTP id o9so4914171pfd.10 for ; Fri, 04 Dec 2020 16:46:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=asXm/R3o12OEmZ60Ws/uh356OUWd4t72k3bkv592RHE=; b=DY8G/wumOi8WFxOcM8igIyidUriMkzLro07dT8Zq56ZkDkc9WjUuKHNtbDGeVn3kRY NE4X0tuVH9VcrOWVXUsuapHiH0T2lhDCax/1YxRW6oxPvDUlF5xia+Hju6QWJEP3PU0f FQI9j7hZ5docHhF+YmcUVaa/bErPUfoQF0CJY= 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; bh=asXm/R3o12OEmZ60Ws/uh356OUWd4t72k3bkv592RHE=; b=j6efarWUprh+oMX53ARZDoTRm2eY+HiHeKp9nocbNggShz1zAxva8PHuToKZGXy8ou GbXt0j+ouV3EOidkye755DcgVE/k970us7WserjREKsUOt4WIiM3jT553lqukqyecV8G YTiAjYwczP+7wIfhFRusSxR3ZKfTxk87trLGXCDcQL9jLKJfC3wkKVwDj/eGrRTxZ2XT rn1C0gixb5eLvCCyM69ovhMU1PSbmNCM0NhoAIr21KlLtZxxT8lf3W29O9avAVGPrv11 G89cloMy578vtUL2jiJIA17kfM7KU7yP5maf+d7TbVxge7KQOAeq90zvz2vg2QThHfok OSOA== X-Gm-Message-State: AOAM5325NvIOFsbUymz1HhTOeTObfHvXunOostY6/DUnruZhz1ST7PVN Ey6PCc3kUm7Xpt7sEN7SfSKgNw== X-Google-Smtp-Source: ABdhPJxGNJvhgaodaFR511VAmyZzwkchxtKWG/VptJKY/whiIgAhDvSFYHmzS4PmYtLBh7/7ICECPg== X-Received: by 2002:a62:27c3:0:b029:196:63f6:cfac with SMTP id n186-20020a6227c30000b029019663f6cfacmr6132838pfn.75.1607129178208; Fri, 04 Dec 2020 16:46:18 -0800 (PST) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id k189sm6844098pfd.99.2020.12.04.16.46.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Dec 2020 16:46:17 -0800 (PST) Date: Fri, 4 Dec 2020 16:46:16 -0800 From: Kees Cook To: Arnd Bergmann Cc: Andrew Morton , Linus Torvalds , Ard Biesheuvel , Arnd Bergmann , Masahiro Yamada , Michal Marek , Nathan Chancellor , Nick Desaulniers , Marco Elver , Randy Dunlap , Dmitry Vyukov , George Popescu , Herbert Xu , Peter Oberparleiter , Andrey Ryabinin , clang-built-linux , Linux Kbuild mailing list , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v2 5/7] ubsan: Enable for all*config builds Message-ID: <202012041643.CB4EEED17@keescook> References: <20201203004437.389959-1-keescook@chromium.org> <20201203004437.389959-6-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 03, 2020 at 09:51:40AM +0100, Arnd Bergmann wrote: > On Thu, Dec 3, 2020 at 1:44 AM Kees Cook wrote: > > > > With UBSAN_OBJECT_SIZE disabled for GCC, only UBSAN_ALIGNMENT remained > > a noisy UBSAN option. Disable it for COMPILE_TEST so the rest of UBSAN > > can be used for full all*config builds or other large combinations. > > > > Link: https://lore.kernel.org/lkml/CAHk-=wgXW=YLxGN0QVpp-1w5GDd2pf1W-FqY15poKzoVfik2qA@mail.gmail.com/ > > Signed-off-by: Kees Cook > > Have you checked if this has a notable impact on allmodconfig compile speed > with gcc or clang? I think I've seen significant increases in build times before > with this, but I don't remember the actual magnitude. > > Making it 20% slower would probably be ok, but making it twice as slow might > be too much. For an x86_64 gcc allmodconfig before, I was seeing around 6m2s. After, I'm seeing around 6m17s, so that's about 8% longer build time. I will double-check clang... -- Kees Cook