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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 82F0AC43142 for ; Mon, 30 Jul 2018 23:25:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 354AC20881 for ; Mon, 30 Jul 2018 23:25:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="k49H+EvV" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 354AC20881 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731913AbeGaBCf (ORCPT ); Mon, 30 Jul 2018 21:02:35 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:41606 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727094AbeGaBCf (ORCPT ); Mon, 30 Jul 2018 21:02:35 -0400 Received: by mail-wr1-f66.google.com with SMTP id j5-v6so14628415wrr.8; Mon, 30 Jul 2018 16:25:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=f4kwbNe8TZKfamTjX/ryewOIGwKFhhGu3uhxZWFopDs=; b=k49H+EvVAcwCrqwjUQUGIguw6YTV2KsBUXaXYVO9upjLXVATHx9/OVkO0zzqgov4Hy Ujlcc4JJIYmM9WMsYIz3khMT5lX9YoDDLJCwlO0NDP3erVIYUeoIrptbGaICcvBjSj6k QElvrqzmmmzmpZuHH6qzLqhK66KX0iu/9zmTolO/jZihVCORkLiImhGuvRZgBxsLIIVF O+4o3cjKL7qWQqHMYyVurSLL3kuNtsQtnctivFapB6qWBp2SYRxWcC7sGDNadjUy2ySH CnfozpzqEVBMlwdTrErPYjbzwcQfHlZlNH4AYovzd8FBM2QfPQ64HNE426BYAMaKGyAA 0nKg== 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:content-transfer-encoding :in-reply-to:user-agent; bh=f4kwbNe8TZKfamTjX/ryewOIGwKFhhGu3uhxZWFopDs=; b=HVM2MGbzzxdcUjjPn/xccdfXECQRUNHGs50E39Cka5x49BWXiPOterjX6yBWBWV3MV cmE2+DdF8oEu5WYLq4tNcjvX2E51zP2jiI45ZYFA5b3jpZAUhkYt4XZi76oHUAGVwQZR QiVuoVdTTAAFiJZs+lnQThDEcSS4wEwMWBEzbo04euJF/USpf/bYqiJz2zH9RLkYTWbs 5/uoEo5G15NTlvCAdKpXhzaRZC9wgIRCxpBhHNNLYFagpstcsNns1fnxSx6A1VT3l6V/ 4/Z2u3rChjV4mjwGHecPDqxiQ0S/upk+BhBO7ldjlMZZB7GyojRgDz6EqDope5IfInZi VqRw== X-Gm-Message-State: AOUpUlEMyX1v/EwiLrXioVQvOoSKP8V6JnV6bQ15YtcS1+/QUe1njY2M COLQPAWaseYhlzrC3+1JaAQ= X-Google-Smtp-Source: AAOMgpc9eP3TUdO+4BWm4ZGHOBLVQtRtEDVveh9lgDSIa7DLVN9+m3Vvhr1K2pe+bJo/21LayZR7gg== X-Received: by 2002:adf:992d:: with SMTP id x42-v6mr18995480wrb.81.1532993114797; Mon, 30 Jul 2018 16:25:14 -0700 (PDT) Received: from flashbox ([2a01:4f8:10b:24a5::2]) by smtp.gmail.com with ESMTPSA id o10-v6sm13467603wrw.79.2018.07.30.16.25.13 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 30 Jul 2018 16:25:14 -0700 (PDT) Date: Mon, 30 Jul 2018 16:25:12 -0700 From: Nathan Chancellor To: Nick Desaulniers Cc: akpm@linux-foundation.org, arnd@arndb.de, paul.burton@mips.com, christophe.leroy@c-s.fr, shorne@gmail.com, yamada.masahiro@socionext.com, keescook@chromium.org, mingo@kernel.org, gregkh@linuxfoundation.org, tglx@linutronix.de, rdunlap@infradead.org, bp@suse.de, neilb@suse.com, linux-kernel@vger.kernel.org, aryabinin@virtuozzo.com, dwmw@amazon.co.uk, sandipan@linux.vnet.ibm.com, linux@rasmusvillemoes.dk, paullawrence@google.com, andreyknvl@google.com, will.deacon@arm.com, ghackmann@android.com, stable@vger.kernel.org, ghackmann@google.com, mka@chromium.org, jpoimboe@redhat.com, wvw@google.com, avagin@openvz.org Subject: Re: [PATCH v2 2/2] kernel.h: Disable -Wreturn-stack-address for _THIS_IP_ Message-ID: <20180730232512.GA1688@flashbox> References: <20180730213412.242849-1-ndesaulniers@google.com> <20180730213412.242849-3-ndesaulniers@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20180730213412.242849-3-ndesaulniers@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 30, 2018 at 02:34:12PM -0700, Nick Desaulniers wrote: > Starting with Clang-7.0, _THIS_IP_ generates -Wreturn-stack-address > warnings for almost every translation unit. In general, I'd prefer to > leave this on (returning the address of a stack allocated variable is in > general a bad idea) and disable it only at whitelisted call sites. > > We can't do something like: > #pragma clang diagnostic push > #pragma clang diagnostic ignored "-Wreturn-stack-address" > > #pragma clang diagnostic pop > > in a GNU Statement Expression or macro, hence we use _Pragma, which is > its raison d'être: https://gcc.gnu.org/onlinedocs/cpp/Pragmas.html > > We also can't use compiler specific pragma's without triggering > -Werror=unknown-pragmas in other compilers, so use __diag. > > Cc: stable@vger.kernel.org # 4.17, 4.14, 4.9, 4.4 > Suggested-by: Nathan Chancellor > Signed-off-by: Nick Desaulniers Tested-and-reviewed-by: Nathan Chancellor > --- > include/linux/kernel.h | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/include/linux/kernel.h b/include/linux/kernel.h > index 941dc0a5a877..909bb771c0ca 100644 > --- a/include/linux/kernel.h > +++ b/include/linux/kernel.h > @@ -168,7 +168,15 @@ > > > #define _RET_IP_ (unsigned long)__builtin_return_address(0) > -#define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; }) > +#define _THIS_IP_ ( \ > +{ \ > + __label__ __here; \ > + __diag_push() \ > + __diag_ignore(CLANG, 7, "-Wreturn-stack-address", "") \ > +__here: (unsigned long)&&__here; \ > + __diag_pop() \ > +} \ > +) > > #ifdef CONFIG_LBDAF > # include > -- > 2.18.0.345.g5c9ce644c3-goog >