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=-8.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 1445FC282C0 for ; Wed, 23 Jan 2019 12:09:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA0702183F for ; Wed, 23 Jan 2019 12:09:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="TdmruNmZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727395AbfAWMJm (ORCPT ); Wed, 23 Jan 2019 07:09:42 -0500 Received: from mail-oi1-f196.google.com ([209.85.167.196]:45871 "EHLO mail-oi1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726207AbfAWMJk (ORCPT ); Wed, 23 Jan 2019 07:09:40 -0500 Received: by mail-oi1-f196.google.com with SMTP id y1so1551567oie.12 for ; Wed, 23 Jan 2019 04:09:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=ozDKIbwcmYuyejXGARNO3jJ/EJ1dH91BZQgRlXa0NVc=; b=TdmruNmZ40rRcOmr5c75vEIE9p7sNtcssBxrB6bd1v49wN7GdrM8dCdTjsFQkdwWpn swJtemBXQ8ZfNyCa1SflX10bZDRPmJb8tjwU7YUSHbALC+X1sn7gMgElfhG0yulEtun3 dI6EjQ0qoKfuvzWguCcBeFpT2cvANhqJOLW8brHwqybryRKfXMLt2jCo+c3z0h0u9cs+ DwJAHlcaYLhJSTROVF0VfKwLWBxSkwFrqjVe5od1op4Pncf0bV9yiTfuJ+VyvjAwTZBa D5nZZ6vI/i6CDyC16YUTSU53EeDC1Pc5YlFAA/BNIwJPdl/R6qmYspFi9kUVWRDYLnSU eOng== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=ozDKIbwcmYuyejXGARNO3jJ/EJ1dH91BZQgRlXa0NVc=; b=qDaKncyQ1D41539GvJdLNHQ7kXxdDWYI7pSQE2V2CmywFLLMAZ1WJspbE3YoHi1fjS 1cYhoVuIvsKfKf8sO90B/AhZnN633LkkpIWYzNWTJiAAbUzVV1lr97T4SOwJhT2XtUKm LXV+JDBfld139ggUfECkAynpuYiH4hBv7VxVj0sM/SEETvz+wjA4ri8PNIFFvyT3/ENQ qI/pcjcLvBnR32xLoPhpPSUBX+DNIXO1ieknWXrUu5FONm/+ZahLtLwSPUlZll+UyDqb t04f/WYM8eJ2sbpgxhVleUacZn7DaIBzvFtiPo5ixLCnkIigpOJLMmpTiRcJe9fisf5H e44w== X-Gm-Message-State: AJcUukc6QtF4DxsENodH9aQ+nVM194smHRasjjA/QmoPTW0t9Dj3BqUm zqRIYbreyiDnJD+pJ/K5z+UAzzrZctRgBKdyGdLDX8MIuiSYoA== X-Google-Smtp-Source: ALg8bN6kOaeSQwPD4LE50phMTwZkQl9VC4fJho1QUCrFhsQiioas7XmkfUH+8ap4a9ntepudRb3YAWzJRoOY/bTa4Q4= X-Received: by 2002:aca:c43:: with SMTP id i3mr1280767oiy.157.1548245379171; Wed, 23 Jan 2019 04:09:39 -0800 (PST) MIME-Version: 1.0 References: <20190123110349.35882-1-keescook@chromium.org> <20190123110349.35882-2-keescook@chromium.org> <20190123115829.GA31385@kroah.com> In-Reply-To: <20190123115829.GA31385@kroah.com> From: Jann Horn Date: Wed, 23 Jan 2019 13:09:13 +0100 Message-ID: Subject: Re: [PATCH 1/3] treewide: Lift switch variables out of switches To: Greg KH Cc: Kees Cook , kernel list , Ard Biesheuvel , Laura Abbott , Alexander Popov , xen-devel , dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, intel-wired-lan@lists.osuosl.org, Network Development , linux-usb@vger.kernel.org, linux-fsdevel@vger.kernel.org, Linux-MM , dev@openvswitch.org, linux-kbuild@vger.kernel.org, linux-security-module , Kernel Hardening Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 23, 2019 at 1:04 PM Greg KH wrote: > On Wed, Jan 23, 2019 at 03:03:47AM -0800, Kees Cook wrote: > > Variables declared in a switch statement before any case statements > > cannot be initialized, so move all instances out of the switches. > > After this, future always-initialized stack variables will work > > and not throw warnings like this: > > > > fs/fcntl.c: In function =E2=80=98send_sigio_to_task=E2=80=99: > > fs/fcntl.c:738:13: warning: statement will never be executed [-Wswitch-= unreachable] > > siginfo_t si; > > ^~ > > That's a pain, so this means we can't have any new variables in { } > scope except for at the top of a function? AFAICS this only applies to switch statements (because they jump to a case and don't execute stuff at the start of the block), not blocks after if/while/... . > That's going to be a hard thing to keep from happening over time, as > this is valid C :( From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: [1/3] treewide: Lift switch variables out of switches From: Jann Horn Message-Id: Date: Wed, 23 Jan 2019 13:09:13 +0100 To: Greg KH Cc: Kees Cook , kernel list , Ard Biesheuvel , Laura Abbott , Alexander Popov , xen-devel , dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, intel-wired-lan@lists.osuosl.org, Network Development , linux-usb@vger.kernel.org, linux-fsdevel@vger.kernel.org, Linux-MM , dev@openvswitch.org, linux-kbuild@vger.kernel.org, linux-security-module , Kernel Hardening List-ID: T24gV2VkLCBKYW4gMjMsIDIwMTkgYXQgMTowNCBQTSBHcmVnIEtIIDxncmVna2hAbGludXhmb3Vu ZGF0aW9uLm9yZz4gd3JvdGU6Cj4gT24gV2VkLCBKYW4gMjMsIDIwMTkgYXQgMDM6MDM6NDdBTSAt MDgwMCwgS2VlcyBDb29rIHdyb3RlOgo+ID4gVmFyaWFibGVzIGRlY2xhcmVkIGluIGEgc3dpdGNo IHN0YXRlbWVudCBiZWZvcmUgYW55IGNhc2Ugc3RhdGVtZW50cwo+ID4gY2Fubm90IGJlIGluaXRp YWxpemVkLCBzbyBtb3ZlIGFsbCBpbnN0YW5jZXMgb3V0IG9mIHRoZSBzd2l0Y2hlcy4KPiA+IEFm dGVyIHRoaXMsIGZ1dHVyZSBhbHdheXMtaW5pdGlhbGl6ZWQgc3RhY2sgdmFyaWFibGVzIHdpbGwg d29yawo+ID4gYW5kIG5vdCB0aHJvdyB3YXJuaW5ncyBsaWtlIHRoaXM6Cj4gPgo+ID4gZnMvZmNu dGwuYzogSW4gZnVuY3Rpb24g4oCYc2VuZF9zaWdpb190b190YXNr4oCZOgo+ID4gZnMvZmNudGwu Yzo3Mzg6MTM6IHdhcm5pbmc6IHN0YXRlbWVudCB3aWxsIG5ldmVyIGJlIGV4ZWN1dGVkIFstV3N3 aXRjaC11bnJlYWNoYWJsZV0KPiA+ICAgIHNpZ2luZm9fdCBzaTsKPiA+ICAgICAgICAgICAgICBe fgo+Cj4gVGhhdCdzIGEgcGFpbiwgc28gdGhpcyBtZWFucyB3ZSBjYW4ndCBoYXZlIGFueSBuZXcg dmFyaWFibGVzIGluIHsgfQo+IHNjb3BlIGV4Y2VwdCBmb3IgYXQgdGhlIHRvcCBvZiBhIGZ1bmN0 aW9uPwoKQUZBSUNTIHRoaXMgb25seSBhcHBsaWVzIHRvIHN3aXRjaCBzdGF0ZW1lbnRzIChiZWNh dXNlIHRoZXkganVtcCB0byBhCmNhc2UgYW5kIGRvbid0IGV4ZWN1dGUgc3R1ZmYgYXQgdGhlIHN0 YXJ0IG9mIHRoZSBibG9jayksIG5vdCBibG9ja3MKYWZ0ZXIgaWYvd2hpbGUvLi4uIC4KCj4gVGhh dCdzIGdvaW5nIHRvIGJlIGEgaGFyZCB0aGluZyB0byBrZWVwIGZyb20gaGFwcGVuaW5nIG92ZXIg dGltZSwgYXMKPiB0aGlzIGlzIHZhbGlkIEMgOigK 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=-8.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 030C5C282C2 for ; 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[209.85.220.65]) by mx.google.com with SMTPS id n8sor9518504oia.75.2019.01.23.04.09.39 for (Google Transport Security); Wed, 23 Jan 2019 04:09:39 -0800 (PST) Received-SPF: pass (google.com: domain of jannh@google.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=TdmruNmZ; spf=pass (google.com: domain of jannh@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=jannh@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=ozDKIbwcmYuyejXGARNO3jJ/EJ1dH91BZQgRlXa0NVc=; b=TdmruNmZ40rRcOmr5c75vEIE9p7sNtcssBxrB6bd1v49wN7GdrM8dCdTjsFQkdwWpn swJtemBXQ8ZfNyCa1SflX10bZDRPmJb8tjwU7YUSHbALC+X1sn7gMgElfhG0yulEtun3 dI6EjQ0qoKfuvzWguCcBeFpT2cvANhqJOLW8brHwqybryRKfXMLt2jCo+c3z0h0u9cs+ DwJAHlcaYLhJSTROVF0VfKwLWBxSkwFrqjVe5od1op4Pncf0bV9yiTfuJ+VyvjAwTZBa D5nZZ6vI/i6CDyC16YUTSU53EeDC1Pc5YlFAA/BNIwJPdl/R6qmYspFi9kUVWRDYLnSU eOng== X-Google-Smtp-Source: ALg8bN6kOaeSQwPD4LE50phMTwZkQl9VC4fJho1QUCrFhsQiioas7XmkfUH+8ap4a9ntepudRb3YAWzJRoOY/bTa4Q4= X-Received: by 2002:aca:c43:: with SMTP id i3mr1280767oiy.157.1548245379171; Wed, 23 Jan 2019 04:09:39 -0800 (PST) MIME-Version: 1.0 References: <20190123110349.35882-1-keescook@chromium.org> <20190123110349.35882-2-keescook@chromium.org> <20190123115829.GA31385@kroah.com> In-Reply-To: <20190123115829.GA31385@kroah.com> From: Jann Horn Date: Wed, 23 Jan 2019 13:09:13 +0100 Message-ID: Subject: Re: [PATCH 1/3] treewide: Lift switch variables out of switches To: Greg KH Cc: Kees Cook , kernel list , Ard Biesheuvel , Laura Abbott , Alexander Popov , xen-devel , dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, intel-wired-lan@lists.osuosl.org, Network Development , linux-usb@vger.kernel.org, linux-fsdevel@vger.kernel.org, Linux-MM , dev@openvswitch.org, linux-kbuild@vger.kernel.org, linux-security-module , Kernel Hardening Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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: Message-ID: <20190123120913.OBfImxJMpKheKJjMy6Kh_IoOo-vStyiZnjGQbl8ASxA@z> On Wed, Jan 23, 2019 at 1:04 PM Greg KH wrote: > On Wed, Jan 23, 2019 at 03:03:47AM -0800, Kees Cook wrote: > > Variables declared in a switch statement before any case statements > > cannot be initialized, so move all instances out of the switches. > > After this, future always-initialized stack variables will work > > and not throw warnings like this: > > > > fs/fcntl.c: In function =E2=80=98send_sigio_to_task=E2=80=99: > > fs/fcntl.c:738:13: warning: statement will never be executed [-Wswitch-= unreachable] > > siginfo_t si; > > ^~ > > That's a pain, so this means we can't have any new variables in { } > scope except for at the top of a function? AFAICS this only applies to switch statements (because they jump to a case and don't execute stuff at the start of the block), not blocks after if/while/... . > That's going to be a hard thing to keep from happening over time, as > this is valid C :( From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jann Horn Date: Wed, 23 Jan 2019 13:09:13 +0100 Subject: [Intel-wired-lan] [PATCH 1/3] treewide: Lift switch variables out of switches In-Reply-To: <20190123115829.GA31385@kroah.com> References: <20190123110349.35882-1-keescook@chromium.org> <20190123110349.35882-2-keescook@chromium.org> <20190123115829.GA31385@kroah.com> Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: intel-wired-lan@osuosl.org List-ID: On Wed, Jan 23, 2019 at 1:04 PM Greg KH wrote: > On Wed, Jan 23, 2019 at 03:03:47AM -0800, Kees Cook wrote: > > Variables declared in a switch statement before any case statements > > cannot be initialized, so move all instances out of the switches. > > After this, future always-initialized stack variables will work > > and not throw warnings like this: > > > > fs/fcntl.c: In function ?send_sigio_to_task?: > > fs/fcntl.c:738:13: warning: statement will never be executed [-Wswitch-unreachable] > > siginfo_t si; > > ^~ > > That's a pain, so this means we can't have any new variables in { } > scope except for at the top of a function? AFAICS this only applies to switch statements (because they jump to a case and don't execute stuff at the start of the block), not blocks after if/while/... . > That's going to be a hard thing to keep from happening over time, as > this is valid C :(