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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 BD2ADC282C2 for ; Wed, 23 Jan 2019 15:44:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 94D4121871 for ; Wed, 23 Jan 2019 15:44:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726864AbfAWPor convert rfc822-to-8bit (ORCPT ); Wed, 23 Jan 2019 10:44:47 -0500 Received: from mga06.intel.com ([134.134.136.31]:53707 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726790AbfAWPoq (ORCPT ); Wed, 23 Jan 2019 10:44:46 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Jan 2019 07:44:38 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,511,1539673200"; d="scan'208";a="140646916" Received: from jnikula-mobl3.fi.intel.com (HELO localhost) ([10.237.66.172]) by fmsmga001.fm.intel.com with ESMTP; 23 Jan 2019 07:44:31 -0800 From: Jani Nikula To: Edwin Zimmerman , 'Greg KH' , 'Kees Cook' Cc: dev@openvswitch.org, 'Ard Biesheuvel' , netdev@vger.kernel.org, intel-gfx@lists.freedesktop.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-mm@kvack.org, linux-security-module@vger.kernel.org, kernel-hardening@lists.openwall.com, intel-wired-lan@lists.osuosl.org, linux-fsdevel@vger.kernel.org, xen-devel@lists.xenproject.org, 'Laura Abbott' , linux-kbuild@vger.kernel.org, 'Alexander Popov' Subject: RE: [Intel-gfx] [PATCH 1/3] treewide: Lift switch variables out of switches In-Reply-To: <000001d4b32a$845e06e0$8d1a14a0$@211mainstreet.net> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20190123110349.35882-1-keescook@chromium.org> <20190123110349.35882-2-keescook@chromium.org> <20190123115829.GA31385@kroah.com> <874l9z31c5.fsf@intel.com> <000001d4b32a$845e06e0$8d1a14a0$@211mainstreet.net> Date: Wed, 23 Jan 2019 17:46:14 +0200 Message-ID: <87va2f1int.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 23 Jan 2019, Edwin Zimmerman wrote: > On Wed, 23 Jan 2019, Jani Nikula wrote: >> On Wed, 23 Jan 2019, 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? >> > >> > That's going to be a hard thing to keep from happening over time, as >> > this is valid C :( >> >> Not all valid C is meant to be used! ;) > > Very true. The other thing to keep in mind is the burden of enforcing > a prohibition on a valid C construct like this. It seems to me that > patch reviewers and maintainers have enough to do without forcing them > to watch for variable declarations in switch statements. Automating > this prohibition, should it be accepted, seems like a good idea to me. Considering that the treewide diffstat to fix this is: 18 files changed, 45 insertions(+), 46 deletions(-) and using the gcc plugin in question will trigger the switch-unreachable warning, I think we're good. There'll probably be the occasional declarations that pass through, and will get fixed afterwards. BR, Jani. -- Jani Nikula, Intel Open Source Graphics Center 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: Jani Nikula Message-Id: <87va2f1int.fsf@intel.com> Date: Wed, 23 Jan 2019 17:46:14 +0200 To: Edwin Zimmerman , 'Greg KH' , 'Kees Cook' Cc: dev@openvswitch.org, 'Ard Biesheuvel' , netdev@vger.kernel.org, intel-gfx@lists.freedesktop.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-mm@kvack.org, linux-security-module@vger.kernel.org, kernel-hardening@lists.openwall.com, intel-wired-lan@lists.osuosl.org, linux-fsdevel@vger.kernel.org, xen-devel@lists.xenproject.org, 'Laura Abbott' , linux-kbuild@vger.kernel.org, 'Alexander Popov' List-ID: T24gV2VkLCAyMyBKYW4gMjAxOSwgRWR3aW4gWmltbWVybWFuIDxlZHdpbkAyMTFtYWluc3RyZWV0 Lm5ldD4gd3JvdGU6Cj4gT24gV2VkLCAyMyBKYW4gMjAxOSwgSmFuaSBOaWt1bGEgPGphbmkubmlr dWxhQGxpbnV4LmludGVsLmNvbT4gd3JvdGU6Cj4+IE9uIFdlZCwgMjMgSmFuIDIwMTksIEdyZWcg S0ggPGdyZWdraEBsaW51eGZvdW5kYXRpb24ub3JnPiB3cm90ZToKPj4gPiBPbiBXZWQsIEphbiAy MywgMjAxOSBhdCAwMzowMzo0N0FNIC0wODAwLCBLZWVzIENvb2sgd3JvdGU6Cj4+ID4+IFZhcmlh YmxlcyBkZWNsYXJlZCBpbiBhIHN3aXRjaCBzdGF0ZW1lbnQgYmVmb3JlIGFueSBjYXNlIHN0YXRl bWVudHMKPj4gPj4gY2Fubm90IGJlIGluaXRpYWxpemVkLCBzbyBtb3ZlIGFsbCBpbnN0YW5jZXMg b3V0IG9mIHRoZSBzd2l0Y2hlcy4KPj4gPj4gQWZ0ZXIgdGhpcywgZnV0dXJlIGFsd2F5cy1pbml0 aWFsaXplZCBzdGFjayB2YXJpYWJsZXMgd2lsbCB3b3JrCj4+ID4+IGFuZCBub3QgdGhyb3cgd2Fy bmluZ3MgbGlrZSB0aGlzOgo+PiA+Pgo+PiA+PiBmcy9mY250bC5jOiBJbiBmdW5jdGlvbiDigJhz ZW5kX3NpZ2lvX3RvX3Rhc2vigJk6Cj4+ID4+IGZzL2ZjbnRsLmM6NzM4OjEzOiB3YXJuaW5nOiBz dGF0ZW1lbnQgd2lsbCBuZXZlciBiZSBleGVjdXRlZCBbLVdzd2l0Y2gtdW5yZWFjaGFibGVdCj4+ ID4+ICAgIHNpZ2luZm9fdCBzaTsKPj4gPj4gICAgICAgICAgICAgIF5+Cj4+ID4KPj4gPiBUaGF0 J3MgYSBwYWluLCBzbyB0aGlzIG1lYW5zIHdlIGNhbid0IGhhdmUgYW55IG5ldyB2YXJpYWJsZXMg aW4geyB9Cj4+ID4gc2NvcGUgZXhjZXB0IGZvciBhdCB0aGUgdG9wIG9mIGEgZnVuY3Rpb24/Cj4+ ID4KPj4gPiBUaGF0J3MgZ29pbmcgdG8gYmUgYSBoYXJkIHRoaW5nIHRvIGtlZXAgZnJvbSBoYXBw ZW5pbmcgb3ZlciB0aW1lLCBhcwo+PiA+IHRoaXMgaXMgdmFsaWQgQyA6KAo+PiAKPj4gTm90IGFs bCB2YWxpZCBDIGlzIG1lYW50IHRvIGJlIHVzZWQhIDspCj4KPiBWZXJ5IHRydWUuICBUaGUgb3Ro ZXIgdGhpbmcgdG8ga2VlcCBpbiBtaW5kIGlzIHRoZSBidXJkZW4gb2YgZW5mb3JjaW5nCj4gYSBw cm9oaWJpdGlvbiBvbiBhIHZhbGlkIEMgY29uc3RydWN0IGxpa2UgdGhpcy4gIEl0IHNlZW1zIHRv IG1lIHRoYXQKPiBwYXRjaCByZXZpZXdlcnMgYW5kIG1haW50YWluZXJzIGhhdmUgZW5vdWdoIHRv IGRvIHdpdGhvdXQgZm9yY2luZyB0aGVtCj4gdG8gd2F0Y2ggZm9yIHZhcmlhYmxlIGRlY2xhcmF0 aW9ucyBpbiBzd2l0Y2ggc3RhdGVtZW50cy4gIEF1dG9tYXRpbmcKPiB0aGlzIHByb2hpYml0aW9u LCBzaG91bGQgaXQgYmUgYWNjZXB0ZWQsIHNlZW1zIGxpa2UgYSBnb29kIGlkZWEgdG8gbWUuCgpD b25zaWRlcmluZyB0aGF0IHRoZSB0cmVld2lkZSBkaWZmc3RhdCB0byBmaXggdGhpcyBpczoKCiAx OCBmaWxlcyBjaGFuZ2VkLCA0NSBpbnNlcnRpb25zKCspLCA0NiBkZWxldGlvbnMoLSkKCmFuZCB1 c2luZyB0aGUgZ2NjIHBsdWdpbiBpbiBxdWVzdGlvbiB3aWxsIHRyaWdnZXIgdGhlIHN3aXRjaC11 bnJlYWNoYWJsZQp3YXJuaW5nLCBJIHRoaW5rIHdlJ3JlIGdvb2QuIFRoZXJlJ2xsIHByb2JhYmx5 IGJlIHRoZSBvY2Nhc2lvbmFsCmRlY2xhcmF0aW9ucyB0aGF0IHBhc3MgdGhyb3VnaCwgYW5kIHdp bGwgZ2V0IGZpeGVkIGFmdGVyd2FyZHMuCgpCUiwKSmFuaS4K From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jani Nikula Subject: Re: [PATCH 1/3] treewide: Lift switch variables out of switches Date: Wed, 23 Jan 2019 17:46:14 +0200 Message-ID: <87va2f1int.fsf@intel.com> References: <20190123110349.35882-1-keescook@chromium.org> <20190123110349.35882-2-keescook@chromium.org> <20190123115829.GA31385@kroah.com> <874l9z31c5.fsf@intel.com> <000001d4b32a$845e06e0$8d1a14a0$@211mainstreet.net> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <000001d4b32a$845e06e0$8d1a14a0$@211mainstreet.net> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Edwin Zimmerman , 'Greg KH' , 'Kees Cook' Cc: dev@openvswitch.org, 'Ard Biesheuvel' , netdev@vger.kernel.org, intel-gfx@lists.freedesktop.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-mm@kvack.org, linux-security-module@vger.kernel.org, intel-wired-lan@lists.osuosl.org, xen-devel@lists.xenproject.org, kernel-hardening@lists.openwall.com, linux-fsdevel@vger.kernel.org, 'Laura Abbott' , linux-kbuild@vger.kernel.org, 'Alexander Popov' List-Id: dri-devel@lists.freedesktop.org T24gV2VkLCAyMyBKYW4gMjAxOSwgRWR3aW4gWmltbWVybWFuIDxlZHdpbkAyMTFtYWluc3RyZWV0 Lm5ldD4gd3JvdGU6Cj4gT24gV2VkLCAyMyBKYW4gMjAxOSwgSmFuaSBOaWt1bGEgPGphbmkubmlr dWxhQGxpbnV4LmludGVsLmNvbT4gd3JvdGU6Cj4+IE9uIFdlZCwgMjMgSmFuIDIwMTksIEdyZWcg S0ggPGdyZWdraEBsaW51eGZvdW5kYXRpb24ub3JnPiB3cm90ZToKPj4gPiBPbiBXZWQsIEphbiAy MywgMjAxOSBhdCAwMzowMzo0N0FNIC0wODAwLCBLZWVzIENvb2sgd3JvdGU6Cj4+ID4+IFZhcmlh YmxlcyBkZWNsYXJlZCBpbiBhIHN3aXRjaCBzdGF0ZW1lbnQgYmVmb3JlIGFueSBjYXNlIHN0YXRl bWVudHMKPj4gPj4gY2Fubm90IGJlIGluaXRpYWxpemVkLCBzbyBtb3ZlIGFsbCBpbnN0YW5jZXMg b3V0IG9mIHRoZSBzd2l0Y2hlcy4KPj4gPj4gQWZ0ZXIgdGhpcywgZnV0dXJlIGFsd2F5cy1pbml0 aWFsaXplZCBzdGFjayB2YXJpYWJsZXMgd2lsbCB3b3JrCj4+ID4+IGFuZCBub3QgdGhyb3cgd2Fy bmluZ3MgbGlrZSB0aGlzOgo+PiA+Pgo+PiA+PiBmcy9mY250bC5jOiBJbiBmdW5jdGlvbiDigJhz ZW5kX3NpZ2lvX3RvX3Rhc2vigJk6Cj4+ID4+IGZzL2ZjbnRsLmM6NzM4OjEzOiB3YXJuaW5nOiBz dGF0ZW1lbnQgd2lsbCBuZXZlciBiZSBleGVjdXRlZCBbLVdzd2l0Y2gtdW5yZWFjaGFibGVdCj4+ ID4+ICAgIHNpZ2luZm9fdCBzaTsKPj4gPj4gICAgICAgICAgICAgIF5+Cj4+ID4KPj4gPiBUaGF0 J3MgYSBwYWluLCBzbyB0aGlzIG1lYW5zIHdlIGNhbid0IGhhdmUgYW55IG5ldyB2YXJpYWJsZXMg aW4geyB9Cj4+ID4gc2NvcGUgZXhjZXB0IGZvciBhdCB0aGUgdG9wIG9mIGEgZnVuY3Rpb24/Cj4+ ID4KPj4gPiBUaGF0J3MgZ29pbmcgdG8gYmUgYSBoYXJkIHRoaW5nIHRvIGtlZXAgZnJvbSBoYXBw ZW5pbmcgb3ZlciB0aW1lLCBhcwo+PiA+IHRoaXMgaXMgdmFsaWQgQyA6KAo+PiAKPj4gTm90IGFs bCB2YWxpZCBDIGlzIG1lYW50IHRvIGJlIHVzZWQhIDspCj4KPiBWZXJ5IHRydWUuICBUaGUgb3Ro ZXIgdGhpbmcgdG8ga2VlcCBpbiBtaW5kIGlzIHRoZSBidXJkZW4gb2YgZW5mb3JjaW5nCj4gYSBw cm9oaWJpdGlvbiBvbiBhIHZhbGlkIEMgY29uc3RydWN0IGxpa2UgdGhpcy4gIEl0IHNlZW1zIHRv IG1lIHRoYXQKPiBwYXRjaCByZXZpZXdlcnMgYW5kIG1haW50YWluZXJzIGhhdmUgZW5vdWdoIHRv IGRvIHdpdGhvdXQgZm9yY2luZyB0aGVtCj4gdG8gd2F0Y2ggZm9yIHZhcmlhYmxlIGRlY2xhcmF0 aW9ucyBpbiBzd2l0Y2ggc3RhdGVtZW50cy4gIEF1dG9tYXRpbmcKPiB0aGlzIHByb2hpYml0aW9u LCBzaG91bGQgaXQgYmUgYWNjZXB0ZWQsIHNlZW1zIGxpa2UgYSBnb29kIGlkZWEgdG8gbWUuCgpD b25zaWRlcmluZyB0aGF0IHRoZSB0cmVld2lkZSBkaWZmc3RhdCB0byBmaXggdGhpcyBpczoKCiAx OCBmaWxlcyBjaGFuZ2VkLCA0NSBpbnNlcnRpb25zKCspLCA0NiBkZWxldGlvbnMoLSkKCmFuZCB1 c2luZyB0aGUgZ2NjIHBsdWdpbiBpbiBxdWVzdGlvbiB3aWxsIHRyaWdnZXIgdGhlIHN3aXRjaC11 bnJlYWNoYWJsZQp3YXJuaW5nLCBJIHRoaW5rIHdlJ3JlIGdvb2QuIFRoZXJlJ2xsIHByb2JhYmx5 IGJlIHRoZSBvY2Nhc2lvbmFsCmRlY2xhcmF0aW9ucyB0aGF0IHBhc3MgdGhyb3VnaCwgYW5kIHdp bGwgZ2V0IGZpeGVkIGFmdGVyd2FyZHMuCgpCUiwKSmFuaS4KCi0tIApKYW5pIE5pa3VsYSwgSW50 ZWwgT3BlbiBTb3VyY2UgR3JhcGhpY3MgQ2VudGVyCl9fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fCkludGVsLWdmeCBtYWlsaW5nIGxpc3QKSW50ZWwtZ2Z4QGxp c3RzLmZyZWVkZXNrdG9wLm9yZwpodHRwczovL2xpc3RzLmZyZWVkZXNrdG9wLm9yZy9tYWlsbWFu L2xpc3RpbmZvL2ludGVsLWdmeAo= From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jani Nikula Date: Wed, 23 Jan 2019 17:46:14 +0200 Subject: [Intel-wired-lan] [Intel-gfx] [PATCH 1/3] treewide: Lift switch variables out of switches In-Reply-To: <000001d4b32a$845e06e0$8d1a14a0$@211mainstreet.net> References: <20190123110349.35882-1-keescook@chromium.org> <20190123110349.35882-2-keescook@chromium.org> <20190123115829.GA31385@kroah.com> <874l9z31c5.fsf@intel.com> <000001d4b32a$845e06e0$8d1a14a0$@211mainstreet.net> Message-ID: <87va2f1int.fsf@intel.com> 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, 23 Jan 2019, Edwin Zimmerman wrote: > On Wed, 23 Jan 2019, Jani Nikula wrote: >> On Wed, 23 Jan 2019, 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? >> > >> > That's going to be a hard thing to keep from happening over time, as >> > this is valid C :( >> >> Not all valid C is meant to be used! ;) > > Very true. The other thing to keep in mind is the burden of enforcing > a prohibition on a valid C construct like this. It seems to me that > patch reviewers and maintainers have enough to do without forcing them > to watch for variable declarations in switch statements. Automating > this prohibition, should it be accepted, seems like a good idea to me. Considering that the treewide diffstat to fix this is: 18 files changed, 45 insertions(+), 46 deletions(-) and using the gcc plugin in question will trigger the switch-unreachable warning, I think we're good. There'll probably be the occasional declarations that pass through, and will get fixed afterwards. BR, Jani. -- Jani Nikula, Intel Open Source Graphics Center