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=-3.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 B4C54C63777 for ; Sat, 28 Nov 2020 21:59:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 81F8022260 for ; Sat, 28 Nov 2020 21:59:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390923AbgK1Vvl (ORCPT ); Sat, 28 Nov 2020 16:51:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731510AbgK1Sw6 (ORCPT ); Sat, 28 Nov 2020 13:52:58 -0500 Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [IPv6:2002:c35c:fd02::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EE14DC0613D1 for ; Fri, 27 Nov 2020 21:23:41 -0800 (PST) Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kishZ-00F0hc-Ex; Sat, 28 Nov 2020 05:23:17 +0000 Date: Sat, 28 Nov 2020 05:23:17 +0000 From: Al Viro To: Walt Drummond Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, brgerst@gmail.com, linux@dominikbrodowski.net, gustavoars@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86/signals: Fix save/restore signal stack to correctly support sigset_t Message-ID: <20201128052317.GY3576660@ZenIV.linux.org.uk> References: <20201119221132.1515696-1-walt@drummond.us> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201119221132.1515696-1-walt@drummond.us> Sender: Al Viro Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 19, 2020 at 02:11:33PM -0800, Walt Drummond wrote: > The macro unsafe_put_sigmask() only handles the first 64 bits of the > sigmask_t, which works today. However, if the definition of the > sigset_t structure ever changed, ... existing userland would get fucked over, since sigset_t is present in user-visible data structures. Including the ones we are using that thing for - struct rt_sigframe, for starters. Layout of those suckers is very much cast in stone. We *can't* change it, no matter what we do kernel-side. NAKed-by: Al Viro