Received: by 2002:a05:6a10:22f:0:0:0:0 with SMTP id 15csp403409pxk; Wed, 23 Sep 2020 06:24:42 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwF4HY3XjBE6Q00wgg+Az4hrXa7J9M8MbKWMphCoh/GQkfqdWsanmzT333Nt15AFAsqalx0 X-Received: by 2002:a17:906:4c84:: with SMTP id q4mr10498690eju.525.1600867482613; Wed, 23 Sep 2020 06:24:42 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1600867482; cv=none; d=google.com; s=arc-20160816; b=voS4eI7v4kQaFmHXHMLUj/bLYe+rjmxCUbEDk9IS1Mg17btNZwooiwCCD2Plwn8VlP qV23BcFZqHdlGrryIPxOrhz7yFO6dXlLFBQo6VBbQhjJsAoK2pVFru1uF1FZ8ytGOTLE AlonFvAHTIRnkjG/8MPyO+2NkBonDo5PYljoanHpOZ3PtZdqYkkZ6aIRRbg94bKtZSna 9jVgvs93JgtRs2dWbRoInguXSmkuH3WnNsNN++BCIXOK1a8u+Kbly7LzTr+upV+Hf2fG FdMLvKuwVlV5uHZerxUNkEVogILC2lDEjFWYDpL5jMUcvWk8m8DMJMoZFOsS+2M1jTnP jtiA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:in-reply-to:content-disposition :mime-version:references:message-id:subject:cc:to:from:date; bh=6dcl2kZlLVAQZk+mHYnBvjlma1GU4eEVxY+nkAkgiJc=; b=EH+lD4SPQOLoMizbXmjWblXDcKP6aYKrqk3L2AgKAhWU/7QKK/X2J3pEEVIw6qDyJw McDPYucagqHWWMlDeHiNde+wPLlYfP9dNu4vF7TlYf6Grka5j1j0zY7QLtzuvYBc6Zez oHBZqR0UV/w1tSbVH6SX2HXm2h2bWNuglBIvbhFxK8wKzy6knVNuPvZ48gPOEMtQ98iT Q+sya5KQI0ddRP2D0sT7riT1VVG3kM7RFmkVegEBw69/f/RKxH3VTP7WljfjCJjNDGkl WTAJcXoaJrPUHo1GRUnIHdHIz+lmfYh9sungEQrdr9y3nGET98V8Fl3AalNOfXz5hOcN 5JLA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id v17si12628370eje.376.2020.09.23.06.24.17; Wed, 23 Sep 2020 06:24:42 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726604AbgIWNXK (ORCPT + 99 others); Wed, 23 Sep 2020 09:23:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726130AbgIWNXI (ORCPT ); Wed, 23 Sep 2020 09:23:08 -0400 Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [IPv6:2002:c35c:fd02::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 97A9BC0613CE; Wed, 23 Sep 2020 06:23:08 -0700 (PDT) Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kL4jW-004YbY-CV; Wed, 23 Sep 2020 13:22:54 +0000 Date: Wed, 23 Sep 2020 14:22:54 +0100 From: Al Viro To: Pavel Begunkov Cc: Arnd Bergmann , Andy Lutomirski , Christoph Hellwig , Andrew Morton , Jens Axboe , David Howells , linux-arm-kernel , X86 ML , LKML , "open list:MIPS" , Parisc List , linuxppc-dev , linux-s390 , sparclinux , linux-block , Linux SCSI List , Linux FS Devel , linux-aio , io-uring@vger.kernel.org, linux-arch , Linux-MM , Network Development , keyrings@vger.kernel.org, LSM List Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag Message-ID: <20200923132254.GI3421308@ZenIV.linux.org.uk> References: <563138b5-7073-74bc-f0c5-b2bad6277e87@gmail.com> <486c92d0-0f2e-bd61-1ab8-302524af5e08@gmail.com> <91209170-dcb4-d9ee-afa0-a819f8877b86@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <91209170-dcb4-d9ee-afa0-a819f8877b86@gmail.com> Sender: Al Viro Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 23, 2020 at 11:01:34AM +0300, Pavel Begunkov wrote: > > I'm not following why that would be considered a valid option, > > as that clearly breaks existing users that update from a 32-bit > > kernel to a 64-bit one. > > Do you mean users who move 32-bit binaries (without recompiling) to a > new x64 kernel? Does the kernel guarantees that to work? Yes. No further (printable) comments for now...