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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 297EAC432C0 for ; Wed, 20 Nov 2019 13:23:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F2A2F224F3 for ; Wed, 20 Nov 2019 13:23:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="URTIsW6t" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730555AbfKTNXj (ORCPT ); Wed, 20 Nov 2019 08:23:39 -0500 Received: from mail-ot1-f67.google.com ([209.85.210.67]:40980 "EHLO mail-ot1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728338AbfKTNXi (ORCPT ); Wed, 20 Nov 2019 08:23:38 -0500 Received: by mail-ot1-f67.google.com with SMTP id 94so21143929oty.8 for ; Wed, 20 Nov 2019 05:23:35 -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; bh=HzMXI8CiEmUCb1T/mIucbXJe4tU8bP4I9jjwwuAfDKQ=; b=URTIsW6tZP01wQOhlnFPO0YcR2fJrVif20Z60qoXjMZfBUIFjhFdnIttZLJoRt+uuB 3TxwmUzCRKtxTIw0FgqbzlDHVQQkUHUVdz8NI5aJliRIL1yH/PdDEX9kOpfb/6EycAuB O1LdwC4IOSbuZEO6F4tkTXlU/50ypy+deG5SBD2P/29ADBG9JfjiJRSnSWHOy7VQpL14 WXZQL4aqd9lPoacYF0jYEu44WV7NfUGqR2y3I8O/1Jm9qTUpaBgXQfY/2euYSseUh9Zb 4TrBQ9TrATgntDENO+UrbQYxv3D/XBY8stKQ/gFDs/Tx+ETUb3u6h06bWtKIdfrYx+9T 6yYA== 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; bh=HzMXI8CiEmUCb1T/mIucbXJe4tU8bP4I9jjwwuAfDKQ=; b=uObhiQTLOGHpTKQCPi7rmFbwwkYNBbk1NjkniSOofwRuEGNiQefV9RraTnfYjhv9zL 7nFbQtGEcTSMe0OgaR9wZ2F8A+VlfzzC7JWvAC2NYLSvw33MPb2mABjzSPzSLZ7n7E8A iODD20Kqo1H5NepCVDoKez6czNqXwzrxOh+9u2HQnWUiydRDAlOppJ/OMgMzNhDxNTpf 9vWusG6HJJgtEtnWQvhiSdlkp7QPSxHp6r/E7JQHQLQYdIzxG1/1/rdxiEm59YDVdtb2 m6Q6Of3x6183xvGT/pub+LyWgMqs527uQW+99XbIwwnM85ARX9YsAqdXnc8NI/2uaeD6 BefQ== X-Gm-Message-State: APjAAAXWa9CvqzvU0qO3mO2/PsVYAH5iw40/e9UQTbI+kx7VsOL5OpET dvIdoJYa8+l4s3dtLskbKO5x4Qw7d2BCYzFm98f67Q== X-Google-Smtp-Source: APXvYqwb9n5MQCN2w1O8tVaiPI3U9z029YRp54J2viOtXwX8ggK0Rw/OJtbItqTD6XRZ/nOBs03tr5yQb3F9wAkYh2E= X-Received: by 2002:a05:6830:1319:: with SMTP id p25mr2092594otq.110.1574256215221; Wed, 20 Nov 2019 05:23:35 -0800 (PST) MIME-Version: 1.0 References: <20191120103613.63563-1-jannh@google.com> <20191120103613.63563-2-jannh@google.com> <20191120111859.GA115930@gmail.com> <20191120112408.GC2634@zn.tnic> <20191120131627.GA54414@gmail.com> In-Reply-To: <20191120131627.GA54414@gmail.com> From: Jann Horn Date: Wed, 20 Nov 2019 14:23:09 +0100 Message-ID: Subject: Re: [PATCH v3 2/4] x86/traps: Print non-canonical address on #GP To: Ingo Molnar Cc: Borislav Petkov , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "the arch/x86 maintainers" , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , kasan-dev , kernel list , Andrey Konovalov , Andy Lutomirski , Sean Christopherson , Andi Kleen Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 20, 2019 at 2:16 PM Ingo Molnar wrote: > * Jann Horn wrote: > > > On Wed, Nov 20, 2019 at 12:24 PM Borislav Petkov wrote: > > > On Wed, Nov 20, 2019 at 12:18:59PM +0100, Ingo Molnar wrote: > > > > How was this maximum string length of '90' derived? In what way will > > > > that have to change if someone changes the message? > > > > > > That was me counting the string length in a dirty patch in a previous > > > thread. We probably should say why we decided for a certain length and > > > maybe have a define for it. > > > > Do you think something like this would be better? > > > > char desc[sizeof(GPFSTR) + 50 + 2*sizeof(unsigned long) + 1] = GPFSTR; > > I'd much prefer this for, because it's a big honking warning for people > to not just assume things but double check the limits. Sorry, I can't parse the start of this sentence. I _think_ you're saying you want me to make the change to "char desc[sizeof(GPFSTR) + 50 + 2*sizeof(unsigned long) + 1]"? > I.e. this mild obfuscation of the array size *helps* code quality in the > long run :-)