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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 EAD2CC10DCE for ; Fri, 6 Mar 2020 18:10:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B1CF3206D7 for ; Fri, 6 Mar 2020 18:10:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583518213; bh=UhXNAVre2EYkV7zoxOLBerLkdYc+pOutqOc+uFnYcec=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=dPjynAYv/U5dG/A9VOneJFzzomBg8vbysS0jpW+2vApcbqxaSWUmaM0qx/pGPWGki Cw1265jEt5iaM72puzzuloQSPUHvxFs8/nNaUc/kpbip4Wn9OoGCeS4tGQH6is+sBn zAAn5PygsaVbgGlRhg8PQR2aA5Yma5FaQobajIH8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726702AbgCFSKM (ORCPT ); Fri, 6 Mar 2020 13:10:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:46734 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726231AbgCFSKM (ORCPT ); Fri, 6 Mar 2020 13:10:12 -0500 Received: from mail-wr1-f44.google.com (mail-wr1-f44.google.com [209.85.221.44]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AC1F1206E2 for ; Fri, 6 Mar 2020 18:10:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583518212; bh=UhXNAVre2EYkV7zoxOLBerLkdYc+pOutqOc+uFnYcec=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=CtzbyL4NAuYPWgUAX3vsD5113YVohkpEKkM3GBJ7/Ljbn+aM6TuPN6NE36XRT2Ip3 YytmTdNIkpzDj4VTxeYwu818w+8rjvFxmaG7i4gGNjCF92lWI9PgOY6YlwINZc760Y +HOBA2t6B57AClqmyM1q/YgD6iWRc0UQ5CbeLRyM= Received: by mail-wr1-f44.google.com with SMTP id v11so3421763wrm.9 for ; Fri, 06 Mar 2020 10:10:11 -0800 (PST) X-Gm-Message-State: ANhLgQ27l/wAyrvCeHReHlrJEVAG7drCj6G5c90fo9xMsx4V6tGw4ylx UlTvN9cl03SvtnIzfIST3nAi8eDIFXA1U1Xz1HnDbw== X-Google-Smtp-Source: ADFU+vv1AOG5tHij0fLjC8000q+s+EtpHoNrB7M+8B5/f4EEjxeLFOS1UA6gWYXyIrJPXB9ljG/iAUbN9+zB2vN/6Tg= X-Received: by 2002:adf:b641:: with SMTP id i1mr5258372wre.18.1583518210189; Fri, 06 Mar 2020 10:10:10 -0800 (PST) MIME-Version: 1.0 References: <20200305181719.GA5490@avx2> In-Reply-To: <20200305181719.GA5490@avx2> From: Andy Lutomirski Date: Fri, 6 Mar 2020 10:09:58 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] x86_64: fixup TASK_SIZE_MAX comment To: Alexey Dobriyan Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , X86 ML , LKML 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 Thu, Mar 5, 2020 at 10:17 AM Alexey Dobriyan wrote: > > Comment says "by preventing anything executable" which is not true. > Even PROT_NONE mapping can't be installed at (1<<47 - 4096). > > mmap(0x7ffffffff000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = -1 ENOMEM Reviewed-by: Andy Lutomirski > > I wonder if CPUs with wider address space carried the bugs... I believe they do. I won't swear to it. FWIW, I specifically asked Intel to kindly fix this bug^Wfeature as part of LA57, and I did not get a helpful response.