Received: by 2002:ac0:a5b6:0:0:0:0:0 with SMTP id m51-v6csp35381imm;
        Thu, 7 Jun 2018 13:19:23 -0700 (PDT)
X-Google-Smtp-Source: ADUXVKJGEwoMN/8P8RsV2fTS72T9xWf/HOVc86ryRvitwmfCJXDC4MusE3ytRb7DUk1AQGHKRrw3
X-Received: by 2002:a63:7341:: with SMTP id d1-v6mr2693350pgn.404.1528402763455;
        Thu, 07 Jun 2018 13:19:23 -0700 (PDT)
ARC-Seal: i=1; a=rsa-sha256; t=1528402763; cv=none;
        d=google.com; s=arc-20160816;
        b=ti5GuTgkK5sdM9uH//pfhFBMN4jLlmrOZLv5NktgJETC3QcS27l52ei2CEzJ5OUfxs
         uqujxti9xc3vV2vGVQGWzaArsrgdPNZMqgM1w/RZHwQ1nvyXAM25nfg8dCBif+dmV6Wb
         rvM6OcCvpvpRBiXEbJ7iiEcz0unRyVai92ruZ8wiAVDiZFCEKsqXM7e3j9c/0RWp9yjS
         zrzFdHQt+68/KdnvBpWBkSFC4TvlRmT0kdGRFsxMeWSxSR/P94VZ4zktO5jpHBh86s8x
         83HRjM5nr2dkaPTv97XLd+ytZOpBmaSx5f7wIJD0uwVBG0g6mu30tatpjmOPMx7HKsGT
         VXMQ==
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816;
        h=list-id:precedence:sender:content-transfer-encoding:mime-version
         :references:in-reply-to:date:cc:to:from:subject:message-id
         :arc-authentication-results;
        bh=eeTz4/obZH/3mwGZlg618jOsrly6w4iA2tzaevuhGe8=;
        b=ZkXvCv7natQr3bvRbEEdOP7fExcwJdLuheiKPUMBDkBiWd+/AKJIVQhaAHomT3wJc5
         ub4KY8CtLV6YAIKp8BsP0+PDoxC6OLuhifimLc105sVaNRaag3Gq130A/zj1NQvEmOH4
         CFw3VNBtC2Y9gQ8L2Ae0bY3aYdY8+1koj4XFqla8gSJ4u5f30HN/koEhHw8Tlcl2a2mN
         1nwh/JTZVOWjm4NytIpYqY6fzNu1astcNa5NgCTtCpHqT5WuTUbAqjTb+LnCmoiJmmf4
         T3NldpzY6kNZiWCdaJRs+HXW55WileqYvPw7GJKAJiElE1ycMNWXcVVDS5OkFbvxZ9Lt
         Yipg==
ARC-Authentication-Results: i=1; mx.google.com;
       spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org;
       dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67])
        by mx.google.com with ESMTP id e95-v6si14399341plb.239.2018.06.07.13.19.08;
        Thu, 07 Jun 2018 13:19:23 -0700 (PDT)
Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Authentication-Results: mx.google.com;
       spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org;
       dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1753529AbeFGUSO (ORCPT <rfc822;yuankui.zhao@gmail.com>
        + 99 others); Thu, 7 Jun 2018 16:18:14 -0400
Received: from mga03.intel.com ([134.134.136.65]:5897 "EHLO mga03.intel.com"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1751155AbeFGUSN (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 7 Jun 2018 16:18:13 -0400
X-Amp-Result: SKIPPED(no attachment in message)
X-Amp-File-Uploaded: False
Received: from fmsmga003.fm.intel.com ([10.253.24.29])
  by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Jun 2018 13:18:12 -0700
X-ExtLoop1: 1
X-IronPort-AV: E=Sophos;i="5.49,487,1520924400"; 
   d="scan'208";a="55592618"
Received: from 2b52.sc.intel.com (HELO [143.183.136.51]) ([143.183.136.51])
  by FMSMGA003.fm.intel.com with ESMTP; 07 Jun 2018 13:18:12 -0700
Message-ID: <1528402501.5265.23.camel@2b52.sc.intel.com>
Subject: Re: [PATCH 10/10] mm: Prevent munmap and remap_file_pages of shadow
 stack
From:   Yu-cheng Yu <yu-cheng.yu@intel.com>
To:     Andy Lutomirski <luto@kernel.org>
Cc:     LKML <linux-kernel@vger.kernel.org>, linux-doc@vger.kernel.org,
        Linux-MM <linux-mm@kvack.org>,
        linux-arch <linux-arch@vger.kernel.org>, X86 ML <x86@kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        "H. J. Lu" <hjl.tools@gmail.com>,
        "Shanbhogue, Vedvyas" <vedvyas.shanbhogue@intel.com>,
        "Ravi V. Shankar" <ravi.v.shankar@intel.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Oleg Nesterov <oleg@redhat.com>, Arnd Bergmann <arnd@arndb.de>,
        mike.kravetz@oracle.com
Date:   Thu, 07 Jun 2018 13:15:01 -0700
In-Reply-To: <CALCETrXTyXYCDJxbCA+cbzZirmMKRQq8XSS4+Lyeo_QMywdxFw@mail.gmail.com>
References: <20180607143807.3611-1-yu-cheng.yu@intel.com>
         <20180607143807.3611-11-yu-cheng.yu@intel.com>
         <CALCETrXTyXYCDJxbCA+cbzZirmMKRQq8XSS4+Lyeo_QMywdxFw@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
X-Mailer: Evolution 3.10.4-0ubuntu2 
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, 2018-06-07 at 11:50 -0700, Andy Lutomirski wrote:
> On Thu, Jun 7, 2018 at 7:41 AM Yu-cheng Yu <yu-cheng.yu@intel.com> wrote:
> 
> blocking remap_file_pages() seems reasonable.  I'm not sure what's
> wrong with munmap().

Yes, maybe we don't need to block munmap().  If the shadow stack is
unmapped, the application gets a fault.  I will remove the patch.