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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 E5ECFC433E2 for ; Fri, 19 Mar 2021 15:16:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B9FF261929 for ; Fri, 19 Mar 2021 15:16:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230041AbhCSPPr (ORCPT ); Fri, 19 Mar 2021 11:15:47 -0400 Received: from mga07.intel.com ([134.134.136.100]:57445 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230190AbhCSPPj (ORCPT ); Fri, 19 Mar 2021 11:15:39 -0400 IronPort-SDR: mrmqTzXK/04Ycy+cJvBvbMh6+C0X2IJ6CXiJ+h0o86ZTDcAwvYukWsi713bJIrPAtLE5laoWiR 3tw/BTl/mn5g== X-IronPort-AV: E=McAfee;i="6000,8403,9928"; a="253912336" X-IronPort-AV: E=Sophos;i="5.81,262,1610438400"; d="scan'208";a="253912336" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Mar 2021 08:15:35 -0700 IronPort-SDR: xqCql09qCKZCcyUj9naOiIO6KtbsHf2bUgXg7u6ReJH6uqO28nq/GVC31qrzwCLql1HWkoZgk8 EoNy+lU/ZQMQ== X-IronPort-AV: E=Sophos;i="5.81,262,1610438400"; d="scan'208";a="450895952" Received: from yyu32-mobl1.amr.corp.intel.com (HELO [10.209.156.180]) ([10.209.156.180]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Mar 2021 08:15:33 -0700 Subject: Re: [PATCH v23 22/28] x86/cet/shstk: User-mode shadow stack support To: Borislav Petkov Cc: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang , Pengfei Xu , Haitao Huang References: <20210316151054.5405-1-yu-cheng.yu@intel.com> <20210316151054.5405-23-yu-cheng.yu@intel.com> <20210318123215.GE19570@zn.tnic> <20210319092806.GB6251@zn.tnic> From: "Yu, Yu-cheng" Message-ID: <3144b030-0f90-717b-b373-2d0b346010c8@intel.com> Date: Fri, 19 Mar 2021 08:15:33 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <20210319092806.GB6251@zn.tnic> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/19/2021 2:28 AM, Borislav Petkov wrote: > On Thu, Mar 18, 2021 at 12:05:58PM -0700, Yu, Yu-cheng wrote: >> Maybe I would add comments here. > > Yap. > > Also, looking forward in the set, I see prctl_set() and that is also > done on current so should be ok. > > In any case, yes, documenting the assumptions and expectations wrt > current here is a good idea. > >> If vm_munmap() returns -EINTR, mmap_lock is held by something else. That >> lock should not be held forever. For other types of error, the loop stops. > > Ok I guess. The subsequent WARN_ON_ONCE() looks weird too but that > should not fire, right? :) > > Thx. > That should not fire. Yu-cheng