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=-7.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 4F178C433E1 for ; Wed, 27 May 2020 06:54:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1E5BB207CB for ; Wed, 27 May 2020 06:54:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1E5BB207CB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B4B3F800B7; Wed, 27 May 2020 02:54:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AFBA280010; Wed, 27 May 2020 02:54:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A11B5800B7; Wed, 27 May 2020 02:54:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0171.hostedemail.com [216.40.44.171]) by kanga.kvack.org (Postfix) with ESMTP id 9594180010 for ; Wed, 27 May 2020 02:54:23 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 5BC4E181AC9CB for ; Wed, 27 May 2020 06:54:23 +0000 (UTC) X-FDA: 76861585206.25.bean37_54045cc26d50 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin25.hostedemail.com (Postfix) with ESMTP id 3A5241804E3A1 for ; Wed, 27 May 2020 06:54:23 +0000 (UTC) X-HE-Tag: bean37_54045cc26d50 X-Filterd-Recvd-Size: 2207 Received: from huawei.com (szxga07-in.huawei.com [45.249.212.35]) by imf47.hostedemail.com (Postfix) with ESMTP for ; Wed, 27 May 2020 06:54:22 +0000 (UTC) Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 2983E3FD399042156E76; Wed, 27 May 2020 14:54:19 +0800 (CST) Received: from [127.0.0.1] (10.67.102.197) by DGGEMS404-HUB.china.huawei.com (10.3.19.204) with Microsoft SMTP Server id 14.3.487.0; Wed, 27 May 2020 14:54:14 +0800 To: , , , , , , , , , , , , , , , , , , , , From: Xiaoming Ni Subject: Re: [PATCH v2 1/1] userfaultfd/sysctl: add vm.unprivileged_userfaultfd Message-ID: <3b64de85-beb4-5a07-0093-cad6e8f2a8d8@huawei.com> Date: Wed, 27 May 2020 14:54:13 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 Content-Type: text/plain; charset="gbk"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.102.197] X-CFilter-Loop: Reflected X-Rspamd-Queue-Id: 3A5241804E3A1 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam01 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Mar 19, 2019 at 11:07:22AM +0800, Peter Xu wrote: > Add a global sysctl knob "vm.unprivileged_userfaultfd" to control > whether userfaultfd is allowed by unprivileged users. When this is > set to zero, only privileged users (root user, or users with the > CAP_SYS_PTRACE capability) will be able to use the userfaultfd > syscalls. Hello I am a bit confused about this patch, can you help to answer it. Why the sysctl interface of fs/userfaultfd.c belongs to vm_table instead of fs_table ? https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cefdca0a86be517bc390fc4541e3674b8e7803b0 Thanks Xiaoming Ni