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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 35346C3F2D2 for ; Fri, 28 Feb 2020 20:20:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 14A19246A8 for ; Fri, 28 Feb 2020 20:20:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727005AbgB1UUX (ORCPT ); Fri, 28 Feb 2020 15:20:23 -0500 Received: from out03.mta.xmission.com ([166.70.13.233]:42060 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726400AbgB1UUX (ORCPT ); Fri, 28 Feb 2020 15:20:23 -0500 Received: from in02.mta.xmission.com ([166.70.13.52]) by out03.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1j7m7S-0001W3-Bn; Fri, 28 Feb 2020 13:20:22 -0700 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.87) (envelope-from ) id 1j7m7R-0002lL-EH; Fri, 28 Feb 2020 13:20:22 -0700 From: ebiederm@xmission.com (Eric W. Biederman) To: Cc: Al Viro , Kernel Hardening , Linux API , Linux FS Devel , Linux Security Module , Akinobu Mita , Alexey Dobriyan , Andrew Morton , Andy Lutomirski , Daniel Micay , Djalal Harouni , "Dmitry V . Levin" , Greg Kroah-Hartman , Ingo Molnar , "J . Bruce Fields" , Jeff Layton , Jonathan Corbet , Kees Cook , Oleg Nesterov , Alexey Gladkov , Linus Torvalds , Jeff Dike , Richard Weinberger , Anton Ivanov References: <20200210150519.538333-8-gladkov.alexey@gmail.com> <87v9odlxbr.fsf@x220.int.ebiederm.org> <20200212144921.sykucj4mekcziicz@comp-core-i7-2640m-0182e6> <87tv3vkg1a.fsf@x220.int.ebiederm.org> <87v9obipk9.fsf@x220.int.ebiederm.org> <20200212200335.GO23230@ZenIV.linux.org.uk> <20200212203833.GQ23230@ZenIV.linux.org.uk> <20200212204124.GR23230@ZenIV.linux.org.uk> <87lfp7h422.fsf@x220.int.ebiederm.org> <87pnejf6fz.fsf@x220.int.ebiederm.org> <871rqpaswu.fsf_-_@x220.int.ebiederm.org> <871rqk2brn.fsf_-_@x220.int.ebiederm.org> <878skmsbyy.fsf_-_@x220.int.ebiederm.org> Date: Fri, 28 Feb 2020 14:18:14 -0600 In-Reply-To: <878skmsbyy.fsf_-_@x220.int.ebiederm.org> (Eric W. Biederman's message of "Fri, 28 Feb 2020 14:17:41 -0600") Message-ID: <8736ausby1.fsf_-_@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1j7m7R-0002lL-EH;;;mid=<8736ausby1.fsf_-_@x220.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1+WuHbOA66kXQc+ge/fBSMlwuwEjasAimw= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH 1/3] uml: Don't consult current to find the proc_mnt in mconsole_proc X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-api-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org Inspection of the control flow reveals that mconsole_proc is either called from mconsole_stop called from mc_work_proc or from mc_work_proc directly. The function mc_work_proc is dispatched to a kernel thread with schedule_work. All of the threads that run dispatched by schedule_work are in the init pid namespace. So make the code clearer and by using init_pid_ns instead of task_active_pid_ns(current). Cc: Jeff Dike Cc: Richard Weinberger Cc: Anton Ivanov Signed-off-by: "Eric W. Biederman" --- arch/um/drivers/mconsole_kern.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c index b80a1d616e4e..e8f5c81c2c6c 100644 --- a/arch/um/drivers/mconsole_kern.c +++ b/arch/um/drivers/mconsole_kern.c @@ -123,7 +123,7 @@ void mconsole_log(struct mc_request *req) void mconsole_proc(struct mc_request *req) { - struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt; + struct vfsmount *mnt = init_pid_ns.proc_mnt; char *buf; int len; struct file *file; -- 2.25.0