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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 6E28BC352AA for ; Tue, 1 Oct 2019 22:54:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 48FD6215EA for ; Tue, 1 Oct 2019 22:54:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727399AbfJAWyV (ORCPT ); Tue, 1 Oct 2019 18:54:21 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:35958 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726050AbfJAWyV (ORCPT ); Tue, 1 Oct 2019 18:54:21 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out01.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1iFR24-00043h-FL; Tue, 01 Oct 2019 16:54:12 -0600 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 1iFR1y-00061d-Ku; Tue, 01 Oct 2019 16:54:12 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Kees Cook Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Linus Torvalds , Andi Kleen , Andi Kleen , Cong Wang , Luis Chamberlain , Apelete Seketeli , Arnd Bergmann , Chee Nouk Phoon , Chris Zankel , Christian Ruppert , Greg Ungerer , Helge Deller , Hongliang Tao , Huacai Chen , Jonas Jensen , Josh Boyer , Jun Nie , Lars-Peter Clausen , Ley Foon Tan , Linus Walleij , Max Filippov , Olof Johansson , Paul Burton , Phil Edworthy , Pierrick Hascoet , Ralf Baechle , Roland Stigge , Vineet Gupta References: <8736gcjosv.fsf@x220.int.ebiederm.org> <201910011140.EA0181F13@keescook> Date: Tue, 01 Oct 2019 17:53:27 -0500 In-Reply-To: <201910011140.EA0181F13@keescook> (Kees Cook's message of "Tue, 1 Oct 2019 11:46:45 -0700") Message-ID: <87imp8hyc8.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=1iFR1y-00061d-Ku;;;mid=<87imp8hyc8.fsf@x220.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1890sJnTfB2radGtM5zpN9fbLEpYr3LK/s= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [RFC][PATCH] sysctl: Remove the sysctl system call 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-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Kees Cook writes: > On Tue, Oct 01, 2019 at 01:36:32PM -0500, Eric W. Biederman wrote: >> >> This system call has been deprecated almost since it was introduced, and >> in a survey of the linux distributions I can no longer find any of them >> that enable CONFIG_SYSCTL_SYSCALL. The only indication that I can find >> that anyone might care is that a few of the defconfigs in the kernel >> enable CONFIG_SYSCTL_SYSCALL. However this appears in only 31 of 414 >> defconfigs in the kernel, so I suspect this symbols presence is simply >> because it is harmless to include rather than because it is necessary. >> >> As there appear to be no users of the sysctl system call, remove the >> code. As this removes one of the few uses of the internal kernel mount >> of proc I hope this allows for even more simplifications of the proc >> filesystem. > > I'm for it. :) I tripped over this being deprecated over a decade ago. :P > > I think you can actually take this further and remove (or at least > empty) the uapi/linux/sysctl.h file too. I copied everyone who had put this into a defconfig and I will wait a little more to see if anyone screams. I think it is a safe guess that several of the affected configurations are dead (or at least unmaintained) as I received 17 bounces when copying everyone. I would make it a followup that removes uapi/linux/sysctl.h. I don't see anything in it that isn't about the sysctl system call. I will keep it a separate patch as I can imagine something silly that needs the header file to compile. A separate patch would make a revert easier if we find something like that. Eric