From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751883AbcBWXVq (ORCPT ); Tue, 23 Feb 2016 18:21:46 -0500 Received: from shards.monkeyblade.net ([149.20.54.216]:42184 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751611AbcBWXVn (ORCPT ); Tue, 23 Feb 2016 18:21:43 -0500 Date: Tue, 23 Feb 2016 18:21:21 -0500 (EST) Message-Id: <20160223.182121.2101846699151527296.davem@davemloft.net> To: khlebnikov@yandex-team.ru Cc: netdev@vger.kernel.org, containers@lists.linux-foundation.org, vvs@virtuozzo.com, linux-kernel@vger.kernel.org, ebiederm@xmission.com Subject: Re: [PATCH] ipv4: in new netns initialize sysctls in net.ipv4.conf.* with defaults From: David Miller In-Reply-To: <20160221071102.9686.63148.stgit@buzz> References: <20160221071102.9686.63148.stgit@buzz> X-Mailer: Mew version 6.7 on Emacs 24.5 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Tue, 23 Feb 2016 15:21:43 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Konstantin Khlebnikov Date: Sun, 21 Feb 2016 10:11:02 +0300 > Currently initial net.ipv4.conf.all.* and net.ipv4.conf.default.* are > copied from init network namespace because static structures are used > for init_net. This makes no sense because new netns might be created > from any netns. This patch makes private copy also for init netns if > network namespaces are enabled. Other sysctls in net.ipv4 and net.ipv6 > already initialized with default values at namespace creation. > > Signed-off-by: Konstantin Khlebnikov > Fixes: 752d14dc6aa9 ("[IPV4]: Move the devinet pointers on the struct net") The horse has long left the stable on this. We cannot change this now without breaking things. Imagine someone who intentionally sets up init_net with a certain set of settings and expects them to propagate into every created namespace. We'll break things for them and given the behavior existed for so long what the administrator is doing is very reasonable. I'm not applying this sorry, we are stuck with the current behavior whether we like it or not.