From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcel Holtmann Subject: Re: [PATCH] net: Fix userspace RTM_NEWLINK notifications. Date: Mon, 14 Dec 2009 03:05:36 +0100 Message-ID: <1260756336.4041.3.camel@localhost.localdomain> References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: David Miller , netdev@vger.kernel.org, stable@kernel.org To: "Eric W. Biederman" Return-path: Received: from senator.holtmann.net ([87.106.208.187]:52644 "EHLO mail.holtmann.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753958AbZLNCFr (ORCPT ); Sun, 13 Dec 2009 21:05:47 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Hi Eric, > I received some bug reports about userspace programs having problems > because after RTM_NEWLINK was received they could not immediate access > files under /proc/sys/net/ because they had not been registered yet. > > The original problem was trivially fixed by moving the userspace > notification from rtnetlink_event() to the end of > register_netdevice(). > > When testing that change I discovered I was still getting RTM_NEWLINK > events before I could access proc and I was also getting RTM_NEWLINK > events after I was seeing RTM_DELLINK. Things practically guaranteed > to confuse userspace. > > After a little more investigation these extra notifications proved to > be from the new notifiers NETDEV_POST_INIT and NETDEV_UNREGISTER_BATCH > hitting the default case in rtnetlink_event, and triggering > unnecessary RTM_NEWLINK messages. > > rtnetlink_event now explicitly handles NETDEV_UNREGISTER_BATCH and > NETDEV_POST_INIT to avoid sending the incorrect userspace > notifications. the POST_INIT and UNREGISTER_BATCH are not 2.6.32 features. They are 2.6.33 features and thus you need to create a separate patch for -stable if you wanna fix the /proc access issue. Regards Marcel