From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next] net: ipv6: Fix refcnt on host routes Date: Thu, 03 Mar 2016 17:26:45 -0500 (EST) Message-ID: <20160303.172645.1966494270005653336.davem@davemloft.net> References: <1456947007-32444-1-git-send-email-dsa@cumulusnetworks.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, avagin@gmail.com, ying.huang@linux.intel.com To: dsa@cumulusnetworks.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:48367 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758487AbcCCW0r (ORCPT ); Thu, 3 Mar 2016 17:26:47 -0500 In-Reply-To: <1456947007-32444-1-git-send-email-dsa@cumulusnetworks.com> Sender: netdev-owner@vger.kernel.org List-ID: From: David Ahern Date: Wed, 2 Mar 2016 11:30:07 -0800 > Andrew and Ying Huang's test robot both reported usage count problems that > trace back to the 'keep address on ifdown' patch. > > From Andrew: > We execute CRIU test on linux-next. On the current linux-next kernel > they hangs on creating a network namespace. > > The kernel log contains many massages like this: > [ 1036.122108] unregister_netdevice: waiting for lo to become free. > Usage count = 2 > [ 1046.165156] unregister_netdevice: waiting for lo to become free. > Usage count = 2 > [ 1056.210287] unregister_netdevice: waiting for lo to become free. > Usage count = 2 > > I tried to revert this patch and the bug disappeared. > > Here is a set of commands to reproduce this bug: > > [root@linux-next-test linux-next]# uname -a > Linux linux-next-test 4.5.0-rc6-next-20160301+ #3 SMP Wed Mar 2 > 17:32:18 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux > > [root@linux-next-test ~]# unshare -n > [root@linux-next-test ~]# ip link set up dev lo > [root@linux-next-test ~]# ip a > 1: lo: mtu 65536 qdisc noqueue state UNKNOWN > group default qlen 1 > link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 > inet 127.0.0.1/8 scope host lo > valid_lft forever preferred_lft forever > inet6 ::1/128 scope host > valid_lft forever preferred_lft forever > [root@linux-next-test ~]# logout > [root@linux-next-test ~]# unshare -n > > ----- > > The problem is a change made to RTM_DELADDR case in __ipv6_ifa_notify that > was added in an early version of the offending patch and is no longer > needed. > > Fixes: f1705ec197e7 ("net: ipv6: Make address flushing on ifdown optional") > Cc: Andrey Wagin > Cc: Ying Huang > Signed-off-by: David Ahern Applied, thanks David.