From: ebiederm@xmission.com (Eric W. Biederman) Subject: [PATCH] netns: foreach_netdev_safe is insufficient in default_device_exit Date: Sun, 28 Dec 2008 00:10:35 -0800 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: To: David Miller Return-path: Received: from out02.mta.xmission.com ([166.70.13.232]:43908 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751789AbYL1IRV (ORCPT ); Sun, 28 Dec 2008 03:17:21 -0500 Sender: netdev-owner@vger.kernel.org List-ID: During network namespace teardown we either move or delete all of the network devices associated with a network namespace. In the case of veth devices deleting one will also delete it's pair device. If both devices are in the same network namespace then for_each_netdev_safe is insufficient as next may point to the second veth device we have deleted. To avoid problems I do what we do in __rtnl_kill_links and restart the scan of the device list, after we have deleted a device. Currently dev_change_netnamespace does not appear to suffer from this problem, but wireless devices are also paired and likely should be moved between network namespaces together. So I have errored on the side of caution and restart the scan of the network devices in that case as well. Signed-off-by: Eric W. Biederman --- net/core/dev.c | 8 +++++--- 1 files changed, 5 insertions(+), 3 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index daca72e..1f154d2 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5059,13 +5059,14 @@ static struct pernet_operations __net_initdata netdev_net_ops = { static void __net_exit default_device_exit(struct net *net) { - struct net_device *dev, *next; + struct net_device *dev; /* * Push all migratable of the network devices back to the * initial network namespace */ rtnl_lock(); - for_each_netdev_safe(net, dev, next) { +restart: + for_each_netdev(net, dev) { int err; char fb_name[IFNAMSIZ]; @@ -5076,7 +5077,7 @@ static void __net_exit default_device_exit(struct net *net) /* Delete virtual devices */ if (dev->rtnl_link_ops && dev->rtnl_link_ops->dellink) { dev->rtnl_link_ops->dellink(dev); - continue; + goto restart; } /* Push remaing network devices to init_net */ @@ -5087,6 +5088,7 @@ static void __net_exit default_device_exit(struct net *net) __func__, dev->name, err); BUG(); } + goto restart; } rtnl_unlock(); } -- 1.5.3.rc6.17.g1911