netns: fix addrconf_ifdown kernel panic
When a network namespace is destroyed the network interfaces are
all unregistered, making addrconf_ifdown called by the netdevice
notifier.
In the other hand, the addrconf exit method does a loop on the network
devices and does addrconf_ifdown on each of them. But the ordering of
the netns subsystem is not right because it uses the register_pernet_device
instead of register_pernet_subsys. If we handle the loopback as
any network device, we can safely use register_pernet_subsys.
But if we use register_pernet_subsys, the addrconf exit method will do
exactly what was already done with the unregistering of the network
devices. So in definitive, this code is pointless.
I removed the netns addrconf exit method and moved the code to the
addrconf cleanup function.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 40fabde..1220e2c 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2611,9 +2611,6 @@
ASSERT_RTNL();
- if ((dev->flags & IFF_LOOPBACK) && how == 1)
- how = 0;
-
rt6_ifdown(net, dev);
neigh_ifdown(&nd_tbl, dev);
@@ -4448,25 +4445,6 @@
EXPORT_SYMBOL(unregister_inet6addr_notifier);
-static void addrconf_net_exit(struct net *net)
-{
- struct net_device *dev;
-
- rtnl_lock();
- /* clean dev list */
- for_each_netdev(net, dev) {
- if (__in6_dev_get(dev) == NULL)
- continue;
- addrconf_ifdown(dev, 1);
- }
- addrconf_ifdown(net->loopback_dev, 2);
- rtnl_unlock();
-}
-
-static struct pernet_operations addrconf_net_ops = {
- .exit = addrconf_net_exit,
-};
-
/*
* Init / cleanup code
*/
@@ -4508,10 +4486,6 @@
if (err)
goto errlo;
- err = register_pernet_device(&addrconf_net_ops);
- if (err)
- return err;
-
register_netdevice_notifier(&ipv6_dev_notf);
addrconf_verify(0);
@@ -4541,15 +4515,22 @@
void addrconf_cleanup(void)
{
struct inet6_ifaddr *ifa;
+ struct net_device *dev;
int i;
unregister_netdevice_notifier(&ipv6_dev_notf);
- unregister_pernet_device(&addrconf_net_ops);
-
unregister_pernet_subsys(&addrconf_ops);
rtnl_lock();
+ /* clean dev list */
+ for_each_netdev(&init_net, dev) {
+ if (__in6_dev_get(dev) == NULL)
+ continue;
+ addrconf_ifdown(dev, 1);
+ }
+ addrconf_ifdown(init_net.loopback_dev, 2);
+
/*
* Check hash table.
*/
@@ -4570,6 +4551,4 @@
del_timer(&addr_chk_timer);
rtnl_unlock();
-
- unregister_pernet_subsys(&addrconf_net_ops);
}