On 6/21/17 5:34 PM, Cong Wang wrote: > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c > index 686c923..1d2dbac 100644 > --- a/net/ipv6/addrconf.c > +++ b/net/ipv6/addrconf.c > @@ -3369,6 +3369,7 @@ static int addrconf_notify(struct notifier_block *this, > unsigned long event, > struct net_device *dev = netdev_notifier_info_to_dev(ptr); > struct netdev_notifier_changeupper_info *info; > struct inet6_dev *idev = __in6_dev_get(dev); > + struct net *net = dev_net(dev);
Given the number of NETDEV events and the fact that only 2 need net, perhaps the dev_net(dev) should be inline ... > int run_pending = 0; > int err; > > @@ -3384,7 +3385,7 @@ static int addrconf_notify(struct notifier_block *this, > unsigned long event, > case NETDEV_CHANGEMTU: > /* if MTU under IPV6_MIN_MTU stop IPv6 on this interface. */ > if (dev->mtu < IPV6_MIN_MTU) { > - addrconf_ifdown(dev, 1); > + addrconf_ifdown(dev, dev != net->loopback_dev); so: addrconf_ifdown(dev, dev != dev_net(dev)->loopback_dev); > break; > } > > @@ -3500,7 +3501,7 @@ static int addrconf_notify(struct notifier_block *this, > unsigned long event, > * IPV6_MIN_MTU stop IPv6 on this interface. > */ > if (dev->mtu < IPV6_MIN_MTU) > - addrconf_ifdown(dev, 1); > + addrconf_ifdown(dev, dev != net->loopback_dev); > } > break; > > The overall idea of not destroying idev for loopback on a failure to set MTU seems correct to me. Acked-by: David Ahern <dsah...@gmail.com>