2019-05-13, 17:13:36 +0200, Nicolas Dichtel wrote:
> Le 13/05/2019 à 17:08, Sabrina Dubroca a écrit :
> > 2019-05-13, 16:50:51 +0200, Nicolas Dichtel wrote:
> >> Le 13/05/2019 à 15:47, Sabrina Dubroca a écrit :
> >>> Currently, nla_put_iflink() doesn't put the IFLA_LINK attribute when
> >>> iflink == ifindex.
> >>>
> >>> In some cases, a device can be created in a different netns with the
> >>> same ifindex as its parent. That device will not dump its IFLA_LINK
> >>> attribute, which can confuse some userspace software that expects it.
> >>> For example, if the last ifindex created in init_net and foo are both
> >>> 8, these commands will trigger the issue:
> >>>
> >>> ip link add parent type dummy # ifindex 9
> >>> ip link add link parent netns foo type macvlan # ifindex 9 in ns foo
> >>>
> >>> So, in case a device puts the IFLA_LINK_NETNSID attribute in a dump,
> >>> always put the IFLA_LINK attribute as well.
> >>>
> >>> Thanks to Dan Winship for analyzing the original OpenShift bug down to
> >>> the missing netlink attribute.
> >>>
> >>> Analyzed-by: Dan Winship <d...@redhat.com>
> >>> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> >> I would say:
> >> Fixes: 5e6700b3bf98 ("sit: add support of x-netns")
> >>
> >> Because before this patch, there was no device with an iflink that can be
> >> put in
> >> another netns.
> >
> > That tells us how far back we might want to backport this fix, but not
> > which commit introduced the bug. I think Fixes should refer to the
> > introduction of the faulty code, not to what patch made it visible (if
> > we can find both).
> No sure to follow you. The problem you describe cannot happen before commit
> 5e6700b3bf98, so there cannot be a "faulty" patch before that commit.
What about macvlan devices?
>From commit b863ceb7ddce ("[NET]: Add macvlan driver"):
static int macvlan_init(struct net_device *dev)
{
...
dev->iflink = lowerdev->ifindex;
...
}
vlan devices also had an iflink assigned since commit ddd7bf9fe4e5.
What am I missing?
--
Sabrina
