Re: [BUG] stable v3.10.16+ introduced by "ip6tnl: allow to use rtnlops on fb tunnel"

[Nicolas Dichtel]

Le 11/12/2013 22:53, David Miller a écrit :
> From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Date: Sun, 8 Dec 2013 16:25:31 -0800
>
> > On Wed, Nov 13, 2013 at 09:14:30PM -0500, Steven Rostedt wrote:
> > > +++ b/net/ipv6/ip6_tunnel.c
> > > @@ -1731,8 +1731,6 @@ static void __net_exit ip6_tnl_destroy_tunnels(struct ip
> > >                  }
> > >          }
> > >
> > > -       t = rtnl_dereference(ip6n->tnls_wc[0]);
> > > -       unregister_netdevice_queue(t->dev, &list);
> > >          unregister_netdevice_many(&list);
> > >   }
> > >
> > >
> > > Which, when applied to 3.10.18, fixes the bug. Was there a reason that
> > > this part of the commit wasn't backported? or was this just an oversight?
> >
> > It looks like it was left out to me as well.
> >
> > David, any objection to me making this fixup in the 3.10-stable tree?
>
> The original patch submitted told me to leave this part of the patch
> out of the backport, explaining that it wasn't necessary in older
> kernels.
Yes, and this was right (in upstream commit, I remove this part because
the fb device is deleted by the loop which check dev->rtnl_ops) , but ...

> Can someone please sort this out?
>
> Nicolas please provide some guidance here, thanks.
The original patch left a bug, which was fixed upstream with this commit:
1e9f3d6f1c40 ip6tnl: fix use after free of fb_tnl_dev

The problem is a bit different in 3.10.y, because there is no x-vrf support.
When ip6_tunnel.ko is unloaded, FB device is deleted by rtnl_link_unregister()
and then we try to delete it again in ip6_tnl_destroy_tunnels().
Thus the fix is different and in fact, the above patch is good.

Steven, will you submit this patch properly or should I do this?
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