On Sat, Apr 23, 2016 at 3:03 PM, Francesco Ruggeri <frugg...@arista.com> wrote:
> If macvlan_common_newlink fails in register_netdevice after macvlan_init
> then it decrements port->count twice, first in macvlan_uninit (from
> register_netdevice or rollback_registered) and then again in
> macvlan_common_newlink.
> A similar problem may exist in the ipvlan driver.
That is correct! The problem exists in ipvlan driver also. I'll cook a
patch to fix this in ipvlan driver.
> This patch consolidates modifications to port->count into macvlan_init
> and macvlan_uninit (thanks to Eric Biederman for suggesting this approach).
>
> v3: remove macvtap specific bits.
>
> Signed-off-by: Francesco Ruggeri <frugg...@arista.com>
> ---
> drivers/net/macvlan.c | 10 ++++------
> 1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
> index 2bcf1f3..cb01023 100644
> --- a/drivers/net/macvlan.c
> +++ b/drivers/net/macvlan.c
> @@ -795,6 +795,7 @@ static int macvlan_init(struct net_device *dev)
> {
> struct macvlan_dev *vlan = netdev_priv(dev);
> const struct net_device *lowerdev = vlan->lowerdev;
> + struct macvlan_port *port = vlan->port;
>
> dev->state = (dev->state & ~MACVLAN_STATE_MASK) |
> (lowerdev->state & MACVLAN_STATE_MASK);
> @@ -812,6 +813,8 @@ static int macvlan_init(struct net_device *dev)
> if (!vlan->pcpu_stats)
> return -ENOMEM;
>
> + port->count += 1;
> +
> return 0;
> }
>
> @@ -1312,10 +1315,9 @@ int macvlan_common_newlink(struct net *src_net, struct
> net_device *dev,
> return err;
> }
>
> - port->count += 1;
> err = register_netdevice(dev);
> if (err < 0)
> - goto destroy_port;
> + return err;
>
> dev->priv_flags |= IFF_MACVLAN;
> err = netdev_upper_dev_link(lowerdev, dev);
> @@ -1330,10 +1332,6 @@ int macvlan_common_newlink(struct net *src_net, struct
> net_device *dev,
>
> unregister_netdev:
> unregister_netdevice(dev);
> -destroy_port:
> - port->count -= 1;
> - if (!port->count)
> - macvlan_port_destroy(lowerdev);
I think you still need this when it fails netdev_upper_dev_link(). The
only thing you should remove is the label.
>
> return err;
> }
> --
> 1.8.1.4
>
