From mboxrd@z Thu Jan 1 00:00:00 1970 From: Francesco Ruggeri Subject: Re: [PATCH net-next] macvlan: fix failure during registration v3 Date: Tue, 26 Apr 2016 12:07:24 -0700 Message-ID: References: <1461449012-7401-1-git-send-email-fruggeri@arista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: linux-netdev , "Eric W. Biederman" , "David S. Miller" To: Mahesh Bandewar Return-path: Received: from mail-oi0-f49.google.com ([209.85.218.49]:34697 "EHLO mail-oi0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752384AbcDZTHZ (ORCPT ); Tue, 26 Apr 2016 15:07:25 -0400 Received: by mail-oi0-f49.google.com with SMTP id k142so25570163oib.1 for ; Tue, 26 Apr 2016 12:07:25 -0700 (PDT) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Apr 26, 2016 at 11:54 AM, Mahesh Bandewar wrote: > > On Sat, Apr 23, 2016 at 3:03 PM, Francesco Ruggeri 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 > > --- > > 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. I don't think so. I think the double decrement also occurred in this case. unregister_netdevice invokes rollback_registered/macvlan_uninit which does the decrement. Thanks, Francesco > > > > return err; > > } > > -- > > 1.8.1.4 > >