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unregister_netdevice : move RTM_DELLINK to until after ndo_uninit

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This patch fixes ordering of rtnl notifications during unregister_netdevice
by moving RTM_DELLINK notification to until after ndo_uninit.

The problem was seen with unregistering bond netdevices.

bond ndo_uninit callback generates a few RTM_NEWLINK notifications for
NETDEV_CHANGEADDR and NETDEV_FEAT_CHANGE. This is seen mostly when the
bond is deleted with slaves still enslaved to the bond.

During unregister netdevice (rollback_registered_many to be specific)
bond ndo_uninit is called after RTM_DELLINK notification goes out.
This results in userspace seeing RTM_DELLINK followed by a couple of
RTM_NEWLINK's.

In userspace problem was seen with libnl. libnl cache deletes the bond
when it sees RTM_DELLINK and re-adds the bond with the following
RTM_NEWLINK. Resulting in a stale bond entry in libnl cache when the kernel
has already deleted the bond.

This patch has been tested for bond, bridges and vlan devices.

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Roopa Prabhu 2014-05-01 11:40:30 -07:00 committed by David S. Miller
parent f4a7b5eec2
commit 56bfa7ee7c
1 changed files with 4 additions and 4 deletions
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8
net/core/dev.c
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@ -5606,10 +5606,6 @@ static void rollback_registered_many(struct list_head *head)
*/
call_netdevice_notifiers(NETDEV_UNREGISTER, dev);
if (!dev->rtnl_link_ops ||
dev->rtnl_link_state == RTNL_LINK_INITIALIZED)
rtmsg_ifinfo(RTM_DELLINK, dev, ~0U, GFP_KERNEL);
/*
* Flush the unicast and multicast chains
*/
@ -5619,6 +5615,10 @@ static void rollback_registered_many(struct list_head *head)
if (dev->netdev_ops->ndo_uninit)
dev->netdev_ops->ndo_uninit(dev);
if (!dev->rtnl_link_ops ||
dev->rtnl_link_state == RTNL_LINK_INITIALIZED)
rtmsg_ifinfo(RTM_DELLINK, dev, ~0U, GFP_KERNEL);
/* Notifier chain MUST detach us all upper devices. */
WARN_ON(netdev_has_any_upper_dev(dev));