bonding: fix event handling for stacked bonds

BugLink: https://bugs.launchpad.net/bugs/1838349
[ Upstream commit 92480b3977fd3884649d404cbbaf839b70035699 ]

When a bond is enslaved to another bond, bond_netdev_event() only
handles the event as if the bond is a master, and skips treating the
bond as a slave.

This leads to a refcount leak on the slave, since we don't remove the
adjacency to its master and the master holds a reference on the slave.

Reproducer:
  ip link add bondL type bond
  ip link add bondU type bond
  ip link set bondL master bondU
  ip link del bondL

No "Fixes:" tag, this code is older than git history.

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 448a12c12041097c9d8138e71d68eee9ba5fa2dd..eedbdeef9a8183b7da16dd9e3472baaf01006a36 100644 (file)
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -3183,8 +3183,12 @@ static int bond_netdev_event(struct notifier_block *this,
                return NOTIFY_DONE;
 
        if (event_dev->flags & IFF_MASTER) {
+               int ret;
+
                netdev_dbg(event_dev, "IFF_MASTER\n");
-               return bond_master_netdev_event(event, event_dev);
+               ret = bond_master_netdev_event(event, event_dev);
+               if (ret != NOTIFY_DONE)
+                       return ret;
        }
 
        if (event_dev->flags & IFF_SLAVE) {