From 6101391d4a381cc0c661d8765235b3cad7da09e5 Mon Sep 17 00:00:00 2001 From: "nikolay@redhat.com" Date: Thu, 11 Apr 2013 09:18:55 +0000 Subject: [PATCH] bonding: fix netdev event NULL pointer dereference In commit 471cb5a33dcbd7c529684a2ac7ba4451414ee4a7 ("bonding: remove usage of dev->master") a bug was introduced which causes a NULL pointer dereference. If a bond device is in mode 6 (ALB) and a slave is added it will dereference a NULL pointer in bond_slave_netdev_event(). This is because in bond_enslave we have bond_alb_init_slave() which changes the MAC address of the slave and causes a NETDEV_CHANGEADDR. Then we have in bond_slave_netdev_event(): struct slave *slave = bond_slave_get_rtnl(slave_dev); struct bonding *bond = slave->bond; bond_slave_get_rtnl() dereferences slave_dev->rx_handler_data which at that time is NULL since netdev_rx_handler_register() is called later. This is fixed by checking if slave is NULL before dereferencing it. v2: Comment style changed. Signed-off-by: Nikolay Aleksandrov Signed-off-by: David S. Miller --- drivers/net/bonding/bond_main.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 07401a3e256b..e074c6b55517 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -3168,11 +3168,20 @@ static int bond_slave_netdev_event(unsigned long event, struct net_device *slave_dev) { struct slave *slave = bond_slave_get_rtnl(slave_dev); - struct bonding *bond = slave->bond; - struct net_device *bond_dev = slave->bond->dev; + struct bonding *bond; + struct net_device *bond_dev; u32 old_speed; u8 old_duplex; + /* A netdev event can be generated while enslaving a device + * before netdev_rx_handler_register is called in which case + * slave will be NULL + */ + if (!slave) + return NOTIFY_DONE; + bond_dev = slave->bond->dev; + bond = slave->bond; + switch (event) { case NETDEV_UNREGISTER: if (bond->setup_by_slave) -- 2.30.2