bonding: fix rx_handler locking
This prevents possible race between bond_enslave and bond_handle_frame
as reported by Nicolas by moving rx_handler register/unregister.
slave->bond is added to hold pointer to master bonding sructure. That
way dev->master is no longer used in bond_handler_frame.
Also, this removes "BUG: scheduling while atomic" message
Reported-by: Nicolas de Pesloüan <nicolas.2p.debian@gmail.com>
Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: Andy Gospodarek <andy@greyhouse.net>
Tested-by: Nicolas de Pesloüan <nicolas.2p.debian@free.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 338bea1..16d6fe9 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1482,21 +1482,16 @@
{
struct sk_buff *skb = *pskb;
struct slave *slave;
- struct net_device *bond_dev;
struct bonding *bond;
- slave = bond_slave_get_rcu(skb->dev);
- bond_dev = ACCESS_ONCE(slave->dev->master);
- if (unlikely(!bond_dev))
- return RX_HANDLER_PASS;
-
skb = skb_share_check(skb, GFP_ATOMIC);
if (unlikely(!skb))
return RX_HANDLER_CONSUMED;
*pskb = skb;
- bond = netdev_priv(bond_dev);
+ slave = bond_slave_get_rcu(skb->dev);
+ bond = slave->bond;
if (bond->params.arp_interval)
slave->dev->last_rx = jiffies;
@@ -1505,10 +1500,10 @@
return RX_HANDLER_EXACT;
}
- skb->dev = bond_dev;
+ skb->dev = bond->dev;
if (bond->params.mode == BOND_MODE_ALB &&
- bond_dev->priv_flags & IFF_BRIDGE_PORT &&
+ bond->dev->priv_flags & IFF_BRIDGE_PORT &&
skb->pkt_type == PACKET_HOST) {
if (unlikely(skb_cow_head(skb,
@@ -1516,7 +1511,7 @@
kfree_skb(skb);
return RX_HANDLER_CONSUMED;
}
- memcpy(eth_hdr(skb)->h_dest, bond_dev->dev_addr, ETH_ALEN);
+ memcpy(eth_hdr(skb)->h_dest, bond->dev->dev_addr, ETH_ALEN);
}
return RX_HANDLER_ANOTHER;
@@ -1698,20 +1693,15 @@
pr_debug("Error %d calling netdev_set_bond_master\n", res);
goto err_restore_mac;
}
- res = netdev_rx_handler_register(slave_dev, bond_handle_frame,
- new_slave);
- if (res) {
- pr_debug("Error %d calling netdev_rx_handler_register\n", res);
- goto err_unset_master;
- }
/* open the slave since the application closed it */
res = dev_open(slave_dev);
if (res) {
pr_debug("Opening slave %s failed\n", slave_dev->name);
- goto err_unreg_rxhandler;
+ goto err_unset_master;
}
+ new_slave->bond = bond;
new_slave->dev = slave_dev;
slave_dev->priv_flags |= IFF_BONDING;
@@ -1907,6 +1897,13 @@
if (res)
goto err_close;
+ res = netdev_rx_handler_register(slave_dev, bond_handle_frame,
+ new_slave);
+ if (res) {
+ pr_debug("Error %d calling netdev_rx_handler_register\n", res);
+ goto err_dest_symlinks;
+ }
+
pr_info("%s: enslaving %s as a%s interface with a%s link.\n",
bond_dev->name, slave_dev->name,
bond_is_active_slave(new_slave) ? "n active" : " backup",
@@ -1916,13 +1913,12 @@
return 0;
/* Undo stages on error */
+err_dest_symlinks:
+ bond_destroy_slave_symlinks(bond_dev, slave_dev);
+
err_close:
dev_close(slave_dev);
-err_unreg_rxhandler:
- netdev_rx_handler_unregister(slave_dev);
- synchronize_net();
-
err_unset_master:
netdev_set_bond_master(slave_dev, NULL);
@@ -1988,6 +1984,14 @@
return -EINVAL;
}
+ /* unregister rx_handler early so bond_handle_frame wouldn't be called
+ * for this slave anymore.
+ */
+ netdev_rx_handler_unregister(slave_dev);
+ write_unlock_bh(&bond->lock);
+ synchronize_net();
+ write_lock_bh(&bond->lock);
+
if (!bond->params.fail_over_mac) {
if (!compare_ether_addr(bond_dev->dev_addr, slave->perm_hwaddr) &&
bond->slave_cnt > 1)
@@ -2104,8 +2108,6 @@
netif_addr_unlock_bh(bond_dev);
}
- netdev_rx_handler_unregister(slave_dev);
- synchronize_net();
netdev_set_bond_master(slave_dev, NULL);
slave_disable_netpoll(slave);
@@ -2186,6 +2188,12 @@
*/
write_unlock_bh(&bond->lock);
+ /* unregister rx_handler early so bond_handle_frame wouldn't
+ * be called for this slave anymore.
+ */
+ netdev_rx_handler_unregister(slave_dev);
+ synchronize_net();
+
if (bond_is_lb(bond)) {
/* must be called only after the slave
* has been detached from the list
@@ -2217,8 +2225,6 @@
netif_addr_unlock_bh(bond_dev);
}
- netdev_rx_handler_unregister(slave_dev);
- synchronize_net();
netdev_set_bond_master(slave_dev, NULL);
slave_disable_netpoll(slave);