[patch net-2.6] bonding: fix rx_handler locking
From: Jiri Pirko <hidden>
Date: 2011-03-22 12:38:17
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 <redacted> Signed-off-by: Jiri Pirko <redacted> --- drivers/net/bonding/bond_main.c | 56 +++++++++++++++++++++----------------- drivers/net/bonding/bonding.h | 1 + 2 files changed, 32 insertions(+), 25 deletions(-)
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 @@ static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb) { 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 @@ static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb) 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 @@ static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb) 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 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev) 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 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev) 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 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev) 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 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev) 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 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev) 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 @@ static int bond_release_all(struct net_device *bond_dev) */ 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 @@ static int bond_release_all(struct net_device *bond_dev) 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);
diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index 6b26962..90736cb 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h@@ -187,6 +187,7 @@ struct slave { struct net_device *dev; /* first - useful for panic debug */ struct slave *next; struct slave *prev; + struct bonding *bond; /* our master */ int delay; unsigned long jiffies; unsigned long last_arp_rx;
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1.7.4