Re: oops / kernel panic in bonding.
From: Jiri Pirko <hidden>
Date: 2011-03-22 10:16:53
Subsystem:
bonding driver, networking drivers, the rest · Maintainers:
Jay Vosburgh, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Sun, Mar 20, 2011 at 10:19:21PM CET, nicolas.2p.debian@gmail.com wrote:
Le 20/03/2011 21:17, Nicolas de Pesloüan a écrit :quoted
Hi Jiri, I suspect we have a race condition somewhere in the new bond_handle_frame function: The following commands produce one of the following errors: modprobe bonding max_bonds=0 echo +bond0>/sys/class/net/bonding_masters echo +bond1>/sys/class/net/bonding_masters echo +eth1>/sys/class/net/bond1/bonding/slaves This is mostly reproducible, under VirtualBox. All tests done with 08351fc6a75731226e1112fc7254542bd3a2912e at the top commit (current net-next-2.6).I suspect netdev_rx_handler_register is called too early in bond_enslave. I think it should be the last thing we do in bond_enslave, if we don't want to face the risk to have bond_handle_frame being called before everything is properly setup. Nicolas.
Nicolas, would you please give the following patch a drive? Signed-off-by: Jiri Pirko <redacted>
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 1a6e9eb..c339eb1 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 +1984,12 @@ 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); + synchronize_net(); + if (!bond->params.fail_over_mac) { if (!compare_ether_addr(bond_dev->dev_addr, slave->perm_hwaddr) && bond->slave_cnt > 1)
@@ -2104,8 +2106,6 @@ 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);
@@ -2171,13 +2171,20 @@ static int bond_release_all(struct net_device *bond_dev) bond_change_active_slave(bond, NULL); while ((slave = bond->first_slave) != NULL) { + slave_dev = slave->dev; + + /* unregister rx_handler early so bond_handle_frame wouldn't + * be called for this slave anymore. + */ + netdev_rx_handler_unregister(slave_dev); + synchronize_net(); + /* Inform AD package of unbinding of slave * before slave is detached from the list. */ if (bond->params.mode == BOND_MODE_8023AD) bond_3ad_unbind_slave(slave); - slave_dev = slave->dev; bond_detach_slave(bond, slave); /* now that the slave is detached, unlock and perform
@@ -2217,8 +2224,6 @@ 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;