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authorMahesh Bandewar <maheshb@google.com>2016-09-01 22:18:34 -0700
committerDavid S. Miller <davem@davemloft.net>2016-09-04 11:41:12 -0700
commit24b27fc4cdf9e10c5e79e5923b6b7c2c5c95096c (patch)
treefc45153ddf713cf24fe6916d531b91c9cee34d91
parent312565a0c38ab12275b6ca5ec75d21f3f3ace844 (diff)
bonding: Fix bonding crash
Following few steps will crash kernel - (a) Create bonding master > modprobe bonding miimon=50 (b) Create macvlan bridge on eth2 > ip link add link eth2 dev mvl0 address aa:0:0:0:0:01 \ type macvlan (c) Now try adding eth2 into the bond > echo +eth2 > /sys/class/net/bond0/bonding/slaves <crash> Bonding does lots of things before checking if the device enslaved is busy or not. In this case when the notifier call-chain sends notifications, the bond_netdev_event() assumes that the rx_handler /rx_handler_data is registered while the bond_enslave() hasn't progressed far enough to register rx_handler for the new slave. This patch adds a rx_handler check that can be performed right at the beginning of the enslave code to avoid getting into this situation. Signed-off-by: Mahesh Bandewar <maheshb@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/bonding/bond_main.c7
-rw-r--r--include/linux/netdevice.h1
-rw-r--r--net/core/dev.c16
3 files changed, 21 insertions, 3 deletions
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 217e8da0628c..9599ed6f1213 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1341,9 +1341,10 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
slave_dev->name);
}
- /* already enslaved */
- if (slave_dev->flags & IFF_SLAVE) {
- netdev_dbg(bond_dev, "Error: Device was already enslaved\n");
+ /* already in-use? */
+ if (netdev_is_rx_handler_busy(slave_dev)) {
+ netdev_err(bond_dev,
+ "Error: Device is in use and cannot be enslaved\n");
return -EBUSY;
}
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 3a788bf0affd..e8d79d4ebcfe 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3267,6 +3267,7 @@ static inline void napi_free_frags(struct napi_struct *napi)
napi->skb = NULL;
}
+bool netdev_is_rx_handler_busy(struct net_device *dev);
int netdev_rx_handler_register(struct net_device *dev,
rx_handler_func_t *rx_handler,
void *rx_handler_data);
diff --git a/net/core/dev.c b/net/core/dev.c
index dd6ce598de89..ea6312057a71 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3975,6 +3975,22 @@ sch_handle_ingress(struct sk_buff *skb, struct packet_type **pt_prev, int *ret,
}
/**
+ * netdev_is_rx_handler_busy - check if receive handler is registered
+ * @dev: device to check
+ *
+ * Check if a receive handler is already registered for a given device.
+ * Return true if there one.
+ *
+ * The caller must hold the rtnl_mutex.
+ */
+bool netdev_is_rx_handler_busy(struct net_device *dev)
+{
+ ASSERT_RTNL();
+ return dev && rtnl_dereference(dev->rx_handler);
+}
+EXPORT_SYMBOL_GPL(netdev_is_rx_handler_busy);
+
+/**
* netdev_rx_handler_register - register receive handler
* @dev: device to register a handler for
* @rx_handler: receive handler to register