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Commit cbbe1efa authored by Roland Dreier's avatar Roland Dreier
Browse files

IPoIB: Fix deadlock between ipoib_open() and child interface create 



Fix a deadlock between child interface creation/deletion and ipoib
start/stop.  The former takes vlan_mutex, and then might take RTNL via
register_netdev()/unregister_netdev().  The latter is executed with
RTNL held, and tries to take vlan_mutex, which can lead to an AB-BA
deadlock.

Fix this by having the child interface creation/deletion code take the
RTNL first so vlan_mutex always nests inside RTNL.  We can use
register_netdevice() for child interfaces because we form the
interface name from the parent interface and hence don't need the '%'
expansion of register_netdev().

Reported-by: default avatarYossi Etigin <yosefe@voltaire.com>
Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent b8a1b1ce

drivers/infiniband/ulp/ipoib/ipoib_vlan.c

+8 −3
Original line number Diff line number Diff line
@@ -61,6 +61,7 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey) 


	ppriv = netdev_priv(pdev);



	rtnl_lock();

	mutex_lock(&ppriv->vlan_mutex);



	/*
@@ -111,7 +112,7 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey) 
		goto device_init_failed;

	}



	result = register_netdev(priv->dev);

	result = register_netdevice(priv->dev);

	if (result) {

		ipoib_warn(priv, "failed to initialize; error %i", result);

		goto register_failed;
@@ -134,12 +135,13 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey) 
	list_add_tail(&priv->list, &ppriv->child_intfs);



	mutex_unlock(&ppriv->vlan_mutex);

	rtnl_unlock();



	return 0;



sysfs_failed:

	ipoib_delete_debug_files(priv->dev);

	unregister_netdev(priv->dev);

	unregister_netdevice(priv->dev);



register_failed:

	ipoib_dev_cleanup(priv->dev);
@@ -149,6 +151,7 @@ device_init_failed: 


err:

	mutex_unlock(&ppriv->vlan_mutex);

	rtnl_unlock();

	return result;

}
@@ -162,10 +165,11 @@ int ipoib_vlan_delete(struct net_device *pdev, unsigned short pkey) 


	ppriv = netdev_priv(pdev);



	rtnl_lock();

	mutex_lock(&ppriv->vlan_mutex);

	list_for_each_entry_safe(priv, tpriv, &ppriv->child_intfs, list) {

		if (priv->pkey == pkey) {

			unregister_netdev(priv->dev);

			unregister_netdevice(priv->dev);

			ipoib_dev_cleanup(priv->dev);

			list_del(&priv->list);

			free_netdev(priv->dev);
@@ -175,6 +179,7 @@ int ipoib_vlan_delete(struct net_device *pdev, unsigned short pkey) 
		}

	}

	mutex_unlock(&ppriv->vlan_mutex);

	rtnl_unlock();



	return ret;

}