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

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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: Yossi Etigin <yosefe@voltaire.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
Roland Dreier 2009-01-14 21:44:39 -08:00
parent b8a1b1ce14
commit cbbe1efa49
1 changed files with 8 additions and 3 deletions
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11
drivers/infiniband/ulp/ipoib/ipoib_vlan.c
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@ -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;
}