IPoIB: Avoid free_netdev() BUG when destroying a child interface

We have to release the RTNL before calling free_netdev() so that the
device state has a chance to become NETREG_UNREGISTERED.  Otherwise
when removing a child interface, we hit the BUG() that tests the
device state in free_netdev().

Reported-by: Yossi Etigin <yosefe@voltaire.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 15 insertions, 10 deletions

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
index 5a76a5510350..4c57f329dd50 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
@@ -70,12 +70,14 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey)
          */
         if (ppriv->pkey == pkey) {
                 result = -ENOTUNIQ;
+                priv = NULL;
                 goto err;
         }
 
         list_for_each_entry(priv, &ppriv->child_intfs, list) {
                 if (priv->pkey == pkey) {
                         result = -ENOTUNIQ;
+                        priv = NULL;
                         goto err;
                 }
         }
@@ -96,7 +98,7 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey)
 
         result = ipoib_set_dev_features(priv, ppriv->ca);
         if (result)
-                goto device_init_failed;
+                goto err;
 
         priv->pkey = pkey;
 
@@ -109,7 +111,7 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey)
                 ipoib_warn(ppriv, "failed to initialize subinterface: "
                            "device %s, port %d",
                            ppriv->ca->name, ppriv->port);
-                goto device_init_failed;
+                goto err;
         }
 
         result = register_netdevice(priv->dev);
@@ -146,19 +148,19 @@ sysfs_failed:
 register_failed:
         ipoib_dev_cleanup(priv->dev);
 
-device_init_failed:
-        free_netdev(priv->dev);
-
 err:
         mutex_unlock(&ppriv->vlan_mutex);
         rtnl_unlock();
+        if (priv)
+                free_netdev(priv->dev);
+
         return result;
 }
 
 int ipoib_vlan_delete(struct net_device *pdev, unsigned short pkey)
 {
         struct ipoib_dev_priv *ppriv, *priv, *tpriv;
-        int ret = -ENOENT;
+        struct net_device *dev = NULL;
 
         if (!capable(CAP_NET_ADMIN))
                 return -EPERM;
@@ -172,14 +174,17 @@ int ipoib_vlan_delete(struct net_device *pdev, unsigned short pkey)
                         unregister_netdevice(priv->dev);
                         ipoib_dev_cleanup(priv->dev);
                         list_del(&priv->list);
-                        free_netdev(priv->dev);
-
-                        ret = 0;
+                        dev = priv->dev;
                         break;
                 }
         }
         mutex_unlock(&ppriv->vlan_mutex);
         rtnl_unlock();
 
-        return ret;
+        if (dev) {
+                free_netdev(dev);
+                return 0;
+        }
+
+        return -ENODEV;
 }