1 files changed, 21 insertions, 0 deletions

diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 6a9b0cb8a1db..497b2fd36df4 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -1148,6 +1148,18 @@ static struct datapath *lookup_datapath(struct net *net,
         return dp ? dp : ERR_PTR(-ENODEV);
 }
 
+static void ovs_dp_reset_user_features(struct sk_buff *skb, struct genl_info *info)
+{
+        struct datapath *dp;
+
+        dp = lookup_datapath(sock_net(skb->sk), info->userhdr, info->attrs);
+        if (!dp)
+                return;
+
+        WARN(dp->user_features, "Dropping previously announced user features\n");
+        dp->user_features = 0;
+}
+
 static void ovs_dp_change(struct datapath *dp, struct nlattr **a)
 {
         if (a[OVS_DP_ATTR_USER_FEATURES])
@@ -1220,6 +1232,15 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info)
                 if (err == -EBUSY)
                         err = -EEXIST;
 
+                if (err == -EEXIST) {
+                        /* An outdated user space instance that does not understand
+                         * the concept of user_features has attempted to create a new
+                         * datapath and is likely to reuse it. Drop all user features.
+                         */
+                        if (info->genlhdr->version < OVS_DP_VER_FEATURES)
+                                ovs_dp_reset_user_features(skb, info);
+                }
+
                 goto err_destroy_ports_array;
         }