vxlan: eliminate cached dst leak

After commit 0c1d70af924b ("net: use dst_cache for vxlan device"),
cached dst entries could be leaked when more than one remote was
present for a given vxlan_fdb entry, causing subsequent netns
operations to block indefinitely and "unregister_netdevice: waiting
for lo to become free." messages to appear in the kernel log.

Fix by properly releasing cached dst and freeing resources in this
case.

Fixes: 0c1d70af924b ("net: use dst_cache for vxlan device")
Signed-off-by: Lance Richardson <lrichard@redhat.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 328b4712683c334bf1de66a3a3789d0a04d734c3..5c1d69e37870dff0286ec1cc35d2802d6e6318b4 100644 (file)
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -740,6 +740,22 @@ static void vxlan_fdb_destroy(struct vxlan_dev *vxlan, struct vxlan_fdb *f)
        call_rcu(&f->rcu, vxlan_fdb_free);
 }
 
+static void vxlan_dst_free(struct rcu_head *head)
+{
+       struct vxlan_rdst *rd = container_of(head, struct vxlan_rdst, rcu);
+
+       dst_cache_destroy(&rd->dst_cache);
+       kfree(rd);
+}
+
+static void vxlan_fdb_dst_destroy(struct vxlan_dev *vxlan, struct vxlan_fdb *f,
+                                 struct vxlan_rdst *rd)
+{
+       list_del_rcu(&rd->list);
+       vxlan_fdb_notify(vxlan, f, rd, RTM_DELNEIGH);
+       call_rcu(&rd->rcu, vxlan_dst_free);
+}
+
 static int vxlan_fdb_parse(struct nlattr *tb[], struct vxlan_dev *vxlan,
                           union vxlan_addr *ip, __be16 *port, __be32 *src_vni,
                           __be32 *vni, u32 *ifindex)
@@ -864,9 +880,7 @@ static int __vxlan_fdb_delete(struct vxlan_dev *vxlan,
         * otherwise destroy the fdb entry
         */
        if (rd && !list_is_singular(&f->remotes)) {
-               list_del_rcu(&rd->list);
-               vxlan_fdb_notify(vxlan, f, rd, RTM_DELNEIGH);
-               kfree_rcu(rd, rcu);
+               vxlan_fdb_dst_destroy(vxlan, f, rd);
                goto out;
        }