vxlan: eliminate cached dst leak

[ Upstream commit 35cf2845563c1aaa01d27bd34d64795c4ae72700 ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 3c4c2cf6d444262d7f5c3a3724ba25ccff74492a..3331b5e5b4ce747e1e6c9b55e021c309e3f8cf2e 100644 (file)
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -717,6 +717,22 @@ 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 *vni,
                           u32 *ifindex)
@@ -847,9 +863,7 @@ static int vxlan_fdb_delete(struct ndmsg *ndm, struct nlattr *tb[],
         * 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;
        }