macvlan: fix a race on port dismantle and possible skb leaks
We need to cancel the work queue after rcu grace period,
otherwise it can be rescheduled by incoming packets.
We need to purge queue if some skbs are still in it.
We can use __skb_queue_head_init() variant in
macvlan_process_broadcast()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: 412ca1550cbec ("macvlan: Move broadcasts into a work queue")
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 29b3bb4..bfb0b6e 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -272,7 +272,7 @@
struct sk_buff *skb;
struct sk_buff_head list;
- skb_queue_head_init(&list);
+ __skb_queue_head_init(&list);
spin_lock_bh(&port->bc_queue.lock);
skb_queue_splice_tail_init(&port->bc_queue, &list);
@@ -1082,9 +1082,15 @@
{
struct macvlan_port *port = macvlan_port_get_rtnl(dev);
- cancel_work_sync(&port->bc_work);
dev->priv_flags &= ~IFF_MACVLAN_PORT;
netdev_rx_handler_unregister(dev);
+
+ /* After this point, no packet can schedule bc_work anymore,
+ * but we need to cancel it and purge left skbs if any.
+ */
+ cancel_work_sync(&port->bc_work);
+ __skb_queue_purge(&port->bc_queue);
+
kfree_rcu(port, rcu);
}