net/packet: fix a race in packet_bind() and packet_notifier()

[pandora-kernel.git] / net / packet / af_packet.c

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 4f6392d..34cc788 100644 (file)
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2516,6 +2516,10 @@ static int packet_do_bind(struct sock *sk, const char *name, int ifindex,
 
        if (po->running) {
                rcu_read_unlock();
+               /* prevents packet_notifier() from calling
+                * register_prot_hook()
+                */
+               po->num = 0;
                __unregister_prot_hook(sk, true);
                rcu_read_lock();
                dev_curr = po->prot_hook.dev;
@@ -2523,6 +2527,7 @@ static int packet_do_bind(struct sock *sk, const char *name, int ifindex,
                        unlisted = !dev_get_by_index_rcu(sock_net(sk),
                                                         dev->ifindex);
        }
+       BUG_ON(po->running);
        po->num = protocol;
        po->prot_hook.type = protocol;