[BRIDGE]: fix for RCU and deadlock on device removal

Change Bridge receive path to correctly handle RCU removal of device
from bridge.  Also fixes deadlock between carrier_check and del_nbp.
This replaces the previous deleted flag fix.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 7 deletions

diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index e3a73cead6b6..4eef83755315 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -45,18 +45,20 @@ static void br_pass_frame_up(struct net_bridge *br, struct sk_buff *skb)
 int br_handle_frame_finish(struct sk_buff *skb)
 {
         const unsigned char *dest = eth_hdr(skb)->h_dest;
-        struct net_bridge_port *p = skb->dev->br_port;
-        struct net_bridge *br = p->br;
+        struct net_bridge_port *p = rcu_dereference(skb->dev->br_port);
+        struct net_bridge *br;
         struct net_bridge_fdb_entry *dst;
         int passedup = 0;
 
+        if (!p || p->state == BR_STATE_DISABLED)
+                goto drop;
+
         /* insert into forwarding database after filtering to avoid spoofing */
-        br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
+        br = p->br;
+        br_fdb_update(br, p, eth_hdr(skb)->h_source);
 
-        if (p->state == BR_STATE_LEARNING) {
-                kfree_skb(skb);
-                goto out;
-        }
+        if (p->state == BR_STATE_LEARNING)
+                goto drop;
 
         if (br->dev->flags & IFF_PROMISC) {
                 struct sk_buff *skb2;
@@ -93,6 +95,9 @@ int br_handle_frame_finish(struct sk_buff *skb)
 
 out:
         return 0;
+drop:
+        kfree_skb(skb);
+        goto out;
 }
 
 /*