From: stephen hemminger <shemminger@vyatta.com>
Date: Tue, 27 Apr 2010 15:01:05 +0000 (+0000)
Subject: bridge: multicast flood
X-Git-Tag: firefly_0821_release~9833^2~2087^2~336
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=168d40ee3d147ae20860e7916bd79b636cbe8fd5;p=firefly-linux-kernel-4.4.55.git

bridge: multicast flood

Fix unsafe usage of RCU. Would never work on Alpha SMP because
of lack of rcu_dereference()

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

diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index 7a241c396981..5b70fc012e40 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -216,7 +216,7 @@ static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
 
 	prev = NULL;
 
-	rp = br->router_list.first;
+	rp = rcu_dereference(br->router_list.first);
 	p = mdst ? mdst->ports : NULL;
 	while (p || rp) {
 		lport = p ? p->port : NULL;
@@ -233,7 +233,7 @@ static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
 		if ((unsigned long)lport >= (unsigned long)port)
 			p = p->next;
 		if ((unsigned long)rport >= (unsigned long)port)
-			rp = rp->next;
+			rp = rcu_dereference(rp->next);
 	}
 
 	if (!prev)