From b5ed54e94d324f17c97852296d61a143f01b227a Mon Sep 17 00:00:00 2001 From: stephen hemminger Date: Mon, 15 Nov 2010 06:38:13 +0000 Subject: bridge: fix RCU races with bridge port The macro br_port_exists() is not enough protection when only RCU is being used. There is a tiny race where other CPU has cleared port handler hook, but is bridge port flag might still be set. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- net/bridge/br_netfilter.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'net/bridge/br_netfilter.c') diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c index 865fd7634b6..ce8b2eed4e7 100644 --- a/net/bridge/br_netfilter.c +++ b/net/bridge/br_netfilter.c @@ -131,17 +131,18 @@ void br_netfilter_rtable_init(struct net_bridge *br) static inline struct rtable *bridge_parent_rtable(const struct net_device *dev) { - if (!br_port_exists(dev)) - return NULL; - return &br_port_get_rcu(dev)->br->fake_rtable; + struct net_bridge_port *port; + + port = br_port_get_rcu(dev); + return port ? &port->br->fake_rtable : NULL; } static inline struct net_device *bridge_parent(const struct net_device *dev) { - if (!br_port_exists(dev)) - return NULL; + struct net_bridge_port *port; - return br_port_get_rcu(dev)->br->dev; + port = br_port_get_rcu(dev); + return port ? port->br->dev : NULL; } static inline struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb) -- cgit v1.2.3