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authorstephen hemminger <shemminger@vyatta.com>2010-11-15 09:38:13 +0300
committerDavid S. Miller <davem@davemloft.net>2010-11-15 22:13:17 +0300
commitb5ed54e94d324f17c97852296d61a143f01b227a (patch)
tree2104d3cde24efc1145bc71beb4b61d79ed841132 /net/bridge/br_fdb.c
parent61391cde9eefac5cfcf6d214aa80c77e58b1626b (diff)
downloadlinux-b5ed54e94d324f17c97852296d61a143f01b227a.tar.xz
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 <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/bridge/br_fdb.c')
-rw-r--r--net/bridge/br_fdb.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 90512ccfd3e9..2872393b2939 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -238,15 +238,18 @@ struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
int br_fdb_test_addr(struct net_device *dev, unsigned char *addr)
{
struct net_bridge_fdb_entry *fdb;
+ struct net_bridge_port *port;
int ret;
- if (!br_port_exists(dev))
- return 0;
-
rcu_read_lock();
- fdb = __br_fdb_get(br_port_get_rcu(dev)->br, addr);
- ret = fdb && fdb->dst->dev != dev &&
- fdb->dst->state == BR_STATE_FORWARDING;
+ port = br_port_get_rcu(dev);
+ if (!port)
+ ret = 0;
+ else {
+ fdb = __br_fdb_get(port->br, addr);
+ ret = fdb && fdb->dst->dev != dev &&
+ fdb->dst->state == BR_STATE_FORWARDING;
+ }
rcu_read_unlock();
return ret;