From 873aca2ee86e533665a73292c4e308ded1e9bafe Mon Sep 17 00:00:00 2001 From: Petr Machata Date: Fri, 8 Jun 2018 15:11:47 +0200 Subject: [PATCH] net: bridge: Fix locking in br_fdb_find_port() Callers of br_fdb_find() need to hold the hash lock, which br_fdb_find_port() doesn't do. However, since br_fdb_find_port() is not doing any actual FDB manipulation, the hash lock is not really needed at all. So convert to br_fdb_find_rcu(), surrounded by rcu_read_lock() / _unlock() pair. The device pointer copied from inside the FDB entry is then kept alive by the RTNL lock, which br_fdb_find_port() asserts. Fixes: 4d4fd36126d6 ("net: bridge: Publish bridge accessor functions") Signed-off-by: Petr Machata Acked-by: Nikolay Aleksandrov Signed-off-by: David S. Miller --- net/bridge/br_fdb.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c index b19e3104afd6..502f66349530 100644 --- a/net/bridge/br_fdb.c +++ b/net/bridge/br_fdb.c @@ -135,9 +135,11 @@ struct net_device *br_fdb_find_port(const struct net_device *br_dev, return NULL; br = netdev_priv(br_dev); - f = br_fdb_find(br, addr, vid); + rcu_read_lock(); + f = br_fdb_find_rcu(br, addr, vid); if (f && f->dst) dev = f->dst->dev; + rcu_read_unlock(); return dev; }