bridge: fix bridge netlink RCU usage
When the STP timer fires, it can call br_ifinfo_notify(),
which in turn ends up in the new br_get_link_af_size().
This function is annotated to be using RTNL locking, which
clearly isn't the case here, and thus lockdep warns:
===============================
[ INFO: suspicious RCU usage. ]
3.19.0+ #569 Not tainted
-------------------------------
net/bridge/br_private.h:204 suspicious rcu_dereference_protected() usage!
Fix this by doing RCU locking here.
Fixes: b7853d73e39b ("bridge: add vlan info to bridge setlink and dellink notification messages")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 3de0eef..c720839 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -81,17 +81,19 @@
struct net_port_vlans *pv;
int num_vlan_infos;
+ rcu_read_lock();
if (br_port_exists(dev))
- pv = nbp_get_vlan_info(br_port_get_rtnl(dev));
+ pv = nbp_get_vlan_info(br_port_get_rcu(dev));
else if (dev->priv_flags & IFF_EBRIDGE)
pv = br_get_vlan_info((struct net_bridge *)netdev_priv(dev));
else
- return 0;
+ pv = NULL;
+ if (pv)
+ num_vlan_infos = br_get_num_vlan_infos(pv, filter_mask);
+ else
+ num_vlan_infos = 0;
+ rcu_read_unlock();
- if (!pv)
- return 0;
-
- num_vlan_infos = br_get_num_vlan_infos(pv, filter_mask);
if (!num_vlan_infos)
return 0;