From: Johannes Berg Date: Tue, 3 Mar 2015 15:02:16 +0000 (+0100) Subject: bridge: fix bridge netlink RCU usage X-Git-Tag: firefly_0821_release~176^2~1974^2~352 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=2f56f6be47dbc6883e28107edfe2f9f98f4d5a24;p=firefly-linux-kernel-4.4.55.git 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 Acked-by: Roopa Prabhu Signed-off-by: David S. Miller --- diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c index 3de0eefe2b82..c72083968768 100644 --- a/net/bridge/br_netlink.c +++ b/net/bridge/br_netlink.c @@ -81,17 +81,19 @@ static size_t br_get_link_af_size_filtered(const struct net_device *dev, 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; - - if (!pv) - 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(); - num_vlan_infos = br_get_num_vlan_infos(pv, filter_mask); if (!num_vlan_infos) return 0;