[PATCH v2] bridge: fix bridge netlink RCU usage
From: Johannes Berg <johannes@sipsolutions.net>
Date: 2015-03-03 13:46:32
Subsystem:
ethernet bridge, networking [general], the rest · Maintainers:
Nikolay Aleksandrov, Ido Schimmel, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Johannes Berg <redacted>
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 <redacted>
---
net/bridge/br_netlink.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 17e0177467f5..1583381eebce 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c@@ -24,20 +24,19 @@ static size_t br_get_link_af_size(const struct net_device *dev) { - struct net_port_vlans *pv; + unsigned int num_vlans; + rcu_read_lock(); if (br_port_exists(dev)) - pv = nbp_get_vlan_info(br_port_get_rtnl(dev)); + num_vlans = nbp_get_vlan_info(br_port_get_rcu(dev))->num_vlans; else if (dev->priv_flags & IFF_EBRIDGE) - pv = br_get_vlan_info((struct net_bridge *)netdev_priv(dev)); + num_vlans = br_get_vlan_info(netdev_priv(dev))->num_vlans; else - return 0; - - if (!pv) - return 0; + num_vlans = 0; + rcu_read_unlock(); /* Each VLAN is returned in bridge_vlan_info along with flags */ - return pv->num_vlans * nla_total_size(sizeof(struct bridge_vlan_info)); + return num_vlans * nla_total_size(sizeof(struct bridge_vlan_info)); } static inline size_t br_port_info_size(void)
--
2.1.4