From b5ed54e94d324f17c97852296d61a143f01b227a Mon Sep 17 00:00:00 2001 From: stephen hemminger Date: Mon, 15 Nov 2010 06:38:13 +0000 Subject: 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 Signed-off-by: David S. Miller --- net/bridge/br_netlink.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'net/bridge/br_netlink.c') diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c index 4a6a378c84e3..e3de0a428f5d 100644 --- a/net/bridge/br_netlink.c +++ b/net/bridge/br_netlink.c @@ -119,11 +119,13 @@ static int br_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb) idx = 0; for_each_netdev(net, dev) { + struct net_bridge_port *port = br_port_get(dev); + /* not a bridge port */ - if (!br_port_exists(dev) || idx < cb->args[0]) + if (!port || idx < cb->args[0]) goto skip; - if (br_fill_ifinfo(skb, br_port_get(dev), + if (br_fill_ifinfo(skb, port, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq, RTM_NEWLINK, NLM_F_MULTI) < 0) @@ -169,9 +171,9 @@ static int br_rtm_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg) if (!dev) return -ENODEV; - if (!br_port_exists(dev)) - return -EINVAL; p = br_port_get(dev); + if (!p) + return -EINVAL; /* if kernel STP is running, don't allow changes */ if (p->br->stp_enabled == BR_KERNEL_STP) -- cgit v1.2.3