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bridge: fix RCU races with bridge port

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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 <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
stephen hemminger
2010-11-15 06:38:13 +00:00
committed by David S. Miller
parent 61391cde9e
commit b5ed54e94d
8 changed files with 44 additions and 34 deletions
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10
net/bridge/br_netlink.c
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@@ -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)