From: Jarno Rajahalme <jrajahalme@nicira.com>
Date: Tue, 11 Feb 2014 23:34:39 +0000 (-0800)
Subject: datapath: Fix race.
X-Git-Tag: v2.1.0~19
X-Git-Url: http://git.cascardo.eti.br/?p=cascardo%2Fovs.git;a=commitdiff_plain;h=b05dd42a168e0e028748f8de7d4a63b761b2d687

datapath: Fix race.

ovs_vport_cmd_dump() did rcu_read_lock() only after getting the
datapath, which could have been deleted in between.  Resolved by
taking rcu_read_lock() before the get_dp() call.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
---

diff --git a/datapath/datapath.c b/datapath/datapath.c
index 5f1b34cbf..f496509ec 100644
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -1764,11 +1764,12 @@ static int ovs_vport_cmd_dump(struct sk_buff *skb, struct netlink_callback *cb)
 	int bucket = cb->args[0], skip = cb->args[1];
 	int i, j = 0;
 
+	rcu_read_lock();
 	dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
-	if (!dp)
+	if (!dp) {
+		rcu_read_unlock();
 		return -ENODEV;
-
-	rcu_read_lock();
+	}
 	for (i = bucket; i < DP_VPORT_HASH_BUCKETS; i++) {
 		struct vport *vport;