[PATCH 4.3 1/2] Revert "vrf: fix double free and memory corruption on register_netdevice failure"

[Ben Hutchings]

This reverts commit b3abad339f8e268bb261e5844ab68b18a7797c29, which
was an attempt to backport commit 7f109f7cc37108cba7243bc832988525b0d85909
upstream.  The backport introduced a deadlock and other bugs.

Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/net/vrf.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index c9e309c..488c6f5 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -581,6 +581,7 @@ static int vrf_newlink(struct net *src_net, struct net_device *dev,
 {
 	struct net_vrf *vrf = netdev_priv(dev);
 	struct net_vrf_dev *vrf_ptr;
+	int err;
 
 	if (!data || !data[IFLA_VRF_TABLE])
 		return -EINVAL;
@@ -589,16 +590,26 @@ static int vrf_newlink(struct net *src_net, struct net_device *dev,
 
 	dev->priv_flags |= IFF_VRF_MASTER;
 
+	err = -ENOMEM;
 	vrf_ptr = kmalloc(sizeof(*dev->vrf_ptr), GFP_KERNEL);
 	if (!vrf_ptr)
-		return -ENOMEM;
+		goto out_fail;
 
 	vrf_ptr->ifindex = dev->ifindex;
 	vrf_ptr->tb_id = vrf->tb_id;
 
+	err = register_netdevice(dev);
+	if (err < 0)
+		goto out_fail;
+
 	rcu_assign_pointer(dev->vrf_ptr, vrf_ptr);
 
-	return register_netdev(dev);
+	return 0;
+
+out_fail:
+	kfree(vrf_ptr);
+	free_netdev(dev);
+	return err;
 }
 
 static size_t vrf_nl_getsize(const struct net_device *dev)

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