[PATCH net v4 07/12] ip6_tunnel: Fix one possbile memleak when fail to register_netdevice

[gfree . wind]

From: Gao Feng <gfree.w...@foxmail.com>

The ip6_tunnel allocates some resources in its ndo_init func, and
free some of them in its destructor func. Then there is one memleak
that some errors happen after register_netdevice invokes the ndo_init
callback. Because only the ndo_uninit callback is invoked in the error
handler of register_netdevice, but destructor not.

Now create one new func ip6_tnl_destructor_free to free the mem in
the destructor, and ndo_uninit func also invokes it when fail to
register the ip6_tunnel device.

It's not only free all resources, but also follow the original desgin
that the resources are freed in the destructor normally after
register the device successfully.

Signed-off-by: Gao Feng <gfree.w...@foxmail.com>
---
 net/ipv6/ip6_tunnel.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index a9692ec..7dcb234 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -247,13 +247,18 @@ static struct net_device_stats *ip6_get_stats(struct 
net_device *dev)
        }
 }
 
-static void ip6_dev_free(struct net_device *dev)
+static void ip6_tnl_destructor_free(struct net_device *dev)
 {
        struct ip6_tnl *t = netdev_priv(dev);
 
        gro_cells_destroy(&t->gro_cells);
        dst_cache_destroy(&t->dst_cache);
        free_percpu(dev->tstats);
+}
+
+static void ip6_dev_free(struct net_device *dev)
+{
+       ip6_tnl_destructor_free(dev);
        free_netdev(dev);
 }
 
@@ -387,6 +392,10 @@ static struct ip6_tnl *ip6_tnl_locate(struct net *net,
                ip6_tnl_unlink(ip6n, t);
        dst_cache_reset(&t->dst_cache);
        dev_put(dev);
+
+       /* dev is not registered, perform the free instead of destructor */
+       if (dev->reg_state == NETREG_UNINITIALIZED)
+               ip6_tnl_destructor_free(dev);
 }
 
 /**
-- 
1.9.1