Re: [PATCH] net_namespace: fixed net_device reference leak

The dst's do disappear but the net device does not. A better solution
is to only hold reference to dst's net device ONLY if it is not a
loopback device. In the case of the loopback device, we want to do
only a "put" on it and skip the "hold".

Updating the patch below:

---
 net/core/dst.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/net/core/dst.c b/net/core/dst.c
index 7e45593..f63027e 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c

@@ -433,12 +433,11 @@ static void dst_ifdown(struct dst_entry *dst,

struct net_device *dev,
                dst->input = dst_discard;
                dst->output = dst_discard_out;
        } else {
-               if (dst->dev == dev_net(dst->dev)->loopback_dev)
-                       dst->dev = init_net.loopback_dev;
-               else
+               if (dst->dev != dev_net(dst->dev)->loopback_dev) {
                        dst->dev = dev_net(dst->dev)->loopback_dev;
+                       dev_hold(dst->dev);
+               }

-               dev_hold(dst->dev);
                dev_put(dev);
        }
 }