netpoll: don't dereference NULL dev from np

It looks like the dev in netpoll_poll can be NULL - at lease it's
checked at the function beginning. Thus the dev->netde_ops dereference
looks dangerous.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 2 deletions

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index b5873bdff61..64f51eec657 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -175,9 +175,13 @@ static void service_arp_queue(struct netpoll_info *npi)
 void netpoll_poll(struct netpoll *np)
 {
         struct net_device *dev = np->dev;
-        const struct net_device_ops *ops = dev->netdev_ops;
+        const struct net_device_ops *ops;
+
+        if (!dev || !netif_running(dev))
+                return;
 
-        if (!dev || !netif_running(dev) || !ops->ndo_poll_controller)
+        ops = dev->netdev_ops;
+        if (!ops->ndo_poll_controller)
                 return;
 
         /* Process pending work on NIC */