[bonding 2.6] fix kernel panic when optional feature used

drivers/net/bonding/bond_main.c

@@ -1559,11 +1559,14 @@ static int bond_enslave(struct net_device *master_dev,
 #endif
 			bond_set_slave_inactive_flags(new_slave);
 		}
+		if (((struct in_device *)slave_dev->ip_ptr) != NULL) {
 			read_lock_irqsave(&(((struct in_device *)slave_dev->ip_ptr)->lock), rflags);
 			ifap= &(((struct in_device *)slave_dev->ip_ptr)->ifa_list);
 			ifa = *ifap;
+			if (ifa != NULL)
 				my_ip = ifa->ifa_address;
 			read_unlock_irqrestore(&(((struct in_device *)slave_dev->ip_ptr)->lock), rflags);
+		}
 
 		/* if there is a primary slave, remember it */
 		if (primary != NULL) {
@@ -2730,9 +2733,7 @@ static void activebackup_arp_monitor(struct net_device *master)
 		/* the current slave must tx an arp to ensure backup slaves
 		 * rx traffic
 		 */
-		if ((slave != NULL) &&
-		    (((jiffies - slave->dev->last_rx) >= the_delta_in_ticks) &&
-		     (my_ip != 0))) {
+		if ((slave != NULL) && (my_ip != 0)) {
 			arp_send_all(slave);
 		}
 	}