ieee802154: Fix possible NULL pointer dereference in wpan_phy_alloc

Check for NULL pointer after kzalloc
Signed-off-by: Denis Kirjanov <dkirjanov@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ieee802154/wpan-class.c

@@ -147,13 +147,15 @@ struct wpan_phy *wpan_phy_alloc(size_t priv_size)
 	struct wpan_phy *phy = kzalloc(sizeof(*phy) + priv_size,
 			GFP_KERNEL);
 
+	if (!phy)
+		goto out;
 	mutex_lock(&wpan_phy_mutex);
 	phy->idx = wpan_phy_idx++;
 	if (unlikely(!wpan_phy_idx_valid(phy->idx))) {
 		wpan_phy_idx--;
 		mutex_unlock(&wpan_phy_mutex);
 		kfree(phy);
-		return NULL;
+		goto out;
 	}
 	mutex_unlock(&wpan_phy_mutex);
 
@@ -168,6 +170,9 @@ struct wpan_phy *wpan_phy_alloc(size_t priv_size)
 	phy->current_page = 0; /* for compatibility */
 
 	return phy;
+
+out:
+	return NULL;
 }
 EXPORT_SYMBOL(wpan_phy_alloc);