diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c b/drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c
index 9419e1ed8466..4e83637715e0 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c
@@ -1703,8 +1703,14 @@ static int nfp_net_fs_add(struct nfp_net *nn, struct ethtool_rxnfc *cmd)
 
 			nn->fs.count--;
 			err = nfp_net_fs_add_hw(nn, new);
-			if (err)
+			if (err) {
+				/* mbox broken, adding the old rule back will
+				 * likely also fail.
+				 */
+				list_del(&entry->node);
+				kfree(entry);
 				goto err;
+			}
 
 			nn->fs.count++;
 			list_replace(&entry->node, &new->node);