diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index d407489cec90..cbe7f35eac98 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -1126,7 +1126,10 @@ cdc_ncm_fill_tx_frame(struct usbnet *dev, struct sk_buff *skb, __le32 sign)
 	 * accordingly. Otherwise, we should check here.
 	 */
 	if (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END)
-		delayed_ndp_size = ALIGN(ctx->max_ndp_size, ctx->tx_ndp_modulus);
+		delayed_ndp_size = ctx->max_ndp_size +
+			max_t(u32,
+			      ctx->tx_ndp_modulus,
+			      ctx->tx_modulus + ctx->tx_remainder) - 1;
 	else
 		delayed_ndp_size = 0;
 
@@ -1307,7 +1310,8 @@ cdc_ncm_fill_tx_frame(struct usbnet *dev, struct sk_buff *skb, __le32 sign)
 	if (!(dev->driver_info->flags & FLAG_SEND_ZLP) &&
 	    skb_out->len > ctx->min_tx_pkt) {
 		padding_count = ctx->tx_curr_size - skb_out->len;
-		skb_put_zero(skb_out, padding_count);
+		if (!WARN_ON(padding_count > ctx->tx_curr_size))
+			skb_put_zero(skb_out, padding_count);
 	} else if (skb_out->len < ctx->tx_curr_size &&
 		   (skb_out->len % dev->maxpacket) == 0) {
 		skb_put_u8(skb_out, 0);	/* force short packet */