diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index dca06ba1c67e..a1d449f2a342 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -385,13 +385,15 @@ static int prepare_inbound_urb(struct snd_usb_endpoint *ep,
 	case SND_USB_ENDPOINT_TYPE_DATA:
 		offs = 0;
 		for (i = 0; i < urb_ctx->packets; i++) {
+			if (offs + ep->curpacksize > urb_ctx->buffer_size)
+				break;
 			urb->iso_frame_desc[i].offset = offs;
 			urb->iso_frame_desc[i].length = ep->curpacksize;
 			offs += ep->curpacksize;
 		}
 
 		urb->transfer_buffer_length = offs;
-		urb->number_of_packets = urb_ctx->packets;
+		urb->number_of_packets = i;
 		break;
 
 	case SND_USB_ENDPOINT_TYPE_SYNC:
@@ -1243,10 +1245,10 @@ static int data_ep_set_params(struct snd_usb_endpoint *ep)
 		u->index = i;
 		u->ep = ep;
 		u->packets = urb_packs;
-		u->buffer_size = maxsize * u->packets;
 
 		if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
 			u->packets++; /* for transfer delimiter */
+		u->buffer_size = maxsize * u->packets;
 		u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
 		if (!u->urb)
 			goto out_of_memory;