Re: [syzbot] [sound?] [usb?] KASAN: slab-out-of-bounds Write in copy_to_urb (2)

[Edward Adam Davis]

#syz test

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 54d01dfd820f..263abb36bb2d 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -1553,7 +1553,7 @@ static int prepare_playback_urb(struct snd_usb_substream *subs,
 
 		for (i = 0; i < ctx->packets; i++) {
 			counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, avail);
-			if (counts < 0)
+			if (counts < 0 || frames + counts >= ep->max_urb_frames)
 				break;
 			/* set up descriptor */
 			urb->iso_frame_desc[i].offset = frames * stride;