diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 6202d2e32914..09fcc54245c7 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -93,7 +93,7 @@ static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn,
 	*_hard_ack = hard_ack;
 	*_top = top;
 
-	pkt->ack.bufferSpace	= htons(8);
+	pkt->ack.bufferSpace	= htons(0);
 	pkt->ack.maxSkew	= htons(0);
 	pkt->ack.firstPacket	= htonl(hard_ack + 1);
 	pkt->ack.previousPacket	= htonl(call->ackr_highest_seq);