In udp_vu_sock_recv(), collect a segment with a size defined to IP_MAX_MTU + ETH_HLEN + sizeof(struct virtio_net_hdr_mrg_rxbuf) The original version double counted the IP header: IP_MAX_MTU includes the IP header, and so did hdrlen. Signed-off-by: Laurent Vivier <lvivier(a)redhat.com> --- udp_vu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/udp_vu.c b/udp_vu.c index 9c697f3be247..41235101b69e 100644 --- a/udp_vu.c +++ b/udp_vu.c @@ -104,7 +104,8 @@ static int udp_vu_sock_recv(const struct ctx *c, int s, uint32_t events, vu_init_elem(elem, iov_vu, VIRTQUEUE_MAX_SIZE); iov_cnt = vu_collect(vdev, vq, elem, VIRTQUEUE_MAX_SIZE, - IP_MAX_MTU - sizeof(struct udphdr) + hdrlen, + IP_MAX_MTU + ETH_HLEN + + sizeof(struct virtio_net_hdr_mrg_rxbuf), NULL); if (iov_cnt == 0) return 0; -- 2.47.1