virtio: fix crash if CQ is not negotiated

Fix NULL dereference if virtio control queue is not negotiated.

Signed-off-by: Damjan Marion <damarion@cisco.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index a71aaa0..fe5f9a1 100644 (file)
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -114,19 +114,20 @@ static int
 virtio_send_command(struct virtqueue *vq, struct virtio_pmd_ctrl *ctrl,
                int *dlen, int pkt_num)
 {
-       uint16_t head = vq->vq_desc_head_idx, i;
+       uint32_t head, i;
        int k, sum = 0;
        virtio_net_ctrl_ack status = ~0;
        struct virtio_pmd_ctrl result;
 
        ctrl->status = status;
 
-       if (!vq->hw->cvq) {
+       if (!(vq && vq->hw->cvq)) {
                PMD_INIT_LOG(ERR,
                             "%s(): Control queue is not supported.",
                             __func__);
                return -1;
        }
+       head = vq->vq_desc_head_idx;
 
        PMD_INIT_LOG(DEBUG, "vq->vq_desc_head_idx = %d, status = %d, "
                "vq->hw->cvq = %p vq = %p",