From: Daniel Verkamp <dverkamp@xxxxxxxxxxxx> commit 5790b53390e18fdd21e70776e46d058c05eda2f2 upstream. Ensure that elements of the callbacks array that correspond to unavailable features are set to NULL; previously, they would be left uninitialized. Since the corresponding names array elements were explicitly set to NULL, the uninitialized callback pointers would not actually be dereferenced; however, the uninitialized callbacks elements would still be read in vp_find_vqs_msix() and used to calculate the number of MSI-X vectors required. Cc: stable@xxxxxxxxxxxxxxx Fixes: 86a559787e6f ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT") Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx> Signed-off-by: Daniel Verkamp <dverkamp@xxxxxxxxxxxx> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/virtio/virtio_balloon.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -475,7 +475,9 @@ static int init_vqs(struct virtio_balloo names[VIRTIO_BALLOON_VQ_INFLATE] = "inflate"; callbacks[VIRTIO_BALLOON_VQ_DEFLATE] = balloon_ack; names[VIRTIO_BALLOON_VQ_DEFLATE] = "deflate"; + callbacks[VIRTIO_BALLOON_VQ_STATS] = NULL; names[VIRTIO_BALLOON_VQ_STATS] = NULL; + callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; names[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {