[PATCH 4.4 012/113] virtio: fix memory leak in virtqueue_add()

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Wei Yongjun <weiyj.lk@xxxxxxxxx>

commit 58625edf9e2515ed41dac2a24fa8004030a87b87 upstream.

When using the indirect buffers feature, 'desc' is allocated in
virtqueue_add() but isn't freed before leaving on a ring full error,
causing a memory leak.

For example, it seems rather clear that this can trigger
with virtio net if mergeable buffers are not used.

Signed-off-by: Wei Yongjun <weiyj.lk@xxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/virtio/virtio_ring.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -202,6 +202,8 @@ static inline int virtqueue_add(struct v
 		 * host should service the ring ASAP. */
 		if (out_sgs)
 			vq->notify(&vq->vq);
+		if (indirect)
+			kfree(desc);
 		END_USE(vq);
 		return -ENOSPC;
 	}