From: Li Qiang <liq3ea@163.com>

If error occurs while processing the virtio request we should call
'virtqueue_detach_element' to detach the element from the virtqueue
before free the elem.

Signed-off-by: Li Qiang <liq3ea@163.com>
Message-Id: <20200816142245.17556-1-liq3ea@163.com>
Fixes: 910b25766b ("virtio-mem: Paravirtualized memory hot(un)plug")
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/virtio/virtio-mem.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c
index 8fbec77ccc..7c8ca9f28b 100644
--- a/hw/virtio/virtio-mem.c
+++ b/hw/virtio/virtio-mem.c
@@ -318,6 +318,7 @@ static void virtio_mem_handle_request(VirtIODevice *vdev, VirtQueue *vq)
         if (iov_to_buf(elem->out_sg, elem->out_num, 0, &req, len) < len) {
             virtio_error(vdev, "virtio-mem protocol violation: invalid request"
                          " size: %d", len);
+            virtqueue_detach_element(vq, elem, 0);
             g_free(elem);
             return;
         }
@@ -327,6 +328,7 @@ static void virtio_mem_handle_request(VirtIODevice *vdev, VirtQueue *vq)
             virtio_error(vdev, "virtio-mem protocol violation: not enough space"
                          " for response: %zu",
                          iov_size(elem->in_sg, elem->in_num));
+            virtqueue_detach_element(vq, elem, 0);
             g_free(elem);
             return;
         }
@@ -348,6 +350,7 @@ static void virtio_mem_handle_request(VirtIODevice *vdev, VirtQueue *vq)
         default:
             virtio_error(vdev, "virtio-mem protocol violation: unknown request"
                          " type: %d", type);
+            virtqueue_detach_element(vq, elem, 0);
             g_free(elem);
             return;
         }
-- 
MST