virtio-net: only delete bh that existed

We delete without check whether it existed during exit. This will lead NULL
pointer deference since it was created conditionally depends on guest driver
status and features. So add a check of existence before trying to delete it.

Cc: qemu-stable@nongnu.org
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 1383728288-28469-1-git-send-email-jasowang@redhat.com
Signed-off-by: Anthony Liguori <aliguori@amazon.com>
(cherry picked from commit fe2dafa02de4f80ab36f6e0f4ddfcd6418c03c49)

Conflicts:

	hw/net/virtio-net.c

*modified to reflect timer function names for 1.6

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index aa1880cb8782586af9e638bd2238ce32c8af3650..bb757b3e679ce49b9dbf4fc206087d07152d5c1c 100644 (file)
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1600,7 +1600,7 @@ static int virtio_net_device_exit(DeviceState *qdev)
         if (q->tx_timer) {
             qemu_del_timer(q->tx_timer);
             qemu_free_timer(q->tx_timer);
-        } else {
+        } else if (q->tx_bh) {
             qemu_bh_delete(q->tx_bh);
         }
     }