I can confirm this to be an issue with 2.5+dfsg-4+b1 and also confirm
that re-compiling it with the upstream patch makes it work correctly.
--- qemu-2.5+dfsg.orig/block.c
+++ qemu-2.5+dfsg/block.c
@@ -2028,7 +2028,7 @@ static void change_parent_backing_link(B
}
if (from->blk) {
blk_set_bs(from->blk, to);
- if (!to->device_list.tqe_prev) {
+ if (!to->device_list.tqe_prev || !*to->device_list.tqe_prev) {
QTAILQ_INSERT_BEFORE(from, to, device_list);
}
QTAILQ_REMOVE(&bdrv_states, from, device_list);
- Michel
