diff --git a/block.c b/block.c
index 9549b9eff9f3034fdfae86e239851db459b9c0da..81a82578a21e2c4f7948b40093e09f3301f28336 100644
--- a/block.c
+++ b/block.c
@@ -730,6 +730,8 @@ void bdrv_detach(BlockDriverState *bs, DeviceState *qdev)
 {
     assert(bs->peer == qdev);
     bs->peer = NULL;
+    bs->change_cb = NULL;
+    bs->change_opaque = NULL;
 }
 
 DeviceState *bdrv_get_attached(BlockDriverState *bs)