diff --git a/client/pool-buffer.c b/client/pool-buffer.c
index 52438303..fa468c0d 100644
--- a/client/pool-buffer.c
+++ b/client/pool-buffer.c
@@ -144,5 +144,6 @@ struct pool_buffer *get_next_buffer(struct wl_shm *shm,
 			return NULL;
 		}
 	}
+	buffer->busy = true;
 	return buffer;
 }