1 files changed, 4 insertions, 0 deletions
diff --git a/replay/replay-internal.c b/replay/replay-internal.c
index bea7b4aa6b..fca8514012 100644
--- a/replay/replay-internal.c
+++ b/replay/replay-internal.c
@@ -195,6 +195,10 @@ void replay_save_instructions(void)
     if (replay_file && replay_mode == REPLAY_MODE_RECORD) {
         replay_mutex_lock();
         int diff = (int)(replay_get_current_step() - replay_state.current_step);
+
+        /* Time can only go forward */
+        assert(diff >= 0);
+
         if (diff > 0) {
             replay_put_event(EVENT_INSTRUCTION);
             replay_put_dword(diff);