diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
index 17daf4c9f79384ad0005fbec5780cc8bd6f63321..cc84d8d8a3c7d6c6c6e06a18080cfb99c50d86fa 100644
--- a/net/core/gen_estimator.c
+++ b/net/core/gen_estimator.c
@@ -128,7 +128,8 @@ static void est_timer(unsigned long arg)
 		spin_unlock(e->stats_lock);
 	}
 
-	mod_timer(&elist[idx].timer, jiffies + ((HZ<<idx)/4));
+	if (elist[idx].list != NULL)
+		mod_timer(&elist[idx].timer, jiffies + ((HZ<<idx)/4));
 	read_unlock(&est_lock);
 }