diff --git a/CHANGES b/CHANGES
index 9882ae4..b3513c1 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,7 @@
 0.4.6 (unreleased)
 =====
 * Fix tracing log.
+* Make sure `Log.stop` atom is idempotent.
 
 0.4.5 (2023-06-27)
 =====
diff --git a/src/dtools_impl.ml b/src/dtools_impl.ml
index 503f22f..8ba24c6 100644
--- a/src/dtools_impl.ml
+++ b/src/dtools_impl.ml
@@ -860,6 +860,7 @@ module Log = struct
       match !log_thread with
         | None -> ()
         | Some th ->
+            log_thread := None;
             Condition.signal log_condition;
             Thread.join th
     end;