Index: lib/tdb/common/mutex.c
===================================================================
--- lib/tdb/common/mutex.c.orig	2021-01-10 05:04:36.047451383 +0000
+++ lib/tdb/common/mutex.c	2021-01-13 16:04:41.890303659 +0000
@@ -644,16 +646,18 @@
 	size_t len;
 	int ret;
 
-	len = tdb_mutex_size(tdb);
-	if (len == 0) {
-		return 0;
-	}
+	if (tdb->mutexes) {
+		len = tdb_mutex_size(tdb);
+		if (len == 0) {
+			return 0;
+		}
 
-	ret = munmap(tdb->mutexes, len);
-	if (ret == -1) {
-		return -1;
+		ret = munmap(tdb->mutexes, len);
+		if (ret == -1) {
+			return -1;
+		}
+		tdb->mutexes = NULL;
 	}
-	tdb->mutexes = NULL;
 
 	return 0;
 }