diff --git a/sysdeps/generic/hp-timing-common.h b/sysdeps/generic/hp-timing-common.h
index 8749d25647..1fc92d1bd7 100644
--- a/sysdeps/generic/hp-timing-common.h
+++ b/sysdeps/generic/hp-timing-common.h
@@ -56,5 +56,5 @@
     char *__cp = _itoa ((Val), __buf + sizeof (__buf), 10, 0);		\
     size_t __cp_len = MIN (__buf + sizeof (__buf) - __cp, __len);	\
     memcpy (__dest, __cp, __cp_len);					\
-    __dest[__len - 1] = '\0';						\
+    __dest[__cp_len - 1] = '\0';					\
   } while (0)