diff --git a/utils/ld-libs.c b/utils/ld-libs.c
index cbc5a608acec46d42d63cbdea5dfad52ce8d8f54..4ec7b388dccd435e6fc1bf62fb19a72d0a15e625 100644
--- a/utils/ld-libs.c
+++ b/utils/ld-libs.c
@@ -479,9 +479,8 @@ search_ldpath (const char *name, const char *ldpath, ld_libs *ldlibs, int i)
     char  *prefix = ldlibs->prefix.path;
     size_t plen   = ldlibs->prefix.len;
 
-    prefix[plen] = '\0';
-
     sanitise_ldlibs(ldlibs);
+    assert( prefix[plen] == '\0' );
 
     LDLIB_DEBUG( ldlibs, DEBUG_SEARCH,
                  "searching for %s in %s (prefix: %s)",