diff --git a/src/common/util.c b/src/common/util.c
index 333cd65e6e08f560f82c4089dc72839f876d5d23..ccc130030e410380b5382f457cb95f7aaa1ec602 100644
--- a/src/common/util.c
+++ b/src/common/util.c
@@ -481,7 +481,7 @@ try_next_line:
   do {
     *s = 0;
     s--;
-  } while (isspace(*s));
+  } while (s >= line && isspace(*s));
 
   key = line;
   while(isspace(*key))