Index: /trunk/source/level-1/linux-files.lisp
===================================================================
--- /trunk/source/level-1/linux-files.lisp	(revision 14325)
+++ /trunk/source/level-1/linux-files.lisp	(revision 14326)
@@ -181,8 +181,11 @@
 
 (defun wait-for-signal (s duration)
+  (if duration
+    (check-type duration (real 0 #x7fffffff))
+    (setq duration #x7fffffff))
   (or (multiple-value-bind (result err)
           (%timed-wait-for-signal s 0 0)
         (or result
-            (if (or (eql err #$EINTR)
+            (if (or (eql err #$EINTR) ; probably not possible
                     (eql err #-windows-target #$ETIMEDOUT #+windows-target #$WAIT_TIMEOUT))
               nil