diff --git a/Lib/test/test_time.py b/Lib/test/test_time.py
index eb4289f..0b029d6 100644
--- a/Lib/test/test_time.py
+++ b/Lib/test/test_time.py
@@ -124,6 +124,16 @@
     def test_asctime(self):
         time.asctime(time.gmtime(self.t))
         self.assertRaises(TypeError, time.asctime, 0)
+        self.assertRaises(TypeError, time.asctime, ())
+        # XXX: Posix compiant asctime should refuse to convert
+        # year > 9999, but Linux implementation does not.
+        # self.assertRaises(ValueError, time.asctime,
+        #                  (12345, 1, 0, 0, 0, 0, 0, 0, 0))
+        # XXX: For now, just make sure we don't have a crash:
+        try:
+            time.asctime((12345, 1, 0, 0, 0, 0, 0, 0, 0))
+        except ValueError:
+            pass
 
     @unittest.skipIf(not hasattr(time, "tzset"),
         "time module has no attribute tzset")
diff --git a/Modules/timemodule.c b/Modules/timemodule.c
index abc43a2..32bdaf7 100644
--- a/Modules/timemodule.c
+++ b/Modules/timemodule.c
@@ -643,6 +643,10 @@
     } else if (!gettmarg(tup, &buf))
         return NULL;
     p = asctime(&buf);
+    if (p == NULL) {
+        PyErr_SetString(PyExc_ValueError, "invalid time");
+        return NULL;
+    }
     if (p[24] == '\n')
         p[24] = '\0';
     return PyUnicode_FromString(p);