--- gc/gcconfig.h.org
+++ gc/gcconfig.h
@@ -601,7 +601,7 @@
       extern int _end;
 #     define DATAEND (&_end)
 #     define SVR4
-#     define STACKBOTTOM ((ptr_t) 0xf0000000)
+#     define STACKBOTTOM ((ptr_t) 0xeffff000)
 #   endif
 # endif