diff -r dadbec3e264c -r 1a4563670c19 src/mem/ruby/system/RubyPort.cc
--- a/src/mem/ruby/system/RubyPort.cc	Thu Jan 06 15:32:21 2011 -0800
+++ b/src/mem/ruby/system/RubyPort.cc	Thu Jan 06 15:32:53 2011 -0800
@@ -245,7 +245,12 @@
         }
     }
 
-    RubyRequest ruby_request(pkt->getAddr(), pkt->getPtr<uint8_t>(),
+    uint8_t* ruby_data = NULL;
+    if (pkt->includesData()) {
+        ruby_data = pkt->getPtr<uint8_t>();
+    }
+
+    RubyRequest ruby_request(pkt->getAddr(), ruby_data,
                              pkt->getSize(), pc, type,
                              RubyAccessMode_Supervisor, pkt);