diff -r 4f2355e395a3 -r 3f46e58acde8 src/mem/packet.hh
--- a/src/mem/packet.hh	Fri Nov 18 16:43:09 2016 +0000
+++ b/src/mem/packet.hh	Fri Nov 18 16:43:41 2016 +0000
@@ -612,6 +612,7 @@
     void setResponderHadWritable()
     {
         assert(cacheResponding());
+        assert(!responderHadWritable());
         flags.set(RESPONDER_HAD_WRITABLE);
     }
     bool responderHadWritable() const