Index: generic/nsf.c
===================================================================
diff -u -r6042ab0563421425280b064579c53aa8daa2bc71 -r1a486b9a82c7dca914702329c0b17cc5e397c8c3
--- generic/nsf.c	(.../nsf.c)	(revision 6042ab0563421425280b064579c53aa8daa2bc71)
+++ generic/nsf.c	(.../nsf.c)	(revision 1a486b9a82c7dca914702329c0b17cc5e397c8c3)
@@ -12651,6 +12651,11 @@
     DECR_REF_COUNT2("returnsObj", ctxPtr->returnsObj);
   }
 
+  if (ctxPtr->execNsPtr != NULL) {
+    /* Balances increment in ParamDefsStore */
+    NSNamespaceRelease(ctxPtr->execNsPtr);
+  }
+
   /*fprintf(stderr, "free %p\n", ctxPtr);*/
   FREE(NsfProcContext, ctxPtr);
 }
@@ -12774,11 +12779,15 @@
    * We assume, that this never called for overwriting paramDefs
    */
   assert(ctxPtr->paramDefs == NULL);
-
+  /* fprintf(stderr, "ParamDefsStore paramDefs %p called: NS %s\n", paramDefs, execNsPtr ? execNsPtr->fullName : "na");*/
   ctxPtr->paramDefs       = paramDefs;
   ctxPtr->checkAlwaysFlag = checkAlwaysFlag;
   ctxPtr->execNsPtr       = execNsPtr;
-  // xxxxx TODO: if the namespace can be lost, we have to incr namespace refcount and call TclNsDecrRefCount() on deallocation
+
+  if (ctxPtr->execNsPtr != NULL) {
+    /* Balanced by decrement in NsfProcDeleteProc */
+    NSNamespacePreserve(ctxPtr->execNsPtr);
+  }
 }
 
 /*