diff --git a/src/corelib/serialization/qxmlstream_p.h b/src/corelib/serialization/qxmlstream_p.h
index 4157fbbd..f8b1ede9 100644
--- a/src/corelib/serialization/qxmlstream_p.h
+++ b/src/corelib/serialization/qxmlstream_p.h
@@ -1250,7 +1250,7 @@ bool QXmlStreamReaderPrivate::parse()
             state_stack[tos] = 0;
             return true;
         } else if (act > 0) {
-            if (++tos == stack_size-1)
+            if (++tos >= stack_size-1)
                 reallocateStack();
 
             Value &val = sym_stack[tos];