diff --git a/src/corelib/serialization/qxmlstream.cpp b/src/corelib/serialization/qxmlstream.cpp
index 1296908110f..ba6e3059dfa 100644
--- a/src/corelib/serialization/qxmlstream.cpp
+++ b/src/corelib/serialization/qxmlstream.cpp
@@ -1484,7 +1484,8 @@ uint QXmlStreamReaderPrivate::getChar_helper()
     const int BUFFER_SIZE = 8192;
     characterOffset += readBufferPos;
     readBufferPos = 0;
-    readBuffer.resize(0);
+    if (readBuffer.size())
+        readBuffer.resize(0);
     if (decoder.isValid())
         nbytesread = 0;
     if (device) {