diff --git a/src/corelib/global/qlogging.cpp b/src/corelib/global/qlogging.cpp
index 22b75afac8..e1b8ef4b6d 100644
--- a/src/corelib/global/qlogging.cpp
+++ b/src/corelib/global/qlogging.cpp
@@ -1039,6 +1039,10 @@ void QMessagePattern::setPattern(const QString &pattern)
         delete [] literals;
     }
     delete [] tokens;
+    timeArgs.clear();
+#ifdef QLOGGING_HAVE_BACKTRACE
+    backtraceArgs.clear();
+#endif
 
     // scanner
     QList<QString> lexemes;