diff --git a/src/widgets/kernel/qwidget.cpp b/src/widgets/kernel/qwidget.cpp
index f36d7f094dd..0a3416a31af 100644
--- a/src/widgets/kernel/qwidget.cpp
+++ b/src/widgets/kernel/qwidget.cpp
@@ -2676,7 +2676,7 @@ void QWidgetPrivate::setStyle_helper(QStyle *newStyle, bool propagate)
     extra->style = newStyle;
 
     // repolish
-    if (polished && q->windowType() != Qt::Desktop) {
+    if (polished && q->windowType() != Qt::Desktop && oldStyle != q->style()) {
         oldStyle->unpolish(q);
         q->style()->polish(q);
     }
diff --git a/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp b/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
index 5c2553ce832..2ecfd262330 100644
--- a/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
+++ b/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
@@ -292,6 +292,7 @@ private slots:
     void setLocale();
     void propagateLocale();
     void deleteStyle();
+    void dontCrashOnSetStyle();
     void multipleToplevelFocusCheck();
     void setFocus();
 #ifndef QT_NO_CURSOR
@@ -6795,6 +6796,37 @@ void tst_QWidget::deleteStyle()
     QCoreApplication::processEvents();
 }
 
+class TestStyle : public QCommonStyle
+{
+    void polish(QWidget *w) override
+    {
+        w->setWindowFlag(Qt::NoDropShadowWindowHint, true);
+    }
+    void unpolish(QWidget *w) override
+    {
+        w->setWindowFlag(Qt::NoDropShadowWindowHint, false);
+    }
+};
+
+void tst_QWidget::dontCrashOnSetStyle()
+{
+    const auto oldStyleName = qApp->style()->name();
+    const auto resetStyleHelper = qScopeGuard([&] {
+        qApp->setStyleSheet({});
+        qApp->setStyle(QStyleFactory::create(oldStyleName));
+    });
+    {
+        qApp->setStyle(new TestStyle);
+        qApp->setStyleSheet("blub");
+        QComboBox w;
+        w.show();
+        QVERIFY(QTest::qWaitForWindowExposed(&w));
+        // this created an infinite loop / stack overflow inside setStyle_helper()
+        // directly call polish instead waiting for the polish event
+        qApp->style()->polish(&w);
+    }
+}
+
 class TopLevelFocusCheck: public QWidget
 {
     Q_OBJECT