diff --git a/src/plugins/platforms/wayland/qwaylandwindow.cpp b/src/plugins/platforms/wayland/qwaylandwindow.cpp
index 557d58c94d6..2a0fdaf6b0b 100644
--- a/src/plugins/platforms/wayland/qwaylandwindow.cpp
+++ b/src/plugins/platforms/wayland/qwaylandwindow.cpp
@@ -478,15 +478,15 @@ void QWaylandWindow::lower()
 
 void QWaylandWindow::setMask(const QRegion &mask)
 {
+    QReadLocker locker(&mSurfaceLock);
+    if (!mSurface)
+        return;
+
     if (mMask == mask)
         return;
 
     mMask = mask;
 
-    QReadLocker locker(&mSurfaceLock);
-    if (!mSurface)
-        return;
-
     if (mMask.isEmpty()) {
         mSurface->set_input_region(nullptr);