3 files changed, 19 insertions, 4 deletions

diff --git a/src/client/qwaylandwindow.cpp b/src/client/qwaylandwindow.cpp
index d32b4fce3..06303de3a 100644
--- a/src/client/qwaylandwindow.cpp
+++ b/src/client/qwaylandwindow.cpp
@@ -416,6 +416,7 @@ void QWaylandWindow::closePopups(QWaylandWindow *parent)
 
 QPlatformScreen *QWaylandWindow::calculateScreenFromSurfaceEvents() const
 {
+    QReadLocker lock(&mSurfaceLock);
     if (mSurface) {
         if (auto *screen = mSurface->oldestEnteredScreen())
             return screen;
@@ -469,6 +470,7 @@ void QWaylandWindow::setMask(const QRegion &mask)
 
     mMask = mask;
 
+    QReadLocker locker(&mSurfaceLock);
     if (!mSurface)
         return;
 
@@ -555,6 +557,10 @@ void QWaylandWindow::sendRecursiveExposeEvent()
 void QWaylandWindow::attach(QWaylandBuffer *buffer, int x, int y)
 {
     Q_ASSERT(!buffer->committed());
+    QReadLocker locker(&mSurfaceLock);
+    if (mSurface == nullptr)
+        return;
+
     if (buffer) {
         handleUpdate();
         buffer->setBusy();
@@ -573,6 +579,10 @@ void QWaylandWindow::attachOffset(QWaylandBuffer *buffer)
 
 void QWaylandWindow::damage(const QRect &rect)
 {
+    QReadLocker locker(&mSurfaceLock);
+    if (mSurface == nullptr)
+        return;
+
     mSurface->damage(rect.x(), rect.y(), rect.width(), rect.height());
 }
 
@@ -603,6 +613,8 @@ void QWaylandWindow::commit(QWaylandBuffer *buffer, const QRegion &damage)
         qCDebug(lcWaylandBackingstore) << "Buffer already committed, ignoring.";
         return;
     }
+
+    QReadLocker locker(&mSurfaceLock);
     if (!mSurface)
         return;
 
@@ -616,7 +628,9 @@ void QWaylandWindow::commit(QWaylandBuffer *buffer, const QRegion &damage)
 
 void QWaylandWindow::commit()
 {
-    mSurface->commit();
+    QReadLocker locker(&mSurfaceLock);
+    if (mSurface != nullptr)
+        mSurface->commit();
 }
 
 const wl_callback_listener QWaylandWindow::callbackListener = {
@@ -707,6 +721,7 @@ QPointF QWaylandWindow::mapFromWlSurface(const QPointF &surfacePosition) const
 
 wl_surface *QWaylandWindow::wlSurface()
 {
+    QReadLocker locker(&mSurfaceLock);
     return mSurface ? mSurface->object() : nullptr;
 }
 
@@ -731,7 +746,8 @@ QWaylandScreen *QWaylandWindow::waylandScreen() const
 
 void QWaylandWindow::handleContentOrientationChange(Qt::ScreenOrientation orientation)
 {
-    if (mDisplay->compositorVersion() < 2)
+    QReadLocker locker(&mSurfaceLock);
+    if (mDisplay->compositorVersion() < 2 || mSurface == nullptr)
         return;
 
     wl_output_transform transform;
diff --git a/src/client/qwaylandwindow_p.h b/src/client/qwaylandwindow_p.h
index 1dbb6f995..45eefdbf2 100644
--- a/src/client/qwaylandwindow_p.h
+++ b/src/client/qwaylandwindow_p.h
@@ -287,7 +287,7 @@ private:
 
     static QWaylandWindow *mMouseGrab;
 
-    QReadWriteLock mSurfaceLock;
+    mutable QReadWriteLock mSurfaceLock;
 
     friend class QWaylandSubSurface;
 };
diff --git a/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.cpp b/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.cpp
index 756eb3cd3..5145d1876 100644
--- a/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.cpp
+++ b/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.cpp
@@ -192,7 +192,6 @@ public:
     }
     void blit(QWaylandEglWindow *window)
     {
-        Q_ASSERT(window->wlSurface());
         QOpenGLTextureCache *cache = QOpenGLTextureCache::cacheForContext(m_context->context());
 
         QSize surfaceSize = window->surfaceSize();