eglfs: Call destroy() from dtors of concrete windows

Calling destroy from the QEglFSWindow dtor() triggers the virtual
invalidateSurface() to be called on a partly destroyed object. As the
child windows deregister themselves from their screens on
invalidateSurface() this is dangerous: It leaves a dangling pointer in
the screen.

Fixes: QTBUG-75075
Change-Id: Idd3fea18562d41973f364340df875a50dbd5691e
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

4 files changed, 11 insertions, 0 deletions

diff --git a/src/plugins/platforms/eglfs/api/qeglfswindow.cpp b/src/plugins/platforms/eglfs/api/qeglfswindow.cpp
index 98e9ee4728..c1d5af47aa 100644
--- a/src/plugins/platforms/eglfs/api/qeglfswindow.cpp
+++ b/src/plugins/platforms/eglfs/api/qeglfswindow.cpp
@@ -167,6 +167,9 @@ void QEglFSWindow::create()
 
 void QEglFSWindow::destroy()
 {
+    if (!m_flags.testFlag(Created))
+        return; // already destroyed
+
 #ifndef QT_NO_OPENGL
     QOpenGLCompositor::instance()->removeWindow(this);
 #endif
diff --git a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmwindow.h b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmwindow.h
index a19cf7e8bc..ee4b7978f1 100644
--- a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmwindow.h
+++ b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmwindow.h
@@ -55,6 +55,9 @@ public:
         : QEglFSWindow(w),
           m_integration(integration)
     { }
+
+    ~QEglFSKmsGbmWindow() { destroy(); }
+
     void resetSurface() override;
     void invalidateSurface() override;
 
diff --git a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_egldevice/qeglfskmsegldeviceintegration.cpp b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_egldevice/qeglfskmsegldeviceintegration.cpp
index ecdfb352ab..3e78196227 100644
--- a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_egldevice/qeglfskmsegldeviceintegration.cpp
+++ b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_egldevice/qeglfskmsegldeviceintegration.cpp
@@ -116,6 +116,8 @@ public:
         , m_egl_stream(EGL_NO_STREAM_KHR)
     { }
 
+    ~QEglFSKmsEglDeviceWindow() { destroy(); }
+
     void invalidateSurface() override;
     void resetSurface() override;
 
diff --git a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_vsp2/qeglfskmsvsp2integration.cpp b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_vsp2/qeglfskmsvsp2integration.cpp
index 0d9b6b6290..d1250ec9bf 100644
--- a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_vsp2/qeglfskmsvsp2integration.cpp
+++ b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_vsp2/qeglfskmsvsp2integration.cpp
@@ -205,6 +205,9 @@ public:
         : QEglFSWindow(w)
         , m_integration(integration)
     {}
+
+    ~QEglFSKmsVsp2Window() { destroy(); }
+
     void resetSurface() override;
     void invalidateSurface() override;
     const QEglFSKmsVsp2Integration *m_integration;