set geometry property in QXcbWindow after checking minimum size

Origin: upstream, https://code.qt.io/cgit/qt/qtbase.git/commit/?id=6a3627b6c5aa5109
Last-Update: 2023-01-04

QXcbWindow::create() bound the window's size to windowMinimumSize(),
after its size had been inherited from parent().
QPlatformWindow::setGeometry() was called before that sanity check.

When a fullscreen window is re-mapped from a deactivated screen to the
remaining screen, the call to QPlatformWindow::setGeometry() assigns
an invalid QRect to QPlatformWindowPrivate::rect
The negative int values x2 and/or y2 cause
QXcbBackingStoreImage::flushPixmap to address unmapped memory and
crash.

This patch moves the call to QPlatformWindow::setGeometry() from
before to after bounding to a minimum value. That assures a valid
rectangle to be assigned in all cases.

Gbp-Pq: Name qxcbwindow_set_geometry.diff

diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index 609e8ac562bad86d8f52421c0acd3ebc1e45be83..abcdce034f7888204d9f63216be74c5fc82a9144 100644 (file)
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -299,11 +299,6 @@ void QXcbWindow::create()
         return;
     }
 
-    QPlatformWindow::setGeometry(rect);
-
-    if (platformScreen != currentScreen)
-        QWindowSystemInterface::handleWindowScreenChanged(window(), platformScreen->QPlatformScreen::screen());
-
     const QSize minimumSize = windowMinimumSize();
     if (rect.width() > 0 || rect.height() > 0) {
         rect.setWidth(qBound(1, rect.width(), XCOORD_MAX));
@@ -315,6 +310,11 @@ void QXcbWindow::create()
         rect.setHeight(QHighDpi::toNativePixels(int(defaultWindowHeight), platformScreen->QPlatformScreen::screen()));
     }
 
+    QPlatformWindow::setGeometry(rect);
+
+    if (platformScreen != currentScreen)
+        QWindowSystemInterface::handleWindowScreenChanged(window(), platformScreen->QPlatformScreen::screen());
+
     xcb_window_t xcb_parent_id = platformScreen->root();
     if (parent()) {
         xcb_parent_id = static_cast<QXcbWindow *>(parent())->xcb_window();