Fixed a rare crash in qt_x11_enforce_cursor

A QPointer was set to point to a QWidget by one of its children, during its
deletion. This happens during the child deletion, and after the call to
QObject::clearGuards(), which means that the QPointer becomes a dangling one.

The fix ensures that qt_x11_enforce_cursor will not be called with a
being-deleted QWidget. The included auto-test doesn't test anything, except
that it doesn't crash.

Reviewed-by: Olivier

1 files changed, 4 insertions, 1 deletions

diff --git a/src/gui/kernel/qapplication.cpp b/src/gui/kernel/qapplication.cpp
index b990fe2..5476e36 100644
--- a/src/gui/kernel/qapplication.cpp
+++ b/src/gui/kernel/qapplication.cpp
@@ -2662,7 +2662,10 @@ void QApplicationPrivate::dispatchEnterLeave(QWidget* enter, QWidget* leave) {
         if (!isAlien(w))
             break;
         if (w->testAttribute(Qt::WA_SetCursor)) {
-            parentOfLeavingCursor = w->parentWidget();
+            QWidget *parent = w->parentWidget();
+            while (parent && parent->d_func()->data.in_destructor)
+                parent = parent->parentWidget();
+            parentOfLeavingCursor = parent;
             //continue looping, we need to find the downest alien widget with a cursor.
             // (downest on the screen)
         }