Null pointer dereference in QWaylandInputDevice::setCursor

void QWaylandInputDevice::setCursor(const QSharedPointer<QWaylandBuffer> &buffer, const QPoint &hotSpot)
{
#ifdef Q_OS_SYLIXOS   // this is a bug for qt.
    if (!buffer.isNull()) {
#endif
    setCursor(buffer->buffer(), hotSpot, buffer->size());
    mPixmapCursor = buffer;
#ifdef Q_OS_SYLIXOS
    }
#endif
}