Deadlock: QThreadPool::start in runnable destructor

As of the documentation, QThreadPool::start is threadsafe. However, when using it from a destructor of a autodeleted QRunnable subclass, it leads to a (guaranteed) deadlock. Sample code:

class TestRunnable : public QRunnable {
public:
    TestRunnable() {
        setAutoDelete(true);
    }
    ~TestRunnable() {
        QThreadPool::globalInstance()->start(new OtherRunnable());
    }
    // ...
}

I attached a test source file which provokes such a situation. By checking the console output, you can see that QThreadPool::start() never returns.