QUdpSocket::bind not reentrant

In different threads I create its QUdpSocket and call QUdpSocket::bind. Sometimes I receive "pure virtual method called". This error occurs in file qabstracksocketengine.cpp in function QAbstractSocketEngine::createSocketEngine at line “if (QAbstractSocketEngine *ret = socketHandlers()>at>createSocketEngine(socketType, proxy, parent))”.
Remark. I receive this error only in first simultaneous calls of QUdpSocket::bind.

If I understood right: QSocketEngineHandler constructor register himself in global list. After that and before call child constructor any other thread may call createSocketEngine which not define yet.