GObject signal connection and disconnection thread safety

Question

Consider following example of C++ class which manages media factory of RTSP server (no matter which exactly entity from Gstreamer is taken, because the question is mostly related to GObject signals):

class CGstreamerStream
{
public:
    void Configure();
    
    ~CGstreamerStream();
    
private:
    static void MediaConfigure( GstRTSPMediaFactory *pFactory, GstRTSPMedia *pMedia, gpointer pUserData );
    
    GstRTSPMediaFactory* pFactory = nullptr;
    gulong m_nMediaConfigureHandlerId = 0;
};


void CGstreamerStream::Configure()
{
    // Assume pFactory was initiated in ctor
    
    m_nMediaConfigureHandlerId = g_signal_connect( pFactory, "media-configure",
        (GCallback)CGstreamerStream::MediaConfigure, this );
}

CGstreamerStream::~CGstreamerStream()
{
    if( m_nMediaConfigureHandlerId )
    {
        g_signal_handler_disconnect( pFactory, m_nMediaConfigureHandlerId );
    }
}

void CGstreamerStream::MediaConfigure( GstRTSPMediaFactory *pFactory, GstRTSPMedia *pMedia, gpointer pUserData )
{
    // Might be called from some Gstreamer thread
    
    CGstreamerStream* self = (CGstreamerStream*)pUserData;
    // Using here some class members
    //...
}

In Configure() method I subscribe to signal and save id of the connection. The handler is static member func and 'this' is passed as a parameter, so in the handler MediaConfigure() I want to use class members. But Gstreamer may use own threads and the handler might be called from such thread. In dtor I use the saved id to disconnect from the signal, but I have a doubt if this approach is safe: what if the handler has already been invoked and now is in process? Would g_signal_handler_disconnect() method block until the handler finishes its execution and thus prevents of destroying the class instance?

GObject docs are unclear for me about this.