Deadlock in IPC during datatransfer when Qt::AutoConnection used

Steps to reproduce:
1. Build and run modified sfwecho example (attached sfwecho_src.zip)
2. Send a message inside sfecho_client
Actual results:
Application freezes

Other info:

EchoService signal (serviceFoo) is connected (Qt::AutoConnection) to client's slot
(clientFoo) where we invoke serviceBar() back on service side.

1. If serviceBar return value type is void - doesn't freeze.

2. If connection type is Qt::QueuedConnection - doesn't freeze.

3. Works on windows desktop with Qt::AutoConnection

4. Logs attached.