Hi Tuomas,

> > > rfcomm_sock_sendmsg() in net/bluetooth/rfcomm/sock.c. It returns
> > > uninitialized variable err, if called with len==0.
> > >
> > > Simple fix is to initialize err to 0.
> >
> > this would only hide the real problem. It should only return err if
> > the sent is still 0. The return statement is
> >
> > 	return sent ? sent : err;
> 
> Yep, exactly. It returns err, which isn't initialized, so it could be 
> positive.
> 
> Am I missing something?

that is really strange. A recent compiler should detect that err can be
used uninitialized.

How about the attached patch. Does it work for you?

Regards

Marcel