On Fri, 2012-08-17 at 22:36 +0000, Hefty, Sean wrote:
> > >   retries = 0, err = 0, index = 16, ctrl_avail = 3, sqe_avail = 1020,
> > 
> >                                       ^^^^^^^^^^^^^^
> > This looks like part of the problem.  There should be 4 control messages
> > available by default.  The receiver has sent a control message to the 
> > sender,
> > but the control message never completed at the receiver.  My guess is that 
> > the
> > sender never received it either.  It may be the missing buffer update, which
> > would be an RDMA write into the sender's 'target_sgl' array.
> > 
> > Have you ever been able to reproduce this problem without using fork() 
> > support?
> 
> A simple check to add is whether the rs_post_write() call ever fails, but in 
> rs_send_credits() in particular.  Checking for an error from 
> ibv_get_cq_event() in rs_get_cq_event() may also be useful.  In neither case 
> do I expect an error, but we could confirm it.

I didn't see any errors with these calls.
So far i have been able to consistently reproduce this hang only when fork 
support is enabled.
I am seeing this issue randomly even with a simple tcp client/server test only 
with fork.

Thanks
Sridhar

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