Re: simultaneous close

Memory tells me we recognized that deadlock, and I thought we resolved
it.

As I remember the right thing is for one end to refuse the close and 
the other accepts it.  We did something arbitrary like initiator
should go ahead and close.  I guess that's not working.

The core dump is coming from the socket close event I think.  So it's
really 2 bugs.

Went and looked at the code.  Fix will be non-trivial.  Problem is that 
the way the code is I have it blocking n a wait loop.  Unfortunately I think
this is blocking the thread that needs to process the close from the other 
end.  There is no quick fix I think.  Major fault.  The wait is in 
waitfor_chan_stat_quiescent() and that is called from 
blw_close_request_non0().

I am not sure if we can put something in the waitfor function to 
process further events in chan 0 because I am not sure what the semaphore 
states are.  Theoretically the waitfor functions allow the right things to 
happen in other threads.  Might be able to solve this by dispatching
the events differently.  Not sure.

-bill


On Fri, Feb 13, 2004 at 01:32:23PM -0800, Lei Zhang wrote:
> Yep.  Looks like both sides wait for the channel status to be QUIESCENT, 
> but both sides are in the HALFCLOSE state.
> 
> William J. Mills wrote:
> 
> >Hmmmm...  well that's a bad bug.
> >
> >Simultaneous from both ends in same channel?
> >
> >-bill
> >
> >
> >On Fri, Feb 13, 2004 at 11:40:31AM -0800, Lei Zhang wrote:
> >
> >>Knowing that beepcore-c is dead, still it's worthwhile reporting this:
> >>
> >>beepcore-c is not able to handle simultaneous channel close.  I see the 
> >>following call sequences:
> >>
> >>  listener                   initiator
> >> 
> >>  close_indication local       close_indication local
> >>  close_indication remote      close_indication remote
> >>
> >>Neither side gets to the close_confirmation stage.  After waiting a 
> >>while, kill one peer, the other peer core dumps saying 'assertion 
> >>"wrap->iostate != 0" failed' in bp_notify.c.
> >>
> >>well, well...
> >>
> 
> 


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