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From: "Daryl Van Vorst" <daryl@wideray.com>
To: "'Marcel Holtmann'" <marcel@holtmann.org>
Cc: "'BlueZ Mailing List'" <bluez-devel@lists.sourceforge.net>
Subject: RE: [Bluez-devel] Rfcomm Use Count
Date: Mon, 20 Sep 2004 11:37:52 -0700
Message-ID: <002901c49f40$f008ac00$1a01010a@baked>
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Marcel,

I can't get it to happen with l2cap. But I did notice that it takes a few
seconds for the use count to go down after the listening program exits.

-Daryl.

> -----Original Message-----
> From: bluez-devel-admin@lists.sourceforge.net 
> [mailto:bluez-devel-admin@lists.sourceforge.net] On Behalf Of 
> Daryl Van Vorst
> Sent: September 20, 2004 10:59 AM
> To: 'Marcel Holtmann'
> Cc: 'BlueZ Mailing List'
> Subject: RE: [Bluez-devel] Rfcomm Use Count
> 
> 
> Hi Marcel,
> 
> > At the moment I must admit that I have no idea how to fix 
> > this in a sane
> > way. It seems that this bug is in there from the beginning 
> and a wrong
> > fix can cause unexpected side effects.
> > 
> > I don't think that the problem is in rfcomm_sock_cleanup_listen(),
> > because the wrong use count is already present after step 3. 
> > So when we
> > close a connected DLC that is not accepted yet, we still have 
> > it on the
> > accept queue then we have a problem. Maybe there is a bug 
> in our state
> > machine and this is not socket related.
> 
> Incoming connections must be added to the accept queue 
> (unless I'm really
> missing something). So the issue is just what to do when the 
> remote side
> closes them before accept() gets to them.
> 
> Making bluez_accept_dequeue() return sockets regardless of state is a
> potential solution. Accept() for rfcomm and l2cap would then 
> need to be
> modified to kill already closed sockets. The existing loop in 
> the accept()'s
> would need to be modified or a new one added to handle
> bluez_accept_dequeue() not always returning an open socket.
> 
> I may not have been clear about my thoughts on 
> rfcomm_sock_cleanup_listen().
> If bluez_accept_dequeue() did return sockets regardless of state, then
> rfcomm_sock_cleanup_listen() should work (unless calling 
> close on an already
> closed socket causes trouble). When it calls 
> rfcomm_sock_kill(), sock_put()
> gets called which calls destruct() which should decrement the 
> use count.
> 
> What if bluez_accept_dequeue() called sk->shutdown() on 
> sockets which are
> already closed in the accept queue?
> 
> I'll try out l2cap later for you. We should see the same thing.
> 
> -Daryl.
> 
> 
> 
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