Re: [ns] TcpApp, problem killing agents

[Tarik Alj <aljtarik@cholla.inrs-telecom.uquebec.ca>]

>Date: Mon, 31 Jul 2000 10:34:46 -0700 (PDT)
>From: Haobo Yu <haoboy@isi.edu>
>To: Tarik Alj <aljtarik@cholla.inrs-telecom.uquebec.ca>
>cc: ns-users@isi.edu
>Subject: Re: [ns] TcpApp, problem killing agents
>MIME-Version: 1.0
>
>Can you describe it in more detail, perhaps give a stack trace?
>TcpApp::process_data() simply returns if given a NULL data pointer so I
>don't see why it should core dump there. Thanks.

there goes the (partial) stack trace :

#0  0x8119f48 in CBuf::~CBuf ()
(gdb) bt
#0  0x8119f48 in CBuf::~CBuf ()
#1  0x809ed1c in TcpApp::recv ()
#2  0x805f84b in Agent::recvBytes ()
#3  0x806daa1 in FullTcpAgent::recv ()
#4  0x8054e5f in Classifier::recv ()
#5  0x8054e5f in Classifier::recv ()
#6  0x80532d3 in Connector::send ()
#7  0x80540a6 in Trace::recv ()
#8  0x80532d3 in Connector::send ()
#9  0x8107251 in TTLChecker::recv ()
#10 0x804f419 in NsObject::handle ()
#11 0x804d274 in Scheduler::dispatch ()
#12 0x804d29d in Scheduler::dispatch ()
#13 0x804d1de in Scheduler::run ()
#14 0x804d389 in Scheduler::command ()
...

apparently the cbuf is null.

 
What happens is: when the Terminal completes it sends a callback to the Gateway 
via a tcp connection, in turn the Gateway kills it connection; basically just 
like Http/Client disconnect { server }, in tcl/webcache/http-agent.tcl. 
Apparently it panics when "... proc done ..." is called. But if I take away the 
call to "close()" it works fine (or so it seems).

Thanks for taking the time,

Tarik.

>
>On Mon, 31 Jul 2000, Tarik Alj wrote:
>
>> Date: Mon, 31 Jul 2000 11:53:59 -0400 (EDT)
>> From: Tarik Alj <aljtarik@cholla.inrs-telecom.uquebec.ca>
>> To: ns-users@ISI.EDU
>> Subject: [ns] TcpApp, problem killing agents
>> 
>> Hi,
>> 
>> 	I am working on a h323 model for NS that is loosely based on the 
>> webcache model. I have a problem killing TCP connections : I have one agent 
send 
>> the other via a TcpApp a "stop-session" request; the instproc stop-session 
kills 
>> the tcp connections and a sigsev happens. It seems that process_data is 
called 
>> with a null pointer (the data...) wich makes the program core dump. 
>> 	Has anybody experienced the same sort of problem? Or is interested by 
>> such a problem...
>> 	Thanks,
>> 	
>> Tarik