[Ace-users] Re: [tao-users] LOCATION FORWARD and _is_a() loop

Douglas C. Schmidt schmidt at dre.vanderbilt.edu
Tue Aug 14 05:30:00 CDT 2007


Hi Christian,

   Thanks very much for using the PRF!

> TAO VERSION: 1.5
> ACE VERSION: 5.5

Please upgrade to ACE+TAO+CIAO x.5.10 (i.e., ACE 5.5.10, TAO 1.5.10, and
CIAO 0.5.10), which you can download from

http://download.dre.vanderbilt.edu

under the heading: "Latest Beta Kit".  We've added lots of improvements
since TAO 1.5, so hopefully this bug is fixed.  If not, please let us
know and we'll try to fix it soon.

The DOC groups at Washington University, UC Irvine, and Vanderbilt
University only provide "best effort" support for non-sponsors for the
latest release, as described in

http://www.dre.vanderbilt.edu/~schmidt/DOC_ROOT/ACE/docs/ACE-bug-process.html

Thus, if you need more "predictable" help for earlier versions of
ACE+TAO, I recommend that you check out

http://www.dre.vanderbilt.edu/support.html

for a list of companies that will provide you with ACE+TAO commercial
support.

Thanks,

        Doug


> HOST MACHINE and OPERATING SYSTEM:
> Intel(R) Xeon(R) CPU 5130  @ 2.00GHz
> Linux 2.6.16.21-0.8-smp #1 SMP i386 GNU/Linux
> 
> TARGET MACHINE and OPERATING SYSTEM, if different from HOST:
> COMPILER NAME AND VERSION (AND PATCHLEVEL):
> gcc version 3.4.3
> 
> DOES THE PROBLEM AFFECT:
>     COMPILATION?
>         No.
>     LINKING?
>         No.
>     EXECUTION?
>         Yes.
> 
> SYNOPSIS:
> Location Forward and _is_a seem to loop over two hosts
> 
> DESCRIPTION:
> Here is the setup:
> 
> Two hosts, both basically running the same set of applications (A
> bunch of CORBA-servers and clients). One of the CORBA-servers
> running on both hosts is a management and control application (from
> now on: "mac-server") which clients can use to retrieve status-info 
> about the whole system.
> 
> The mac-server is implemented in a way that lets you retrieve
> status info about any of the two physical machines via any of the
> two mac-servers. (That means you can ask mac-server on host A about
> the status of the application on host B, and vice versa) Both
> mac-servers offer the same CORBA interface. If you ask one about the
> state of the other, it will internally try to resolve the object
> reference to its peer mac-server and ask him using the same
> interface that someone just used to call him. (Hope it is clear what
> I mean here)
> 
> Now, on certain conditions (which I not isolated completely yet), I
> see a loop between the two mac-servers:
> I ask server A about the status of server B and the ORB of
> mac-server on server A starts the request by sending a _is_a()
> request to server B. Server B then -- for some reason I don't
> understand -- sends a LOCATION FORWARD back to server A, which again
> sends _is_a() to server B, and so on and on and on.
> 
> After about 4500 requests in about 3 seconds time, one of the 
> mac-servers dies with segmentation fault.
> 
> My question: Is there a way to completely disable LOCATION FORWARDs
> and/or do you have any idea where this might come from?
> 
> SAMPLE FIX/WORKAROUND:
> None.
> 
> I can send the 3.5MB pcap logfile if anyone is interested.
> 
> Thanks in advance,
> Christian Fromme
> 
> _______________________________________________
> tao-users mailing list
> tao-users at mail.cse.wustl.edu
> http://mail.cse.wustl.edu/mailman/listinfo/tao-users



More information about the Ace-users mailing list