Mary,
I suppose there may be someplace to draw a line, but these race
conditions are mostly corner cases. In my experience, any corner case
you can find, as improbable as it might seem, will be observed in
practice, probably much more often than you think.
If these things are real, and are not just variants of the ones we have
already identified, and covered by them, then it *may* be worth revisiting.
I have exchanged several messages with Pamela on this, but have not
examined her work in detail. She has made a number of simplifying
assumptions that IMO are not realistic ones to make in practice. But I
*think* that if she is finding races under those simplifying assumptions
then they presumably should continue to be real under looser conditions.
But I haven't had the time to understand her formalisms to make a
meaningful judgment on what she has found. Maybe somebody else has time?
(Perhaps someone like Iñaki (hint hint) who seems to have an interest in
arcane things.)
Thanks,
Paul
Mary Barnes wrote:
I think we also need to consider that some of these may be corner cases.
The idea of the doc in SIPPING was to document the most common race
conditions and the ones that had plagued folks in the past. If we can
get feedback from folks that these other cases occur "in the wild" and
are not rare cases (and not when there's buggy SW), then it might be
quite reasonable to bring this doc back to the WG.
Regards,
Mary.
-----Original Message-----
From: sipping-bounces@xxxxxxxx [mailto:sipping-bounces@xxxxxxxx] On
Behalf Of Paul Kyzivat
Sent: Friday, October 24, 2008 7:10 AM
To: Saverio Niccolini
Cc: sip@xxxxxxxx; sipping@xxxxxxxx; hasebe.miki@xxxxxxxxxxxxxx
Subject: Re: [Sip] INVITE dialogs
I think it is up to the wg and the chairs whether the draft is opened up
for inclusion of more races. I haven't had time to examine Pamela's
document in detail, so I can't speak to the specific races she has found
right now. I would not be terribly surprised if there are more. But I am
surprised if there are 40 more. Perhaps many of those are variants on a
theme and might be viewed by others as some smaller number.
Thanks,
Paul
Saverio Niccolini wrote:
It would be a very interesting "live fire demonstration" of the value
of the formalism if it discovered race conditions that we hadn't
identified by informal means.
I would not be surprise to discover that race conditions identified by
informal means are much less than the ones identified using a
formalism (even if one using simplifications).
Paul was saying there is not chance to touch the
draft-ietf-sipping-race-examples
is there any plan to address the identified new race conditions in
another draft then? (Pamela was speaking of about 40 more...)
Saverio
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