[Info-vax] hung program location

[VAXman- at SendSpamHere.ORG]

In article <kg0duj$ttj$1 at dont-email.me>, Stephen Hoffman <seaohveh at hoffmanlabs.invalid> writes:
>On 2013-02-19 17:35:37 +0000, Tom Adams said:
>
>> There is only one AST programmed in. It's a resource wait AST that
>> only fires when the system is telling the process to shutdown, so it
>> did not cause the problem.
>
>Um, you're *debugging*.  Have you *proved* that it only fires once, and 
>when you expect it?
>
>> None of the QIOs or QIOWs use ASTs.
>
>So you have asynchornous code.
>
>> My theory is that the process got stuck in a LIB$WAIT call, but I
>> don't know why that would happen.  But it could be that the program
>> gets into HIB somewhere else in the code processing, and there is the
>> possibility that I am overlooking some bug that would screw up a LIB
>> $WAIT.
>
>You're *really* fixated on that call.
>
>Are you sure that lib$wait call isn't masking a deeper problem, for instance?
>
>> One odd thing is that the same process hung on three different
>> Alphas.   But I don't know if they all got hung at the same time.  The
>> three process would all be trying to get (or had or lost) a network
>> connection to the same IP address of the same analyzer.  The analyzer
>> is turned off and on and moved around to different physical connection
>> points.   The code has been stable for a long time, but the practice
>> of moving devices around like this is kind of  a new practice.
>
>Even apparently stable code is necessarily free of latent errors.
>
>There was a bug latent in RMS in VMS — hardly unused code — for most of 
>thirty years, when it was found.

Yup!  I recently (a year ago) discovered a bug in the self-relative queue
primitives on Itanium that had been there since the first OpenVMS Itanium
release.


>Debug.  Desk reviews.  Add diagnostics and detailed logging, as appropriate.
>
>Theorize.  Prove.  Or disprove.  But don't assume.

There's an Oscar Wilde quote that applies here:

  "When you assume, you make an ass out of u and me."

;)

-- 
VAXman- A Bored Certified VMS Kernel Mode Hacker    VAXman(at)TMESIS(dot)ORG

Well I speak to machines with the voice of humanity.