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Re^4: panic: COND_DESTROY(6)

by menth0l (Monk)
on Jan 27, 2012 at 11:33 UTC ( #950334=note: print w/ replies, xml ) Need Help??


in reply to Re^3: panic: COND_DESTROY(6)
in thread panic: COND_DESTROY(6)

Thanks for shedding some light on semaphore case.

I'd really like to create a test case but there's a few obstacles that i'd have to overcome in order to do this. First of all the app is pretty large. In minimal version there are at least 4 threads involved:

  1. thread hosting rpc server
  2. thread preparing load balancing for sql data related to rpc request
  3. thread that sends request with data definition to remote host
  4. thread keeping track of available hosts
I can't pinpoint which thread is to blame (i can't guess it neither from log nor from the message itself).
Second of all, the app is tied to local sql database and i can't see any sane way to simulate that in a script.

I know about the threads::shared bug that was fixed (i reported it to J.D. Hedden ;) but downgrading seems to me like "out of the frying pan, into the fire" - type situation :) But i guess You are right - maybe i could spot this problem more easily with this.

Although i'm still in a deep dark wood some light can be seen ;) Thanks to You i know it's something related to locks. I'll try to mess around with the code which uses lock the most and test, test, test.... Maybe i create a bug report after all.


Comment on Re^4: panic: COND_DESTROY(6)
Re^5: panic: COND_DESTROY(6)
by BrowserUk (Pope) on Jan 27, 2012 at 11:45 UTC
    I can't pinpoint which thread is to blame (i can't guess it neither from log nor from the message itself).

    Do you have the ability to build your own Perl and run that in a production-like environment?

    Adding some useful extra information to the specific error message would be quite easy. If you can, and want some suggestions ...


    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.

    The start of some sanity?

      Ability, yes. Knowledge to do so... not really. As i said: i'm using ActiveState installation so until now i didn't mess with the perl itself.

      But if it's not that hard then maybe i could give it a chance. So, what do i do? :)

        Building perl from source is quite easy assuming you have an appropriate compiler.

        For consistency and simplicity, I'd recommend using the MS free edition.

        Once you've installed the compiler, download the active state source code for your version of perl.

        Gunzip the *.source.tar.gz. Edit the win32\Makefile to set the compiler (CC) and install directories and then do nmake Makefile and go to lunch. When you return you should be able to do nmake test, and if your company would object to you taking another lunch you could do some work for an hour. Preferably on another machine :)

        Then nmake install. Then install any non-core dependencies required by your application, and the application itself. At that point you should be able to run the application.

        Once you have it running, you can then tweak the source code where the message is produced, re-build, and then try to recreate the failure with the benefit of whatever extra information you've added.

        I'd suggest adding at least the threadid and caller information. It should also be possible to discover the name of the perl-level cond-var that is giving the problem. That lot should go quite a way to helping you track down the source of the problem.


        With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority".
        In the absence of evidence, opinion is indistinguishable from prejudice.

        The start of some sanity?

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