Success was: hanging tasks

Joel Sherrill joel.sherrill at OARcorp.com
Mon Feb 3 15:31:49 UTC 2003



Peter Mueller wrote:
> 
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> Hi Joel,
> 
> your hint solved my problem. The serial interface works for a long time
> now without problems. Thanks!
> I wonder what the best source of information is regarding all issues for a
> specific cpu family. For example you mentioned a m68k code generation
> issue in some of your last mail now solved in the latest gcc. II was not
> aware of this neither of the bug 267 in gnats. Even I do my mest to follow
> this mailing list closely.
> 
> What is the best way to get all this information (for a cpu family)? Is it
> all in gnats?

I wish it were but it isn't because all problems don't become PRs.

In general, if you are looking for fixed problems look at the ChangeLog
files.  The releases now come with ChangeLog diffs.

> Peter
> 
> On Mon, 27 Jan 2003 13:15:31 -0600
> Joel Sherrill <joel.sherrill at OARcorp.com> wrote:
> 
> >
> >
> > Peter Mueller wrote:
> > >
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> > > Hi Joel,
> > >
> > > yes I'm using m68k (variant of efi332) and the snapshop 20020628.
> >
> > Hmmm... a 332 is a cpu32 which I think was one of the variants
> > exhibiting this behavior.
> >
> > > What is PR267? Is there a description of this bug and its solution
> > > (btw. is there a bug tracking system like bugzilla available for
> > > rtems?)?
> >
> > Yes.  We have been using GNATS for a while now (we are over PR300 now).
> >
> > http://www.oarcorp.com/cgi-bin/gnatsweb.pl
> >
> > User/Password == guest/guest
> >
> > > In what snapshot is the PR267 fixed?
> >
> > Based upon the ChangeLog in score/cpu/m68k, it looks like any snapshot
> > newer than 26 Aug 2002.
> >
> > > Thanks,
> > > Peter
> > >
> > > On Mon, 27 Jan 2003 08:18:45 -0600
> > > Joel Sherrill <joel.sherrill at OARcorp.com> wrote:
> > >
> > > >
> > > > Peter .. what CPU are you using?  This sounds a lot like the
> > > > behavior people got before an m68k specific fix went in.  It was
> > > > tracked as PR267 and CVS shows the last fix as back in August.  Any
> > > > chance you are using an m68k and something that old?
> > > >
> > > > Thomas Doerfler wrote:
> > > > >
> > > > > Hello Peter,
> > > > >
> > > > > > -----BEGIN PGP SIGNED MESSAGE-----
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> > > > > > Hi Joel, Thomas,
> > > > > >
> > > > > > thanks for your replies. dump_tasks finally helped me to find
> > > > > > one problem. A task waiting for an event that gets usually sent
> > > > > > from an irq. It turned out that the hardware triggering the irq
> > > > > > hangs sometimes so that the irq is missing and my task waits
> > > > > > forever.
> > > > >
> > > > > Normally I know things the other way round: Software guys find
> > > > > "hardware errors" and later on the hardware guys find out that
> > > > > the hardware was not initialized/used properly by the
> > > > > software... :-)
> > > > >
> > > > > >
> > > > > > The other thing is not solved. Here I like to ask again for your
> > > > > > advice.. One of my tasks handles serial input. After my system
> > > > > > runs for a while this task seems to get not scheduled anymore
> > > > > > even if the system is not fully loaded. The task state is
> > > > > > 8->STATES_DELAYING which means wait for timeout. This is ok
> > > > > > because my old efi332 serial driver polls the rcv buffer to
> > > > > > check if there is new data and waits for some ticks if nothing
> > > > > > is there. Could it be possible that rtems_task_wake_after does
> > > > > > not return for any reason?
> > > > >
> > > > > Hm, the only reasons I could think of would be:
> > > > >
> > > > > - Interrupts for System Tick do no longer occure, because: The
> > > > > interrupt is blocked, the timer has stopped or something
> > > > > similar. Can you check, whether the system tick still occures
> > > > > when your task hangs? You are working with a 68332 and BDM?
> > > > > Stop the system when your task hangs and set a breakpoint into
> > > > > the timer interrupt function. Does it get hit still?
> > > > >
> > > > > - You call "rtems_task_wake_after" with a VERY long delay...
> > > > > (quite improbable)
> > > > >
> > > > > maybe this helps a bit...
> > > > > Thomas.
> > > > >
> > > > > >
> > > > > > Thanks,
> > > > > > Peter
> > > > > >
> > > > > > >
> > > > > > > Peter, the gdb script I have posted a couple of times is a
> > > > > > > good start on seeing what the tasks in the system are up to.
> > > > > > > I would like to see the gdb script eventually enhanced so that
> > > > > > > it could give you some details
> > > > > > > like decoding the task state into English and know that if in
> > > > > > > certain states,
> > > > > > > that Wait.id is what the task is waiting on.
> > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Peter
> > > > > > > >
> > > > > > -----BEGIN PGP SIGNATURE-----
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> > > > >
> > > > > --------------------------------------------
> > > > > IMD Ingenieurbuero fuer Microcomputertechnik
> > > > > Thomas Doerfler           Herbststrasse 8
> > > > > D-82178 Puchheim          Germany
> > > > > email:    Thomas.Doerfler at imd-systems.de
> > > > > PGP public key available at: http://www.imd-
> > > > > systems.de/pgp_keys.htm
> > > >
> > > > --
> > > > Joel Sherrill, Ph.D.             Director of Research & Development
> > > > joel at OARcorp.com                 On-Line Applications Research
> > > > Ask me about RTEMS: a free RTOS  Huntsville AL 35805
> > > > Support Available                (256) 722-9985
> > > >
> > >
> > > - --
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> > > h2nMtyob4C+Q0GRbC52ADt4=
> > > =rDda
> > > -----END PGP SIGNATURE-----
> >
> > --
> > Joel Sherrill, Ph.D.             Director of Research & Development
> > joel at OARcorp.com                 On-Line Applications Research
> > Ask me about RTEMS: a free RTOS  Huntsville AL 35805
> > Support Available                (256) 722-9985
> >
> 
> - --
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