Blown Stack in ISR, i960

Gerwin Pfab pb at
Wed Jan 26 07:34:09 UTC 2000


you're right. Thank you and sorry for the silly question. 
Conclusion: Never write emails after an 8 hour debugging session.


Gerwin Pfab <pb at>   Dr. Schenk Industriemesstechnik GmbH
Dipl. Ing.                        Einsteinstrasse 37 
Software Engineering              D-82152 Martinsried
                                  Tel: +49-89-85695-0
                                  Fax: +49-89-85695-200

On 25 Jan 2000, Ian Lance Taylor wrote:

>    Date: Tue, 25 Jan 2000 18:19:38 +0100 (MET)
>    From: Gerwin Pfab <pb at>
>    BUT: every call to rtems_task_resume() decrements
>    Thread_dispatch_disable_level and will (when 0 is reached) call
>    ThreadDispatch() (and _Context_Switch()) and therefore make the Context
>    Switch on the Interrupt stack. So the task that Context_Switch switches to
>    now runs with the Interrupt Stack????!
>    What is wrong with this scenario or is this really possible?
> What's wrong with that scenario is that rtems_task_resume calls
> _Thread_Get, and _Thread_Get calls _Thread_Disable_dispatch.  The call
> to _Thread_Enable_dispatch in rtems_task_resume enables the
> dispatching which it just disabled.  If dispatching was already
> disabled when the call started, it remains disabled.
> Ian

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