Stack Checker in rtems-4.8.0 - is it broken?

[Joel Sherrill]

Robert S. Grimes wrote:
> Joel Sherrill wrote:
>   
>> Robert S. Grimes wrote:
>>     
>>> Hi,
>>>
>>> Does the stack checker still work?  My app using powerpc/virtex BSP
>>> seems to fail on startup when the stack checker task is created in
>>> taskinitusers.c/_RTEMS_tasks_Initialize_user_tasks_body().  I get an
>>> exception 7 - here is the dump:
>>>
>>>
>>>       
>> There is no stack checker task.  It is a user extension.
>>     
> That makes infinitely more sense! ;-)  I was misled by the context -
> silly me.
>
>   
>> It works in 4.8 as far as the test program stackchk.exe goes.
>>     
> I figured you'd say that...
>   
>> You are on the "BSP initialization stack" at this point in the program
>> initialization.  I suspect you have blown your initialization stack
>> or the RTEMS workspace and the BSP initialization stack overlap.
>> Thus when the stack checker writes the pattern for the first
>> created task, it destroys the stack you are running on.
>>
>> Does this make sense?
>>     
> Sure, if that is indeed what is going on.  I'm not sure where to look on
> this, and I won't be able to check on it until Friday (FWIW - the only
> truly frustrating thing about my project is I only work 18-20 hours
> during two days a week, and I always seem to be finding problems at the
> end of one day, and I can't get back to it until several days later!)
> Anyway, I'll look into it then, and report back - until then, assume it
> is in my BSP...
>   
My standard recommendation in this case is to carefully
draw a memory map which includes the starting and ending
address of the following:

+ Initialization stack
+ C Program Heap
+ RTEMS Workspace
+ Your code data and bss sections
+ any interrupt vector areas
+ any memory reserved for rom monitor or loader

This information should be documented with the BSP anyway. but
usually isn't.

In your case, I am almost certain the initialization stack and the
RTEMS Workspace overlap.

--joel
> Thanks!
> -Bob
>   
>>>     Exception handling initialization done
>>>     opb_intc_init: m
exception handler called for exception 7
>>>          Next PC or Address of fault = A5A5A5A4
>>>          Saved MSR = 0
>>>          R0 = A5A5A5A5
>>>          R1 = 4A7EB4
>>>          R2 = 4853A8
>>>          R3 = 1
>>>          R4 = A5
>>>          R5 = 0
>>>          R6 = FEFFFFFF
>>>          R7 = 490000
>>>          R8 = 490AAC
>>>          R9 = 4A9C78
>>>          R10 = 1
>>>          R11 = 4A9C78
>>>          R12 = 0
>>>          R13 = FFFEAAFC
>>>          R14 = FFFFFFFF
>>>          R15 = FFFFFFFF
>>>          R16 = FFFFFFFF
>>>          R17 = FFFFFFFF
>>>          R18 = FFFFFFFF
>>>          R19 = FFFFFFFF
>>>          R20 = FFFFFFFF
>>>          R21 = FFFE2E6C
>>>          R22 = FFFE0000
>>>          R23 = FFFE0000
>>>          R24 = 0
>>>          R25 = 490984
>>>          R26 = 1
>>>          R27 = 0
>>>          R28 = 490000
>>>          R29 = 490C2C
>>>          R30 = 4A0F38
>>>          R31 = A5A5A5A5
>>>          CR = 28008022
>>>          CTR = 0
>>>          XER = 20000000
>>>          LR = A5A5A5A5
>>>          MSR = 0
>>>          DAR = 0
>>>     Stack Trace:
>>>       IP: 0xA5A5A5A4, LR: 0xA5A5A5A5
>>>     --^ 0x00000000
>>>     unrecoverable exception!!! Push reset button
>>>
>>> Turning off the stack checker allows my application to proceed
>>> normally...
>>>
>>> Any ideas?  Thanks!
>>> -Bob
>>>
>>> _______________________________________________
>>> rtems-users mailing list
>>> rtems-users at rtems.com
>>> http://rtems.rtems.org/mailman/listinfo/rtems-users
>>>
>>>       
>>     
>
>
>   


-- 
Joel Sherrill, Ph.D.             Director of Research & Development
joel.sherrill at OARcorp.com        On-Line Applications Research
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