task stack overflow

Hi Mohamed,

A few questions. How are you declaring the local arrays ? And are these local arrays being initialized and used in the app ? If they are not used, the compiler will most likely optimize them out.

Best,

Ashish

Also, if you're allocating memory dynamically, it will be allocated from heap, not stack.

Hello Guys,

Sorry for replying late but it seems that the picture that i capture during my first post is removed my somehow, anyway.

i'm taking about the array that is allocated inside the task function, so they should be allocated inside the task stack, and the following are the pic that i capture, the first one is when i'm allocating arrays and some local variable that will fully consume the stack and the second when when i added 100 byte to some of the array while the ROV is displaying 0 in the used stack amount. i hope this time the pic reach you.

BTW, i was in the middle of debugging when i got the screen shoots, and the optimization is disabled.

thanks,

Mohamed Fawzy

Hi Mohamed,

Your first picture shows that the task stack overflowed. The stack peak is 2048 (same as stack size) and marked in red. If you hover the mouse over the highlighted stack peak, it will show a stack overrun message.

It looks to me that the app is behaving as expected. With large local arrays, the stack is overflowing.

Best,

Ashish

Hi Ashish,

actually i don't have any concern in the first picture, i just put it to persuade you that the arrays are located in the stack and  if the arrays size are increased, it won't be noticed by the ROV and this was obvious in the second picture.

so my post is for the second image.

Best Regards,

Mohamed Fawzy

Mohamed,
BIOS did notice the stack overflow and that is evident from the detailed view that shows the stack peak.

Did you get the basic view screenshot at the same time you got the detailed view screenshot ?

Best,

Ashish

Hi,

Actually, what I understood is that the two screenshots are from different codes. The second one shows that when clearly there's a stack overflow (because we had it with a smaller array) the basic view shows a stack size of zero and altough we can see that there's an overflow using ROV, BIOS didn't throw an error message in console. Maybe there wasn't a context switch?

Regards

J.

Hi Ashish,

i thought that to give you the chance to help me more to send you the code that i used for testing and two screen shoots for the basic view and the detailed view.

Best Regards,

Mohamed Fawzy4774.memory_TivaTM4C129XNCZAD.rar

Hi Mohamed,

I imported your project and tried it out on my machine. I believe you are not seeing the stack overflow because the buffers are declared but never used. The compiler optimizes them out. In order to see the stack overflow problem you would have to use the buffers so the compiler allocates them on the stack. Try adding the following to your task2 func:

Void task2Fxn(UArg arg0, UArg arg1)
{
	UInt idx;
	Char buf0[1024];

	// Add bug init code
	for (idx = 0; idx < 1024; idx++) {
		buf0[idx] = idx;
	}
        ....
}

With the above code, you will notice ROV show the stack has overflowed.

Best,

Ashish

Hi Ashish,

I believe that it isn't  an optimization issue, such that the stack overflow will be detected if the stack usage is below certain limit and upper this limit the stack over flow won't be detected, and you can check it on your setup and here is the update to the function

Void task2Fxn(UArg arg0, UArg arg1)

{

HeapMultiBuf_Params prms;

HeapMultiBuf_Handle heap;

/* Create the buffers to manage */

Char buf0[900];

Char buf1[256];

Char buf2[1640];

int idx;

Ptr bufs[1];

System_printf("\n************************************************");

System_printf("Initial task2 heap status\n");

/* print initial task1Heap status */

// printHeapStats(heap);

for (idx = 0; idx < 900; idx++) {

buf0[idx] = idx;

}

for (idx = 0; idx < 256; idx++) {

buf1[idx] = idx;

}

for (idx = 0; idx < 1640; idx++) {

buf2[idx] = idx;

}

anyway, all my questions regarding this topic because I want to know how can I discover the over flow in the runtime so I can get the reasonable reaction inside the application.

so please advice.

thanks,

Mohamed Fawzy

Hi,

Check section 3.5.4 (Testing for Stack Overflow, page 88) of SYS/BIOS user guide (www.ti.com/lit/pdf/spruex3) and see if it's what you want.

Regards

J

Hi,

the "Task_stat" will return the same result like the ROV and both of them can't detect the overflow for the example that I demo previously.

Thanks,

Mohamed Fawzy