Hello The local variables that I’m creating in a task, are not getting stored on the task’s stack. Here is my task creation: xTaskCreateStatic(dummy, "dummy", 200, &data, 3, xStack, &xTaskBuffer); Here is my data struct that I’ve passed to the task: typedef struct Data_t { uint32_t …

Hi @cobusve @gedeonag @aggarg Here is my PR: Updated configMINIMAL_STACK_SIZE for POSIX demo FreeRTOS:main ← arshi016:bluechip opened 08:45PM - 10 Oct 22 UTC (UTC) [arshi016] ar…

The POSIX port uses pthread_attr_setstack to set the memory you supply to xTaskCreateStatic to be used as the stack. As mentioned on this page , pthread_attr_setstack fails with EINVAL if stack size is less than PTHREAD_STACK_MIN (16384) bytes. This is what is happening I guess. Can you try the follo…

Thanks a lot Gaurav! This makes a lot of sense. Is this mentioned in the FreeRTOS documentation somewhere? Another follow-up question: If the stack is created using pthread_attr_setstack, what is the role of the stack we pass as an argument to the xTaskCreateStatic?

[image] bluechip: Is this mentioned in the FreeRTOS documentation somewhere? Not yet. We need to confirm if the above is right. Would you please do the 2 things that I suggested and let us know what you find? [image] bluechip: If the stack is created using pthread_attr_setstack, what is …

Yes, I did. Here are my observations: Check the return value of pthread_attr_setstack on this line . Value turned out to be: 22 Increase the stack size to PTHREAD_STACK_MIN. It gave me segmentation fault in the output. Is there an explanation for segfault in 2? Edit: I increased the puxSt…

@aggarg Can you please check the edited 7/8th answer? Thank you!

[image] bluechip: Then I got print values from on this line as: 0 22 22 It was invoked 3 times with your code. The other 2 times it is getting invoked for idle task and timer task. You need to adjust configMINIMAL_STACK_SIZE in your FreeRTOSConfig.h so that the stacks for these two tasks …

Ohh! Understood. So if the stack overflows, it never actually gets passed to the task. And thus, it doesn’t show up in the task’s stack. Right?

One suggestion from this conversation, the configMINIMAL_STACK_SIZE should by default be equal to PTHREAD_STACK_MIN in POSIX demos. I want to raise a PR with this fix in the POSIX demos. Do you also agree? Also, it should be properly documented in the official documentation as well. Or some error m…

Right, for this to work, a minimum size of PTHREAD_STACK_MIN has to be passed to the all the static functions which is probably larger than what you really want in the field. In that case using the normal dynamic functions (without static), only when using the posix port would be more accurate. ch…

Hi @gedeonag Dynamic allocation also requires PTHREAD_STACK_MIN according to this this page it mentions… A limitation exists for the minimal stack size that can be created. This limitation is platform dependent and is equal to PTHREAD_STACK_MIN…As a workaround, always pass a stack of size PTHREAD_S…

C question about stacks, not sure if FreeRTOS has a role to play

Kernel

bluechip (bluechip) October 10, 2022, 8:46pm 18

Hi @cobusve @gedeonag @aggarg
Here is my PR:

Thank you!

In POSIX simulation layer uxTaskGetStackHighWaterMark is not giving expected results

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C question about stacks, not sure if FreeRTOS has a role to play

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