K_TIMER() - HARD_FAULT - Data Access Violation - nrf9160

[ReneDelgado]

Hi,

Currently we working on a project that uses:

• nRF9160
•  Zyphre OS
•  Segger Embedded Studio for  Arm (Nordic Edition) V5.10d
•  SDK v1.4

We need to handle multiple timeouts, to handle our processes, but we have a problem that we think occurs when our K_TIMERS expire. We are looking for restrictions on using multiple timers but we do not find any, the functions we are using are the following:

1. k_timer_init(timer, NULL, NULL);
2. k_timer_start(timer, K_MSEC(timeout), K_NO_WAIT);

And this is the error:

• Is this a known bug?
• Does anyone know of any restrictions that can cause this?
• What could we be doing wrong?

Thanks a lot.

[ReneDelgado]

Sorry, I forgot to attach this image:

[Håkon Alseth]

Hi,

 

In the assert message, you have two addresses that points out:

And:

 

What is located at these addresses? You can do a lookup using "arm-none-eabi-addr2line -e build-folder/zephyr/zephyr.elf 0xADDR". If you have re-compiled or done any changes to application, these addresses will move.

Note that all k_timer instances are running in interrupt context, so you should be very careful of what you're calling in those callbacks. It is recommended to push tasks to a workqueue or similar instead.

 

Kind regards,

Håkon

[ReneDelgado]

Hi Håkon, thanks for your prompt answer, this is the result from the address mentioned:

PS C:\...\build_nrf9160dk_nrf9160ns\zephyr> arm-none-eabi-addr2line -e zephyr.elf 0x217e7
C:/.../ncs/v1.4.0/zephyr/include/sys/dlist.h:325

PS C:\...\build_nrf9160dk_nrf9160ns\zephyr> arm-none-eabi-addr2line -e zephyr.elf 0x00021834
C:/.../ncs/v1.4.0/zephyr/include/spinlock.h:92

Regarding your note, I don't understand.

Our context:

We are calling k_timer_init(timer, NULL, NULL); & k_timer_start(timer, K_MSEC(timeout), K_NO_WAIT);  from a thread context without functions for callback, we set NULL in the k_timer_ini() function. We are not running nothing in any callback, We just verify if the timer has ended.

• Could you expand your note a little more?
• Which callbacks are you referring to?

Kind regards,

René D.

[Håkon Alseth]

Hi René,

 

From the logic that you posted, you're doing something similar to this sequence:

https://docs.zephyrproject.org/latest/reference/kernel/timing/timers.html#reading-timer-status 

Looking at the assert information, the second one is interesting:

https://github.com/nrfconnect/sdk-zephyr/blob/master/include/spinlock.h#L92

This means that you have a nested (recursive) locking sequence somewhere, as per the documentation:

https://docs.zephyrproject.org/apidoc/latest/spinlock_8h_aac60da4347f5b29ff8c4e5f24c99b3bf.html 

   

Is there anything specific in the thread you're calling this from that might call k_spin_lock()? Could you share a snippet or similar?

 

Kind regards,

Håkon

[ReneDelgado]

Hello Håkon,

Sorry for the delay, I have the most popular virus from this year.

Yes regarding to our sequence is like you mentioned, but regarding to spinlock.h#L92 we do not calling this function explicit neither we are using recursive functions. As note, we are using mutex as the documentation suggest.

Also note that if I enable the segger system view this cracks earlier.

CONFIG_SEGGER_SYSTEMVIEW=y

CONFIG_USE_SEGGER_RTT=y

CONFIG_TRACING=y

If you  want I  can send you an  email with a basic sample of the code.

Thanks,

René D.