Calling date_time_update_async from main thread leads to stack overflow

Question

Dear Nordic Support Team,

I am using nRF Connect 1.9.1 together with the modem firmware 1.3.2 on a nRF9160 DK.

I noticed that calling the function date_time_update_async in the main thread produces a stack overflow error. This is the case even if a connection to the cellular network was established before calling date_time_update_async .

I have attached three files:

[minimalExample.c] Minimal example to produce the error
[log_dateTimeStackOverflow.txt] Error log for the case when date_time_update_async is called without prior connection to the cellular network
[log_dateTimeStackOverflow_lte.txt] Error log for the case when date_time_update_async is called after a connection to the cellular network was established

Fullscreen 4478.minimalExample.c Download

// Zephyr
#include <zephyr.h>

// Nordic
#include <date_time.h>
#include <modem/lte_lc.h>



static bool isDateTimeUpdateDone = false;

static void callback_dateTimeEvent(const struct date_time_evt *evt)
{
    printk("Event %d\n", evt->type);
    isDateTimeUpdateDone = true;
}



void main(void)
{
    printk("I am running!\n");


    int error = 0;

    // error = lte_lc_init();
    // printk("lte_lc_init: %d\n", error);

    // error = lte_lc_connect();
    // printk("lte_lc_connect: %d\n", error);

    error = date_time_update_async(callback_dateTimeEvent);
    printk("date_time_update_async: %d\n", error);

    while (!isDateTimeUpdateDone)
    {
        printk("Waiting...\n");
        k_sleep(K_MSEC(500));
    }


    printk("I am returning!\n");
}

Fullscreen log_dateTimeStackOverflow.txt Download

*** Booting Zephyr OS build v2.7.99-ncs1-1  ***<CR><LF>
I: Starting bootloader<CR><LF>
I: Primary image: magic=good, swap_type=0x4, copy_done=0x1, image_ok=0x1<CR><LF>
I: Secondary image: magic=unset, swap_type=0x1, copy_done=0x3, image_ok=0x3<CR><LF>
I: Boot source: none<CR><LF>
I: Swap type: none<CR><LF>
I: Bootloader chainload address offset: 0x10000<CR><LF>
I: Jumping to the first image slot<CR>
*** Booting Zephyr OS build v2.7.99-ncs1-1  ***<CR><LF>
I am running!<CR><LF>
date_time_update_async: 0<CR><LF>
Waiting...<CR><LF>
[00008712] <ESC>[1;31m<err> os: ***** USAGE FAULT *****<ESC>[0m<CR><LF>
[00008712] <ESC>[1;31m<err> os:   Stack overflow (context area not valid)<ESC>[0m<CR><LF>
[00008713] <ESC>[1;31m<err> os: r0/a1:  0x00038834  r1/a2:  0x41000000  r2/a3:  0x0001001a<ESC>[0m<CR><LF>
[00008713] <ESC>[1;31m<err> os: r3/a4:  0xabddef67 r12/ip:  0x00038fd4 r14/lr:  0x41000000<ESC>[0m<CR><LF>
[00008714] <ESC>[1;31m<err> os:  xpsr:  0xadffbc00<ESC>[0m<CR><LF>
[00008714] <ESC>[1;31m<err> os: Faulting instruction address (r15/pc): 0x00010079<ESC>[0m<CR><LF>
[00008715] <ESC>[1;31m<err> os: >>> ZEPHYR FATAL ERROR 2: Stack overflow on CPU 0<ESC>[0m<CR><LF>
[00008716] <ESC>[1;31m<err> os: Current thread: 0x2000e2b8 (unknown)<ESC>[0m<CR><LF>
[00010417] <ESC>[1;31m<err> fatal_error: Resetting system<ESC>[0m<CR>

Fullscreen log_dateTimeStackOverflow_lte.txt Download

*** Booting Zephyr OS build v2.7.99-ncs1-1  ***<CR><LF>
I: Starting bootloader<CR><LF>
I: Primary image: magic=good, swap_type=0x4, copy_done=0x1, image_ok=0x1<CR><LF>
I: Secondary image: magic=unset, swap_type=0x1, copy_done=0x3, image_ok=0x3<CR><LF>
I: Boot source: none<CR><LF>
I: Swap type: none<CR><LF>
I: Bootloader chainload address offset: 0x10000<CR><LF>
I: Jumping to the first image slot<CR>
*** Booting Zephyr OS build v2.7.99-ncs1-1  ***<CR><LF>
I am running!<CR><LF>
lte_lc_init: 0<CR><LF>
lte_lc_connect: 0<CR><LF>
date_time_update_async: 0<CR><LF>
Waiting...<CR><LF>
[00146596] <ESC>[1;31m<err> os: ***** USAGE FAULT *****<ESC>[0m<CR><LF>
[00146597] <ESC>[1;31m<err> os:   Stack overflow (context area not valid)<ESC>[0m<CR><LF>
[00146597] <ESC>[1;31m<err> os: r0/a1:  0x00038fc4  r1/a2:  0x41000000  r2/a3:  0xa8044105<ESC>[0m<CR><LF>
[00146597] <ESC>[1;31m<err> os: r3/a4:  0xadffbd6b r12/ip:  0x48fc6800 r14/lr:  0x6fedee7e<ESC>[0m<CR><LF>
[00146598] <ESC>[1;31m<err> os:  xpsr:  0x00038800<ESC>[0m<CR><LF>
[00146598] <ESC>[1;31m<err> os: Faulting instruction address (r15/pc): 0x20010808<ESC>[0m<CR><LF>
[00146599] <ESC>[1;31m<err> os: >>> ZEPHYR FATAL ERROR 2: Stack overflow on CPU 0<ESC>[0m<CR><LF>
[00146600] <ESC>[1;31m<err> os: Current thread: 0x2000e2c0 (unknown)<ESC>[0m<CR><LF>
[00148295] <ESC>[1;31m<err> fatal_error: Resetting system<ESC>[0m<CR>

In the following are the Kconfig settings I believe to be relevant for this case:

CONFIG_NRF_MODEM_LIB=y
CONFIG_MODEM_KEY_MGMT=y
CONFIG_MODEM_INFO=y

CONFIG_LTE_LINK_CONTROL=y
CONFIG_LTE_NETWORK_MODE_LTE_M=y
CONFIG_LTE_AUTO_INIT_AND_CONNECT=n

CONFIG_DATE_TIME=y
CONFIG_DATE_TIME_AUTO_UPDATE=n
CONFIG_DATE_TIME_UPDATE_INTERVAL_SECONDS=7200

CONFIG_MAIN_STACK_SIZE=32768
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=32768
CONFIG_HEAP_MEM_POOL_SIZE=32768

A little more context:

In my application I have multiple time sources. One of them is Nordic's date time library and another is a RTC. I try to initialize both on system startup when a connection to the cellular network isn't established yet. I am expecting the RTC to do its thing and I expect Nordic's date time library to fail gracefully with the event DATE_TIME_NOT_OBTAINED. However my application crashes with the aforementioned error.

I would like to understand what causes the error and how it can be prevented.

Thank you allot for your help! Please don't hesitate to ask if you have any questions.

Cheers,
Sebastian