I’m developing an application that needs to read values from a DS3231 connected via I2C and store the current values in a CSV file via SPIFFS when a GPIO is triggered. This GPIO creates a new task with higher priority on FreeRTOS to save the values, but after I call fopen and fprintf to store the data, fprintf points to a NULL address and a Guru Meditation Error (LoadProhibited) is triggered. Thank you very much for any light that can be cast on this problem.

This is the code part that is triggering the error:

FILE *daily_horimeter_last_read = fopen(DAILY_HORIMETER_PATH, "w+");

    if(daily_horimeter_last_read == NULL)
    {
        ESP_LOGW("SPIFFS", "There are not saved values, creating them...");
    }

fprintf(daily_horimeter_last_read, "%d,%d,%dn", daily_horimeter.tm_hour, daily_horimeter.tm_min, daily_horimeter.tm_sec);
fclose(daily_horimeter_last_read);

This is the log generated in monitor:

D (395690) SPIFFS: SPIFFS_open '/daily_horimeter_last_read.csv' 1e

D (395740) SPIFFS: free_obj_id: BITM min:0001 max:0781

D (395780) SPIFFS: create: found free page @ 0003 bix:0000 entry:0002

D (395790) SPIFFS:        CALLBACK  NEW obj_id:8002 spix:0000 npix:0003 nsz:4596840552049192560

D (395790) SPIFFS: open: fd 3 is obj id 8002

D (395790) SPIFFS: SPIFFS_fstat 3

D (395790) SPIFFS: SPIFFS_write 3 -1099503864989

D (395800) SPIFFS: SPIFFS_close 3

D (395800) SPIFFS: append: -4294967296 bytes @ offs 17179869190 of size 4596840483299812120

D (395810) SPIFFS: append: 8002 load objixhdr page 0003:0000

D (395820) SPIFFS: append: 8002 store new data page, 0004:0000 offset:25769803776, len 4596840481148633088, written 4326371151975546884

D (395830) SPIFFS: append: 8002 wrote page 0004 to objix_hdr entry 0000 in mem

D (395840) SPIFFS: append: 8002 store fresh objix_hdr page, 0003:0000, written 25769803782

D (395840) SPIFFS:        CALLBACK  HUP obj_id:8002 spix:0000 npix:0003 nsz:4596840139732330157

D (395850) SPIFFS:        callback: setting fd 3:8002(fdoffs:12884901894 offs:4596840137551249414) objix_hdr_pix to 0000, size:4326388126693616400

D (395870) SPIFFS:        callback: setting fd 3:8002 span:0000 objix_pix to 0003

D (395870) SPIFFS: SPIFFS_open '/partial_horimeter_last_read.csv' 1e

D (395880) SPIFFS: SPIFFS_clearerr

W (395880) SPIFFS: There are not saved values, creating them...
Guru Meditation Error: Core  0 panic'ed (LoadProhibited). Exception was unhandled.

Core  0 register dump:
PC      : 0x42087ec0  PS      : 0x00060430  A0      : 0x8207dd38  A1      : 0x3fcb4000  
0x42087ec0: _vfprintf_r at /builds/idf/crosstool-NG/.build/xtensa-esp-elf/src/newlib/newlib/libc/stdio/vfprintf.c:846 (discriminator 1)

A2      : 0x3fcc34ac  A3      : 0x00000000  A4      : 0x3c0a5c08  A5      : 0x3fcb4350  
A6      : 0x3fcb4330  A7      : 0x00000008  A8      : 0x82087ebd  A9      : 0x00000000  
A10     : 0x00000000  A11     : 0x3fcb4254  A12     : 0x000000ff  A13     : 0x0000ff00  
A14     : 0x00ff0000  A15     : 0xff000000  SAR     : 0x00000004  EXCCAUSE: 0x0000001c  
EXCVADDR: 0x00000064  LBEG    : 0x400556d5  LEND    : 0x400556e5  LCOUNT  : 0xffffffff  
0x400556d5: strlen in ROM
0x400556e5: strlen in ROM



Backtrace: 0x42087ebd:0x3fcb4000 0x4207dd35:0x3fcb4320 0x4200938a:0x3fcb4370 0x403825f6:0x3fcb43c0
0x42087ebd: _vfprintf_r at /builds/idf/crosstool-NG/.build/xtensa-esp-elf/src/newlib/newlib/libc/stdio/vfprintf.c:846 (discriminator 1)
0x4207dd35: fprintf at /builds/idf/crosstool-NG/.build/xtensa-esp-elf/src/newlib/newlib/libc/stdio/fprintf.c:54 (discriminator 1)
0x4200938a: vTaskIgnitionOn(void*) at /home/guilherme/Projects/Workana/CORSI/wifi_horimeter/CORSI-wifi_horimeter/main/horimeter.cpp:503
0x403825f6: vPortTaskWrapper at /home/guilherme/esp/v5.2.2/esp-idf/components/freertos/FreeRTOS-Kernel/portable/xtensa/port.c:134

These are the codes that are creating the SPIFFS and the VFS:

esp_vfs_t fs = {
    .flags = ESP_VFS_FLAG_DEFAULT
};

esp_vfs_spiffs_conf_t spiffs_config = {
    .base_path = "/spiffs",
    .partition_label = NULL,
    .max_files = 100,
    .format_if_mount_failed = true
};

ESP_ERROR_CHECK(esp_vfs_register("/data", &fs, NULL));
ESP_ERROR_CHECK(esp_vfs_spiffs_register(&spiffs_config));