freeRTOS tickcount stop increase and OS hang at Timer task

Hi all,

I’m using Cortex M33 and CMSIS FreeRTOS 10.5.1. In my project, I have total 5 tasks.

Idle: Priority 0,
App_CyclicTask: xTaskCreateStatic (Priority 1, puxStackBuffer: 600)
App_EventTask: xTaskCreateStatic (Priority 3, puxStackBuffer: 500)
App_CriticalTask: xTaskCreateStatic (Priority 5, puxStackBuffer: 500)
TmrTask: Priority 6

At first, it seems to work ok but after amount of time, I see tickcount does not increase and task is not switching anymore, I assume that OS is hanging (no hardfault, it just hang there)

So, if anyone has experienced with this issue or if you need more info, please let know!

Here is the FreeRTOSConfig

/*
 * FreeRTOS Kernel V10.4.0
 * Copyright (C) 2019 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * http://www.FreeRTOS.org
 * http://aws.amazon.com/freertos
 *
 * 1 tab == 4 spaces!
 */


#ifndef FREERTOS_CONFIG_H
#define FREERTOS_CONFIG_H

/*-----------------------------------------------------------
 * Application specific definitions.
 *
 * These definitions should be adjusted for your particular hardware and
 * application requirements.
 *
 * THESE PARAMETERS ARE DESCRIBED WITHIN THE 'CONFIGURATION' SECTION OF THE
 * FreeRTOS API DOCUMENTATION AVAILABLE ON THE FreeRTOS.org WEB SITE.
 *
 * See http://www.freertos.org/a00110.html
 *----------------------------------------------------------*/

#if (defined(__ARMCC_VERSION) || defined(__GNUC__) || defined(__ICCARM__))
#include <stdint.h>

extern uint32_t SystemCoreClock;
#endif


/* Constants that describe the hardware and memory usage. */
#define configCPU_CLOCK_HZ                    	((uint32_t)48000000)
#define configTICK_RATE_HZ                    	((TickType_t)1000)
#define configTOTAL_HEAP_SIZE                 	((size_t)0x3000)
#define configMINIMAL_STACK_SIZE              	((uint16_t)128)
#define configIDLE_TASK_STACK_DEPTH 		  	((uint16_t)(128))
#define configSUPPORT_DYNAMIC_ALLOCATION     	 1
#define configSUPPORT_STATIC_ALLOCATION       	1
#define configRECORD_STACK_HIGH_ADDRESS 	  	1
#define configNUM_THREAD_LOCAL_STORAGE_POINTERS 2

/* Constants related to the behaviour or the scheduler. */
#define configMAX_PRIORITIES                  10
#define configUSE_PREEMPTION                  1
#define configUSE_TIME_SLICING                1
#define configIDLE_SHOULD_YIELD               0
#define configMAX_TASK_NAME_LEN               (12)
#define configUSE_16_BIT_TICKS                0

/* Software timer definitions. */
#define configUSE_TIMERS                      1
#define configTIMER_TASK_PRIORITY             6
#define configTIMER_QUEUE_LENGTH              50
#define configTIMER_TASK_STACK_DEPTH          ((uint16_t)(512))

/* Constants that build features in or out. */
#define configUSE_MUTEXES                     1
#define configUSE_RECURSIVE_MUTEXES           1
#define configUSE_COUNTING_SEMAPHORES         1
#define configUSE_QUEUE_SETS                  0
#define configUSE_TASK_NOTIFICATIONS          1
#define configUSE_TRACE_FACILITY              1
#define configUSE_TICKLESS_IDLE               1
#define configUSE_APPLICATION_TASK_TAG        1
#define configUSE_NEWLIB_REENTRANT            0
#define configUSE_CO_ROUTINES                 0

/* Constants provided for debugging and optimisation assistance. */
#define configCHECK_FOR_STACK_OVERFLOW        2
#define configQUEUE_REGISTRY_SIZE             0
#define configASSERT( x )                     if( ( x ) == 0 ) { taskDISABLE_INTERRUPTS(); for( ;; ); }

/* Constants that define which hook (callback) functions should be used. */
#define configUSE_IDLE_HOOK                   0
#define configUSE_TICK_HOOK                   0
#define configUSE_DAEMON_TASK_STARTUP_HOOK    0
#define configUSE_MALLOC_FAILED_HOOK          0

/* Port specific configuration. */
#define configENABLE_MPU                      	0
#define configENABLE_FPU                      	0
#define configENABLE_MVE                      	0
#define configENABLE_TRUSTZONE                	0
#define configMINIMAL_SECURE_STACK_SIZE       	((uint32_t)1024)
#define configRUN_FREERTOS_SECURE_ONLY        	1
#define configUSE_PORT_OPTIMISED_TASK_SELECTION 0
#define configEXPECTED_IDLE_TIME_BEFORE_SLEEP 	2

/* Cortex-M specific definitions. */
#ifdef __NVIC_PRIO_BITS
  /* __NVIC_PRIO_BITS will be specified when CMSIS is being used. */
  #define configPRIO_BITS                     __NVIC_PRIO_BITS
#else
  /* 7 priority levels */
  #define configPRIO_BITS                     3
#endif

/* The lowest interrupt priority that can be used in a call to a "set priority" function. */
#define configLIBRARY_LOWEST_INTERRUPT_PRIORITY       7

/* The highest interrupt priority that can be used by any interrupt service
 * routine that makes calls to interrupt safe FreeRTOS API functions.  DO NOT
 * CALL INTERRUPT SAFE FREERTOS API FUNCTIONS FROM ANY INTERRUPT THAT HAS A
 * HIGHER PRIORITY THAN THIS! (higher priorities are lower numeric values). */
#define configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY  1

/* Interrupt priorities used by the kernel port layer itself.  These are generic
 * to all Cortex-M ports, and do not rely on any particular library functions. */
#define configKERNEL_INTERRUPT_PRIORITY               (configLIBRARY_LOWEST_INTERRUPT_PRIORITY << (8 - configPRIO_BITS))

/* !!!! configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to zero !!!!
 * See http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html. */
#define configMAX_SYSCALL_INTERRUPT_PRIORITY          (configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY << (8 - configPRIO_BITS))

/* Set the following definitions to 1 to include the API function, or zero
 * to exclude the API function.  NOTE:  Setting an INCLUDE_ parameter to 0 is
 * only necessary if the linker does not automatically remove functions that are
 * not referenced anyway. */
#define INCLUDE_vTaskPrioritySet              1
#define INCLUDE_uxTaskPriorityGet             1
#define INCLUDE_vTaskDelete                   1
#define INCLUDE_vTaskSuspend                  1
#define INCLUDE_xTaskDelayUntil               1
#define INCLUDE_vTaskDelay                    1
#define INCLUDE_xTaskGetIdleTaskHandle        0
#define INCLUDE_xTaskAbortDelay               0
#define INCLUDE_xQueueGetMutexHolder          0
#define INCLUDE_xSemaphoreGetMutexHolder      0
#define INCLUDE_xTaskGetHandle                0
#define INCLUDE_uxTaskGetStackHighWaterMark   0
#define INCLUDE_uxTaskGetStackHighWaterMark2  0
#define INCLUDE_eTaskGetState                 1
#define INCLUDE_xTaskResumeFromISR            0
#define INCLUDE_xTimerPendFunctionCall        1
#define INCLUDE_xTaskGetSchedulerState        1
#define INCLUDE_xTaskGetCurrentTaskHandle     1

/* Map the FreeRTOS port interrupt handlers to their CMSIS standard names. */
#define xPortPendSVHandler                    PendSV_Handler
#define vPortSVCHandler                       SVC_Handler
#define xPortSysTickHandler                   SysTick_Handler

#if (defined(__ARMCC_VERSION) || defined(__GNUC__) || defined(__ICCARM__))
/* Include debug event definitions */
#include "freertos_evr.h"
#endif

#endif /* FREERTOS_CONFIG_H */

So SysTick is not firing? What is the value of tick count when it hangs?

Can you break the code in the debugger and see what it is doing when it appears hang?

Which FreeRTOS version are you using? Do you have confiASSERT defined and stack overflow check enabled?

Hi Aggarg,

  1. What is the value of tick count when it hangs?
    → Do you mean xTickCount in the Watch? if yes then it’s random value for every test. You can see in below picture

  2. Can you break the code in the debugger and see what it is doing when it appears hang?
    → the code keep stuck in this loop

  3. Which FreeRTOS version are you using? Do you have confiASSERT defined and stack overflow check enabled?

  • I use CMSIS FreeRTOS 10.5.1 and I upload the freeRTOS config in my question. Please have a glance into it
  • As you can see configCHECK_FOR_STACK_OVERFLOW is defined as 2 and break point never jump into vApplicationStackOverflowHook
  • About configASSERT, I keep it as default.

Can you examine the ready task list and verify that the state of the tasks that are not running?

Can you use the latest FreeRTOS version 10.6.0. The reason I ask is - some asserts have been added to catch incorrect priority configuration.

The FreeRTOSConfig looks okay.

Which hardware are you using?

Thank for your quick support but I would like to be pending this topic to next month because I have a demo with higher priority.
So, I will provide more info later!

FreeRTOS StackOverflow will never trigger on an M33 because it has hardware stack limits (PSPLIM) that are set correctly by the port. So it will run into a UseageFault before the overflow would be detected by the FreeRTOS logic.