stm32 freertos hardfault - snprintf/vsnprintf/sprintf - stm32

Question

I'm having quite a trouble finding the reason for my current hardfault.
I'm using freertos with static memory allocation (no malloc ever used) I use new with pre-allocated buffers (new (&buffer).
I have made sure that all threads are aligned(4).
whenever I use a form of printf, my application jumps to the hardfault from the freertos call "start the first task".
I write "embedded C++" code, what is basically C89 with namespaces and classes, so nothing other than is included from c++. each includes from c files (.h) are wrapped with extern "C" so there is never ever a linkage issue.
I have tested with newlib, newlib nano and the tinyprintf from spare time libs. no difference.
also, I have never an assert failure on the malloc calls, so I am "quite" sure no newlib function accesses malloc (am I right here?)
the internet suggests its either a dynamic memory allocation issue or a stack issue. how can I prove what is causing the hardfault? I believe the hint my stack gets corrupted because of my printf calls isn't that wrong. how can I prove this? (i have never debugged stacks and would need some help debugging the stack pointer).
any other ideas?
thank you very much
example:
(void) vsnprintf( _log_buffer, C_LOG_BUFFER_SIZE, format, args ); // hardfault
(void) sprintf( _log_buffer, "huhu" ); // no hardfault
dynamic allocation overwrites:
__ATL_LINK_EXTERN_C void *malloc( size_t size )
{
(void) size;
atl::os::assert::failed((char*)__FILE__,__LINE__);
return NULL;
}
__ATL_LINK_EXTERN_C void * calloc(size_t size1, size_t size2)
{
(void) size1;
(void) size2;
atl::os::assert::failed((char*)__FILE__,__LINE__);
return NULL;
}
__ATL_LINK_EXTERN_C void *realloc(void * ptr, size_t size)
{
(void) ptr;
(void) size;
atl::os::assert::failed((char*)__FILE__,__LINE__);
return NULL;
}
__ATL_LINK_EXTERN_C void free( void * ptr )
{
(void) ptr;
atl::os::assert::failed((char*)__FILE__,__LINE__);
}
freertos config:
/*
FreeRTOS V9.0.0 - Copyright (C) 2016 Real Time Engineers Ltd.
All rights reserved
VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
This file is part of the FreeRTOS distribution.
FreeRTOS is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License (version 2) as published by the
Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
***************************************************************************
>>! NOTE: The modification to the GPL is included to allow you to !<<
>>! distribute a combined work that includes FreeRTOS without being !<<
>>! obliged to provide the source code for proprietary components !<<
>>! outside of the FreeRTOS kernel. !<<
***************************************************************************
FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. Full license text is available on the following
link: http://www.freertos.org/a00114.html
***************************************************************************
* *
* FreeRTOS provides completely free yet professionally developed, *
* robust, strictly quality controlled, supported, and cross *
* platform software that is more than just the market leader, it *
* is the industry's de facto standard. *
* *
* Help yourself get started quickly while simultaneously helping *
* to support the FreeRTOS project by purchasing a FreeRTOS *
* tutorial book, reference manual, or both: *
* http://www.FreeRTOS.org/Documentation *
* *
***************************************************************************
http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
the FAQ page "My application does not run, what could be wrong?". Have you
defined configASSERT()?
http://www.FreeRTOS.org/support - In return for receiving this top quality
embedded software for free we request you assist our global community by
participating in the support forum.
http://www.FreeRTOS.org/training - Investing in training allows your team to
be as productive as possible as early as possible. Now you can receive
FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
Ltd, and the world's leading authority on the world's leading RTOS.
http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
including FreeRTOS+Trace - an indispensable productivity tool, a DOS
compatible FAT file system, and our tiny thread aware UDP/IP stack.
http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
licenses offer ticketed support, indemnification and commercial middleware.
http://www.SafeRTOS.com - High Integrity Systems also provide a safety
engineered and independently SIL3 certified version for use in safety and
mission critical applications that require provable dependability.
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.
*----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
/* Section where include file can be added */
/* USER CODE END Includes */
/* Ensure stdint is only used by the compiler, and not the assembler. */
#if defined(__ICCARM__) || defined(__CC_ARM) || defined(__GNUC__)
#include <stdint.h>
extern uint32_t SystemCoreClock;
/* USER CODE BEGIN 0 */
extern void configureTimerForRunTimeStats(void);
extern unsigned long getRunTimeCounterValue(void);
/* USER CODE END 0 */
#endif
#define configUSE_PREEMPTION 1
#define configSUPPORT_STATIC_ALLOCATION 1
#define configSUPPORT_DYNAMIC_ALLOCATION 0
#define configUSE_IDLE_HOOK 1
#define configUSE_TICK_HOOK 1
#define configCPU_CLOCK_HZ ( SystemCoreClock )
#define configTICK_RATE_HZ ((TickType_t)1000)
#define configMAX_PRIORITIES ( 7 )
#define configMINIMAL_STACK_SIZE ((uint16_t)32) // MOD was 128
#define configMAX_TASK_NAME_LEN ( 32 ) // mod was 16
#define configGENERATE_RUN_TIME_STATS 1
#define configUSE_TRACE_FACILITY 1
#define configUSE_STATS_FORMATTING_FUNCTIONS 1
#define configUSE_16_BIT_TICKS 0
#define configUSE_MUTEXES 1
#define configQUEUE_REGISTRY_SIZE 8
#define configCHECK_FOR_STACK_OVERFLOW 1
#define configUSE_MALLOC_FAILED_HOOK 1
#define configUSE_DAEMON_TASK_STARTUP_HOOK 1
#define configUSE_PORT_OPTIMISED_TASK_SELECTION 1
/* Co-routine definitions. */
#define configUSE_CO_ROUTINES 0
#define configMAX_CO_ROUTINE_PRIORITIES ( 2 )
/* Software timer definitions. */
#define configUSE_TIMERS 1
#define configTIMER_TASK_PRIORITY ( 2 )
#define configTIMER_QUEUE_LENGTH 10
#define configTIMER_TASK_STACK_DEPTH 256
/* Set the following definitions to 1 to include the API function, or zero
to exclude the API function. */
#define INCLUDE_vTaskPrioritySet 1
#define INCLUDE_uxTaskPriorityGet 1
#define INCLUDE_vTaskDelete 1
#define INCLUDE_vTaskCleanUpResources 1
#define INCLUDE_vTaskSuspend 1
#define INCLUDE_vTaskDelayUntil 1
#define INCLUDE_vTaskDelay 1
#define INCLUDE_xTaskGetSchedulerState 1
#define INCLUDE_xTimerPendFunctionCall 1
#define INCLUDE_xQueueGetMutexHolder 1
#define INCLUDE_xSemaphoreGetMutexHolder 1
#define INCLUDE_pcTaskGetTaskName 1
#define INCLUDE_uxTaskGetStackHighWaterMark 1
#define INCLUDE_xTaskGetCurrentTaskHandle 1
#define INCLUDE_eTaskGetState 1
#define INCLUDE_xTaskAbortDelay 1
#define INCLUDE_xTaskGetHandle 1
/* Cortex-M specific definitions. */
#ifdef __NVIC_PRIO_BITS
/* __BVIC_PRIO_BITS will be specified when CMSIS is being used. */
#define configPRIO_BITS __NVIC_PRIO_BITS
#else
#define configPRIO_BITS 4
#endif
/* The lowest interrupt priority that can be used in a call to a "set priority"
function. */
#define configLIBRARY_LOWEST_INTERRUPT_PRIORITY 15
/* 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 5
/* 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) )
/* Normal assert() semantics without relying on the provision of an assert.h
header file. */
/* USER CODE BEGIN 1 */
#define configASSERT( x ) if ((x) == 0) {taskDISABLE_INTERRUPTS(); for( ;; );}
/* USER CODE END 1 */
/* Definitions that map the FreeRTOS port interrupt handlers to their CMSIS
standard names. */
#define vPortSVCHandler SVC_Handler
#define xPortPendSVHandler PendSV_Handler
/* IMPORTANT: This define MUST be commented when used with STM32Cube firmware,
to prevent overwriting SysTick_Handler defined within STM32Cube HAL */
/* #define xPortSysTickHandler SysTick_Handler */
/* USER CODE BEGIN 2 */
/* Definitions needed when configGENERATE_RUN_TIME_STATS is on */
#define portCONFIGURE_TIMER_FOR_RUN_TIME_STATS configureTimerForRunTimeStats
#define portGET_RUN_TIME_COUNTER_VALUE getRunTimeCounterValue
/* USER CODE END 2 */
/* USER CODE BEGIN Defines */
/* Section where parameter definitions can be added (for instance, to override default ones in FreeRTOS.h) */
/* USER CODE END Defines */
#endif /* FREERTOS_CONFIG_H */

Answer 1

And what does your debugger say? Did you check what is the actual HF, and where it occured? Do you have one handler for all possible HF? It makes debugging much more complicated - and write the proper ones, google "how to get stored register values from the stack when HF occurs" (http://www.freertos.org/Debugging-Hard-Faults-On-Cortex-M-Microcontrollers.html). When you have it all done you can start investigate it proper way.
Unfortunately the HF-s are difficult to diagnose the "lazy way". Some code writing is absolutely necessary .