Quality RTOS & Embedded Software

 Real time embedded FreeRTOS RSS feed 
Quick Start Supported MCUs PDF Books Trace Tools Ecosystem


Freeing memory before the system reset

Posted by ankumarank on December 6, 2013


I am trying to use FreeRTOS on one of our boards which has Microblaze on it. We also have a watchdog in our board, to protect from software hang scenarios.

I observed that, when watchdog issues reset, all the tasks are getting killed. However, the stack that got created for these tasks, is not getting freed/ the malloc pointer is not coming back to the beginning of the heap region. This I confirmed by checking the pointer "pvReturn" in heap_3.c file.

When the tasks get deleted, does the FreeRTOS free the associated memories of a task? If not, what is best way to free the memory?

Any help in this regard would be of great help. Thanks in Advance,


Freeing memory before the system reset

Posted by rtel on December 6, 2013

What is the watchdog exactly? If it is a hardware watchdog that is hard resetting the hardware then the C start up code should execute again and re-initialise all your memory just as if you turned the system on the first time.

If it is a soft reset that is just restarting the program from main() then you will have to re-initialise the memory yourself. That would be true for all your application code, not just FreeRTOS.

If your watchdog is a pure software routine that is deleting the tasks then the memory allocated to the tasks is freed by the idle task so you must let the idle task run for a bit before restarting.

Be careful of your heap3 implementation too - it may result in memory fragmentation, and that could be the route of the problem. If that is the case then using heap4.c in its place should fix it.


[ Back to the top ]    [ About FreeRTOS ]    [ Privacy ]    [ Sitemap ]    [ ]

Copyright (C) Amazon Web Services, Inc. or its affiliates. All rights reserved.

Latest News

FreeRTOS v10.2.0 is available for immediate download. MIT licensed, and including RISC-V and ARMv8-M (Cortex-M33) demos.

NXP tweet showing LPC5500 (ARMv8-M Cortex-M33) running FreeRTOS.

View a recording of the "OTA Update Security and Reliability" webinar, presented by TI and AWS.


FreeRTOS and other embedded software careers at AWS.

FreeRTOS Partners

ARM Connected RTOS partner for all ARM microcontroller cores

Cadence Tensilica Cortes

Espressif ESP32

IAR Partner

Microchip Premier RTOS Partner

RTOS partner of NXP for all NXP ARM microcontrollers





STMicro RTOS partner supporting ARM7, ARM Cortex-M3, ARM Cortex-M4 and ARM Cortex-M0

Texas Instruments MCU Developer Network RTOS partner for ARM and MSP430 microcontrollers

OpenRTOS and SafeRTOS

Xilinx Microblaze and Zynq partner