Quality RTOS & Embedded Software

 Real time embedded FreeRTOS RSS feed 
Real time embedded FreeRTOS mailing list 
Quick Start Supported MCUs PDF Books Trace Tools Ecosystem TCP & FAT Training


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 ]    [ Sitemap ]    [ ]

Copyright (C) 2004-2010 Richard Barry. Copyright (C) 2010-2016 Real Time Engineers Ltd.
Any and all data, files, source code, html content and documentation included in the FreeRTOSTM distribution or available on this site are the exclusive property of Real Time Engineers Ltd.. See the files license.txt (included in the distribution) and this copyright notice for more information. FreeRTOSTM and FreeRTOS.orgTM are trade marks of Real Time Engineers Ltd.

Latest News:

FreeRTOS V9.0.0 is now available for download.

Free TCP/IP and file system demos for the RTOS

Sponsored Links

⇓ Now With No Code Size Limit! ⇓
⇑ Free Download Without Registering ⇑

FreeRTOS Partners

ARM Connected RTOS partner for all ARM microcontroller cores

Renesas Electronics Gold Alliance RTOS Partner.jpg

Microchip Premier RTOS Partner

RTOS partner of NXP for all NXP ARM microcontrollers

Atmel RTOS partner supporting ARM Cortex-M3 and AVR32 microcontrollers

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

Xilinx Microblaze and Zynq partner

Silicon Labs low power RTOS partner

Altera RTOS partner for Nios II and Cortex-A9 SoC

Freescale Alliance RTOS Member supporting ARM and ColdFire microcontrollers

Infineon ARM Cortex-M microcontrollers

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

Cypress RTOS partner supporting ARM Cortex-M3

Fujitsu RTOS partner supporting ARM Cortex-M3 and FM3

Microsemi (previously Actel) RTOS partner supporting ARM Cortex-M3

Atollic Partner

IAR Partner

Keil ARM Partner

Embedded Artists