Gaurav Aggarwal 618e165fa7 Fix NULL pointer dereference in vPortGetHeapStats
When the heap is exhausted (no free block), start and end markers are
the only blocks present in the free block list:

     +---------------+     +-----------> NULL
     |               |     |
     |               V     |
+ ----- +            + ----- +
|   |   |            |   |   |
|   |   |            |   |   |
+ ----- +            + ----- +
  xStart               pxEnd

The code block which traverses the list of free blocks to calculate heap
stats used a do..while loop that moved past the end marker when the heap
had no free block resulting in a NULL pointer dereference. This commit
changes the do..while loop to while loop thereby ensuring that we never
move past the end marker.

This was reported here - https://github.com/FreeRTOS/FreeRTOS-Kernel/issues/534

Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
2022-08-04 09:57:59 -07:00
..
2022-06-01 15:00:10 -07:00
2021-10-06 15:32:07 -07:00
2021-10-06 15:32:07 -07:00

Each real time kernel port consists of three files that contain the core kernel
components and are common to every port, and one or more files that are
specific to a particular microcontroller and/or compiler.


+ The FreeRTOS/Source/Portable/MemMang directory contains the five sample
memory allocators as described on the https://www.FreeRTOS.org WEB site.

+ The other directories each contain files specific to a particular
microcontroller or compiler, where the directory name denotes the compiler
specific files the directory contains.



For example, if you are interested in the [compiler] port for the [architecture]
microcontroller, then the port specific files are contained in
FreeRTOS/Source/Portable/[compiler]/[architecture] directory.  If this is the
only port you are interested in then all the other directories can be
ignored.