A stack overflow is a very common source of support requests, but FreeRTOS provides some features to help debug such issues.
Stack overflow occurs when a task tries to push more elements on the stack
than there is room for. The stack size is specified when a task is created. To find out
how close a task is to overflowing its stack, the
uxTaskGetStackHighWaterMark(TaskHandle_t xTask) function can be
used. It returns the minimum of unused stack in words. If an 8-bit MCU is used, a return
value of 1 will mean 1 byte. For a 32-bit MCU, 1 word means 4 bytes. To use this
function, the INCLUDE_uxTaskGetStackHighWaterMark must be set to 1 in
the configuration file.
It is also possible to check for stack overflow during run-time. By setting
the configCHECK_FOR_STACK_OVERFLOW to 1, the kernel checks that the
stack pointer remains within the valid stack space. If not, the stack overflow hook
function is called. A hook function is a function that allows the application to react
when something happens and provide different behavior. For example, an LED can be turned
on when a stack has overflowed. Another option might be to print an error message and
reboot the system. The vApplicationStackOverflowHook() function must be
provided by the application.
See https://www.freertos.org/Stacks-and-stack-overflow-checking.html for more information about FreeRTOS and stack overflow.