Hi Phillip,
I just stumbled upon the return type of uxTaskGetStackHighWaterMark(): It's UBaseType_t, and that is defined as unsigned char in this port. The stack size is provided as unsigned short words to xTaskCreate(), thus theoretically 64kB are possible here.
Wouldn't it be better to patch tasks.c to make it return unsigned short instead of UBaseType_t, as prvTaskCheckFreeStackSpace() correctly returns a uint16_t? Otherwise uxTaskGetStackHighWaterMark() will return a misguiding value.
Thanks,
Flössie