FreeRTOS example for small memory footprint

BTW I’d also #define configUSE_PORT_OPTIMISED_TASK_SELECTION 1
However, are you sure that the essential handlers like SVC_Handler etc. are correctly installed ? Can you step into and trough start of the scheduler resp. is your initial task started ? Can you set breakpoints into those handlers ?
Depending on your setup (using STM HAL ?) this post might be interesting, too.