FreeRTOS find the task waiting address

Question

I have a FreeRTOS project with 4 tasks. In some cases, the device stops responding. When the MCU (stm32f4) breaks, in most cases it is located in the task switching routines ( tasks.c) and goes to vApplicationIdleHook. How to find the address of the main task at which it is stopped?

Edit: I have tskTCBan interesting task structure. Is it possible to find the return address for this task when I interrupt execution in vApplicationIdleHookfor example? It seems the first member pxTopOfStackmay help, but it points to unused memory ...