Error when using vPortFree(ptr) CMSIS-RTOS on STM32F4

I will need to handle dynamic memory using malloc and free. Looking on FreeRTOS documentation, I found pvPortMalloc(size) and vPortFree(ptr) , pvPortMalloc(size) works fine. When try to release memory using vPortFree(ptr) inside a Thread, the code hangs on that call.

I'm using heap_4 for CMSIS-RTOS on TrueStudio.