HAL_ADC_ConvCpltCallback is a weak function which you seem to override in freertos.c. Examine HAL_ADC_ConvCpltCallback in freertos.c and see why task handle is NULL. As @hs2 suggested, most likely the interrupt is firing before the task is created.
HAL_ADC_ConvCpltCallback is a weak function which you seem to override in freertos.c. Examine HAL_ADC_ConvCpltCallback in freertos.c and see why task handle is NULL. As @hs2 suggested, most likely the interrupt is firing before the task is created.