A method for multicore processor fault detection during execution of safety critical software applications in a multicore processor environment involves dedicating the complete resources of at least a part of at least one processor core to execution of diagnostics software application whilst dedicating remaining resources to execution of a safety-critical software application, thereby enabling parallel execution of the diagnostics software application and the safety-critical software application. There is also provided a controller for multicore processor fault detection during execution of safety critical software applications in a multicore processor environment. The controller includes a multicore processor environment. The controller may be part of a control system. The method may be provided as a computer program.