Techniques and systems described herein relate to monitoring executions of computer instructions on computing devices based on learning and generating a control flow directed graph. The techniques and systems include determining a learned control flow directed graph for a process executed on the computing system. A system call is identified during execution of the process as well as a predetermined number of transitions leading to the system call. A validity of the transitions leading the system call is determined based on the learned control flow directed graph and the computing system may perform an action based on the validity.