The ever-increasing complexity of embedded computer software also increases the difficulty to debug and verify the correctness of the real-world execution. In addition, today the development process must often be proved to fulfill a large number of safety requirements stated in a standard or regulation. One common way to perform verification and debugging is by facilitating some method of online-monitoring, like software instrumentation. However, in safety related systems, it is not obvious that traditional software instrumentation techniques can be applied. In this article, we will elaborate on several aspects when applying software instrumentation into safety-related systems. Problems that need to be considered will be identified, but also consequences to the problems will be analyzed.