Reversible debugging provides developers with a way to execute their applications both forward and backward, seeking the cause of an unexpected or undesired event. In a concurrent setting, reversing actions in the exact reverse order they have been executed may lead to undo many actions that were not related to the bug under analysis. On the other hand, undoing actions in some order that violates causal dependencies may lead to states that could not be reached in a forward execution.

We propose an approach based on causal-consistent reversibility: each action can be reversed if all its consequences have already been reversed. The main feature of the approach is that it allows the programmer to easily individuate and undo exactly the actions that caused a given misbehavior till the corresponding bug is reached. CaReDeb is the first prototype implementation of a causal-consistent reversible debugger.