Towards Instruction Level Record and Replay of Sensor Network Applications

Debugging wireless sensor network (WSN) applications has been complicated for multiple reasons, among which the lack of visibility is one of the most challenging. To address this issue, in this paper, we present a systematic approach to record and replay WSN applications at the granularity of instructions. This approach differs from previous ones in that it is purely software based, therefore, no additional hardware component is needed. Our key idea is to combine the static, structural information of the assembly-level code with their dynamic, run-time traces as measured by timestamps and basic block counters, so that we can faithfully infer and replay the actual execution paths of applications at instruction level in a post-mortem manner. The evaluation results show that this approach is feasible despite of the resource constraints of sensor nodes. We also provide two case studies to demonstrate that our instruction level record-and-replay approach can be used to: (1) discover randomness of EEPROM writing time, (2) localize stack smashing bugs in sensor network applications.