Embedded software reliability testing by unit-level fault injection

Decreasing device sizes in integrated circuits lead to increasing vulnerability of hardware to errors resulting from radiation, crosstalk or power-supply disturbances. Especially in the automotive domain many tasks of electronics are safety relevant, so that solid error detection and correction is imperative. However, completely safe hardware is too expensive for the cost sensitive automotive market. Hence, software safety mechanisms must deal with errors originating from hardware to ensure safe system behavior. To verify safe system behavior under the influence of hardware errors, fault injection is currently done at integration level, but software redesign at this design stage should be avoided due to high costs. To early detect code vulnerable to hardware errors, we propose fault injection at unit level. Thanks to short simulation scenarios and good parallelization capability, even exhaustive fault injection is possible for multiple representative workloads. Using the results from the fault-injection campaigns, the software designer is able to consider reliability during the implementation phase and avoid costly redesigns.