Fault Injection (FI) is a commonly used technique to evaluate the reliability of systems. As soft errors become more commonplace in computer systems, it is often necessary to involve the software in the overall system's resilience. Therefore, it is important to inject faults at the ISA level to emulate soft errors that are visible to the software, in order to test software resilience mechanisms. Consequently, there is a need to develop Instruction Set Architecture (ISA)-level FI tools and techniques. We start by outlining the goals of ISA-level FI, followed by the main metrics that can be measured by the same. We then present a survey of techniques in the literature that attempt to inject faults at the ISA-level and up in the system stack. Finally, we present an overview of LLFI and PINFI, two fault injectors developed inour research group, that allow programers to inject faults at the LLVM compiler's Intermediate Representation (IR) level and x86 assembly code level, respectively. We conclude with a survey of the open challenges in the area.

Chapter Contents:

• 9.1 Introduction
• 9.2 Background
• 9.2.1 Terms and definitions
• 9.2.2 Failure outcomes
• 9.2.3 Metrics
• 9.2.4 Fault Injection process
• 9.2.5 Fault model
• 9.3 Classification of injection techniques
• 9.3.1 Simulation versus direct
• 9.3.2 Intrusive versus nonintrusive
• 9.3.3 Level of injection
• 9.3.4 Platform
• 9.3.5 Classification results
• 9.4 LLFI and PINFI fault injectors
• 9.4.1 LLVM fault injector: LLFI
• 9.4.2 PINFI
• 9.5 Open challenges and conclusion
• 9.5.1 Challenge 1: level of injection
• 9.5.2 Challenge 2: target platform
• 9.5.3 Challenge 3: bit-flip model
• 9.5.4 Conclusion
• Acknowledgments
• References

Inspec keywords: software architecture; instruction sets; software fault tolerance; program testing

Other keywords: fault injection; software resilience mechanisms; assembly code level; computer systems; soft errors; fault injectors; system stack; ISA-level

Subjects: Software engineering techniques; Diagnostic, testing, debugging and evaluating systems