Real-Time Operating Systems (RTOSes) play a crucial role in safety-critical domains, where deterministic and predictable task execution is essential. Yet they are increasingly exposed to ionizing radiation, which can compromise system dependability. To assess FreeRTOS under such conditions, we introduce KRONOS, a software-based, non-intrusive post-propagation Fault Injection (FI) framework that injects transient and permanent faults into Operating System-visible kernel data structures without specialized hardware or debug interfaces. Using KRONOS, we conduct an extensive FI campaign on core FreeRTOS kernel components, including scheduler-related variables and Task Control Blocks (TCBs), characterizing the impact of kernel-level corruptions on functional correctness, timing behavior, and availability. The results show that corruption of pointer and key scheduler-related variables frequently leads to crashes, whereas many TCB fields have only a limited impact on system availability.

翻译：实时操作系统在安全关键领域发挥着重要作用，这类场景要求任务执行具有确定性与可预测性。然而，这些系统正日益暴露于电离辐射环境中，可能损害系统可靠性。为评估FreeRTOS在此类条件下的表现，我们提出KRONOS框架——一种基于软件的非侵入式后传播故障注入框架，无需专用硬件或调试接口即可向操作系统可见的内核数据结构注入瞬态与永久性故障。利用KRONOS，我们对FreeRTOS核心内核组件（包括调度器相关变量及任务控制块）开展了广泛故障注入实验，量化分析了内核级数据损坏对功能正确性、时序行为及可用性的影响。实验结果表明，指针及关键调度器相关变量的损坏频繁导致系统崩溃，而多数TCB字段对系统可用性的影响相对有限。