A command-level study of Linux kernel bugs

As computer systems increase in size and complexity, bugs become ever subtler and more difficult to detect and diagnose. A bug could exist at different layers of computer systems (e.g., applications, shared libraries, file systems, device firmware), or could be caused by the incompatibility among layers. In many cases, bugs would require a very specific combination of events to be triggered and are difficult to replicate, making detection and diagnosis more complicated. Most existing tools for debugging focus on a single layer of the systems (e.g., applications), which are intrusive to the target layer and are fundamentally limited for analyzing issues involving multiple layers. As the first step towards building a multi-layer diagnostic framework, this paper presents our efforts to study the behaviors of Linux kernel bugs at the host-device interface. More specifically, we designed workloads to trigger known kernel bugs, recorded the SCSI commands observed under different kernels, and analyzed the impact of kernel bug patches after multiple runs of the workloads by counting the occurrence of individual SCSI commands. Our preliminary results show that it is possible to identify potential synchronization bugs in the kernel from information at the host-device interface level.