MoIO: Run-time monitoring for I/O protocol violations in storage device drivers

Bugs affecting storage device drivers include the so-called protocol violation bugs, which silently corrupt data and commands exchanged with I/O devices. Protocol violations are very difficult to prevent, since testing device driver is notoriously difficult. To address them, we present a monitoring approach for device drivers (MoIO) to detect HO protocol violations at run-time. The approach infers a model of the interactions between the storage device driver, the OS kernel, and the hardware (the device driver protocol) by analyzing execution traces. The model is then used as a reference for detecting violations in production. The approach has been designed to have a low overhead and to overcome the lack of source code and protocol documentation. We show that the approach is feasible and effective by applying it on the SATA/AHCI storage device driver of the Linux kernel, and by performing fault injection and long-running tests.