Unit Testing of Flash Memory Device Driver through a SAT-Based Model Checker

Abstract

Flash memory has become virtually indispensable in most mobile devices. In order for mobile devices to operate successfully, it is essential that the flash memory be controlled correctly through the device driver software. However, as is typical for embedded software, conventional testing methods often fail to detect hidden flaws in the complex device driver software. This deficiency incurs significant development and operation overheads to the manufacturers. Model checking techniques have been proposed to compensate for the weaknesses of conventional testing methods through exhaustive analyses. These techniques, however, require significant manual efforts to create an abstract target model and, thus, are not widely applied in industry. In this project, we applied a model checking technique based on a Boolean satisfiability (SAT) solver. One advantage of SAT-based model checking is that a target C code can be analyzed directly without an abstract model, thereby enabling automated and bit-level accurate verification. In this project, we have applied CBMC, a SAT-based software model checker, to the unit testing of the Samsung OneNANDtrade device driver. Through this project, we detected several bugs that had not been discovered previously.