Abstract Reference counting bugs in Linux kernel drivers can lead to severe resource mismanagement and security vulnerabilities. We introduce DrvHorn , a novel automated tool to detect these bugs by reducing reference counting verification to an assertion checking problem leveraging the Linux driver interface. Through efficient modeling of the Linux kernel and aggressive program slicing, DrvHorn discovered 545 bugs, of which 424 were previously unknown, across all platform drivers in v6.6 Linux kernel, with a lower false positive rate of 29.9% compared to prior studies. To address the root causes of these newly discovered bugs, we submitted patches to the Linux kernel, and 45 of them were merged.

Serverless computing is a new paradigm that aims to remove the burdens of cloud management from developers. Yet rightsizing serverless functions remains a pain point for developers. Choosing the right memory configuration is necessary to ensure cost and/or performance optimality for serverless workloads. In this work, we identify that using parametric regression can significantly simplify function rightsizing compared to black-box optimization techniques currently available. With this insight, we build a tool, called Parrotfish, which finds optimal configurations through an online learning process. It also allows users to communicate constraints on execution time, or to relax cost optimality to gain performance. Parrotfish achieves substantially lower exploration costs (1.81-9.96×) compared with the state-of-the-art tools, while delivering similar or better recommendations.