A Passion for Operating Systems: An Illinois Student’s Contributions to Linux | Computing



YiFei Zhu

A programming enthusiast who began writing Python code in high school, recent computer engineering graduate YiFei Zhu (BS CE ’21) has put his knowledge and skills to the service of impactful contributions to Linux, arguably the most powerful system software. used in the world.

The Linux operating system runs on millions of hardware devices. Ninety percent of all cloud infrastructure is powered by Linux, including supercomputers and cloud providers, 74% of the world’s smartphones are Linux-based, and even NASA’s Mars helicopter runs on it. Linux. The Linux kernel, as the operating system kernel, manages hardware resources such as processor, memory, and peripherals and provides programming interfaces to user applications.

Professor Tianyin Xu
Tianyin Xu

“Contributing to the Linux kernel with so many adoptions is a tremendous achievement, given its wider impacts and the technical challenges involved,” said Tianyin Xu, assistant professor at Illinois CS. Xu taught Zhu in one of his classes and then mentored him as a member of his research group during the 2020-21 school year. “YiFei contributed 25 commits of code merged into the Linux kernel during his summer internship at Google, his undergraduate research with my group, and his own hobby.”

During the summer of 2020, Zhu completed a remote internship in Google’s network infrastructure team, improving the storage functionality of the eBPF subsystem in the Linux kernel. eBPF is a trendy technology that allows you to run sandboxed programs in the Linux kernel without modifying the kernel source code or loading kernel modules.

Google uses eBPF for critical network operations, such as network configuration and traffic control. Zhu’s work improves the ease of sharing and flexibility of eBPF storage, enabling many new use cases. The Linux kernel has adopted his work and is also used by Google’s large-scale production network infrastructures.

“YiFei did an impressive job during his internship,” said Stanislav Fomichev, YiFei internship manager at Google. “The features he developed are very important parts of our new network operations. We were really hoping to work with him again after he graduated, so we offered him a full-time position. glad he accepted it. “

Another Zhu contribution to the Linux kernel took place as a member of Xu’s research group and focused on operating system security through a collaborative project with researchers at the University of Illinois. and IBM.

The primary programming interface provided by an operating system is the system call interface – User applications invoke system calls to interact with the operating system kernel in order to request operating system services and hardware resources. Therefore, system call security is a foundation of operating system security because malicious applications can attack the shared operating system through attack vectors that exploit system calls.

Recently, system call security has gained considerable attention, with the increased use of lightweight sharing and virtualization technologies such as containers. Since a computer server can host dozens or hundreds of containers on a shared operating system kernel, researchers must develop effective ways to enforce system call security to protect the shared operating system against malicious or buggy containers.

Josep torrellas
Josep torrellas

In his undergraduate research, Zhu developed a new feature, now known as constant-action bitmaps, that can effectively speed up security checks of system calls by eliminating the need to run redundant checks. The idea was first proposed in a research paper published at the 53rd IEEE / ACM International Symposium on Microarchitecture, co-authored by Xu and CS and ECE professor Josep Torrellas and their graduate students.

However, as noted by their IBM collaborator, Dr Hubertus Franke, there are many new technical challenges that need to be addressed to turn a research idea into a practical solution that the Linux kernel can adopt. Nonetheless, Zhu overcame all the challenges along the way and managed to escalate his work back to the Linux kernel.

As a hobbyist, Zhu also contributed code to support other software platforms. For example, it provided fixes to render 3D YouTube videos in third party players.

Within the ECE, Zhu also worked with Associate Professor Kirill Levchenko on a research project that allows embedded system firmware to run outside of its native environment, known as firmware rehosting. Their research paper was published at the 30th USENIX Security Symposium, with Zhu as the third author.

Zhu’s interest in operating systems began while he was taking ECE 220, Computer Systems and Programming, in his first year.

Kirill Levchenko

“I was intrigued by operating systems, which for me are the fundamental IT infrastructures that enable all user applications,” Zhu said. “I had read how the operating system kernel worked and sometimes worked all night, learning more and more.”

From there he took ECE 391, Computer Systems Engineering, where he turned his interests into passions and went beyond the course requirements to write a simple operating system, generating over 10,000 lines of code. .

“My friends sometimes ask me how I know all the pieces of the operating system, and I tell them to find projects that they like and just write their code to make things work,” he said. . “The school teaches us the basics, which is the tip of the iceberg. There is a lot more to learn underneath, which you must find on your own.”

Later this summer, Zhu will return to Google’s network infrastructure team as a full-time core engineer.

Xu notes that Illinois’ interdisciplinary and collaborative engineering culture played a vital role in her mentoring such an exceptional student.

“I got to know YiFei when he took my CS 423, Operating System Design course from the CS program. He was the top student in the class. YiFei’s work is supported by the C3SR center of the Coordinated Science Lab (CSL), along with the NSF and the Illinois Office of Undergraduate Research None of this could happen if CS, ECE and CSL are not closely linked.

Xu added, “YiFei is one of the best undergraduates I have worked with. His technical abilities, his courage to face challenges and solve problems are truly exceptional.”

See the original story of Illinois ECE.


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