How Linux is built with Greg Kroah-Hartman

Supported by Our Partners• WorkOS — The modern identity platform for B2B SaaS.• Vanta — Automate compliance and simplify security with Vanta.—Linux is the most widespread operating system, globally – but how is it built? Few people are better to answer this than Greg Kroah-Hartman: a Linux kernel maintainer for 25 years, and one of the 3 Linux Kernel Foundation Fellows (the other two are Linus Torvalds and Shuah Khan). Greg manages the Linux kernel’s stable releases, and is a maintainer of multiple kernel subsystems.We cover the inner workings of Linux kernel development, exploring everything from how changes get implemented to why its community-driven approach produces such reliable software. Greg shares insights about the kernel's unique trust model and makes a case for why engineers should contribute to open-source projects. We go into:• How widespread is Linux?• What is the Linux kernel responsible for – and why is it a monolith?• How does a kernel change get merged? A walkthrough• The 9-week development cycle for the Linux kernel• Testing the Linux kernel• Why is Linux so widespread?• The career benefits of open-source contribution• And much more!—Timestamps(00:00) Intro(02:23) How widespread is Linux?(06:00) The difference in complexity in different devices powered by Linux (09:20) What is the Linux kernel?(14:00) Why trust is so important with the Linux kernel development(16:02) A walk-through of a kernel change(23:20) How Linux kernel development cycles work(29:55) The testing process at Kernel and Kernel CI (31:55) A case for the open source development process(35:44) Linux kernel branches: Stable vs. development(38:32) Challenges of maintaining older Linux code (40:30) How Linux handles bug fixes(44:40) The range of work Linux kernel engineers do (48:33) Greg’s review process and its parallels with Uber’s RFC process(51:48) Linux kernel within companies like IBM(53:52) Why Linux is so widespread (56:50) How Linux Kernel Institute runs without product managers (1:02:01) The pros and cons of using Rust in Linux kernel (1:09:55) How LLMs are utilized in bug fixes and coding in Linux (1:12:13) The value of contributing to the Linux kernel or any open-source project (1:16:40) Rapid fire round—The Pragmatic Engineer deepdives relevant for this episode:What TPMs do and what software engineers can learn from themThe past and future of modern backend practicesBackstage: an open-source developer portal—See the transcript and other references from the episode at ⁠⁠https://newsletter.pragmaticengineer.com/podcast⁠⁠—Production and marketing by ⁠⁠⁠⁠⁠⁠⁠⁠https://penname.co/⁠⁠⁠⁠⁠⁠⁠⁠. For inquiries about sponsoring the podcast, email [email protected]. Get full access to The Pragmatic Engineer at newsletter.pragmaticengineer.com/subscribe