How Linux is built with Greg Kroah-Hartman

This is a re-release of the original upload, and fixes audio issues. See the original release (with poor audio) here: https://youtu.be/7WbREHtc5sU. I (Gergely) apologize for the original audio issues.

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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!

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The Pragmatic Engineer deepdives relevant for this episode:
• What TPMs do and what software engineers can learn from them: https://newsletter.pragmaticengineer.com/p/what-tpms-do
• The past and future of modern backend practices: https://newsletter.pragmaticengineer.com/p/the-past-and-future-of-backend-practices
• Backstage: an open-source developer portal: https://newsletter.pragmaticengineer.com/p/backstage

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Where to find Greg Kroah-Hartman:
• Social: https://social.kernel.org/gregkh
• Website: http://www.kroah.com/log/about/

Where to find Gergely Orosz:
• X: https://x.com/GergelyOrosz
• LinkedIn: https://www.linkedin.com/in/gergelyorosz/
• Bluesky: https://bsky.app/profile/gergely.pragmaticengineer.com
• Newsletter and blog: https://www.pragmaticengineer.com/

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In this episode, we cover:
(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

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See the transcript and other references from the episode at https://newsletter.pragmaticengineer.com/podcast

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Production and marketing by https://penname.co/. For inquiries about sponsoring the podcast, email podcast@pragmaticengineer.com.

Видео How Linux is built with Greg Kroah-Hartman канала The Pragmatic Engineer