My Linux Kernel Mentorship Journey

Introduction

My expiernce with the Linux Kernel Bug Fixing [Summer 2025] Mentorship Program

Summer 2025

Participating in the Linux Kernel Mentorship Program has been one of the most transformative experiences in my career. Over the past months, I had the privilege of working on upstream kernel contributions, collaborating with mentors, and learning from both fellow mentees and the broader kernel community.

In this blog, I’ll share:

  1. My technical contributions (sysfs cleanup & driver backports).
  2. The tools and debugging methods I relied on.
  3. What I learned from mentors, fellow mentees, and the Linux kernel community.
  4. Key takeaways and reflections from this journey.

You can also explore my contributions on the mailing list archives: lore.kernel.org search for Sumanth Gavini.

Cleaning Up sysfs Show Functions

One of my first tasks was migrating sysfs *_show() functions from scnprintf() to the newer sysfs_emit() helper.

Why This Change Matters

  • Consistency: Kernel documentation (Documentation/filesystems/sysfs.rst) mandates sysfs_emit() in sysfs functions.
  • Safety: It handles buffer boundaries correctly, minimizing risks of overflow.
  • Maintainability: Brings consistency across kernel subsystems.

Example Contributions

Though small, these patches aligned the code with kernel best practices and improved quality.

Backporting Driver Fixes to Stable

I also worked on backporting patches to long-term stable (LTS) branches (linux-6.1.y), ensuring reliability for production systems.

My Backport Contributions

Why Backporting Is Important

  • Stability: Ensures critical fixes reach LTS users without forcing upgrades.
  • Reliability: Embedded, industrial, and automotive systems depend on stable kernels.
  • Learning: Improved my ability to adapt patches across kernel versions and resolve conflicts.

Tools & Debugging

Some of the tools I relied on during the mentorship:

  • cscope/ctags + ripgrep – efficient code navigation.
  • smatch – static analysis for detecting issues.
  • make htmldocs – verifying documentation changes.
  • syzbot – automated fuzzing via Syzkaller.
    • Worked with syzbot reproducers (especially C repros) to debug crashes and verify fixes.
  • QEMU/KVM – running instrumented kernels in virtual machines.
  • gdb/objdump – analyzing and debugging kernel crashes.
  • printk/ftrace – runtime tracing and performance debugging.

These tools mirrored professional workflows and deepened my debugging and analysis skills.

Learning from Mentors

Working under Shuah Khan and David Hunter was invaluable.

  • They stressed kernel documentation compliance, clean patch design, and subsystem best practices.
  • Reviews taught me to write better commit messages, improve readability, and handle revisions.
  • I also learned how to communicate clearly on mailing lists and collaborate in a distributed open-source project.

Their guidance gave me confidence to contribute meaningfully.

Learning from Fellow Mentees

Being part of a cohort was equally rewarding:

  • Peer discussions often revealed new approaches to debugging and development.
  • Collaboration helped me learn different styles of structuring patches and handling feedback.
  • Encouragement from peers kept me motivated during challenging debugging sessions.

Learning from the Linux Kernel Community

The broader kernel community was an incredible learning resource:

  • Mailing lists (lore.kernel.org): Observing discussions and reviews showed me how collaborative decision-making works.
  • Patchwork and Subspace: Helped me understand how patches are tracked and integrated.
  • Syzbot & KernelCI: Reinforced the importance of automated fuzzing and CI in maintaining kernel quality.

Key Takeaways

  • Attention to Detail: Even small changes like using sysfs_emit matter in large codebases.
  • Collaboration First: Open-source thrives on communication, review, and iteration.
  • Backport Skills: Learned how to carry modern fixes to LTS kernels.
  • Proactive Debugging: Gained hands-on experience with syzbot and kernel fuzz testing.

References

Acknowledgments

I am deeply grateful to the Linux Foundation for this program.

Special thanks to my mentors:

Their mentorship and support made this journey possible.

Conclusion

My Linux Kernel Mentorship journey combined technical contributions (sysfs cleanup and stable backports) with community learning (mentorship, peer collaboration, and mailing list participation).

It taught me the value of small, consistent contributions, the importance of collaboration, and the professional workflows that keep the Linux kernel reliable.

I look forward to continuing as a contributor in kernel subsystems such as USB, HID, networking, and real-time Linux.