Linux Plumbers Conf 2013

One Line Summary

Abstract

Catching RCU usage bugs

RCU was described to me once as, “You read the papers, and think you have gotten a hold of it. Then you make the mistake of reading code and wonder, what the heck did this McKenney guy do”. Users of RCU at this point depend mainly on a relatively small subset of developers to review it being used correctly. This BoF looks at how one can detect some usage issues at runtime, with the thought of (ab)using Intel’s non-canonical addressing and general protection fault handler to provide unlimited watchpoints.

This BoF should be of interest to folks who review RCU users, and the architecture people.

Presentation Materials

Speakers

• Dhaval Giani

  Biography

  Dhaval is a graduate student at the University of Toronto. He is working on making RCU easy to debug. He hopes to post those patches very soon.

  In the past he has worked on a lot of varied stuff.

  Sessions

  • * New and Not Ready for Prime Time - Short Lightning Talks
    • Title: New and Not Ready for Prime Time - Short Lightning Talks
    • Microconference: File and Storage Systems II
    • Time: 6:25 – 8:55am
    • One Line Summary:

      Reserved time to discuss new ideas in an open conversation.

    • slides
    • Speakers: Ric Wheeler, Dhaval Giani
  • * Detecting RCU Usage Bugs
    • Title: Detecting RCU Usage Bugs
    • Microconference: BoFs
    • Room: Celestin G
    • Time: 4:50 – 5:50pm
    • One Line Summary:

      Runtime detection of RCU usage bugs such as pointer leaks

    • slides
    • Speakers: Dhaval Giani, Paul McKenney, Frederic Weisbecker
• 

  Paul McKenney

  IBM Linux Technology Center
  • Website: http://www.rdrop.com/users/paulmck
  • Blog: http://paulmck.livejournal.com/

  Biography

  Paul E. McKenney has been coding for almost four decades, more than half of that on parallel hardware, where his work has earned him a reputation among some as a flaming heretic. Over the past decade, Paul has been an IBM Distinguished Engineer at the IBM Linux Technology Center. Paul maintains the RCU implementation within the Linux kernel, where the variety of workloads present highly entertaining performance, scalability, real-time response, and energy-efficiency challenges. Prior to that, he worked on the DYNIX/ptx kernel at Sequent, and prior to that on packet-radio and Internet protocols (but long before it was polite to mention Internet at cocktail parties), system administration, business applications, and real-time systems. His hobbies include what passes for running at his age along with the usual house-wife-and-kids habit.

  Sessions

  • * Detecting RCU Usage Bugs
    • Title: Detecting RCU Usage Bugs
    • Microconference: BoFs
    • Room: Celestin G
    • Time: 4:50 – 5:50pm
    • One Line Summary:

      Runtime detection of RCU usage bugs such as pointer leaks

    • slides
    • Speakers: Dhaval Giani, Paul McKenney, Frederic Weisbecker
  • * Advances in Validation of Concurrent Software
    • Title: Advances in Validation of Concurrent Software
    • Microconference: Refereed Talk
    • Room: Celestin A
    • Time: 10:50 – 11:40am
    • One Line Summary:

      Audience: Aggresssive developers and testers.

    • Speakers: Paul McKenney
  • * Bare Metal Performance, Timekeeping, and Energy Efficiency
    • Title: Bare Metal Performance, Timekeeping, and Energy Efficiency
    • Microconference: Refereed Talk
    • Room: Celestin B
    • Time: 11:50am – 12:40pm
    • One Line Summary:

      Audience: Developers, moderate expertise.

    • Speakers: Paul McKenney

• Frederic Weisbecker

  Red Hat
  Biography

  Frederic Weisbecker is a Linux Kernel developer working for Red Hat. His involvement and role in the Linux community has evolved over time: he has been working on tracing with ftrace and perf events subsystems, on timers and dynticks-mode, and he helped to remove the big kernel lock.

  Sessions

  • * Full dynticks status
    • Title: Full dynticks status
    • Microconference: Scaling
    • Time: 2:30 – 5:00pm
    • One Line Summary:

      Present state of full dynticks, current limitations and what remains to be done

    • slides
    • Speakers: Frederic Weisbecker
  • * Detecting RCU Usage Bugs
    • Title: Detecting RCU Usage Bugs
    • Microconference: BoFs
    • Room: Celestin G
    • Time: 4:50 – 5:50pm
    • One Line Summary:

      Runtime detection of RCU usage bugs such as pointer leaks

    • slides
    • Speakers: Dhaval Giani, Paul McKenney, Frederic Weisbecker