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    Subjectkernel-testers - finding regressions in the kernel
    [ Please send further questions only on the kernel-testers list. ]

    One big problem we face in kernel development are regressions - a kernel
    that worked for the user and a more recent kernel no longer works for
    the user.

    Another problem is for newbies to get into kernel development.
    There aren't many useful coding tasks for newbies available.

    Testing the kernel and learning how to debug problems both brings
    immediate value to the kernel and can be a good way to get started
    with kernel development.

    Regressions are bad since they make it harder for users to upgrade the
    kernel. They cause problems for people when upgrading the kernel and
    result in many people running old kernels with known security holes.

    There are easy to find regressions like compile errors, but the real
    problems are things like for example:
    - system doesn't boot
    - system crashes with a specific workload
    - mp3 playback now stutters when copying files in the background
    - when doing this or that the system feels worse

    Automated tests can find some of these problems, but many of the
    problems that affect only some specific hardware or the interactive
    feeling of the computer can not be found automatically.

    And a helpful property of regressions is that for a reproducible
    regression it's relatively easy to figure out what broke it through

    There are usually two months between some kernel developer adding a new
    regression to the kernel and the regression reaching a stable kernel,
    and it's important to catch as many of them as early as possible.

    The next step will be to also test -next and -mm kernels for identifying
    regressions even before they reach Linus' tree.

    Mailing list:

    The list is primarily for people starting at testing kernels, but if
    people with experiences in kernel testing and/or kernel debugging want
    to join that's highly appreciated.



    What will be discussed on the mailing list?

    - which kernels to test
    - how to test them
    - how to turn observed problems into proper bugreports

    What are the prerequisites for participating?

    You should already know how to build and install your own kernel
    ( is a good introduction).

    And be willing to spend quite some time with debugging problems
    you discover.

    How to start?

    Run 2.6.25 for a week.
    If you already did this, check what the latest snapshot listed at is and try this kernel.

    The snapshot worked just fine for some days.

    The kernel was less broken than expected. :-)
    (Well, this actually should be the normal case...)

    Try a more recent snapshot and follow the discussions on the mailing
    list what to test next.

    Is it dangerous to test such kernels?

    Most of the times there are no problems.

    But your system might crash, and in the worst case it might turn the
    contents of your disks into garbage.

    But you anyway have a backup, don't you?

    If you need your system to work for reaching some deadline in real life
    you obviously shouldn't test any kernels.

    I found a regression!


    Please tell the details on the mailing list.

    What about bugs that are not regressions?

    Such bugs can also be discussed, but they are not the primary target.

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      Last update: 2008-05-07 22:03    [W:0.065 / U:11.252 seconds]
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