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  • MP kernels broken with version 5.4.0-1

    From Frank Scheiner@21:1/5 to All on Sun Feb 20 13:50:01 2022
    Dear all,

    I'm unsure if someone already noticed, but it looks like the MP kernels
    for the alpha arch are broken since at least 5.4.0-1 ([1]), tested on:

    * quad processor ES45 (with 5.4.0-1, 5.7.0-1)
    * single processor AS 800 (with 5.7.0-1)
    * dual processor DS25 (with 5.4.0-1 and 5.15.0-1)

    [1]: http://snapshot.debian.org/archive/debian-ports/20191229T085938Z/pool-alpha/main/l/linux/linux-image-5.4.0-1-alpha-smp_5.4.6-1_alpha.deb

    5.3.x still works fine, tested on:

    * DS25 (with 5.3.0-6)
    * AS 800 (with 5.3.0-2))

    And now guess what, the SP kernel still works, up to 5.15.0-1, and
    tested on the DS25.

    I assume the multiprocessor alpha buildds should have the same problem,
    but for the one I checked it still ran with 5.3.6 [2], though the linked
    log is already from 2020.

    [2]: https://buildd.debian.org/status/fetch.php?pkg=ppx-tools-versioned&arch=alpha&ver=5.4.0-1%2Bb2&stamp=1608280942&raw=0

    I wonder if there is some current or better live information about the
    hardware and software of the buildds available somewhere on the web?

    ****

    If time allows I will try to bisect this issue, but as I am already
    behind with figuring out what broke the kernel for UltraSPARC III(i), I wouldn't mind someone else being faster with bisecting the Alpha MP issue.

    ****

    @Michael:
    If you remember my first email to you and this list from early 2017, we
    had a similar situation, though the SP kernels were toast back then and
    now it's the MP ones. Well, the situation back then was definitely
    better for us. :-)

    Cheers,
    Frank

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  • From Frank Scheiner@21:1/5 to Michael Cree on Sun Feb 20 19:50:01 2022
    On 20.02.22 19:34, Michael Cree wrote:
    On Sun, Feb 20, 2022 at 01:39:44PM +0100, Frank Scheiner wrote:
    I'm unsure if someone already noticed, but it looks like the MP kernels
    for the alpha arch are broken since at least 5.4.0-1 ([1]), tested on:

    * quad processor ES45 (with 5.4.0-1, 5.7.0-1)
    * single processor AS 800 (with 5.7.0-1)
    * dual processor DS25 (with 5.4.0-1 and 5.15.0-1)

    Commit f2f84b05e02b7710a201f0017b3272ad7ef703d1 is the problem.
    Reverting that results in a working SMP kernel, at least up to
    version 5.8.y.

    Great! I hoped you would have a look. :-)

    There is another problem (causing occassional memory corruptions
    in user space) introduced into the 5.9.0 kernel which has proved
    tricky to nail down. I have an idea where it is but not what
    the actual problem is.

    I think I can confirm that, because the panic on my DS25 with 5.15.0-1
    looks different than with 5.4.0-1. I didn't create a log, but IIRC the
    panic originated from systemd there.

    How should we proceed from here?

    Cheers,
    Frank

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  • From Michael Cree@21:1/5 to Frank Scheiner on Sun Feb 20 20:10:02 2022
    On Sun, Feb 20, 2022 at 01:39:44PM +0100, Frank Scheiner wrote:
    I'm unsure if someone already noticed, but it looks like the MP kernels
    for the alpha arch are broken since at least 5.4.0-1 ([1]), tested on:

    * quad processor ES45 (with 5.4.0-1, 5.7.0-1)
    * single processor AS 800 (with 5.7.0-1)
    * dual processor DS25 (with 5.4.0-1 and 5.15.0-1)

    Commit f2f84b05e02b7710a201f0017b3272ad7ef703d1 is the problem.
    Reverting that results in a working SMP kernel, at least up to
    version 5.8.y.

    There is another problem (causing occassional memory corruptions
    in user space) introduced into the 5.9.0 kernel which has proved
    tricky to nail down. I have an idea where it is but not what
    the actual problem is.

    Cheers
    Michael.

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