ACK: [SRU][J][PATCH 0/1] Kernel oops while removing device from cio_ignore list (LP: 1980951)

[Luke Nowakowski-Krijger]

Acked-by: Luke Nowakowski-Krijger <luke.nowakowskikrijger at canonical.com>

On Thu, Jul 7, 2022 at 9:24 AM <frank.heimes at canonical.com> wrote:

> BugLink: https://bugs.launchpad.net/bugs/1980951
>
> SRU Justification:
>
> [Impact]
>
>  * A kernel Oops occurs when a device is removed from the cio_ignore list
>    (that is used to hide ccw devices) on a system with non-I/O subchannels
>    (e.g. SCM or CHSC subchannels).
>
>  * As a result, previously ignored devices cannot be activated again,
>    and new devices cannot be found.
>
> [Fix]
>
>  * 0c3812c347bf 0c3812c347bfb0dc213556a195e79850c55702f5 "s390/cio: derive
> cdev information only for IO-subchannels"
>
> [Test Plan]
>
>  * An IBM zSystems or LinuxONE LPAR with with non-I/O subchannels.
>
>  * Ubuntu Server 22.04 LTS (with GA kernel 5.15) installed.
>
>  * Define a cio_ignore list (to hide ccw devices).
>
>  * Remove a device from the cio_ignore list.
>
>  * Due to hardware requirements this test needs to be conducted by IBM.
>
> [Where problems could occur]
>
>  * General problems may occur with ccw device activation/deactivation
>    in case the new initialization is erroneous.
>
>  * Issues may also have an impact on the type of ccw devices,
>    and may no longer be limited to non-I/O subchannels.
>
>  * Things could still go wrong in case cdev is still not properly
>    derived from sch-type SUBCHANNEL_TYPE_IO.
>
> [Other Info]
>
>  * The commit is upstream since kernel 5.16 (next-20220315).
>
> Vineeth Vijayan (1):
>   s390/cio: derive cdev information only for IO-subchannels
>
>  drivers/s390/cio/css.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
>
> --
> 2.25.1
>
>
> --
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>
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