Question on the decision making process for kernel variants' configurations

[Lexi Haley]

Khaled,

Thank you for your reply; and also for the tip that this setting is enabled
in the 5.15 series.  I wonder if a 5.15 gcp package will make its way into
the 20.04 focal release; that would be perfectly sufficient to meet my
interests in this.

Best wishes,
Lexi

On Thu, Mar 10, 2022 at 4:26 PM Khaled Elmously <
khalid.elmously at canonical.com> wrote:

> Hello,
>
>
> On 2022-03-10 13:02:03 , Lexi Haley wrote:
> > Hello and greetings,
> >
> > I am attempting to gain some insight into the decision making process
> that
> > goes into the kernel configuration choices selected for a given variant
> > kernel.  I have rummaged around the Ubuntu Kernel Wiki, applied search
> > strings to the downloaded kernel-archive mailing list mbox, and bounced
> > around on the Ubuntu Launchpad - all without finding either information
> on
> > the general review process, or finding specifics on the particular detail
> > I'm interested in.
> >
> > What am I interested in exactly?  In the gcp kernel variants the
> > CONFIG_UNICODE (UTF-8 normalization and casefolding support) option is
> > disabled.  This configuration option arrived via (assuming I've trawled
> > around correctly):
> >
> https://git.launchpad.net/~canonical-kernel/ubuntu/+source/linux-gcp/+git/eoan/commit/debian.gcp/config/config.common.ubuntu?id=2116ddb07ec8700610fbb17f751d76e0602a6109
> > , and was set to unset (off).
> >
> > As to why, there are two guesses I might make:
> >
> > One: As the gcp kernel variant already exists with a set of known
> > configuration values, perhaps anything new and considered optional is
> left
> > unset, until such time as an issue is made asking for it (example,
> > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1849493) - perhaps
> I
> > should submit an issue?
> >
> > Two: Perhaps this specific configuration was left unset per concerns a la
> > https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-21300 - in which
> > case submitting an issue would probably not be fruitful?  ( though I
> > believe the post
> >
> https://groups.google.com/g/linux.debian.kernel/c/cjjL57wyVYY/m/ld3tC39UBgAJ
> > makes a nice case for why the CVE isn't precisely cause to leave this
> > unavailable).
>
> I think your guesses are mostly accurate.
>
> The Ubuntu variant kernels are based on the Ubuntu master kernels, which
> are in
> turn based on the mainline kernels (plus patches from upstream stable
> kernels).
> At any stage, we generally make changes only as necessary.
>
> That necessity can come from any of several places. It can come from our
> own needs/testing, or in the case of something like the cloud kernels, it
> can come as a request from the cloud partner, or it can come from users
> who call our attention to specific things. It can be for CVEs or
> bug-fixes, or it can be for feature-enablement. There is no one hard rule.
>
> I do not know why CONFIG_UNICODE specifically is off. My guess is that we
> just
> simply had no reason to change the default value. (That CVE that you
> mentioned
> appears to be a git CVE, not a kernel CVE, so it may not be relevant).
>
> CONFIG_UNICODE is enabled in the main kernels and in the 5.15 gcp kernel.
> I
> am not aware of a reason that prevents it from being enabled for the 5.4
> gcp
> kernel too.
>
> I have created this bug to track the issue:
> https://bugs.launchpad.net/ubuntu/+source/linux-gcp/+bug/1964527
>
>
> Feel free to add any additional info.
> Thanks
> Khaled
>
> >
> > And of course, the rationale might be something I have no clue at - So I
> am
> > asking if someone might point me in the right direction - either towards
> > the background information I seek, or perhaps specifically suggesting
> that
> > I open an issue.
> >
> > My thanks, and I appreciate your time,
> > Lexi Haley
> >
> > --
> >
> > Lexi Haley (she/her/hers)
> >
> > Computer Scientist, System Tools, Advanced Technology Division
> >
> > Medical Information Technology, Inc.
> >
> > Office: 781-774-5156 | Mobile: 508-713-2499
> >
> > lhaley at meditech.com
> >
> > MEDITECH Circle, Westwood, MA 02090
> >
> > Main: 781-821-3000 | Fax: 781-821-2199
> >
> >
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-- 

Lexi Haley (she/her/hers)

Computer Scientist, System Tools, Advanced Technology Division

Medical Information Technology, Inc.

Office: 781-774-5156 | Mobile: 508-713-2499

lhaley at meditech.com

MEDITECH Circle, Westwood, MA 02090

Main: 781-821-3000 | Fax: 781-821-2199


*Diversity at MEDITECH* <https://ehr.meditech.com/diversity-at-meditech>

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