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    SubjectRe: [PATCH v1 0/2] Add support to capture external module's SCM version
    +++ William Mcvicker [23/11/20 14:13 -0800]:
    >On Mon, Nov 23, 2020 at 09:02:57AM +0000, Christoph Hellwig wrote:
    >> On Sat, Nov 21, 2020 at 01:16:49AM +0000, Will McVicker wrote:
    >> > These two patches add module support to capture an external module's SCM
    >> > version as a MODULE_INFO() attribute. This allows users to identity the SCM
    >> > version of a given kernel module by using the modinfo tool or on the device
    >> > via sysfs:
    >>
    >> As this obviously is of no use for in-tree modules it falls under the we
    >> don't add code to support things that are not in tree rule and has no
    >> business in the kernel.
    >
    >Hi Christoph,
    >
    >Ah sorry, I didn't intend this to come across as only for external modules.
    >That just seemed like the easiest way to explain how the scmversion attribute
    >can be different from the vermagic. We mainly need this for in-tree kernel
    >modules since that's where most our drivers are. Let me re-phrase this with
    >that in mind. Basically, I like to look at this as an improved version of the
    >existing srcversion module attribute since it allows you to easily identify the
    >module version with a quick SCM version string check instead of doing a full
    >checksum on the module source.
    >
    >For example, we have a setup to test kernel changes on the hikey and db845c
    >devices without updating the kernel modules. Without this scmversion module
    >attribute, you can't identify the original module version using `uname
    >-r`. And for kernel modules in the initramfs, you can't even use modinfo to get
    >the module vermagic. With this patch, you are able to get the SCM version for
    >*all* kernel modules (on disk and in the initramfs) via the sysfs node:
    >/sys/module/<mod>/scmversion. This also works the other way around when
    >developers update their kernel modules to fix some bug (like a security
    >vulnerability) but don't need to update the full kernel.

    Hi Will,

    If this were also intended for in-tree kernel modules, then why do
    intree modules only get the UTS_RELEASE string in their scmversion
    field, which basically already exists in the vermagic? Or do you plan
    to change that?

    Jessica

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