Messages in this thread | | | Date | Tue, 24 Nov 2020 10:31:18 +0100 | From | Jessica Yu <> | Subject | Re: [PATCH v1 0/2] Add support to capture external module's SCM version |
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+++ 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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