Removing build metadata, for reproducible kernel builds

Andriy Gapon avg at
Wed Dec 2 21:53:46 UTC 2015

On 02/12/2015 19:36, Ed Maste wrote:
> The main issue currently preventing kernel builds from being
> reproducible[1] is the build metadata itself that's included (time,
> user, host, build path). In order to make the kernel build
> reproducible I plan to remove these by default, and add a src.conf
> knob to enable them for developers who want them in their own builds.
> The user-facing effect of this is that the kern.version sysctl no
> longer conveys this information, and uname -a changes from something
> like:
> FreeBSD 11.0-CURRENT FreeBSD 11.0-CURRENT #0
> r288681: Mon Oct  5 01:40:11 UTC 2015
> peter at  amd64
> to something like:
> FreeBSD feynman 10.2-STABLE FreeBSD 10.2-STABLE #44
> r288174+7644546(stable-10) amd64
> The current version of the change is available for review at
> [1] See for more information on the
> reproducible builds project.

Personally, I would prefer that, at least initially, KERNEL_METADATA is "yes" by
default.  My thinking is that people who really need reproducible builds would
have no trouble toggling the knob and the rest would have the traditional behavior.

Andriy Gapon

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