Thanks for the reply! Alan Maguire wrote on Wed, Jun 26, 2024 at 03:29:37PM +0100: > On 26/06/2024 04:22, Dominique Martinet wrote: > > The SOURCE_DATE_EPOCH environment variable is used in reproducible > > builds to set build timestamps and is generally synonymous with > > reproducible builds: instead of making users figure out how to pass > > pahole flags (e.g. explicitly setting PAHOLE_FLAGS in linux) just assume > > that the user wants a reproducible build if this variable is set. > > From the kernel perspective it looks like as a result of [1] > [1] https://patchwork.kernel.org/project/linux-kbuild/patch/1443741332.2730.75.camel@xxxxxxxxxxxxxxxxx/ > the setting of SOURCE_DATE_EPOCH will be converted into > KBUILD_BUILD_TIMESTAMP; I thought the plan was to add the > BTF feature flag explicitly if KBUILD_BUILD_TIMESTAMP was set? Hmm, that patch (2015) never got in apparently?... And I don't see anythiing that'd make pahole output reproducible if either variables are set in the kernel either right now; we still build plenty of older kernels so even if such a patch gets in I'd rather this is checked in pahole than kbuild. For context, the patch I'm replacing right now is this one in nixpkgs (2023): https://github.com/NixOS/nixpkgs/commit/e1daacf987d6064bd7dc65a30e7715990bc1c011 (Where we used to force -j1 if SOURCE_DATE_EPOCH is set, and the new feature makes it more appropriate for upstreaming so I decided to send the patch) > Are you planning for use-cases outside of kernel BTF generation?
