On Fri, Oct 4, 2019 at 7:40 PM Dmitry Goldin <dgol...@protonmail.ch> wrote: > > From: Dmitry Goldin <dgoldin+l...@protonmail.ch> > > In commit 43d8ce9d65a5 ("Provide in-kernel headers to make > extending kernel easier") a new mechanism was introduced, for kernels > >=5.2, which embeds the kernel headers in the kernel image or a module > and exposes them in procfs for use by userland tools. > > The archive containing the header files has nondeterminism caused by > header files metadata. This patch normalizes the metadata and utilizes > KBUILD_BUILD_TIMESTAMP if provided and otherwise falls back to the > default behaviour. > > In commit f7b101d33046 ("kheaders: Move from proc to sysfs") it was > modified to use sysfs and the script for generation of the archive was > renamed to what is being patched. > > Signed-off-by: Dmitry Goldin <dgoldin+l...@protonmail.ch> > > ---
Applied to linux-kbuild. Thanks. > > v1: Initial fix > > v2: Added a bit of info about kheaders to the reproducible builds > documentation and used the opportunity to fix a few typos in the > original patch. > > --- > Documentation/kbuild/reproducible-builds.rst | 13 +++++++++---- > kernel/gen_kheaders.sh | 5 ++++- > 2 files changed, 13 insertions(+), 5 deletions(-) > > diff --git a/Documentation/kbuild/reproducible-builds.rst > b/Documentation/kbuild/reproducible-builds.rst > index ab92e98c89c8..ce6a408b3303 100644 > --- a/Documentation/kbuild/reproducible-builds.rst > +++ b/Documentation/kbuild/reproducible-builds.rst > @@ -16,16 +16,21 @@ the kernel may be unreproducible, and how to avoid them. > Timestamps > ---------- > > -The kernel embeds a timestamp in two places: > +The kernel embeds timestamps in three places: > > * The version string exposed by ``uname()`` and included in > ``/proc/version`` > > * File timestamps in the embedded initramfs > > -By default the timestamp is the current time. This must be overridden > -using the `KBUILD_BUILD_TIMESTAMP`_ variable. If you are building > -from a git commit, you could use its commit date. > +* If enabled via ``CONFIG_IKHEADERS``, file timestamps of kernel > + headers embedded in the kernel or respective module, > + exposed via ``/sys/kernel/kheaders.tar.xz`` > + > +By default the timestamp is the current time and in the case of > +``kheaders`` the various files' modification times. This must > +be overridden using the `KBUILD_BUILD_TIMESTAMP`_ variable. > +If you are building from a git commit, you could use its commit date. > > The kernel does *not* use the ``__DATE__`` and ``__TIME__`` macros, > and enables warnings if they are used. If you incorporate external > diff --git a/kernel/gen_kheaders.sh b/kernel/gen_kheaders.sh > index 9ff449888d9c..aff79e461fc9 100755 > --- a/kernel/gen_kheaders.sh > +++ b/kernel/gen_kheaders.sh > @@ -71,7 +71,10 @@ done | cpio --quiet -pd $cpio_dir >/dev/null 2>&1 > find $cpio_dir -type f -print0 | > xargs -0 -P8 -n1 perl -pi -e 'BEGIN {undef $/;}; > s/\/\*((?!SPDX).)*?\*\///smg;' > > -tar -Jcf $tarfile -C $cpio_dir/ . > /dev/null > +# Create archive and try to normalize metadata for reproducibility > +tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \ > + --owner=0 --group=0 --sort=name --numeric-owner \ > + -Jcf $tarfile -C $cpio_dir/ . > /dev/null > > echo "$src_files_md5" > kernel/kheaders.md5 > echo "$obj_files_md5" >> kernel/kheaders.md5 > -- > 2.23.0 -- Best Regards Masahiro Yamada