linux-kernel - [PATCH 1/4] kheaders: exclude include/generated/utsversion.h from kheaders

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Message-ID: <20241218103716.137489-1-masahiroy@kernel.org>
Date: Wed, 18 Dec 2024 19:37:05 +0900
From: Masahiro Yamada <masahiroy@...nel.org>
To: linux-kbuild@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
	Masahiro Yamada <masahiroy@...nel.org>
Subject: [PATCH 1/4] kheaders: exclude include/generated/utsversion.h from kheaders_data.tar.xz

CONFIG_IKHEADERS has a reproducibility issue because the contents of
kernel/kheaders_data.tar.xz can vary depending on how you build the
kernel.

If you build the kernel with CONFIG_IKHEADERS enabled from a pristine
state, the tarball does not include include/generated/utsversion.h.

  $ make -s mrproper
  $ make -s defconfig
  $ scripts/config -e CONFIG_IKHEADERS
  $ tar Jtf kernel/kheaders_data.tar.xz | grep utsversion

However, if you build the kernel with CONFIG_IKHEADERS disabled first
and then enable it later, the tarball does include
include/generated/utsversion.h.

  $ make -s mrproper
  $ make -s defconfig
  $ make -s
  $ scripts/config -e CONFIG_IKHEADERS
  $ make -s
  $ tar Jtf kernel/kheaders_data.tar.xz | grep utsversion
  ./include/generated/utsversion.h

It is not predictable whether a stale include/generated/utsversion.h
remains when kheaders_data.tar.xz is generated.

For better reproducibility, include/generated/utsversions.h should
always be omitted. It is not necessary for the kheaders anyway.

Signed-off-by: Masahiro Yamada <masahiroy@...nel.org>
---

 kernel/gen_kheaders.sh | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/gen_kheaders.sh b/kernel/gen_kheaders.sh
index 383fd43ac612..a0e3fbf4afa4 100755
--- a/kernel/gen_kheaders.sh
+++ b/kernel/gen_kheaders.sh
@@ -83,6 +83,10 @@ for f in $dir_list;
 	do find "$f" -name "*.h";
 done | cpio --quiet -pdu $cpio_dir >/dev/null 2>&1

+# Always exclude include/generated/utsversion.h
+# Otherwise, the contents of the tarball may vary depending on the build steps.
+rm -f "${cpio_dir}/include/generated/utsversion.h"
+
 # Remove comments except SDPX lines
 find $cpio_dir -type f -print0 |
 	xargs -0 -P8 -n1 perl -pi -e 'BEGIN {undef $/;}; s/\/\*((?!SPDX).)*?\*\///smg;'
-- 
2.43.0