6.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Masahiro Yamada masahiroy@kernel.org
[ Upstream commit 626c54af35764b0b8a4ed5c446458ba6ddfe9cc8 ]
When a header file is changed, kernel/gen_kheaders.sh may fail to update kernel/kheaders_data.tar.xz.
[steps to reproduce]
[1] Build kernel/kheaders_data.tar.xz
$ make -j$(nproc) kernel/kheaders.o DESCEND objtool INSTALL libsubcmd_headers CALL scripts/checksyscalls.sh CHK kernel/kheaders_data.tar.xz GEN kernel/kheaders_data.tar.xz CC kernel/kheaders.o
[2] Modify a header without changing the file size
$ sed -i s/0xdeadbeef/0xfeedbeef/ include/linux/elfnote.h
[3] Rebuild kernel/kheaders_data.tar.xz
$ make -j$(nproc) kernel/kheaders.o DESCEND objtool INSTALL libsubcmd_headers CALL scripts/checksyscalls.sh CHK kernel/kheaders_data.tar.xz
kernel/kheaders_data.tar.xz is not updated if steps [1] - [3] are run within the same minute.
The headers_md5 variable stores the MD5 hash of the 'ls -l' output for all header files. This hash value is used to determine whether kheaders_data.tar.xz needs to be rebuilt. However, 'ls -l' prints the modification times with minute-level granularity. If a file is modified within the same minute and its size remains the same, the MD5 hash does not change.
To reliably detect file modifications, this commit rewrites kernel/gen_kheaders.sh to output header dependencies to kernel/.kheaders_data.tar.xz.cmd. Then, Make compares the timestamps and reruns kernel/gen_kheaders.sh when necessary. This is the standard mechanism used by Make and Kbuild.
Signed-off-by: Masahiro Yamada masahiroy@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/.gitignore | 2 + kernel/Makefile | 47 ++++++++++++++++++--- kernel/gen_kheaders.sh | 94 ++++++++++-------------------------------- 3 files changed, 66 insertions(+), 77 deletions(-)
diff --git a/kernel/.gitignore b/kernel/.gitignore index c6b299a6b786..a501bfc80694 100644 --- a/kernel/.gitignore +++ b/kernel/.gitignore @@ -1,3 +1,5 @@ # SPDX-License-Identifier: GPL-2.0-only /config_data /kheaders.md5 +/kheaders-objlist +/kheaders-srclist diff --git a/kernel/Makefile b/kernel/Makefile index 32e80dd626af..9a9ff405ea89 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -158,11 +158,48 @@ filechk_cat = cat $< $(obj)/config_data: $(KCONFIG_CONFIG) FORCE $(call filechk,cat)
+# kheaders_data.tar.xz $(obj)/kheaders.o: $(obj)/kheaders_data.tar.xz
-quiet_cmd_genikh = CHK $(obj)/kheaders_data.tar.xz - cmd_genikh = $(CONFIG_SHELL) $(srctree)/kernel/gen_kheaders.sh $@ -$(obj)/kheaders_data.tar.xz: FORCE - $(call cmd,genikh) +quiet_cmd_kheaders_data = GEN $@ + cmd_kheaders_data = "$<" "$@" "$(obj)/kheaders-srclist" "$(obj)/kheaders-objlist" + cmd_kheaders_data_dep = cat $(depfile) >> $(dot-target).cmd; rm -f $(depfile)
-clean-files := kheaders_data.tar.xz kheaders.md5 +define rule_kheaders_data + $(call cmd_and_savecmd,kheaders_data) + $(call cmd,kheaders_data_dep) +endef + +targets += kheaders_data.tar.xz +$(obj)/kheaders_data.tar.xz: $(src)/gen_kheaders.sh $(obj)/kheaders-srclist $(obj)/kheaders-objlist $(obj)/kheaders.md5 FORCE + $(call if_changed_rule,kheaders_data) + +# generated headers in objtree +# +# include/generated/utsversion.h is ignored because it is generated +# after gen_kheaders.sh is executed. (utsversion.h is unneeded for kheaders) +filechk_kheaders_objlist = \ + for d in include "arch/$(SRCARCH)/include"; do \ + find "$${d}/generated" ! -path "include/generated/utsversion.h" -a -name "*.h" -print; \ + done + +$(obj)/kheaders-objlist: FORCE + $(call filechk,kheaders_objlist) + +# non-generated headers in srctree +filechk_kheaders_srclist = \ + for d in include "arch/$(SRCARCH)/include"; do \ + find "$(srctree)/$${d}" -path "$(srctree)/$${d}/generated" -prune -o -name "*.h" -print; \ + done + +$(obj)/kheaders-srclist: FORCE + $(call filechk,kheaders_srclist) + +# Some files are symlinks. If symlinks are changed, kheaders_data.tar.xz should +# be rebuilt. +filechk_kheaders_md5sum = xargs -r -a $< stat -c %N | md5sum + +$(obj)/kheaders.md5: $(obj)/kheaders-srclist FORCE + $(call filechk,kheaders_md5sum) + +clean-files := kheaders.md5 kheaders-srclist kheaders-objlist diff --git a/kernel/gen_kheaders.sh b/kernel/gen_kheaders.sh index c9e5dc068e85..0ff7beabb21a 100755 --- a/kernel/gen_kheaders.sh +++ b/kernel/gen_kheaders.sh @@ -4,79 +4,33 @@ # This script generates an archive consisting of kernel headers # for CONFIG_IKHEADERS. set -e -sfile="$(readlink -f "$0")" -outdir="$(pwd)" tarfile=$1 -tmpdir=$outdir/${tarfile%/*}/.tmp_dir - -dir_list=" -include/ -arch/$SRCARCH/include/ -" - -# Support incremental builds by skipping archive generation -# if timestamps of files being archived are not changed. - -# This block is useful for debugging the incremental builds. -# Uncomment it for debugging. -# if [ ! -f /tmp/iter ]; then iter=1; echo 1 > /tmp/iter; -# else iter=$(($(cat /tmp/iter) + 1)); echo $iter > /tmp/iter; fi -# find $all_dirs -name "*.h" | xargs ls -l > /tmp/ls-$iter - -all_dirs= -if [ "$building_out_of_srctree" ]; then - for d in $dir_list; do - all_dirs="$all_dirs $srctree/$d" - done -fi -all_dirs="$all_dirs $dir_list" - -# include/generated/utsversion.h is ignored because it is generated after this -# script is executed. (utsversion.h is unneeded for kheaders) -# -# When Kconfig regenerates include/generated/autoconf.h, its timestamp is -# updated, but the contents might be still the same. When any CONFIG option is -# changed, Kconfig touches the corresponding timestamp file include/config/*. -# Hence, the md5sum detects the configuration change anyway. We do not need to -# check include/generated/autoconf.h explicitly. -# -# Ignore them for md5 calculation to avoid pointless regeneration. -headers_md5="$(find $all_dirs -name "*.h" -a \ - ! -path include/generated/utsversion.h -a \ - ! -path include/generated/autoconf.h | - xargs ls -l | md5sum | cut -d ' ' -f1)" - -# Any changes to this script will also cause a rebuild of the archive. -this_file_md5="$(ls -l $sfile | md5sum | cut -d ' ' -f1)" -if [ -f $tarfile ]; then tarfile_md5="$(md5sum $tarfile | cut -d ' ' -f1)"; fi -if [ -f kernel/kheaders.md5 ] && - [ "$(head -n 1 kernel/kheaders.md5)" = "$headers_md5" ] && - [ "$(head -n 2 kernel/kheaders.md5 | tail -n 1)" = "$this_file_md5" ] && - [ "$(tail -n 1 kernel/kheaders.md5)" = "$tarfile_md5" ]; then - exit -fi - -echo " GEN $tarfile" +srclist=$2 +objlist=$3 + +dir=$(dirname "${tarfile}") +tmpdir=${dir}/.tmp_dir +depfile=${dir}/.$(basename "${tarfile}").d + +# generate dependency list. +{ + echo + echo "deps_${tarfile} := \" + sed 's:(.*): \1 \:' "${srclist}" + sed -n '/^include/generated/autoconf.h$/!s:(.*): \1 \:p' "${objlist}" + echo + echo "${tarfile}: $(deps_${tarfile})" + echo + echo "$(deps_${tarfile}):" + +} > "${depfile}"
rm -rf "${tmpdir}" mkdir "${tmpdir}"
-if [ "$building_out_of_srctree" ]; then - ( - cd $srctree - for f in $dir_list - do find "$f" -name "*.h"; - done | tar -c -f - -T - | tar -xf - -C "${tmpdir}" - ) -fi - -for f in $dir_list; - do find "$f" -name "*.h"; -done | tar -c -f - -T - | tar -xf - -C "${tmpdir}" - -# Always exclude include/generated/utsversion.h -# Otherwise, the contents of the tarball may vary depending on the build steps. -rm -f "${tmpdir}/include/generated/utsversion.h" +# shellcheck disable=SC2154 # srctree is passed as an env variable +sed "s:^${srctree}/::" "${srclist}" | tar -c -f - -C "${srctree}" -T - | tar -xf - -C "${tmpdir}" +tar -c -f - -T "${objlist}" | tar -xf - -C "${tmpdir}"
# Remove comments except SDPX lines # Use a temporary file to store directory contents to prevent find/xargs from @@ -92,8 +46,4 @@ tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \ --owner=0 --group=0 --sort=name --numeric-owner --mode=u=rw,go=r,a+X \ -I $XZ -cf $tarfile -C "${tmpdir}/" . > /dev/null
-echo $headers_md5 > kernel/kheaders.md5 -echo "$this_file_md5" >> kernel/kheaders.md5 -echo "$(md5sum $tarfile | cut -d ' ' -f1)" >> kernel/kheaders.md5 - rm -rf "${tmpdir}"