diff options
authorMasahiro Yamada <>2019-07-17 15:17:57 +0900
committerMasahiro Yamada <>2019-07-18 02:19:31 +0900
commitb7dca6dd1e591ad19a9aae716f3898be8063f880 (patch)
parent7deb55f57159f9de696ef8d5e93b201a6aba871c (diff)
kbuild: create *.mod with full directory path and remove MODVERDIR
While descending directories, Kbuild produces objects for modules, but do not link final *.ko files; it is done in the modpost. To keep track of modules, Kbuild creates a *.mod file in $(MODVERDIR) for every module it is building. Some post-processing steps read the necessary information from *.mod files. This avoids descending into directories again. This mechanism was introduced in 2003 or so. Later, commit 551559e13af1 ("kbuild: implement modules.order") added modules.order. So, we can simply read it out to know all the modules with directory paths. This is easier than parsing the first line of *.mod files. $(MODVERDIR) has a flat directory structure, that is, *.mod files are named only with base names. This is based on the assumption that the module name is unique across the tree. This assumption is really fragile. Stephen Rothwell reported a race condition caused by a module name conflict: In parallel building, two different threads could write to the same $(MODVERDIR)/*.mod simultaneously. Non-unique module names are the source of all kind of troubles, hence commit 3a48a91901c5 ("kbuild: check uniqueness of module names") introduced a new checker script. However, it is still fragile in the build system point of view because this race happens before scripts/ is invoked. If it happens again, the modpost will emit unclear error messages. To fix this issue completely, create *.mod with full directory path so that two threads never attempt to write to the same file. $(MODVERDIR) is no longer needed. Since modules with directory paths are listed in modules.order, Kbuild is still able to find *.mod files without additional descending. I also killed cmd_secanalysis; scripts/mod/sumversion.c computes MD4 hash for modules with MODULE_VERSION(). When CONFIG_DEBUG_SECTION_MISMATCH=y, it occurs not only in the modpost stage, but also during directory descending, where sumversion.c may parse stale *.mod files. It would emit 'No such file or directory' warning when an object consisting a module is renamed, or when a single-obj module is turned into a multi-obj module or vice versa. Signed-off-by: Masahiro Yamada <> Acked-by: Nicolas Pitre <>
10 files changed, 22 insertions, 67 deletions
diff --git a/.gitignore b/.gitignore
index 7587ef56b92d..8f5422cba6e2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -30,6 +30,7 @@
diff --git a/Documentation/dontdiff b/Documentation/dontdiff
index 5eba889ea84d..9f4392876099 100644
--- a/Documentation/dontdiff
+++ b/Documentation/dontdiff
@@ -30,6 +30,7 @@
diff --git a/Makefile b/Makefile
index d9103e731187..6308c8cea121 100644
--- a/Makefile
+++ b/Makefile
-# When compiling out-of-tree modules, put MODVERDIR in the module
-# tree rather than in the kernel tree. The kernel tree might
-# even be read-only.
-export MODVERDIR := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_versions
# Files to ignore in find ... statements
export RCS_FIND_IGNORE := \( -name SCCS -o -name BitKeeper -o -name .svn -o \
@@ -1029,8 +1024,8 @@ vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)
# Recurse until is satisfied
PHONY += autoksyms_recursive
-autoksyms_recursive: $(vmlinux-deps)
+autoksyms_recursive: $(vmlinux-deps) modules.order
$(Q)$(CONFIG_SHELL) $(srctree)/scripts/ \
"$(MAKE) -f $(srctree)/Makefile vmlinux"
@@ -1113,7 +1108,6 @@ endif
prepare1: prepare3 outputmakefile asm-generic $(version_h) $(autoksyms_h) \
- $(cmd_crmodverdir)
archprepare: archheaders archscripts prepare1 scripts
@@ -1371,7 +1365,7 @@ endif # CONFIG_MODULES
# make distclean Remove editor backup files, patch leftover files and the like
# Directories & files removed with 'make clean'
-CLEAN_DIRS += $(MODVERDIR) include/ksym
+CLEAN_DIRS += include/ksym
CLEAN_FILES += modules.builtin.modinfo
# Directories & files removed with 'make mrproper'
@@ -1641,7 +1635,6 @@ PHONY += $(clean-dirs) clean
$(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
-clean: rm-dirs := $(MODVERDIR)
clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers
PHONY += help
@@ -1655,8 +1648,6 @@ help:
@echo ''
PHONY += prepare
- $(cmd_crmodverdir)
clean: $(clean-dirs)
@@ -1667,7 +1658,7 @@ clean: $(clean-dirs)
-o -name '*.ko.*' \
-o -name '*.dtb' -o -name '*.dtb.S' -o -name '*.dt.yaml' \
-o -name '*.dwo' -o -name '*.lst' \
- -o -name '*.su' \
+ -o -name '*.su' -o -name '*.mod' \
-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
-o -name '*.lex.c' -o -name '*.tab.[ch]' \
-o -name '*.asn1.[ch]' \
@@ -1794,11 +1785,6 @@ quiet_cmd_depmod = DEPMOD $(KERNELRELEASE)
cmd_depmod = $(CONFIG_SHELL) $(srctree)/scripts/ $(DEPMOD) \
-# Create temporary dir for module support files
-# clean it up only when building all modules
-cmd_crmodverdir = $(Q)mkdir -p $(MODVERDIR) \
- $(if $(KBUILD_MODULES),; rm -f $(MODVERDIR)/*)
# read saved command lines for existing targets
existing-targets := $(wildcard $(sort $(targets)))
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 4ac4ca21a30a..cde5675340ba 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -353,23 +353,13 @@ config DEBUG_SECTION_MISMATCH
which results in the code/data being placed in specific sections.
The section mismatch analysis is always performed after a full
kernel build, and enabling this option causes the following
- additional steps to occur:
+ additional step to occur:
- Add the option -fno-inline-functions-called-once to gcc commands.
When inlining a function annotated with __init in a non-init
function, we would lose the section information and thus
the analysis would not catch the illegal reference.
This option tells gcc to inline less (but it does result in
a larger kernel).
- - Run the section mismatch analysis for each module/built-in.a file.
- When we run the section mismatch analysis on vmlinux.o, we
- lose valuable information about where the mismatch was
- introduced.
- Running the analysis for each module/built-in.a file
- tells where the mismatch happens much closer to the
- source. The drawback is that the same mismatch is
- reported at least twice.
- - Enable verbose reporting from modpost in order to help resolve
- the section mismatches that are reported.
bool "Make section mismatch errors non-fatal"
diff --git a/scripts/ b/scripts/
index be32a3752de4..c6dfcc028f56 100644
--- a/scripts/
+++ b/scripts/
@@ -67,8 +67,6 @@ ifeq ($(CONFIG_MODULES)$(need-modorder),y1)
modorder-target := $(obj)/modules.order
-# We keep a list of all modules in $(MODVERDIR)
__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
$(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
$(subdir-ym) $(always)
@@ -87,11 +85,6 @@ ifneq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),)
cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $<
-# Do section mismatch analysis for each module/built-in.a
- cmd_secanalysis = ; scripts/mod/modpost $@
# Compile C sources (.c)
# ---------------------------------------------------------------------------
@@ -278,13 +271,11 @@ $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
$(call cmd,force_checksrc)
$(call if_changed_rule,cc_o_c)
-# Single-part modules are special since we need to mark them in $(MODVERDIR)
$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
$(call cmd,force_checksrc)
$(call if_changed_rule,cc_o_c)
@{ echo $(@:.o=.ko); echo $@; \
- $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
+ $(cmd_undef_syms); } > $(patsubst %.o,%.mod,$@)
quiet_cmd_cc_lst_c = MKLST $@
cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
@@ -461,12 +452,12 @@ endif
# module is turned into a multi object module, $^ will contain header file
# dependencies recorded in the .*.cmd file.
quiet_cmd_link_multi-m = LD [M] $@
-cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) $(cmd_secanalysis)
+ cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^)
$(multi-used-m): FORCE
$(call if_changed,link_multi-m)
@{ echo $(@:.o=.ko); echo $(filter %.o,$^); \
- $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
+ $(cmd_undef_syms); } > $(patsubst %.o,%.mod,$@)
$(call multi_depend, $(multi-used-m), .o, -objs -y -m)
targets += $(multi-used-m)
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 5841508ffca9..6b19c1a4eae5 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -6,8 +6,8 @@
# Stage one of module building created the following:
# a) The individual .o files used for the module
# b) A <module>.o file which is the .o files above linked together
-# c) A <module>.mod file in $(MODVERDIR)/, listing the name of the
-# the preliminary <module>.o file, plus all .o files
+# c) A <module>.mod file, listing the name of the preliminary <module>.o file,
+# plus all .o files
# d) modules.order, which lists all the modules
# Stage 2 is handled by this file and does the following
diff --git a/scripts/ b/scripts/
index aab4e299d7a2..2e4a7320bfb4 100755
--- a/scripts/
+++ b/scripts/
@@ -8,8 +8,7 @@
# Create/update the include/generated/autoksyms.h file from the list
-# of all module's needed symbols as recorded on the third line of
-# .tmp_versions/*.mod files.
+# of all module's needed symbols as recorded on the third line of *.mod files.
# For each symbol being added or removed, the corresponding dependency
# file's timestamp is updated to force a rebuild of the affected source
@@ -47,13 +46,10 @@ cat > "$new_ksyms_file" << EOT
-[ "$(ls -A "$MODVERDIR")" ] &&
-for mod in "$MODVERDIR"/*.mod; do
- sed -n -e '3{s/ /\n/g;/^$/!p;}' "$mod"
-done | sort -u |
-while read sym; do
- echo "#define __KSYM_${sym} 1"
-done >> "$new_ksyms_file"
+sed 's/ko$/mod/' modules.order |
+xargs -n1 sed -n -e '3{s/ /\n/g;/^$/!p;}' -- |
+sort -u |
+sed -e 's/\(.*\)/#define __KSYM_\1 1/' >> "$new_ksyms_file"
# Special case for modversions (see modpost.c)
if [ -n "$CONFIG_MODVERSIONS" ]; then
diff --git a/scripts/mod/sumversion.c b/scripts/mod/sumversion.c
index 0f6dcb4011a8..166f3fa247a9 100644
--- a/scripts/mod/sumversion.c
+++ b/scripts/mod/sumversion.c
@@ -396,21 +396,11 @@ void get_src_version(const char *modname, char sum[], unsigned sumlen)
unsigned long len;
struct md4_ctx md;
char *sources, *end, *fname;
- const char *basename;
char filelist[PATH_MAX + 1];
- char *modverdir = getenv("MODVERDIR");
- if (!modverdir)
- modverdir = ".";
- /* Source files for module are in .tmp_versions/modname.mod,
- after the first line. */
- if (strrchr(modname, '/'))
- basename = strrchr(modname, '/') + 1;
- else
- basename = modname;
- snprintf(filelist, sizeof(filelist), "%s/%.*s.mod", modverdir,
- (int) strlen(basename) - 2, basename);
+ /* objects for a module are listed in the second line of *.mod file. */
+ snprintf(filelist, sizeof(filelist), "%.*smod",
+ (int)strlen(modname) - 1, modname);
file = grab_file(filelist, &len);
if (!file)
diff --git a/scripts/package/mkspec b/scripts/package/mkspec
index 2d29df4a0a53..8640c278f1aa 100755
--- a/scripts/package/mkspec
+++ b/scripts/package/mkspec
@@ -29,7 +29,7 @@ fi
__KERNELRELEASE=$(echo $KERNELRELEASE | sed -e "s/-/_/g")
-EXCLUDES="$RCS_TAR_IGNORE --exclude=.tmp_versions --exclude=*vmlinux* \
+EXCLUDES="$RCS_TAR_IGNORE --exclude=*vmlinux* --exclude=*.mod \
--exclude=*.o --exclude=*.ko --exclude=*.cmd --exclude=Documentation \
--exclude=.config.old --exclude=.missing-syscalls.d --exclude=*.s"
diff --git a/tools/power/cpupower/debug/kernel/Makefile b/tools/power/cpupower/debug/kernel/Makefile
index c23e5a6ceb7e..7b5c43684be1 100644
--- a/tools/power/cpupower/debug/kernel/Makefile
+++ b/tools/power/cpupower/debug/kernel/Makefile
@@ -12,8 +12,8 @@ default:
- - rm -rf *.o *.ko .tmp-versions .*.cmd .*.mod.* *.mod.c
- - rm -rf .tmp_versions* Module.symvers modules.order
+ - rm -rf *.o *.ko .*.cmd .*.mod.* *.mod.c
+ - rm -rf Module.symvers modules.order
install: default
install -d $(KMISC)