[PATCH v2 00/11] kbuild: create *.mod with directory path and remove MODVERDIR

[PATCH v2 00/11] kbuild: create *.mod with directory path and remove MODVERDIR

[Masahiro Yamada]

This series kills the long standing MODVERDIR.

Since MODVERDIR has a flat structure, it cannot avoid a race
condition when somebody introduces a module name conflict.

Kbuild now reads modules.order to get the list of all modules.

The post-processing/installation stages will be more robust
and simpler.


Masahiro Yamada (11):
  kbuild: do not create empty modules.order in the prepare stage
  kbuild: get rid of kernel/ prefix from in-tree modules.{order,builtin}
  kbuild: remove duplication from modules.order in sub-directories
  scsi: remove pointless $(MODVERDIR)/$(obj)/53c700.ver
  kbuild: modinst: read modules.order instead of $(MODVERDIR)/*.mod
  kbuild: modsign: read modules.order instead of $(MODVERDIR)/*.mod
  kbuild: modpost: read modules.order instead of $(MODVERDIR)/*.mod
  kbuild: create *.mod with full directory path and remove MODVERDIR
  kbuild: remove the first line of *.mod files
  kbuild: remove 'prepare1' target
  kbuild: split out *.mod out of {single,multi}-used-m rules

 .gitignore                  |  1 +
 Documentation/dontdiff      |  1 +
 Makefile                    | 36 ++++++++++--------------------------
 drivers/scsi/Makefile       |  2 +-
 scripts/Makefile.build      | 33 +++++++++++++++------------------
 scripts/Makefile.modbuiltin |  2 +-
 scripts/Makefile.modinst    |  5 +----
 scripts/Makefile.modpost    | 17 +++++++++--------
 scripts/Makefile.modsign    |  3 +--
 scripts/adjust_autoksyms.sh | 11 ++++-------
 scripts/mod/sumversion.c    | 23 ++++-------------------
 scripts/modules-check.sh    |  2 +-
 scripts/package/mkspec      |  2 +-
 13 files changed, 50 insertions(+), 88 deletions(-)

-- 
2.17.1

[PATCH v2 08/11] kbuild: create *.mod with full directory path and remove MODVERDIR

[Masahiro Yamada]

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:

  https://lkml.org/lkml/2019/5/13/991

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/modules-check.sh is invoked. If it
happens again, the modpost will emit unclear error messages.

To fix this issue completely, create *.mod in the same directory as
*.ko 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.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
---

Changes in v2:
 - Remove -r of xargs, which is a GNU extension
 - Add '--' for extra safety

 .gitignore                  |  1 +
 Documentation/dontdiff      |  1 +
 Makefile                    | 20 +++-----------------
 scripts/Makefile.build      |  8 ++------
 scripts/Makefile.modpost    |  4 ++--
 scripts/adjust_autoksyms.sh | 11 ++++-------
 scripts/mod/sumversion.c    | 16 +++-------------
 scripts/package/mkspec      |  2 +-
 8 files changed, 17 insertions(+), 46 deletions(-)

diff --git a/.gitignore b/.gitignore
index 7587ef56b92d..8f5422cba6e2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -30,6 +30,7 @@
 *.lz4
 *.lzma
 *.lzo
+*.mod
 *.mod.c
 *.o
 *.o.*
diff --git a/Documentation/dontdiff b/Documentation/dontdiff
index 5eba889ea84d..9f4392876099 100644
--- a/Documentation/dontdiff
+++ b/Documentation/dontdiff
@@ -30,6 +30,7 @@
 *.lzo
 *.mo
 *.moc
+*.mod
 *.mod.c
 *.o
 *.o.*
diff --git a/Makefile b/Makefile
index b5e21d676ee2..4243b6daffcf 100644
--- a/Makefile
+++ b/Makefile
@@ -488,11 +488,6 @@ export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
 export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
 export KBUILD_ARFLAGS
 
-# 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    \
@@ -1033,7 +1028,7 @@ vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)
 
 # Recurse until adjust_autoksyms.sh is satisfied
 PHONY += autoksyms_recursive
-autoksyms_recursive: $(vmlinux-deps)
+autoksyms_recursive: $(vmlinux-deps) modules.order
 ifdef CONFIG_TRIM_UNUSED_KSYMS
 	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh \
 	  "$(MAKE) -f $(srctree)/Makefile vmlinux"
@@ -1117,7 +1112,6 @@ endif
 
 prepare1: prepare3 outputmakefile asm-generic $(version_h) $(autoksyms_h) \
 						include/generated/utsrelease.h
-	$(cmd_crmodverdir)
 
 archprepare: archheaders archscripts prepare1 scripts
 
@@ -1375,7 +1369,7 @@ 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'
@@ -1636,7 +1630,6 @@ PHONY += $(clean-dirs) clean
 $(clean-dirs):
 	$(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
 
-clean:	rm-dirs := $(MODVERDIR)
 clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers
 
 PHONY += help
@@ -1650,8 +1643,6 @@ help:
 	@echo  ''
 
 PHONY += prepare
-prepare:
-	$(cmd_crmodverdir)
 endif # KBUILD_EXTMOD
 
 clean: $(clean-dirs)
@@ -1662,7 +1653,7 @@ 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]' \
@@ -1791,11 +1782,6 @@ quiet_cmd_depmod = DEPMOD  $(KERNELRELEASE)
       cmd_depmod = $(CONFIG_SHELL) $(srctree)/scripts/depmod.sh $(DEPMOD) \
                    $(KERNELRELEASE)
 
-# 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/scripts/Makefile.build b/scripts/Makefile.build
index 98dede0b2ca8..9fb30633acd2 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -67,8 +67,6 @@ ifeq ($(CONFIG_MODULES)$(need-modorder),y1)
 modorder-target := $(obj)/modules.order
 endif
 
-# 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)
@@ -278,13 +276,11 @@ $(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 $< && \
@@ -466,7 +462,7 @@ cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) $(cmd_secanalysis
 $(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 2ab1694a7df3..3e229d4f4d72 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/adjust_autoksyms.sh b/scripts/adjust_autoksyms.sh
index aab4e299d7a2..8b44bb80a451 100755
--- a/scripts/adjust_autoksyms.sh
+++ b/scripts/adjust_autoksyms.sh
@@ -47,13 +47,10 @@ cat > "$new_ksyms_file" << EOT
  */
 
 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
 
 PROVIDES="$PROVIDES kernel-$KERNELRELEASE"
 __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"
 
-- 
2.17.1

Re: [PATCH v2 08/11] kbuild: create *.mod with full directory path and remove MODVERDIR

[Joe Lawrence]

On Thu, Jul 11, 2019 at 02:44:31PM +0900, Masahiro Yamada wrote:
> 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:
> 
>   https://lkml.org/lkml/2019/5/13/991
> 
> 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/modules-check.sh is invoked. If it
> happens again, the modpost will emit unclear error messages.
> 
> To fix this issue completely, create *.mod in the same directory as
> *.ko 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.
> 
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> Acked-by: Nicolas Pitre <nico@fluxnic.net>
> ---
> 
> Changes in v2:
>  - Remove -r of xargs, which is a GNU extension
>  - Add '--' for extra safety
> 
>  .gitignore                  |  1 +
>  Documentation/dontdiff      |  1 +
>  Makefile                    | 20 +++-----------------
>  scripts/Makefile.build      |  8 ++------
>  scripts/Makefile.modpost    |  4 ++--
>  scripts/adjust_autoksyms.sh | 11 ++++-------
>  scripts/mod/sumversion.c    | 16 +++-------------
>  scripts/package/mkspec      |  2 +-
>  8 files changed, 17 insertions(+), 46 deletions(-)
> 
> diff --git a/.gitignore b/.gitignore
> index 7587ef56b92d..8f5422cba6e2 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -30,6 +30,7 @@
>  *.lz4
>  *.lzma
>  *.lzo
> +*.mod
>  *.mod.c
>  *.o
>  *.o.*
> diff --git a/Documentation/dontdiff b/Documentation/dontdiff
> index 5eba889ea84d..9f4392876099 100644
> --- a/Documentation/dontdiff
> +++ b/Documentation/dontdiff
> @@ -30,6 +30,7 @@
>  *.lzo
>  *.mo
>  *.moc
> +*.mod
>  *.mod.c
>  *.o
>  *.o.*
> diff --git a/Makefile b/Makefile
> index b5e21d676ee2..4243b6daffcf 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -488,11 +488,6 @@ export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
>  export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
>  export KBUILD_ARFLAGS
>  
> -# 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    \
> @@ -1033,7 +1028,7 @@ vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)
>  
>  # Recurse until adjust_autoksyms.sh is satisfied
>  PHONY += autoksyms_recursive
> -autoksyms_recursive: $(vmlinux-deps)
> +autoksyms_recursive: $(vmlinux-deps) modules.order
>  ifdef CONFIG_TRIM_UNUSED_KSYMS
>  	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh \
>  	  "$(MAKE) -f $(srctree)/Makefile vmlinux"
> @@ -1117,7 +1112,6 @@ endif
>  
>  prepare1: prepare3 outputmakefile asm-generic $(version_h) $(autoksyms_h) \
>  						include/generated/utsrelease.h
> -	$(cmd_crmodverdir)
>  
>  archprepare: archheaders archscripts prepare1 scripts
>  
> @@ -1375,7 +1369,7 @@ 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'
> @@ -1636,7 +1630,6 @@ PHONY += $(clean-dirs) clean
>  $(clean-dirs):
>  	$(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
>  
> -clean:	rm-dirs := $(MODVERDIR)
>  clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers
>  
>  PHONY += help
> @@ -1650,8 +1643,6 @@ help:
>  	@echo  ''
>  
>  PHONY += prepare
> -prepare:
> -	$(cmd_crmodverdir)
>  endif # KBUILD_EXTMOD
>  
>  clean: $(clean-dirs)
> @@ -1662,7 +1653,7 @@ 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]' \
> @@ -1791,11 +1782,6 @@ quiet_cmd_depmod = DEPMOD  $(KERNELRELEASE)
>        cmd_depmod = $(CONFIG_SHELL) $(srctree)/scripts/depmod.sh $(DEPMOD) \
>                     $(KERNELRELEASE)
>  
> -# 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 $(targets)))
>  
> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index 98dede0b2ca8..9fb30633acd2 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -67,8 +67,6 @@ ifeq ($(CONFIG_MODULES)$(need-modorder),y1)
>  modorder-target := $(obj)/modules.order
>  endif
>  
> -# 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)
> @@ -278,13 +276,11 @@ $(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 $< && \
> @@ -466,7 +462,7 @@ cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) $(cmd_secanalysis
>  $(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 2ab1694a7df3..3e229d4f4d72 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 $(MODVERDIR)/, listing the name of the
> -#    the preliminary <module>.o file, plus all .o files
> +# c) A <module>.mod file, listing the name of the preliminary <module>.o file,
> +#    plus all .o files
>  # d) modules.order, which lists all the modules
>  
>  # Stage 2 is handled by this file and does the following
> diff --git a/scripts/adjust_autoksyms.sh b/scripts/adjust_autoksyms.sh
> index aab4e299d7a2..8b44bb80a451 100755
> --- a/scripts/adjust_autoksyms.sh
> +++ b/scripts/adjust_autoksyms.sh
> @@ -47,13 +47,10 @@ cat > "$new_ksyms_file" << EOT
>   */
>  
>  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
>  
>  PROVIDES="$PROVIDES kernel-$KERNELRELEASE"
>  __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"
>  
> -- 
> 2.17.1
> 

Hi Masahiro,

I'm following this patchset changes as they will affect the klp-convert
series [1] that the livepatching folks have been working on...

Just wondering if these other files should be checked for more MODVERDIR
fallout:

  % grep -R 'tmp_versions'
  tools/power/cpupower/debug/kernel/Makefile:     - rm -rf .tmp_versions* Module.symvers modules.order
  scripts/export_report.pl:    while (<.tmp_versions/*.mod>) {
  scripts/adjust_autoksyms.sh:# .tmp_versions/*.mod files.

export_report.pl is probably the only interesting one on this list.

Also, can you cc me on subsequent patchset versions?

Thanks,

-- Joe

[1] https://lore.kernel.org/lkml/20190509143859.9050-1-joe.lawrence@redhat.com/

Re: [PATCH v2 08/11] kbuild: create *.mod with full directory path and remove MODVERDIR

[Masahiro Yamada]

Hi Joe

On Wed, Jul 17, 2019 at 6:40 AM Joe Lawrence <joe.lawrence@redhat.com> wrote:
>
> On Thu, Jul 11, 2019 at 02:44:31PM +0900, Masahiro Yamada wrote:
> > 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:
> >
> >   https://lkml.org/lkml/2019/5/13/991
> >
> > 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/modules-check.sh is invoked. If it
> > happens again, the modpost will emit unclear error messages.
> >
> > To fix this issue completely, create *.mod in the same directory as
> > *.ko 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.
> >
> > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> > Acked-by: Nicolas Pitre <nico@fluxnic.net>

> >
>
> Hi Masahiro,
>
> I'm following this patchset changes as they will affect the klp-convert
> series [1] that the livepatching folks have been working on...

Empty files .tmp_versions/*.livepatch are touched
to keep track of 'LIVEPATCH_* := y', right?

Perhaps, adding a new field
to *.mod files might be cleaner.



> Just wondering if these other files should be checked for more MODVERDIR
> fallout:
>
>   % grep -R 'tmp_versions'
>   tools/power/cpupower/debug/kernel/Makefile:     - rm -rf .tmp_versions* Module.symvers modules.order
>   scripts/export_report.pl:    while (<.tmp_versions/*.mod>) {
>   scripts/adjust_autoksyms.sh:# .tmp_versions/*.mod files.
>
> export_report.pl is probably the only interesting one on this list.

Good catch. I will fix it.

> Also, can you cc me on subsequent patchset versions?

Yes, will do.



--
Best Regards
Masahiro Yamada

Re: [PATCH v2 08/11] kbuild: create *.mod with full directory path and remove MODVERDIR

[Joe Lawrence]

On 7/17/19 1:21 AM, Masahiro Yamada wrote:
>> Hi Masahiro,
>>
>> I'm following this patchset changes as they will affect the klp-convert
>> series [1] that the livepatching folks have been working on...
> 
> Empty files .tmp_versions/*.livepatch are touched
> to keep track of 'LIVEPATCH_* := y', right?
> 

Pretty much.  From that patchset I think the rework would need to  modify..

- [PATCH v4 02/10] kbuild: Support for Symbols.list creation: creates a 
Symbols.list file of kernel and module symbols, but *not* including any 
from LIVEPATCH_* modules.

- [PATCH v4 05/10] modpost: Integrate klp-convert: if a LIVEPATCH_* 
module has changed, call a newly introduced klp-convert script on it.

- [PATCH v4 06/10] modpost: Add modinfo flag to livepatch modules: find 
any LIVEPATCH_* mod, add it to a livepatchmods file, then pass that file 
to modpost

> Perhaps, adding a new field
> to *.mod files might be cleaner.

I can look into that.  By "field" you mean a new row in the file?

Regards,

-- Joe

Re: [PATCH v2 08/11] kbuild: create *.mod with full directory path and remove MODVERDIR

[Masahiro Yamada]

Hi Joe,

On Fri, Jul 19, 2019 at 5:18 AM Joe Lawrence <joe.lawrence@redhat.com> wrote:

> > Perhaps, adding a new field
> > to *.mod files might be cleaner.
>
> I can look into that.  By "field" you mean a new row in the file?

Yes.


-- 
Best Regards
Masahiro Yamada