On Mon, Mar 14, 2022 at 11:59 PM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Sun, Mar 13, 2022 at 09:52:14AM +0100, Peter Zijlstra wrote:
> > On Sat, Mar 12, 2022 at 05:33:39PM -0800, Alexei Starovoitov wrote:
> > > During the build with gcc 8.5 I see:
> > >
> > > arch/x86/crypto/crc32c-intel.o: warning: objtool: file already has
> > > .ibt_endbr_seal, skipping
> > > arch/x86/crypto/crc32c-intel.o: warning: objtool: file already has
> > > .orc_unwind section, skipping
> > > LD [M] crypto/async_tx/async_xor.ko
> > > LD [M] crypto/authenc.ko
> > > make[3]: *** [../scripts/Makefile.modfinal:61:
> > > arch/x86/crypto/crc32c-intel.ko] Error 255
> > > make[3]: *** Waiting for unfinished jobs....
> > >
> > > but make clean cures it.
> > > I suspect it's some missing makefile dependency.
> >
> > Yes, I recently ran into it; I've been trying to kick Makefile into
> > submission but have not had success yet. Will try again on Monday.
> >
> > Problem appears to be that it will re-link .ko even though .o hasn't
> > changed, resulting in duplicate objtool runs. I've been trying to have
> > makefile generate .o.objtool empty file to serve as dependency marker to
> > avoid doing second objtool run, but like said, no luck yet.
>
> Masahiro-san, I'm trying the below, but afaict it's not working because
> the rule for the .o file itself:
>
> $(multi-obj-m): FORCE
> $(call if_changed,link_multi-m)
>
> will in fact update the timestamp of the .o file, even if if_changed
> nops out the cmd. Concequently all rules that try to use if_changed with
> this .o file as a dependency will find it newer and run anyway.
>
>
> remake -x output of a fs/f2fs/ module (re)build:
>
> Prerequisite 'FORCE' of target 'fs/f2fs/f2fs.o' does not exist.
> Must remake target 'fs/f2fs/f2fs.o'.
> ../scripts/Makefile.build:454: target 'fs/f2fs/f2fs.o' does not exist
> ##>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> :
> ##<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
> Successfully remade target file 'fs/f2fs/f2fs.o'.
> Prerequisite 'fs/f2fs/f2fs.o' is newer than target 'fs/f2fs/f2fs.mod'.
> Prerequisite 'FORCE' of target 'fs/f2fs/f2fs.mod' does not exist.
> Must remake target 'fs/f2fs/f2fs.mod'.
> ../scripts/Makefile.build:281: update target 'fs/f2fs/f2fs.mod' due to: fs/f2fs/f2fs.o
> ##>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> set -e; { echo fs/f2fs/dir.o fs/f2fs/file.o fs/f2fs/inode.o fs/f2fs/namei.o fs/f2fs/hash.o fs/f2fs/super.o fs/f2fs/inline.o fs/f2fs/checkpoint.o fs/f2fs/gc.o fs/f2fs/data.o fs/f2fs/node.o fs/f2fs/segment.o fs/f2fs/recovery.o fs/f2fs/shrinker.o fs/f2fs/extent_cache.o fs/f2fs/sysfs.o fs/f2fs/debug.o fs/f2fs/xattr.o fs/f2fs/acl.o fs/f2fs/iostat.o; echo; } > fs/f2fs/f2fs.mod; printf '%s\n' 'cmd_fs/f2fs/f2fs.mod := { echo fs/f2fs/dir.o fs/f2fs/file.o fs/f2fs/inode.o fs/f2fs/namei.o fs/f2fs/hash.o fs/f2fs/super.o fs/f2fs/inline.o fs/f2fs/checkpoint.o fs/f2fs/gc.o fs/f2fs/data.o fs/f2fs/node.o fs/f2fs/segment.o fs/f2fs/recovery.o fs/f2fs/shrinker.o fs/f2fs/extent_cache.o fs/f2fs/sysfs.o fs/f2fs/debug.o fs/f2fs/xattr.o fs/f2fs/acl.o fs/f2fs/iostat.o; echo; } > fs/f2fs/f2fs.mod' > fs/f2fs/.f2fs.mod.cmd
> ##<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
> Successfully remade target file 'fs/f2fs/f2fs.mod'.
> Prerequisite 'fs/f2fs/f2fs.o' is newer than target 'fs/f2fs/f2fs.objtool'.
> Prerequisite 'FORCE' of target 'fs/f2fs/f2fs.objtool' does not exist.
> Must remake target 'fs/f2fs/f2fs.objtool'.
> ../scripts/Makefile.build:287: update target 'fs/f2fs/f2fs.objtool' due to: fs/f2fs/f2fs.o
> ##>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> set -e; { echo fs/f2fs/f2fs.o ; ./tools/objtool/objtool orc generate --module --lto --ibt --no-fp --uaccess fs/f2fs/f2fs.o ; } > fs/f2fs/f2fs.objtool; printf '%s\n' 'cmd_fs/f2fs/f2fs.objtool := { echo fs/f2fs/f2fs.o ; ./tools/objtool/objtool orc generate --module --lto --ibt --no-fp --uaccess fs/f2fs/f2fs.o ; } > fs/f2fs/f2fs.objtool' > fs/f2fs/.f2fs.objtool.cmd
> ##<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
> fs/f2fs/f2fs.o: warning: objtool: file already has .static_call_sites section, skipping
> fs/f2fs/f2fs.o: warning: objtool: file already has .ibt_endbr_seal, skipping
> fs/f2fs/f2fs.o: warning: objtool: file already has .orc_unwind section, skipping
> ../scripts/Makefile.build:286: *** [fs/f2fs/f2fs.objtool] error 255
>
>
> Where we can see that we don't re-generate f2fs.o (empty command), but
> then we do re-generate f2fs.mod because f2fs.o is newer and the same
> happens for the new f2fs.objtool.
>
> Help?
Help?
I had never noticed this thread before because
you did not CC me or kbuild ML.
Looking at the build system changes:
https://lore.kernel.org/all/20220308154319.528181453@xxxxxxxxxxxxx/
https://lore.kernel.org/all/20220308154319.822545231@xxxxxxxxxxxxx/
Both patches are wrong.
So is the fix-up you appended lator in this thread.
Apparently, you were screwing up Kbuild in a brown paper bag.
So scared.
>
> ---
> Index: linux-2.6/scripts/Makefile.build
> ===================================================================
> --- linux-2.6.orig/scripts/Makefile.build
> +++ linux-2.6/scripts/Makefile.build
> @@ -92,6 +92,10 @@ ifdef CONFIG_LTO_CLANG
> targets-for-modules += $(patsubst %.o, %.lto.o, $(filter %.o, $(obj-m)))
> endif
>
> +ifdef CONFIG_X86_KERNEL_IBT
> +targets-for-modules += $(patsubst %.o, %.objtool, $(filter %.o, $(obj-m)))
> +endif
> +
> ifdef need-modorder
> targets-for-modules += $(obj)/modules.order
> endif
> @@ -276,6 +280,12 @@ cmd_mod = { \
> $(obj)/%.mod: $(obj)/%$(mod-prelink-ext).o FORCE
> $(call if_changed,mod)
>
> +cmd_objtool_mod = \
> + { echo $< $(cmd_objtool) ; } > $@
> +
> +$(obj)/%.objtool: $(obj)/%$(mod-prelink-ext).o FORCE
> + $(call if_changed,objtool_mod)
> +
> quiet_cmd_cc_lst_c = MKLST $@
> cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
> $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
> Index: linux-2.6/scripts/Makefile.lib
> ===================================================================
> --- linux-2.6.orig/scripts/Makefile.lib
> +++ linux-2.6/scripts/Makefile.lib
> @@ -552,9 +552,8 @@ objtool_args = \
> $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \
> $(if $(CONFIG_SLS), --sls)
>
> -cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $@)
> -cmd_objtool_mod = $(if $(objtool-enabled), $(objtool) $(objtool_args) $(@:.ko=.o) ; )
> -cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd)
> +cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $(@:.objtool=.o))
> +cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$(@:.objtool=.o): $$(wildcard $(objtool))' ; } >> $(dot-target).cmd)
>
> endif # CONFIG_STACK_VALIDATION
>
> @@ -575,8 +574,8 @@ $(obj)/%.o: objtool-enabled :=
>
> # instead run objtool on the module as a whole, right before
> # the final link pass with the linker script.
> -%.ko: objtool-enabled = y
> -%.ko: part-of-module := y
> +$(obj)/%.objtool: objtool-enabled = y
> +$(obj)/%.objtool: part-of-module := y
>
> else
>
> Index: linux-2.6/scripts/Makefile.modfinal
> ===================================================================
> --- linux-2.6.orig/scripts/Makefile.modfinal
> +++ linux-2.6/scripts/Makefile.modfinal
> @@ -32,7 +32,6 @@ ARCH_POSTLINK := $(wildcard $(srctree)/a
>
> quiet_cmd_ld_ko_o = LD [M] $@
> cmd_ld_ko_o += \
> - $(cmd_objtool_mod) \
> $(LD) -r $(KBUILD_LDFLAGS) \
> $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
> -T scripts/module.lds -o $@ $(filter %.o, $^); \
--
Best Regards
Masahiro Yamada
