Re: [Linux-kernel-mentees] [PATCH v2 2/2] kbuild: use interpreters to invoke scripts

[Lukas Bulwahn <lukas.bulwahn@gmail.com>]

On Tue, 13 Oct 2020, Ujjwal Kumar wrote:

> On 12/10/20 11:50 pm, Lukas Bulwahn wrote:
> > 
> > 
> > On Mon, 12 Oct 2020, Ujjwal Kumar wrote:
> > 
> >> We cannot rely on execute bits to be set on files in the repository.
> >> The build script should use the explicit interpreter when invoking any
> >> script from the repository.
> >>
> >> Link: https://lore.kernel.org/lkml/20200830174409.c24c3f67addcce0cea9a9d4c@linux-foundation.org/
> >> Link: https://lore.kernel.org/lkml/202008271102.FEB906C88@keescook/
> >>
> >> Suggested-by: Andrew Morton <akpm@linux-foundation.org>
> >> Suggested-by: Kees Cook <keescook@chromium.org>
> >> Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
> >> Signed-off-by: Ujjwal Kumar <ujjwalkumar0501@gmail.com>
> >> ---
> >>  Makefile                          | 4 ++--
> >>  arch/arm64/kernel/vdso/Makefile   | 2 +-
> >>  arch/arm64/kernel/vdso32/Makefile | 2 +-
> >>  arch/ia64/Makefile                | 4 ++--
> >>  arch/nds32/kernel/vdso/Makefile   | 2 +-
> >>  scripts/Makefile.build            | 2 +-
> >>  scripts/Makefile.package          | 4 ++--
> >>  7 files changed, 10 insertions(+), 10 deletions(-)
> >>
> >> diff --git a/Makefile b/Makefile
> >> index 0af7945caa61..df20e71dd7c8 100644
> >> --- a/Makefile
> >> +++ b/Makefile
> >> @@ -1256,7 +1256,7 @@ include/generated/utsrelease.h: include/config/kernel.release FORCE
> >>  PHONY += headerdep
> >>  headerdep:
> >>  	$(Q)find $(srctree)/include/ -name '*.h' | xargs --max-args 1 \
> >> -	$(srctree)/scripts/headerdep.pl -I$(srctree)/include
> >> +	$(PERL) $(srctree)/scripts/headerdep.pl -I$(srctree)/include
> >>
> >>  # ---------------------------------------------------------------------------
> >>  # Kernel headers
> >> @@ -1312,7 +1312,7 @@ PHONY += kselftest-merge
> >>  kselftest-merge:
> >>  	$(if $(wildcard $(objtree)/.config),, $(error No .config exists, config your kernel first!))
> >>  	$(Q)find $(srctree)/tools/testing/selftests -name config | \
> >> -		xargs $(srctree)/scripts/kconfig/merge_config.sh -m $(objtree)/.config
> >> +		xargs $(CONFIG_SHELL) $(srctree)/scripts/kconfig/merge_config.sh -m $(objtree)/.config
> >>  	$(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig
> >>
> >>  # ---------------------------------------------------------------------------
> >> diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
> >> index edccdb77c53e..fb07804b7fc1 100644
> >> --- a/arch/arm64/kernel/vdso/Makefile
> >> +++ b/arch/arm64/kernel/vdso/Makefile
> >> @@ -65,7 +65,7 @@ $(obj)/%.so: $(obj)/%.so.dbg FORCE
> >>  # Generate VDSO offsets using helper script
> >>  gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh
> >>  quiet_cmd_vdsosym = VDSOSYM $@
> >> -      cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
> >> +      cmd_vdsosym = $(NM) $< | $(CONFIG_SHELL) $(gen-vdsosym) | LC_ALL=C sort > $@
> >>
> >>  include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
> >>  	$(call if_changed,vdsosym)
> >> diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile
> >> index 7f96a1a9f68c..617c9ac58156 100644
> >> --- a/arch/arm64/kernel/vdso32/Makefile
> >> +++ b/arch/arm64/kernel/vdso32/Makefile
> >> @@ -205,7 +205,7 @@ quiet_cmd_vdsomunge = MUNGE   $@
> >>  gen-vdsosym := $(srctree)/$(src)/../vdso/gen_vdso_offsets.sh
> >>  quiet_cmd_vdsosym = VDSOSYM $@
> >>  # The AArch64 nm should be able to read an AArch32 binary
> >> -      cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
> >> +      cmd_vdsosym = $(NM) $< | $(CONFIG_SHELL) $(gen-vdsosym) | LC_ALL=C sort > $@
> >>
> >>  # Install commands for the unstripped file
> >>  quiet_cmd_vdso_install = INSTALL32 $@
> >> diff --git a/arch/ia64/Makefile b/arch/ia64/Makefile
> >> index 703b1c4f6d12..86d42a2d09cb 100644
> >> --- a/arch/ia64/Makefile
> >> +++ b/arch/ia64/Makefile
> >> @@ -27,8 +27,8 @@ cflags-y	:= -pipe $(EXTRA) -ffixed-r13 -mfixed-range=f12-f15,f32-f127 \
> >>  		   -falign-functions=32 -frename-registers -fno-optimize-sibling-calls
> >>  KBUILD_CFLAGS_KERNEL := -mconstant-gp
> >>
> >> -GAS_STATUS	= $(shell $(srctree)/arch/ia64/scripts/check-gas "$(CC)" "$(OBJDUMP)")
> >> -KBUILD_CPPFLAGS += $(shell $(srctree)/arch/ia64/scripts/toolchain-flags "$(CC)" "$(OBJDUMP)" "$(READELF)")
> >> +GAS_STATUS	= $(shell $(CONFIG_SHELL) $(srctree)/arch/ia64/scripts/check-gas "$(CC)" "$(OBJDUMP)")
> >> +KBUILD_CPPFLAGS += $(shell $(CONFIG_SHELL) $(srctree)/arch/ia64/scripts/toolchain-flags "$(CC)" "$(OBJDUMP)" "$(READELF)")
> > 
> > Here is an instance of what Masahiro-san pointed out being wrong.
> > 
> > Ujjwal, will you send a v3?
> 
> Following is the quoted text from the reply mail from Masahiro
> 
> >> -GAS_STATUS     = $(shell $(srctree)/arch/ia64/scripts/check-gas "$(CC)" "$(OBJDUMP)")
> >> -KBUILD_CPPFLAGS += $(shell $(srctree)/arch/ia64/scripts/toolchain-flags "$(CC)" "$(OBJDUMP)" "$(READELF)")
> >> +GAS_STATUS     = $($(CONFIG_SHELL) $(srctree)/arch/ia64/scripts/check-gas "$(CC)" "$(OBJDUMP)")
> >> +KBUILD_CPPFLAGS += $($(CONFIG_SHELL) $(srctree)/arch/ia64/scripts/toolchain-flags "$(CC)" "$(OBJDUMP)" "$(READELF)")
> > 
> > 
> > 
> > These changes look wrong to me.
> > 
> > $($(CONFIG_SHELL)    ->  $(shell $(CONFIG_SHELL)
> > 
> 
> From the above text, I understand as follows:
> 
> That my proposed change:
> $(shell $(src...)    ->  $($(CONFIG_SHELL) $(src...)
> 
> is WRONG
> 
> and in the next line he suggested the required correction.
> That being:
> $($(CONFIG_SHELL)    ->  $(shell $(CONFIG_SHELL)
> 
> Which is in v2 of the patch series.
> 
> Lukas, please correct me if I'm wrong so that I can work on v3
> if required.
>

Sorry, my memory tricked me; I got it confused. Your patch looks good.
 
> Also, Nathan reviewed both the patches in v1 of this series. So,
> should I be the one who adds his tag in next iterations?
>

Masahiro-san will probably just add them when he picks the patches.

Lukas
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