Re: [PATCH] gcc-plugins: Require utsrelease.h before scripts target

From: Masahiro Yamada <masahiroy@kernel.org>
To: Kees Cook <keescook@chromium.org>
Cc: Guenter Roeck <linux@roeck-us.net>,
	kernel test robot <lkp@intel.com>,
	Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
	Michal Marek <michal.lkml@markovi.net>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-hardening@vger.kernel.org
Subject: Re: [PATCH] gcc-plugins: Require utsrelease.h before scripts target
Date: Tue, 24 May 2022 23:03:23 +0900	[thread overview]
Message-ID: <CAK7LNAQmfxpSe_HVh=Gvk2gHqJMvH_HAodAvxSJqfn24Etxi-A@mail.gmail.com> (raw)
In-Reply-To: <CAK7LNASWUH-ZYU76Xj3YPc1na6ALo0dULSR0UNWe=_L9GcVXjQ@mail.gmail.com>

Hi Kees

On Tue, May 24, 2022 at 5:20 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> On Tue, May 24, 2022 at 5:02 AM Kees Cook <keescook@chromium.org> wrote:
> >
> > The "utsrelease.h" target was in parallel with the "scripts" target,
> > which meant -j1 or unlucky parallel builds from a distclean state would
> > fail to build the GCC plugins.
> >
> > Reported-by: kernel test robot <lkp@intel.com>
> > Link: https://lore.kernel.org/linux-mm/202205230239.EZxeZ3Fv-lkp@intel.com
> > Reported-by: Guenter Roeck <linux@roeck-us.net>
> > Link: https://lore.kernel.org/lkml/YouX6g1T7w3FDeM8@cmpxchg.org
> > Fixes: 61f60bac8c05 ("gcc-plugins: Change all version strings match kernel")
> > Cc: Guenter Roeck <linux@roeck-us.net>
> > Cc: Masahiro Yamada <masahiroy@kernel.org>
> > Cc: linux-kbuild@vger.kernel.org
> > Signed-off-by: Kees Cook <keescook@chromium.org>

This will work but I do not want to complex the build order.

I'd like to suggest to use KERNELVERSION.

Please consider this as an alternative.
https://lore.kernel.org/lkml/20220524135541.1453693-1-masahiroy@kernel.org/T/#u

> > ---
> >  Makefile                     | 2 +-
> >  scripts/gcc-plugins/Makefile | 2 +-
> >  2 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/Makefile b/Makefile
> > index 91c91fcf3c24..c04420d5aa3d 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -1175,7 +1175,7 @@ include/config/kernel.release: FORCE
> >  # Carefully list dependencies so we do not try to build scripts twice
> >  # in parallel
> >  PHONY += scripts
> > -scripts: scripts_basic scripts_dtc
> > +scripts: include/generated/utsrelease.h scripts_basic scripts_dtc
> >         $(Q)$(MAKE) $(build)=$(@)
> >
> >  # Things we need to do before we recursively start building the kernel
> > diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile
> > index 6f0aecad5d67..c29334669a16 100644
> > --- a/scripts/gcc-plugins/Makefile
> > +++ b/scripts/gcc-plugins/Makefile
> > @@ -64,5 +64,5 @@ $(foreach m, $(notdir $(plugin-multi)), $(eval $(obj)/$m: $(addprefix $(obj)/, $
> >  quiet_cmd_plugin_cxx_o_c = HOSTCXX $@
> >        cmd_plugin_cxx_o_c = $(HOSTCXX) $(plugin_cxxflags) -c -o $@ $<
> >
> > -$(plugin-objs): $(obj)/%.o: $(src)/%.c FORCE
> > +$(plugin-objs): $(obj)/%.o: $(src)/%.c $(objdir)/include/generated/utsrelease.h FORCE
>
>
> This change is unneeded.
>
> The header dependencies are automatically generated
> by the -MMD option.
>
>      plugin_cxxflags = -Wp,-MMD,$(depfile) $(KBUILD_HOSTCXXFLAGS) -fPIC \
>
>
>
>
>
>
> >         $(call if_changed_dep,plugin_cxx_o_c)
> > --
> > 2.32.0
> >
>
>
> --
> Best Regards
> Masahiro Yamada

-- 
Best Regards
Masahiro Yamada