Re: [PATCH] kbuild: Never respect CONFIG_WERROR / W=e to fixdep

Nathan Chancellor
2026-04-22T20:05:30Z

On Wed, Apr 22, 2026 at 05:10:27PM +0200, Thomas Weißschuh wrote:
> The fixdep hostprog may be built multiple times during a single build.
> Once during the configuration phase and later during the regular phase.
> As only the regular build phase respects CONFIG_WERROR / W=e, the
> compiler flags might change between the phases, leading to rebuilds.
>
> Example, the rebuilds will happen twice on each invocation of the build:
>
> $ make allyesconfig prepare
> make[1]: Entering directory '/tmp/deleteme'
> HOSTCC scripts/basic/fixdep
> #
> # No change to .config
> #
> HOSTCC scripts/basic/fixdep
> DESCEND objtool
> INSTALL libsubcmd_headers
> make[1]: Leaving directory '/tmp/deleteme'
>
> Fix the compilation flags used for scripts/basic/ before
> scripts/Makefile.warn is evaluated to stop CONFIG_WERROR / W=e
> influencing the fixdep build to avoid the spurious rebuilds.
>
> Fixes: 7ded7d37e5f5 ("scripts/Makefile.extrawarn: Respect CONFIG_WERROR / W=e for hostprogs")
> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>

Reviewed-by: Nathan Chancellor <nathan@kernel.org>

> ---
> Makefile | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/Makefile b/Makefile
> index 54e1ae602000..6c8a1b2e7c8a 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -657,6 +657,8 @@ export RCS_FIND_IGNORE := \( -name SCCS -o -name BitKeeper -o -name .svn -o \
>
> # Basic helpers built in scripts/basic/
> PHONY += scripts_basic
> +scripts_basic: KBUILD_HOSTCFLAGS := $(KBUILD_HOSTCFLAGS)
> +scripts_basic: KBUILD_HOSTLDFLAGS := $(KBUILD_HOSTLDFLAGS)
> scripts_basic:
> $(Q)$(MAKE) $(build)=scripts/basic
>
>
> ---
> base-commit: 6596a02b207886e9e00bb0161c7fd59fea53c081
> change-id: 20260422-kbuild-scripts-basic-werror-f8f7bfc39cfc
>
> Best regards,
> --
> Thomas Weißschuh <linux@weissschuh.net>
>