Re: [PATCH] scripts/Makefile.extrawarn: Respect CONFIG_WERROR / W=e for hostprogs

[Miguel Ojeda]

On Mon, Oct 6, 2025 at 11:40 PM Nathan Chancellor <nathan@xxxxxxxxxx> wrote:
>
> Commit 27758d8c2583 ("kbuild: enable -Werror for hostprogs")
> unconditionally enabled -Werror for the compiler, assembler, and linker
> when building the host programs, as the build footprint of the host
> programs is small (thus risk of build failures from warnings are low)
> and that stage of the build may not have Kconfig values (thus
> CONFIG_WERROR could not be used as a precondition).
>
> While turning warnings into errors unconditionally happens in a few
> places within the kernel, it can be disruptive to people who may be
> building with newer compilers, such as while doing a bisect. While it is
> possible to avoid this behavior by passing HOSTCFLAGS=-w or
> HOSTCFLAGS=-Wno-error, it may not be the most intuitive for regular
> users not intimately familiar with Kbuild.
>
> Avoid being disruptive to the entire build by depending on the explicit
> opt-in of CONFIG_WERROR or W=e to enable -Werror and the like while
> building the host programs. While this means there is a small portion of
> the build that does not have -Werror enabled (namely scripts/kconfig/*
> and scripts/basic/fixdep), it is better than not having it altogether.
>
> Fixes: 27758d8c2583 ("kbuild: enable -Werror for hostprogs")
> Link: https://lore.kernel.org/20251005011100.1035272-1-safinaskar@xxxxxxxxx/
> Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>

Acked-by: Miguel Ojeda <ojeda@xxxxxxxxxx>

Cheers,
Miguel