The hostprog compilers and linkers do not share the regular compiler flags,
so they are not affected by CONFIG_WERROR or W=e. As hostprogs are used
during the bootstrap of the build, they can't depend on kconfig options.

Enable -Werror unconditionally.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>

---
For testing in -next, as discussed in
https://lore.kernel.org/lkml/20250812-kbuild-werror-v1-2-36c9ff653700@linutronix.de/
---
 scripts/Makefile.extrawarn | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index 96ff3f5582d651f0016c8ccd49d46022cc6fe070..1434cb6208cb82f20aeb29cc8c059220d1a1f6d2 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -224,3 +224,8 @@ KBUILD_USERLDFLAGS	+= -Wl,--fatal-warnings
 KBUILD_RUSTFLAGS	+= -Dwarnings
 
 endif
+
+# Hostprog flags are used during build bootstrapping and can not rely on CONFIG_ symbols.
+KBUILD_HOSTCFLAGS	+= -Werror
+KBUILD_HOSTLDFLAGS	+= -Wl,--fatal-warnings
+KBUILD_HOSTRUSTFLAGS	+= -Dwarnings

-- 
2.50.1

On Thu, Aug 14, 2025 at 12:15 PM Thomas Weißschuh
<thomas.weissschuh@linutronix.de> wrote:
>
> The hostprog compilers and linkers do not share the regular compiler flags,
> so they are not affected by CONFIG_WERROR or W=e. As hostprogs are used
> during the bootstrap of the build, they can't depend on kconfig options.
>
> Enable -Werror unconditionally.
>
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
>
> ---
> For testing in -next, as discussed in
> https://lore.kernel.org/lkml/20250812-kbuild-werror-v1-2-36c9ff653700@linutronix.de/

The discussion was on patch 0, i.e. the next message in Lore's tree
view -- I would suggest adding it to the commit message for reference:

Link: https://lore.kernel.org/rust-for-linux/CANiq72k-PdSH2BNgbq=X+FhpyEErifSCKfO5ObXz6bu9_J8+fA@mail.gmail.com/

Anyway, since Nathan already applied it, and I see a couple patches on
top, no big deal if it cannot be added.

Thanks!

Cheers,
Miguel

On Sun, Aug 17, 2025 at 06:31:06PM +0200, Miguel Ojeda wrote:
> The discussion was on patch 0, i.e. the next message in Lore's tree
> view -- I would suggest adding it to the commit message for reference:
> 
> Link: https://lore.kernel.org/rust-for-linux/CANiq72k-PdSH2BNgbq=X+FhpyEErifSCKfO5ObXz6bu9_J8+fA@mail.gmail.com/
> 
> Anyway, since Nathan already applied it, and I see a couple patches on
> top, no big deal if it cannot be added.

I dropped the top patch due to a build failure:

https://lore.kernel.org/20250818140143.61b8c466@canb.auug.org.au/

So I was okay with just rebasing the top commit to amend this one,
especially when giving more context to the patch. Thanks for the
suggestion!

Cheers,
Nathan

On Thu, Aug 14, 2025 at 12:14:46PM +0200, Thomas Weißschuh wrote:
> The hostprog compilers and linkers do not share the regular compiler flags,
> so they are not affected by CONFIG_WERROR or W=e. As hostprogs are used
> during the bootstrap of the build, they can't depend on kconfig options.
> 
> Enable -Werror unconditionally.
> 
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
> 
> ---
> For testing in -next, as discussed in
> https://lore.kernel.org/lkml/20250812-kbuild-werror-v1-2-36c9ff653700@linutronix.de/

yeah, I am not sure if this is a good change, but I am ok with testing
it in next, as Nathan suggested.

For the rest of the series:

Reviewed-by: Nicolas Schier <nsc@kernel.org>

Thanks.

> ---
>  scripts/Makefile.extrawarn | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
> index 96ff3f5582d651f0016c8ccd49d46022cc6fe070..1434cb6208cb82f20aeb29cc8c059220d1a1f6d2 100644
> --- a/scripts/Makefile.extrawarn
> +++ b/scripts/Makefile.extrawarn
> @@ -224,3 +224,8 @@ KBUILD_USERLDFLAGS	+= -Wl,--fatal-warnings
>  KBUILD_RUSTFLAGS	+= -Dwarnings
>  
>  endif
> +
> +# Hostprog flags are used during build bootstrapping and can not rely on CONFIG_ symbols.
> +KBUILD_HOSTCFLAGS	+= -Werror
> +KBUILD_HOSTLDFLAGS	+= -Wl,--fatal-warnings
> +KBUILD_HOSTRUSTFLAGS	+= -Dwarnings
> 
> -- 
> 2.50.1
> 

On Thu, Aug 14, 2025 at 02:10:13PM +0200, Nicolas Schier wrote:
> On Thu, Aug 14, 2025 at 12:14:46PM +0200, Thomas Weißschuh wrote:
> > The hostprog compilers and linkers do not share the regular compiler flags,
> > so they are not affected by CONFIG_WERROR or W=e. As hostprogs are used
> > during the bootstrap of the build, they can't depend on kconfig options.
> > 
> > Enable -Werror unconditionally.
> > 
> > Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
> > 
> > ---
> > For testing in -next, as discussed in
> > https://lore.kernel.org/lkml/20250812-kbuild-werror-v1-2-36c9ff653700@linutronix.de/
> 
> yeah, I am not sure if this is a good change, but I am ok with testing
> it in next, as Nathan suggested.

Yeah, I will leave this as the top patch in kbuild-next for now so that
we can easily back out if it is disruptive.

> For the rest of the series:
> 
> Reviewed-by: Nicolas Schier <nsc@kernel.org>

I applied this tag to patches 1 through 5 and left it off of this one,
based on "for the rest of the series". Let me know if that was
unintentional.

Cheers,
Nathan