[PATCH 0/6] kbuild: uapi: various fixes

[PATCH 0/6] kbuild: uapi: various fixes

[Thomas Weißschuh]

Various fixes and promotion of warnings to real errors.

I didn't add Fixes: tags as digging up the original changes would be
cumbersome as the code moved a lot over the years.
Backporting this doesn't make sense anyways.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
Thomas Weißschuh (6):
      kbuild: uapi: rerun header tests when headers_check.pl changes
      kbuild: uapi: only update hdrtest output on success
      kbuild: uapi: fail header test on compiler warnings
      kbuild: uapi: upgrade warning on asm/types.h inclusion to error
      kbuild: uapi: upgrade check_sizetypes() warning to error
      kbuild: uapi: upgrade check_declarations() warning to error

 usr/include/Makefile         | 8 ++++----
 usr/include/headers_check.pl | 9 ++++-----
 2 files changed, 8 insertions(+), 9 deletions(-)
---
base-commit: 8f5ae30d69d7543eee0d70083daf4de8fe15d585
change-id: 20250811-kbuild-hdrtest-fixes-1bf147b3ddd3

Best regards,
-- 
Thomas Weißschuh <thomas.weissschuh@linutronix.de>

[PATCH 1/6] kbuild: uapi: rerun header tests when headers_check.pl changes

[Thomas Weißschuh]

If the checks change they need to be rerun.

Add a Makefile dependency so this happens.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
 usr/include/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/usr/include/Makefile b/usr/include/Makefile
index f02f41941b60c88d921da2b955076bbff7884c1c..c7f164952b33acf6c7b8eb7ce91cd192bfc39ad2 100644
--- a/usr/include/Makefile
+++ b/usr/include/Makefile
@@ -85,7 +85,7 @@ quiet_cmd_hdrtest = HDRTEST $<
 		$(PERL) $(src)/headers_check.pl $(obj) $<; \
 		touch $@
 
-$(obj)/%.hdrtest: $(obj)/%.h FORCE
+$(obj)/%.hdrtest: $(obj)/%.h $(src)/headers_check.pl FORCE
 	$(call if_changed_dep,hdrtest)
 
 # Since GNU Make 4.3, $(patsubst $(obj)/%/,%,$(wildcard $(obj)/*/)) works.

-- 
2.50.1

[PATCH 2/6] kbuild: uapi: only update hdrtest output on success

[Thomas Weißschuh]

If a header test fails, the output should not be updated.
Otherwise the next make invocation will not rerun the test.

Also headers_check.pl should only run if the syntax check invocation
before succeeded.

Add explicit sequencening.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
 usr/include/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/usr/include/Makefile b/usr/include/Makefile
index c7f164952b33acf6c7b8eb7ce91cd192bfc39ad2..6868d183f36d532cd3d4023b936c67b8a58a9ba5 100644
--- a/usr/include/Makefile
+++ b/usr/include/Makefile
@@ -81,8 +81,8 @@ always-y := $(patsubst $(obj)/%.h,%.hdrtest, $(shell find $(obj) -name '*.h' 2>/
 quiet_cmd_hdrtest = HDRTEST $<
       cmd_hdrtest = \
 		$(CC) $(c_flags) -fsyntax-only -x c /dev/null \
-			$(if $(filter-out $(no-header-test), $*.h), -include $< -include $<); \
-		$(PERL) $(src)/headers_check.pl $(obj) $<; \
+			$(if $(filter-out $(no-header-test), $*.h), -include $< -include $<) && \
+		$(PERL) $(src)/headers_check.pl $(obj) $< && \
 		touch $@
 
 $(obj)/%.hdrtest: $(obj)/%.h $(src)/headers_check.pl FORCE

-- 
2.50.1

Re: [PATCH 2/6] kbuild: uapi: only update hdrtest output on success

[Masahiro Yamada]

On Tue, Aug 12, 2025 at 2:33 PM Thomas Weißschuh
<thomas.weissschuh@linutronix.de> wrote:
>
> If a header test fails, the output should not be updated.
> Otherwise the next make invocation will not rerun the test.
>
> Also headers_check.pl should only run if the syntax check invocation
> before succeeded.
>
> Add explicit sequencening.

Did you test this?

See scripts/Kbuild.include line 153

The macro 'cmd' has "set -e".

Any single error in a series of commands
bails out.



>
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
> ---
>  usr/include/Makefile | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/usr/include/Makefile b/usr/include/Makefile
> index c7f164952b33acf6c7b8eb7ce91cd192bfc39ad2..6868d183f36d532cd3d4023b936c67b8a58a9ba5 100644
> --- a/usr/include/Makefile
> +++ b/usr/include/Makefile
> @@ -81,8 +81,8 @@ always-y := $(patsubst $(obj)/%.h,%.hdrtest, $(shell find $(obj) -name '*.h' 2>/
>  quiet_cmd_hdrtest = HDRTEST $<
>        cmd_hdrtest = \
>                 $(CC) $(c_flags) -fsyntax-only -x c /dev/null \
> -                       $(if $(filter-out $(no-header-test), $*.h), -include $< -include $<); \
> -               $(PERL) $(src)/headers_check.pl $(obj) $<; \
> +                       $(if $(filter-out $(no-header-test), $*.h), -include $< -include $<) && \
> +               $(PERL) $(src)/headers_check.pl $(obj) $< && \
>                 touch $@
>
>  $(obj)/%.hdrtest: $(obj)/%.h $(src)/headers_check.pl FORCE
>
> --
> 2.50.1
>
>


-- 
Best Regards
Masahiro Yamada

Re: [PATCH 2/6] kbuild: uapi: only update hdrtest output on success

[Thomas Weißschuh]

On Wed, Aug 13, 2025 at 09:29:31AM +0900, Masahiro Yamada wrote:
> On Tue, Aug 12, 2025 at 2:33 PM Thomas Weißschuh
> <thomas.weissschuh@linutronix.de> wrote:
> >
> > If a header test fails, the output should not be updated.
> > Otherwise the next make invocation will not rerun the test.
> >
> > Also headers_check.pl should only run if the syntax check invocation
> > before succeeded.
> >
> > Add explicit sequencening.
> 
> Did you test this?

At least I thought so.

> See scripts/Kbuild.include line 153
> 
> The macro 'cmd' has "set -e".
> 
> Any single error in a series of commands
> bails out.

Indeed, this patch is pointless. I will drop it.

Thanks!

> >
> > Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
> > ---
> >  usr/include/Makefile | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/usr/include/Makefile b/usr/include/Makefile
> > index c7f164952b33acf6c7b8eb7ce91cd192bfc39ad2..6868d183f36d532cd3d4023b936c67b8a58a9ba5 100644
> > --- a/usr/include/Makefile
> > +++ b/usr/include/Makefile
> > @@ -81,8 +81,8 @@ always-y := $(patsubst $(obj)/%.h,%.hdrtest, $(shell find $(obj) -name '*.h' 2>/
> >  quiet_cmd_hdrtest = HDRTEST $<
> >        cmd_hdrtest = \
> >                 $(CC) $(c_flags) -fsyntax-only -x c /dev/null \
> > -                       $(if $(filter-out $(no-header-test), $*.h), -include $< -include $<); \
> > -               $(PERL) $(src)/headers_check.pl $(obj) $<; \
> > +                       $(if $(filter-out $(no-header-test), $*.h), -include $< -include $<) && \
> > +               $(PERL) $(src)/headers_check.pl $(obj) $< && \
> >                 touch $@
> >
> >  $(obj)/%.hdrtest: $(obj)/%.h $(src)/headers_check.pl FORCE

Re: [PATCH 2/6] kbuild: uapi: only update hdrtest output on success

[Nicolas Schier]

On Wed, Aug 13, 2025 at 09:29:31AM +0900, Masahiro Yamada wrote:
> On Tue, Aug 12, 2025 at 2:33 PM Thomas Weißschuh
> <thomas.weissschuh@linutronix.de> wrote:
> >
> > If a header test fails, the output should not be updated.
> > Otherwise the next make invocation will not rerun the test.
> >
> > Also headers_check.pl should only run if the syntax check invocation
> > before succeeded.
> >
> > Add explicit sequencening.
> 
> Did you test this?
> 
> See scripts/Kbuild.include line 153
> 
> The macro 'cmd' has "set -e".
> 
> Any single error in a series of commands
> bails out.

Ah thanks!  Yes, for me it works correct w/o the patch.

I was struggling with this: If I apply this patch, make no more forwards
the error code if headers_check.pl exits with error.

It's actually a bit funny:

W/o this patch, we have a command sequence like:

    set -e; date ; false ; true; date

which bails out at false at stops processing subsequent commands.
Replacing the semicolons by '&&'

    set -e; date && false && true; date

will prevent 'true' to be run, but the trailing 'date' will still be
executed.

Kind regards,
Nicolas

[PATCH 3/6] kbuild: uapi: fail header test on compiler warnings

[Thomas Weißschuh]

Compiler warnings also indicate issues with the headers.

Make sure they don't go unnoticed.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
 usr/include/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/usr/include/Makefile b/usr/include/Makefile
index 6868d183f36d532cd3d4023b936c67b8a58a9ba5..2846fe216ee4f2054effbfbb5778b4e5b24649ae 100644
--- a/usr/include/Makefile
+++ b/usr/include/Makefile
@@ -80,7 +80,7 @@ always-y := $(patsubst $(obj)/%.h,%.hdrtest, $(shell find $(obj) -name '*.h' 2>/
 # Include the header twice to detect missing include guard.
 quiet_cmd_hdrtest = HDRTEST $<
       cmd_hdrtest = \
-		$(CC) $(c_flags) -fsyntax-only -x c /dev/null \
+		$(CC) $(c_flags) -fsyntax-only -Werror -x c /dev/null \
 			$(if $(filter-out $(no-header-test), $*.h), -include $< -include $<) && \
 		$(PERL) $(src)/headers_check.pl $(obj) $< && \
 		touch $@

-- 
2.50.1

[PATCH 4/6] kbuild: uapi: upgrade warning on asm/types.h inclusion to error

[Thomas Weißschuh]

No usages of '#include <asm/types.h> in the UAPI headers exist anymore.

Make sure it stays this way.

Add a semicolon to the end of the previous printf call to keep the
syntax valid.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
 usr/include/headers_check.pl | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/usr/include/headers_check.pl b/usr/include/headers_check.pl
index 2b70bfa5558e64518808a22f2f926291da6e47a9..36307a137cc1e109e3e1c253f66f3e5935499fc8 100755
--- a/usr/include/headers_check.pl
+++ b/usr/include/headers_check.pl
@@ -98,9 +98,8 @@ sub check_asm_types
 	if ($line =~ m/^\s*#\s*include\s+<asm\/types.h>/) {
 		$linux_asm_types = 1;
 		printf STDERR "$filename:$lineno: " .
-		"include of <linux/types.h> is preferred over <asm/types.h>\n"
-		# Warn until headers are all fixed
-		#$ret = 1;
+		"include of <linux/types.h> is preferred over <asm/types.h>\n";
+		$ret = 1;
 	}
 }
 

-- 
2.50.1

[PATCH 5/6] kbuild: uapi: upgrade check_sizetypes() warning to error

[Thomas Weißschuh]

No problematic type usages exist anymore.

Make sure it stays this way.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
 usr/include/headers_check.pl | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/usr/include/headers_check.pl b/usr/include/headers_check.pl
index 36307a137cc1e109e3e1c253f66f3e5935499fc8..36349b21cef5d55241b68ca24dabe6a321b7ce27 100755
--- a/usr/include/headers_check.pl
+++ b/usr/include/headers_check.pl
@@ -159,7 +159,6 @@ sub check_sizetypes
 		              "found __[us]{8,16,32,64} type " .
 		              "without #include <linux/types.h>\n";
 		$linux_types = 2;
-		# Warn until headers are all fixed
-		#$ret = 1;
+		$ret = 1;
 	}
 }

-- 
2.50.1

[PATCH 6/6] kbuild: uapi: upgrade check_declarations() warning to error

[Thomas Weißschuh]

No problematic declarations exist anymore.

Make sure it stays this way.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
 usr/include/headers_check.pl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/usr/include/headers_check.pl b/usr/include/headers_check.pl
index 36349b21cef5d55241b68ca24dabe6a321b7ce27..21c2fb9520e6af2d6ebf2decce69f6eea64efd88 100755
--- a/usr/include/headers_check.pl
+++ b/usr/include/headers_check.pl
@@ -74,6 +74,7 @@ sub check_declarations
 		printf STDERR "$filename:$lineno: " .
 			      "userspace cannot reference function or " .
 			      "variable defined in the kernel\n";
+		$ret = 1;
 	}
 }
 

-- 
2.50.1

Re: [PATCH 0/6] kbuild: uapi: various fixes

[Nathan Chancellor]

Hi Thomas,

On Tue, Aug 12, 2025 at 07:33:03AM +0200, Thomas Weißschuh wrote:
> Various fixes and promotion of warnings to real errors.
> 
> I didn't add Fixes: tags as digging up the original changes would be
> cumbersome as the code moved a lot over the years.
> Backporting this doesn't make sense anyways.
> 
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
> ---
> Thomas Weißschuh (6):
>       kbuild: uapi: rerun header tests when headers_check.pl changes
>       kbuild: uapi: only update hdrtest output on success
>       kbuild: uapi: fail header test on compiler warnings
>       kbuild: uapi: upgrade warning on asm/types.h inclusion to error
>       kbuild: uapi: upgrade check_sizetypes() warning to error
>       kbuild: uapi: upgrade check_declarations() warning to error

This series seems reasonable. I did a build of usr/ on arm64 and x86_64
allmodconfig, which showed no issues. I will give Nicolas a few days to
comment, after which I will apply these to the Kbuild tree so we can
start soak testing in -next.

Cheers,
Nathan

Re: [PATCH 0/6] kbuild: uapi: various fixes

[Nicolas Schier]

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On Tue, Aug 12, 2025 at 04:44:58PM -0700, Nathan Chancellor wrote:
> Hi Thomas,
> 
> On Tue, Aug 12, 2025 at 07:33:03AM +0200, Thomas Weißschuh wrote:
> > Various fixes and promotion of warnings to real errors.
> > 
> > I didn't add Fixes: tags as digging up the original changes would be
> > cumbersome as the code moved a lot over the years.
> > Backporting this doesn't make sense anyways.
> > 
> > Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
> > ---
> > Thomas Weißschuh (6):
> >       kbuild: uapi: rerun header tests when headers_check.pl changes
> >       kbuild: uapi: only update hdrtest output on success
> >       kbuild: uapi: fail header test on compiler warnings
> >       kbuild: uapi: upgrade warning on asm/types.h inclusion to error
> >       kbuild: uapi: upgrade check_sizetypes() warning to error
> >       kbuild: uapi: upgrade check_declarations() warning to error
> 
> This series seems reasonable. I did a build of usr/ on arm64 and x86_64
> allmodconfig, which showed no issues. I will give Nicolas a few days to
> comment, after which I will apply these to the Kbuild tree so we can
> start soak testing in -next.

thanks.  With the exception of the already canceled patch 2, this looks
good to me.

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

Kind regards,
Nicolas

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