Re: kbuild problem: ERROR: modpost: missing MODULE_LICENSE() in drivers/iio/afe/iio-rescale.o

[Liam Beguin <liambeguin@gmail.com>]

Hi Randy,

On Thu, May 26, 2022 at 01:04:41PM -0700, Randy Dunlap wrote:
> 
> 
> On 5/26/22 09:04, Liam Beguin wrote:
> > Hi Randy,
> > 
> > On Thu, May 26, 2022 at 08:36:34AM -0700, Randy Dunlap wrote:
> >> Liam:
> >>
> >> Any comment on this?
> >> Otherwise I'll just send a formal patch like this (below).
> > 
> > Apologies for not answering earlier.
> > 
> > I wanted to look more into Masahiro's comment and try to fix the
> > Makefile, but that can be done after.
> > 
> > IMO your patch improves the current Kconfig, so I'd recommend sending
> > the patch. If it can wait a bit, I can look at the Makefile over the
> > weekend.
> > 
> 
> Liam,
> 
> I'll wait until next week to see if you come up with anything.
> 

The following patch fixes the issue while addressing Masahiro's comment.
I also considered `select IIO_RESCALE`, but I'm not sure what's usually
preferred.

diff --git a/drivers/iio/test/Kconfig b/drivers/iio/test/Kconfig
index 56ca0ad7e77a..4c66c3f18c34 100644
--- a/drivers/iio/test/Kconfig
+++ b/drivers/iio/test/Kconfig
@@ -6,7 +6,7 @@
 # Keep in alphabetical order
 config IIO_RESCALE_KUNIT_TEST
 	bool "Test IIO rescale conversion functions"
-	depends on KUNIT=y && !IIO_RESCALE
+	depends on KUNIT=y && IIO_RESCALE=y
 	default KUNIT_ALL_TESTS
 	help
 	  If you want to run tests on the iio-rescale code say Y here.
diff --git a/drivers/iio/test/Makefile b/drivers/iio/test/Makefile
index f15ae0a6394f..880360f8d02c 100644
--- a/drivers/iio/test/Makefile
+++ b/drivers/iio/test/Makefile
@@ -4,6 +4,6 @@
 #
 
 # Keep in alphabetical order
-obj-$(CONFIG_IIO_RESCALE_KUNIT_TEST) += iio-test-rescale.o ../afe/iio-rescale.o
+obj-$(CONFIG_IIO_RESCALE_KUNIT_TEST) += iio-test-rescale.o
 obj-$(CONFIG_IIO_TEST_FORMAT) += iio-test-format.o
 CFLAGS_iio-test-format.o += $(DISABLE_STRUCTLEAK_PLUGIN)

I'll send a patch as soon as you confirm this works for you too.

Cheers,
Liam

> 
> > 
> >>
> >> Thanks.
> >>
> >> On 5/20/22 20:51, Randy Dunlap wrote:
> >>> Ok, one more.
> >>> [also adding Liam here]
> >>>
> >>> On 5/20/22 20:17, Randy Dunlap wrote:
> >>>>
> >>>>
> >>>> On 5/20/22 20:08, Randy Dunlap wrote:
> >>>>>
> >>>>>
> >>>>> On 5/20/22 19:40, Randy Dunlap wrote:
> >>>>>> Hi,
> >>>>>>
> >>>>>> In March I reported that a randconfig build complained:
> >>>>>>
> >>>>>> ERROR: modpost: missing MODULE_LICENSE() in drivers/iio/afe/iio-rescale.o
> >>>>>>
> >>>>>> (https://lore.kernel.org/all/16509fb6-e40c-e31b-2c80-264c44b0beb9@infradead.org/)
> >>>>>>
> >>>>>> I am still seeing this problem so I tried to dig into it a bit.
> >>>>>> However, I don't see why get_next_modinfo() and friends don't find the
> >>>>>> MODULE_LICENSE() since it is in the iio-rescale.o file.
> >>>>>>
> >>>>>> (BTW, I see this build error on many different $ARCH [around 15 tested]
> >>>>>> and with 2 different versions of GCC.)
> >>>>>>
> >>>>>> Q1: Is modpost checking both vmlinux and iio-rescale.o for modinfo license
> >>>>>> strings?
> >>>>>>
> >>>>>> It looks like it is, because it appears (?) that modpost is looking at
> >>>>>> drivers/iio/test/iio-test-rescale.o (<<<<< a kunit test, which is builtin
> >>>>>> in my .config) and at drivers/iio/afe/iio-rescale.o (which is built as a
> >>>>>> loadable module).
> >>>>>>
> >>>>>> Is this confusing modpost?
> >>>>>> I renamed drivers/iio/afe/iio-rescale.c to afe-rescale.c and changed its
> >>>>>> Makefile entry accordingly and the MODULE_LICENSE error goes away.
> >>>>>
> >>>>> Oh well. This rename causes drivers/iio/test/iio-test-rescale.c to have
> >>>>> build errors, so that's not a solution, just some info...
> >>>>
> >>>> and that was due to not updating drivers/iio/test/Makefile.
> >>>> When that is done, the missing MODULE_LICENSE() is back in afe-rescale.o.
> >>>>
> >>>>>
> >>>>>> Is this a modpost error or is kunit messing things up?
> >>>>>>
> >>>>>> thanks for looking.
> >>>
> >>> Does this look OK? It allows afe/iio-rescale.o to build XOR
> >>> test/iio-rescale.o (not both of them).
> >>>
> >>> --- a/drivers/iio/test/Kconfig
> >>> +++ b/drivers/iio/test/Kconfig
> >>> @@ -6,7 +6,7 @@
> >>>  # Keep in alphabetical order
> >>>  config IIO_RESCALE_KUNIT_TEST
> >>>         bool "Test IIO rescale conversion functions"
> >>> -       depends on KUNIT=y && !IIO_RESCALE
> >>> +       depends on KUNIT=y && IIO_RESCALE=n
> >>>         default KUNIT_ALL_TESTS
> >>>         help
> >>>           If you want to run tests on the iio-rescale code say Y here.
> >>>
> >>>
> >>
> >> -- 
> >> ~Randy
> 
> -- 
> ~Randy