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From:   Vlad Dronov <vdronov@redhat.com>
Date:   Mon, 4 Jul 2022 17:42:10 +0200
Message-ID: <CAMusb+Rr9_TBLad1UQN52nWBN48j8V1c8GmMPNz=ezsEZfGKOg@mail.gmail.com>
Subject: Re: include/crypto/chacha.h:100: undefined reference to `chacha_crypt_arch'
To:     kernel test robot <lkp@intel.com>
Cc:     kbuild-all@lists.01.org, LKML <linux-kernel@vger.kernel.org>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Harald Freudenberger <freude@linux.ibm.com>
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Hi,

On Mon, Jul 4, 2022 at 5:24 PM Vlad Dronov <vdronov@redhat.com> wrote:
>
> Hi,
>
> On Mon, Jul 4, 2022 at 4:58 PM Vlad Dronov <vdronov@redhat.com> wrote:
> >
> > Hi,
> >
> > On Mon, Jul 4, 2022 at 4:35 PM Vlad Dronov <vdronov@redhat.com> wrote:
> > >
> > > Hi,
> > >
> > > On Sun, Jul 3, 2022 at 12:51 AM kernel test robot <lkp@intel.com> wro=
te:
> > > > ...
> > > > config: s390-buildonly-randconfig-r005-20220703 (https://download.0=
1.org/0day-ci/archive/20220703/202207030630.6SZVkrWf-lkp@intel.com/config)
> > > > ...
> > > >    s390-linux-ld: lib/crypto/chacha20poly1305.o: in function `chach=
a_crypt':
> > > > >> include/crypto/chacha.h:100: undefined reference to `chacha_cryp=
t_arch'
> > > > >> s390-linux-ld: include/crypto/chacha.h:100: undefined reference =
to `chacha_crypt_arch'
> > > > ...
> > > > Kconfig warnings: (for reference only)
> > > >    WARNING: unmet direct dependencies detected for CRYPTO_LIB_CHACH=
A20POLY1305
> > > >    Depends on (CRYPTO_ARCH_HAVE_LIB_CHACHA || !CRYPTO_ARCH_HAVE_LIB=
_CHACHA && (CRYPTO_ARCH_HAVE_LIB_POLY1305 || !CRYPTO_ARCH_HAVE_LIB_POLY1305=
 && CRYPTO
> > >
> > > Ok, this is either weird or I do not understand how the Kconfig syste=
m works.
> > >
> > > What I look at is CRYPTO_LIB_CHACHA20POLY1305 definition:
> > >
> > > [ lib/crypto/Kconfig ]
> > > config CRYPTO_LIB_CHACHA20POLY1305
> > >     tristate "ChaCha20-Poly1305 AEAD support (8-byte nonce library ve=
rsion)"
> > >     depends on CRYPTO_ARCH_HAVE_LIB_CHACHA || !CRYPTO_ARCH_HAVE_LIB_C=
HACHA
> > >     depends on CRYPTO_ARCH_HAVE_LIB_POLY1305 || !CRYPTO_ARCH_HAVE_LIB=
_POLY1305
> > >     depends on CRYPTO
> > >
> > > and this test's random config (s390-buildonly-randconfig-r005-2022070=
3):
> > >
> > > $ grep -e CRYPTO_LIB_CHACHA20POLY1305 -e CRYPTO_ARCH_HAVE_LIB_CHACHA
> > > -e CRYPTO_ARCH_HAVE_LIB_POLY1305 -e CRYPTO=3D config
> > > CONFIG_CRYPTO=3Dy
> > > CONFIG_CRYPTO_ARCH_HAVE_LIB_CHACHA=3Dm
> > > CONFIG_CRYPTO_LIB_CHACHA20POLY1305=3Dy
> > > // missing CRYPTO_ARCH_HAVE_LIB_POLY1305 implies =3Dn (I guess?)
> > >
> > > I'm following the canonical "Kconfig Language" doc (
> > > https://www.kernel.org/doc/html/latest/kbuild/kconfig-language.html )
> > > which states:
> > >
> > > > - dependencies: =E2=80=9Cdepends on=E2=80=9D <expr>
> > > > This defines a dependency for this menu entry. If multiple dependen=
cies are defined, they are connected with =E2=80=98&&=E2=80=99.
> > >
> > > and
> > >
> > > >         '!' <expr>                           (6)
> > > >         <expr> '&&' <expr>                   (7)
> > > >         <expr> '||' <expr>                   (8)
> > > >
> > > > 6. Returns the result of (2-/expr/).
> > > > 7. Returns the result of min(/expr/, /expr/).
> > > > 8. Returns the result of max(/expr/, /expr/).
> > > > An expression can have a value of =E2=80=98n=E2=80=99, =E2=80=98m=
=E2=80=99 or =E2=80=98y=E2=80=99 (or 0, 1, 2 respectively for calculations)=
.
> > >
> > > So calculating:
> > >
> > > (CRYPTO_ARCH_HAVE_LIB_CHACHA || !CRYPTO_ARCH_HAVE_LIB_CHACHA) &&
> > > (CRYPTO_ARCH_HAVE_LIB_POLY1305 || !CRYPTO_ARCH_HAVE_LIB_POLY1305) &&
> > > CRYPTO
> > >
> > > I find it equal to:
> > >
> > > (m || !m) && (n || !n) && y  =3D>  m && y && y  =3D>  m
> > >
> > > So CRYPTO_LIB_CHACHA20POLY1305 should be no higher than M, but it is
> > > =3DY in a config file =3D> weird :\ (or me wrong somewhere).
> > >
> > > WDYT?
> >
> > Ok, I should have tested this beforehand. With the configs set as above=
:
> >
> > CONFIG_CRYPTO=3Dy
> > CONFIG_CRYPTO_CHACHA20_X86_64=3Dm // implies the next line =3Dm
> > CONFIG_CRYPTO_ARCH_HAVE_LIB_CHACHA=3Dm
> > CONFIG_CRYPTO_ARCH_HAVE_LIB_POLY1305 is not set // =3Dn
> >
> > "make menuconfig" allows only =3Dn and =3Dm for CRYPTO_LIB_CHACHA20POLY=
1305 indeed.
> > So the test robot has fed an invalid config to a build process. Let me
> > forward this thread to lkp@lists.01.org to report this issue.
>
> Hi,
>
> False alarm, I apologize.
>
> CRYPTO_LIB_CHACHA20POLY1305=3Dy was selected by CONFIG_WIREGUARD=3Dy:
>
> config WIREGUARD
>     tristate "WireGuard secure network tunnel"
>     depends on NET && INET
>     depends on IPV6 || !IPV6
>     select CRYPTO_LIB_CHACHA20POLY1305
>
> $ grep -e CONFIG_WIREGUARD=3D -e CONFIG_NETDEVICES=3D -e CONFIG_NET_CORE=
=3D
> -e CONFIG_NET=3D -e CONFIG_INET=3D -e CONFIG_IPV6=3D config
> CONFIG_NET=3Dy
> CONFIG_INET=3Dy
> CONFIG_IPV6=3Dy
> CONFIG_NETDEVICES=3Dy
> CONFIG_NET_CORE=3Dy
> CONFIG_WIREGUARD=3Dy
>
> This breaks the "In general use select only for non-visible symbols
> (no prompts anywhere)
> and for symbols with no dependencies" rules from the "Kconfig
> Language" doc, but I'm not
> sure how to proceed from here.

JFYI: fed with a config in question, "make menuconfig" just silently change=
s
CONFIG_CRYPTO_CHACHA_S390=3Dm to =3Dy
and, accordingly,
CONFIG_CRYPTO_ARCH_HAVE_LIB_CHACHA=3Dm to =3Dy
thus allowing a correct build.

Still not sure how to proceed from here with this clarification above.

Best regards,
Vladis Dronov | Red Hat, Inc. | The Core Kernel | Senior Software Engineer