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From:   Vlad Dronov <vdronov@redhat.com>
Date:   Mon, 4 Jul 2022 17:24:22 +0200
Message-ID: <CAMusb+QJ3yvEF8rUQ7=4Xf4dGG3Bs_ZOb2muJPKQ9ftXO+mX5g@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 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> wrote=
:
> > > ...
> > > config: s390-buildonly-randconfig-r005-20220703 (https://download.01.=
org/0day-ci/archive/20220703/202207030630.6SZVkrWf-lkp@intel.com/config)
> > > ...
> > >    s390-linux-ld: lib/crypto/chacha20poly1305.o: in function `chacha_=
crypt':
> > > >> include/crypto/chacha.h:100: undefined reference to `chacha_crypt_=
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_CHACHA2=
0POLY1305
> > >    Depends on (CRYPTO_ARCH_HAVE_LIB_CHACHA || !CRYPTO_ARCH_HAVE_LIB_C=
HACHA && (CRYPTO_ARCH_HAVE_LIB_POLY1305 || !CRYPTO_ARCH_HAVE_LIB_POLY1305 &=
& CRYPTO
> >
> > Ok, this is either weird or I do not understand how the Kconfig system =
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 vers=
ion)"
> >     depends on CRYPTO_ARCH_HAVE_LIB_CHACHA || !CRYPTO_ARCH_HAVE_LIB_CHA=
CHA
> >     depends on CRYPTO_ARCH_HAVE_LIB_POLY1305 || !CRYPTO_ARCH_HAVE_LIB_P=
OLY1305
> >     depends on CRYPTO
> >
> > and this test's random config (s390-buildonly-randconfig-r005-20220703)=
:
> >
> > $ 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 dependenci=
es 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_CHACHA20POLY13=
05 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.

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