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Message-ID: <c68e9299e755b38c38d63d8cb121800639f5e07a.camel@redhat.com>
Subject: Re: [PATCH] selftests/net/tcp-ao: Use LDLIBS instead of LDFLAGS
From: Paolo Abeni <pabeni@redhat.com>
To: Dmitry Safonov <dima@arista.com>, "David S. Miller"
 <davem@davemloft.net>,  Eric Dumazet <edumazet@google.com>, Jakub Kicinski
 <kuba@kernel.org>, Shuah Khan <shuah@kernel.org>
Cc: netdev@vger.kernel.org, linux-kselftest@vger.kernel.org, 
 linux-kernel@vger.kernel.org, kernel test robot <lkp@intel.com>, Dmitry
 Safonov <0x7f454c46@gmail.com>
Date: Thu, 11 Jan 2024 15:42:02 +0100
In-Reply-To: <20240110-tcp_ao-selftests-makefile-v1-1-aa07d043f052@arista.com>
References: 
	<20240110-tcp_ao-selftests-makefile-v1-1-aa07d043f052@arista.com>
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On Wed, 2024-01-10 at 21:34 +0000, Dmitry Safonov wrote:
> The rules to link selftests are:
>=20
> > $(OUTPUT)/%_ipv4: %.c
> > 	$(LINK.c) $^ $(LDLIBS) -o $@
> >=20
> > $(OUTPUT)/%_ipv6: %.c
> > 	$(LINK.c) -DIPV6_TEST $^ $(LDLIBS) -o $@
>=20
> The intel test robot uses only selftest's Makefile, not the top linux
> Makefile:
>=20
> > make W=3D1 O=3D/tmp/kselftest -C tools/testing/selftests
>=20
> So, $(LINK.c) is determined by environment, rather than by kernel
> Makefiles. On my machine (as well as other people that ran tcp-ao
> selftests) GNU/Make implicit definition does use $(LDFLAGS):
>=20
> > [dima@Mindolluin ~]$ make -p -f/dev/null | grep '^LINK.c\>'
> > make: *** No targets.  Stop.
> > LINK.c =3D $(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) $(TARGET_ARCH)
>=20
> But, according to build robot report, it's not the case for them.
> While I could just avoid using pre-defined $(LINK.c), it's also used by
> selftests/lib.mk by default.
>=20
> Anyways, according to GNU/Make documentation [1], I should have used
> $(LDLIBS) instead of $(LDFLAGS) in the first place, so let's just do it:
>=20
> > LDFLAGS
> >     Extra flags to give to compilers when they are supposed to invoke
> >     the linker, =E2=80=98ld=E2=80=99, such as -L. Libraries (-lfoo) sho=
uld be added
> >     to the LDLIBS variable instead.
> > LDLIBS
> >     Library flags or names given to compilers when they are supposed
> >     to invoke the linker, =E2=80=98ld=E2=80=99. LOADLIBES is a deprecat=
ed (but still
> >     supported) alternative to LDLIBS. Non-library linker flags, such
> >     as -L, should go in the LDFLAGS variable.
>=20
> [1]: https://www.gnu.org/software/make/manual/html_node/Implicit-Variable=
s.html
>=20
> Fixes: cfbab37b3da0 ("selftests/net: Add TCP-AO library")
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202401011151.veyYTJzq-lkp@i=
ntel.com/
> Signed-off-by: Dmitry Safonov <dima@arista.com>

Acked-by: Paolo Abeni <pabeni@redhat.com>