The rules to link selftests are:

$(OUTPUT)/%_ipv4: %.c $(LINK.c) $^ $(LDLIBS) -o $@

$(OUTPUT)/%_ipv6: %.c $(LINK.c) -DIPV6_TEST $^ $(LDLIBS) -o $@

The intel test robot uses only selftest's Makefile, not the top linux Makefile:

make W=1 O=/tmp/kselftest -C tools/testing/selftests

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):

[dima@Mindolluin ~]$ make -p -f/dev/null | grep '^LINK.c>' make: *** No targets. Stop. LINK.c = $(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) $(TARGET_ARCH)

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.

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:

LDFLAGS Extra flags to give to compilers when they are supposed to invoke the linker, ‘ld’, such as -L. Libraries (-lfoo) should be added to the LDLIBS variable instead. LDLIBS Library flags or names given to compilers when they are supposed to invoke the linker, ‘ld’. LOADLIBES is a deprecated (but still supported) alternative to LDLIBS. Non-library linker flags, such as -L, should go in the LDFLAGS variable.

[1]: https://www.gnu.org/software/make/manual/html_node/Implicit-Variables.html

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@intel.com/ Signed-off-by: Dmitry Safonov dima@arista.com --- tools/testing/selftests/net/tcp_ao/Makefile | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/net/tcp_ao/Makefile b/tools/testing/selftests/net/tcp_ao/Makefile index 8e60bae67aa9..522d991e310e 100644 --- a/tools/testing/selftests/net/tcp_ao/Makefile +++ b/tools/testing/selftests/net/tcp_ao/Makefile @@ -52,5 +52,5 @@ $(OUTPUT)/%_ipv6: %.c

$(OUTPUT)/icmps-accept_ipv4: CFLAGS+= -DTEST_ICMPS_ACCEPT $(OUTPUT)/icmps-accept_ipv6: CFLAGS+= -DTEST_ICMPS_ACCEPT -$(OUTPUT)/bench-lookups_ipv4: LDFLAGS+= -lm -$(OUTPUT)/bench-lookups_ipv6: LDFLAGS+= -lm +$(OUTPUT)/bench-lookups_ipv4: LDLIBS+= -lm +$(OUTPUT)/bench-lookups_ipv6: LDLIBS+= -lm

--- base-commit: 8cb47d7cd090a690c1785385b2f3d407d4a53ad0 change-id: 20240110-tcp_ao-selftests-makefile-3dafb1e96df8

Best regards,