diff mbox series

[2/3] selftests: seccomp: use LDLIBS instead of LDFLAGS

Message ID 20170628170859.28583-3-fathi.boudra@linaro.org
State Superseded
Headers show
Series selftests: fixes for undefined reference (LDFLAGS -> LDLIBS) | expand

Commit Message

Fathi Boudra June 28, 2017, 5:08 p.m. UTC
seccomp_bpf fails to build due to undefined reference errors:

 aarch64-linaro-linux-gcc --sysroot=/build/tmp-rpb-glibc/sysroots/hikey
 -O2 -pipe -g -feliminate-unused-debug-types -Wl,-no-as-needed -Wall
 -Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed -lpthread seccomp_bpf.c -o
 /build/tmp-rpb-glibc/work/hikey-linaro-linux/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf
 /tmp/ccrlR3MW.o: In function `tsync_sibling':
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1920: undefined reference to `sem_post'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1920: undefined reference to `sem_post'
 /tmp/ccrlR3MW.o: In function `TSYNC_setup':
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1863: undefined reference to `sem_init'
 /tmp/ccrlR3MW.o: In function `TSYNC_teardown':
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1904: undefined reference to `sem_destroy'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1897: undefined reference to `pthread_kill'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1898: undefined reference to `pthread_cancel'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1899: undefined reference to `pthread_join'
 /tmp/ccrlR3MW.o: In function `tsync_start_sibling':
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'
 /tmp/ccrlR3MW.o: In function `TSYNC_siblings_fail_prctl':
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1978: undefined reference to `sem_wait'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1990: undefined reference to `pthread_join'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1992: undefined reference to `pthread_join'
 /tmp/ccrlR3MW.o: In function `tsync_start_sibling':
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'
 /tmp/ccrlR3MW.o: In function `TSYNC_two_siblings_with_ancestor':
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2016: undefined reference to `sem_wait'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2032: undefined reference to `pthread_join'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2034: undefined reference to `pthread_join'
 /tmp/ccrlR3MW.o: In function `tsync_start_sibling':
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'
 /tmp/ccrlR3MW.o: In function `TSYNC_two_sibling_want_nnp':
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2046: undefined reference to `sem_wait'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2058: undefined reference to `pthread_join'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2060: undefined reference to `pthread_join'
 /tmp/ccrlR3MW.o: In function `tsync_start_sibling':
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'
 /tmp/ccrlR3MW.o: In function `TSYNC_two_siblings_with_no_filter':
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2073: undefined reference to `sem_wait'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2098: undefined reference to `pthread_join'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2100: undefined reference to `pthread_join'
 /tmp/ccrlR3MW.o: In function `tsync_start_sibling':
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'
 /tmp/ccrlR3MW.o: In function `TSYNC_two_siblings_with_one_divergence':
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2125: undefined reference to `sem_wait'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2143: undefined reference to `pthread_join'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2145: undefined reference to `pthread_join'
 /tmp/ccrlR3MW.o: In function `tsync_start_sibling':
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'
 /tmp/ccrlR3MW.o: In function `TSYNC_two_siblings_not_under_filter':
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2169: undefined reference to `sem_wait'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2202: undefined reference to `pthread_join'
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2227: undefined reference to `pthread_join'
 /tmp/ccrlR3MW.o: In function `tsync_start_sibling':
 /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

It's GNU Make and linker specific.

The default Makefile rule looks like:

$(CC) $(CFLAGS) $(LDFLAGS) $@ $^ $(LDLIBS)

When linking is done by gcc itself, no issue, but when it needs to be passed
to proper ld, only LDLIBS follows and then ld cannot know what libs to link
with.

More detail:
https://www.gnu.org/software/make/manual/html_node/Implicit-Variables.html

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.

https://lkml.org/lkml/2010/2/10/362

tools/perf: libraries must come after objects

Link order matters, use LDLIBS instead of LDFLAGS to properly link against
libpthread.

Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>

---
 tools/testing/selftests/seccomp/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

-- 
2.13.0

Comments

SeongJae Park June 28, 2017, 9:40 p.m. UTC | #1
Hi Fathi,

On Wed, 28 Jun 2017, Fathi Boudra wrote:

> seccomp_bpf fails to build due to undefined reference errors:

>

>  aarch64-linaro-linux-gcc --sysroot=/build/tmp-rpb-glibc/sysroots/hikey

>  -O2 -pipe -g -feliminate-unused-debug-types -Wl,-no-as-needed -Wall

>  -Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed -lpthread seccomp_bpf.c -o

>  /build/tmp-rpb-glibc/work/hikey-linaro-linux/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf

>  /tmp/ccrlR3MW.o: In function `tsync_sibling':

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1920: undefined reference to `sem_post'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1920: undefined reference to `sem_post'

>  /tmp/ccrlR3MW.o: In function `TSYNC_setup':

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1863: undefined reference to `sem_init'

>  /tmp/ccrlR3MW.o: In function `TSYNC_teardown':

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1904: undefined reference to `sem_destroy'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1897: undefined reference to `pthread_kill'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1898: undefined reference to `pthread_cancel'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1899: undefined reference to `pthread_join'

>  /tmp/ccrlR3MW.o: In function `tsync_start_sibling':

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>  /tmp/ccrlR3MW.o: In function `TSYNC_siblings_fail_prctl':

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1978: undefined reference to `sem_wait'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1990: undefined reference to `pthread_join'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1992: undefined reference to `pthread_join'

>  /tmp/ccrlR3MW.o: In function `tsync_start_sibling':

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>  /tmp/ccrlR3MW.o: In function `TSYNC_two_siblings_with_ancestor':

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2016: undefined reference to `sem_wait'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2032: undefined reference to `pthread_join'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2034: undefined reference to `pthread_join'

>  /tmp/ccrlR3MW.o: In function `tsync_start_sibling':

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>  /tmp/ccrlR3MW.o: In function `TSYNC_two_sibling_want_nnp':

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2046: undefined reference to `sem_wait'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2058: undefined reference to `pthread_join'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2060: undefined reference to `pthread_join'

>  /tmp/ccrlR3MW.o: In function `tsync_start_sibling':

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>  /tmp/ccrlR3MW.o: In function `TSYNC_two_siblings_with_no_filter':

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2073: undefined reference to `sem_wait'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2098: undefined reference to `pthread_join'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2100: undefined reference to `pthread_join'

>  /tmp/ccrlR3MW.o: In function `tsync_start_sibling':

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>  /tmp/ccrlR3MW.o: In function `TSYNC_two_siblings_with_one_divergence':

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2125: undefined reference to `sem_wait'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2143: undefined reference to `pthread_join'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2145: undefined reference to `pthread_join'

>  /tmp/ccrlR3MW.o: In function `tsync_start_sibling':

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>  /tmp/ccrlR3MW.o: In function `TSYNC_two_siblings_not_under_filter':

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2169: undefined reference to `sem_wait'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2202: undefined reference to `pthread_join'

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2227: undefined reference to `pthread_join'

>  /tmp/ccrlR3MW.o: In function `tsync_start_sibling':

>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>

> It's GNU Make and linker specific.

>

> The default Makefile rule looks like:

>

> $(CC) $(CFLAGS) $(LDFLAGS) $@ $^ $(LDLIBS)

>

> When linking is done by gcc itself, no issue, but when it needs to be passed

> to proper ld, only LDLIBS follows and then ld cannot know what libs to link

> with.

>

> More detail:

> https://www.gnu.org/software/make/manual/html_node/Implicit-Variables.html

>

> 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.

>

> https://lkml.org/lkml/2010/2/10/362

>

> tools/perf: libraries must come after objects

>

> Link order matters, use LDLIBS instead of LDFLAGS to properly link against

> libpthread.

>

> Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>

> ---

>  tools/testing/selftests/seccomp/Makefile | 4 ++--

>  1 file changed, 2 insertions(+), 2 deletions(-)

>

> diff --git a/tools/testing/selftests/seccomp/Makefile b/tools/testing/selftests/seccomp/Makefile

> index aeb0c805f3ca..d1c74ce70f08 100644

> --- a/tools/testing/selftests/seccomp/Makefile

> +++ b/tools/testing/selftests/seccomp/Makefile

> @@ -1,8 +1,8 @@

>  TEST_GEN_PROGS := seccomp_bpf

>  CFLAGS += -Wl,-no-as-needed -Wall

> -LDFLAGS += -lpthread

> +LDLIBS += -lpthread

>

>  include ../lib.mk

>

>  $(TEST_GEN_PROGS): seccomp_bpf.c ../kselftest_harness.h

> -	$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@

> +	$(CC) $(CFLAGS) $(LDLIBS) $< -o $@


Shouldn't $(LDLIBS) follow $< ?


Thanks,
SeongJae Park

> --

> 2.13.0

>

>
Fathi Boudra June 29, 2017, 7:02 a.m. UTC | #2
On 29 June 2017 at 00:40, sjpark <sj38.park@gmail.com> wrote:
> Hi Fathi,

>

> On Wed, 28 Jun 2017, Fathi Boudra wrote:

>

>> seccomp_bpf fails to build due to undefined reference errors:

>>

>>  aarch64-linaro-linux-gcc --sysroot=/build/tmp-rpb-glibc/sysroots/hikey

>>  -O2 -pipe -g -feliminate-unused-debug-types -Wl,-no-as-needed -Wall

>>  -Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed -lpthread seccomp_bpf.c -o

>>  /build/tmp-rpb-glibc/work/hikey-linaro-linux/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf

>>  /tmp/ccrlR3MW.o: In function `tsync_sibling':

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1920: undefined reference to `sem_post'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1920: undefined reference to `sem_post'

>>  /tmp/ccrlR3MW.o: In function `TSYNC_setup':

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1863: undefined reference to `sem_init'

>>  /tmp/ccrlR3MW.o: In function `TSYNC_teardown':

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1904: undefined reference to `sem_destroy'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1897: undefined reference to `pthread_kill'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1898: undefined reference to `pthread_cancel'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1899: undefined reference to `pthread_join'

>>  /tmp/ccrlR3MW.o: In function `tsync_start_sibling':

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>>  /tmp/ccrlR3MW.o: In function `TSYNC_siblings_fail_prctl':

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1978: undefined reference to `sem_wait'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1990: undefined reference to `pthread_join'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1992: undefined reference to `pthread_join'

>>  /tmp/ccrlR3MW.o: In function `tsync_start_sibling':

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>>  /tmp/ccrlR3MW.o: In function `TSYNC_two_siblings_with_ancestor':

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2016: undefined reference to `sem_wait'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2032: undefined reference to `pthread_join'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2034: undefined reference to `pthread_join'

>>  /tmp/ccrlR3MW.o: In function `tsync_start_sibling':

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>>  /tmp/ccrlR3MW.o: In function `TSYNC_two_sibling_want_nnp':

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2046: undefined reference to `sem_wait'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2058: undefined reference to `pthread_join'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2060: undefined reference to `pthread_join'

>>  /tmp/ccrlR3MW.o: In function `tsync_start_sibling':

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>>  /tmp/ccrlR3MW.o: In function `TSYNC_two_siblings_with_no_filter':

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2073: undefined reference to `sem_wait'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2098: undefined reference to `pthread_join'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2100: undefined reference to `pthread_join'

>>  /tmp/ccrlR3MW.o: In function `tsync_start_sibling':

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>>  /tmp/ccrlR3MW.o: In function `TSYNC_two_siblings_with_one_divergence':

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2125: undefined reference to `sem_wait'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2143: undefined reference to `pthread_join'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2145: undefined reference to `pthread_join'

>>  /tmp/ccrlR3MW.o: In function `tsync_start_sibling':

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>>  /tmp/ccrlR3MW.o: In function `TSYNC_two_siblings_not_under_filter':

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2169: undefined reference to `sem_wait'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2202: undefined reference to `pthread_join'

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:2227: undefined reference to `pthread_join'

>>  /tmp/ccrlR3MW.o: In function `tsync_start_sibling':

>>  /usr/src/debug/kselftests/4.12-r0/linux-4.12-rc7/tools/testing/selftests/seccomp/seccomp_bpf.c:1941: undefined reference to `pthread_create'

>>

>> It's GNU Make and linker specific.

>>

>> The default Makefile rule looks like:

>>

>> $(CC) $(CFLAGS) $(LDFLAGS) $@ $^ $(LDLIBS)

>>

>> When linking is done by gcc itself, no issue, but when it needs to be passed

>> to proper ld, only LDLIBS follows and then ld cannot know what libs to link

>> with.

>>

>> More detail:

>> https://www.gnu.org/software/make/manual/html_node/Implicit-Variables.html

>>

>> 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.

>>

>> https://lkml.org/lkml/2010/2/10/362

>>

>> tools/perf: libraries must come after objects

>>

>> Link order matters, use LDLIBS instead of LDFLAGS to properly link against

>> libpthread.

>>

>> Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>

>> ---

>>  tools/testing/selftests/seccomp/Makefile | 4 ++--

>>  1 file changed, 2 insertions(+), 2 deletions(-)

>>

>> diff --git a/tools/testing/selftests/seccomp/Makefile b/tools/testing/selftests/seccomp/Makefile

>> index aeb0c805f3ca..d1c74ce70f08 100644

>> --- a/tools/testing/selftests/seccomp/Makefile

>> +++ b/tools/testing/selftests/seccomp/Makefile

>> @@ -1,8 +1,8 @@

>>  TEST_GEN_PROGS := seccomp_bpf

>>  CFLAGS += -Wl,-no-as-needed -Wall

>> -LDFLAGS += -lpthread

>> +LDLIBS += -lpthread

>>

>>  include ../lib.mk

>>

>>  $(TEST_GEN_PROGS): seccomp_bpf.c ../kselftest_harness.h

>> -     $(CC) $(CFLAGS) $(LDFLAGS) $< -o $@

>> +     $(CC) $(CFLAGS) $(LDLIBS) $< -o $@

>

> Shouldn't $(LDLIBS) follow $< ?


Good catch. Thanks, will add to v3.

>

> Thanks,

> SeongJae Park

>

>> --

>> 2.13.0

>>

>>
diff mbox series

Patch

diff --git a/tools/testing/selftests/seccomp/Makefile b/tools/testing/selftests/seccomp/Makefile
index aeb0c805f3ca..d1c74ce70f08 100644
--- a/tools/testing/selftests/seccomp/Makefile
+++ b/tools/testing/selftests/seccomp/Makefile
@@ -1,8 +1,8 @@ 
 TEST_GEN_PROGS := seccomp_bpf
 CFLAGS += -Wl,-no-as-needed -Wall
-LDFLAGS += -lpthread
+LDLIBS += -lpthread
 
 include ../lib.mk
 
 $(TEST_GEN_PROGS): seccomp_bpf.c ../kselftest_harness.h
-	$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
+	$(CC) $(CFLAGS) $(LDLIBS) $< -o $@