[3/4] selftests: seccomp: use LDLIBS instead of LDFLAGS

Message ID 20190116174320.14938-3-daniel.diaz@linaro.org
State New
Headers show
Series
  • [1/4] selftests: lib: allow to override CC in the top-level Makefile
Related show

Commit Message

Daniel Díaz Jan. 16, 2019, 5:43 p.m.
From: Fathi Boudra <fathi.boudra@linaro.org>


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 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
2.17.1

Comments

Kees Cook Jan. 16, 2019, 6:13 p.m. | #1
On Wed, Jan 16, 2019 at 9:44 AM Daniel Díaz <daniel.diaz@linaro.org> wrote:
>

> From: Fathi Boudra <fathi.boudra@linaro.org>

>

> 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>


Acked-by: Kees Cook <keescook@chromium.org>


Shuah, can you take this?

-Kees

> ---

>  tools/testing/selftests/seccomp/Makefile | 2 +-

>  1 file changed, 1 insertion(+), 1 deletion(-)

>

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

> index fce7f4ce0692..1760b3e39730 100644

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

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

> @@ -9,7 +9,7 @@ BINARIES := seccomp_bpf seccomp_benchmark

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

>

>  seccomp_bpf: seccomp_bpf.c ../kselftest_harness.h

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

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

>

>  TEST_PROGS += $(BINARIES)

>  EXTRA_CLEAN := $(BINARIES)

> --

> 2.17.1

>



-- 
Kees Cook
shuah Jan. 16, 2019, 6:26 p.m. | #2
On 1/16/19 11:13 AM, Kees Cook wrote:
> On Wed, Jan 16, 2019 at 9:44 AM Daniel Díaz <daniel.diaz@linaro.org> wrote:

>>

>> From: Fathi Boudra <fathi.boudra@linaro.org>

>>

>> 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>

> 


Thanks for the patch.

> Acked-by: Kees Cook <keescook@chromium.org>

> 

> Shuah, can you take this?

> 


Thanks for Ack. I will get this in for 5.0-rc3 or rc4.

thanks,
-- Shuah

Patch

diff --git a/tools/testing/selftests/seccomp/Makefile b/tools/testing/selftests/seccomp/Makefile
index fce7f4ce0692..1760b3e39730 100644
--- a/tools/testing/selftests/seccomp/Makefile
+++ b/tools/testing/selftests/seccomp/Makefile
@@ -9,7 +9,7 @@  BINARIES := seccomp_bpf seccomp_benchmark
 CFLAGS += -Wl,-no-as-needed -Wall
 
 seccomp_bpf: seccomp_bpf.c ../kselftest_harness.h
-	$(CC) $(CFLAGS) $(LDFLAGS) -lpthread $< -o $@
+	$(CC) $(CFLAGS) $(LDFLAGS) $< -lpthread -o $@
 
 TEST_PROGS += $(BINARIES)
 EXTRA_CLEAN := $(BINARIES)