Subject: Re: [PATCH 1/2] selftests: cgroup: build error multiple outpt files
To:     Anders Roxell <anders.roxell@linaro.org>, shuah@kernel.org,
        christian@brauner.io
Cc:     nathan@kernel.org, ndesaulniers@google.com,
        linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
        llvm@lists.linux.dev, Arnd Bergmann <arnd@arndb.de>,
        Shuah Khan <skhan@linuxfoundation.org>
References: <20211105162530.3307666-1-anders.roxell@linaro.org>
From:   Shuah Khan <skhan@linuxfoundation.org>
Message-ID: <61b21c4b-fc26-5e41-3aed-22a7e56b04ba@linuxfoundation.org>
Date:   Fri, 19 Nov 2021 17:22:20 -0700
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On 11/5/21 10:25 AM, Anders Roxell wrote:
> When building selftests/cgroup: with clang the following error are seen:
> 
> clang -Wall -pthread    test_memcontrol.c cgroup_util.c ../clone3/clone3_selftests.h  -o /home/anders/.cache/tuxmake/builds/current/kselftest/cgroup/test_memcontrol
> clang: error: cannot specify -o when generating multiple output files
> make[3]: *** [../lib.mk:146: /home/anders/.cache/tuxmake/builds/current/kselftest/cgroup/test_memcontrol] Error 1
> 
> Rework to add the header files to LOCAL_HDRS before including ../lib.mk,
> since the dependency is evaluated in '$(OUTPUT)/%:%.c $(LOCAL_HDRS)' in
> file lib.mk.
> 
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
> ---
>   tools/testing/selftests/cgroup/Makefile | 12 +++++++-----
>   tools/testing/selftests/lib.mk          |  2 +-
>   2 files changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/tools/testing/selftests/cgroup/Makefile b/tools/testing/selftests/cgroup/Makefile
> index 59e222460581..745fe25fa0b9 100644
> --- a/tools/testing/selftests/cgroup/Makefile
> +++ b/tools/testing/selftests/cgroup/Makefile
> @@ -11,10 +11,12 @@ TEST_GEN_PROGS += test_core
>   TEST_GEN_PROGS += test_freezer
>   TEST_GEN_PROGS += test_kill
>   
> +LOCAL_HDRS += $(selfdir)/clone3/clone3_selftests.h $(selfdir)/pidfd/pidfd.h
> +

This looks odd to me. Why are we introducing dependencies between tests?
clone3 includes in cgroup? Looks odd to me.

thanks,
-- Shuah