Subject: Re: [PATCH 1/2] selftests: cgroup: build error multiple outpt files
To:     Christian Brauner <christian.brauner@ubuntu.com>
Cc:     Anders Roxell <anders.roxell@linaro.org>, shuah@kernel.org,
        christian@brauner.io, 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>
 <61b21c4b-fc26-5e41-3aed-22a7e56b04ba@linuxfoundation.org>
 <20211123142600.r5d52iwhbqhujiux@wittgenstein>
From:   Shuah Khan <skhan@linuxfoundation.org>
Message-ID: <815f4089-49e0-aada-aaf4-83fb079abef7@linuxfoundation.org>
Date:   Tue, 30 Nov 2021 09:41:49 -0700
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On 11/23/21 7:26 AM, Christian Brauner wrote:
> On Fri, Nov 19, 2021 at 05:22:20PM -0700, Shuah Khan wrote:
>> 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.
> 
> The cgroup tests need access to clone3() functionality in order to test
> CLONE_INTO_CGROUP which is more suited to be placed alongside the cgroup
> tests. There are a few other tests that include the clone3 header.
> 

If other tests are also including this header, we could move it up under
selftests level. Might have to add include directory.

thanks,
-- Shuah