From: Yonghong Song <yhs@fb.com>
To: <sedat.dilek@gmail.com>
Cc: <bpf@vger.kernel.org>, Andrii Nakryiko <andrii@kernel.org>,
Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>,
<kernel-team@fb.com>, Nick Desaulniers <ndesaulniers@google.com>
Subject: Re: [PATCH bpf-next 4/5] selftests/bpf: silence clang compilation warnings
Date: Sun, 11 Apr 2021 10:40:46 -0700 [thread overview]
Message-ID: <e1c53fa7-f088-da5a-667c-8139ddf887f0@fb.com> (raw)
In-Reply-To: <CA+icZUXZY+dhv+JHnpiz+tkN4T9f2XCd02Btp9QGRfnT2n6qBg@mail.gmail.com>
On 4/11/21 4:12 AM, Sedat Dilek wrote:
> On Sat, Apr 10, 2021 at 6:49 PM Yonghong Song <yhs@fb.com> wrote:
>>
>> With clang compiler:
>> make -j60 LLVM=1 LLVM_IAS=1 <=== compile kernel
>> make -j60 -C tools/testing/selftests/bpf LLVM=1 LLVM_IAS=1
>> Some linker flags are not used/effective for some binaries and
>> we have warnings like:
>> warning: -lelf: 'linker' input unused [-Wunused-command-line-argument]
>>
>> We also have warnings like:
>> .../selftests/bpf/prog_tests/ns_current_pid_tgid.c:74:57: note: treat the string as an argument to avoid this
>> if (CHECK(waitpid(cpid, &wstatus, 0) == -1, "waitpid", strerror(errno)))
>> ^
>> "%s",
>> .../selftests/bpf/test_progs.h:129:35: note: expanded from macro 'CHECK'
>> _CHECK(condition, tag, duration, format)
>> ^
>> .../selftests/bpf/test_progs.h:108:21: note: expanded from macro '_CHECK'
>> fprintf(stdout, ##format); \
>> ^
>> Let us add proper compilation flags to silence the above two kinds of warnings.
>>
>> Signed-off-by: Yonghong Song <yhs@fb.com>
>> ---
>> tools/testing/selftests/bpf/Makefile | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
>> index bbd61cc3889b..a9c0a64a4c49 100644
>> --- a/tools/testing/selftests/bpf/Makefile
>> +++ b/tools/testing/selftests/bpf/Makefile
>> @@ -24,6 +24,8 @@ SAN_CFLAGS ?=
>> CFLAGS += -g -Og -rdynamic -Wall $(GENFLAGS) $(SAN_CFLAGS) \
>> -I$(CURDIR) -I$(INCLUDE_DIR) -I$(GENDIR) -I$(LIBDIR) \
>> -I$(TOOLSINCDIR) -I$(APIDIR) -I$(OUTPUT) \
>> + -Wno-unused-command-line-argument \
>> + -Wno-format-security \
>
> Are both compliler flags available for GCC (I simply don't know or
> have checked)?
Good question. gcc/g++ (8.4.1) does not complain these two flags
and I assume they are okay as well. But further digging shows
gcc only support -W[no-]format-security
https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
and does not support -Wno-unused-command-line-argument.
gcc/g++ simply just ignored it.
I will make -Wno-unused-command-line-argument for clang
only in v2. Thanks for catching this.
>
> - Sedat -
>
>> -Dbpf_prog_load=bpf_prog_test_load \
>> -Dbpf_load_program=bpf_test_load_program
>> LDLIBS += -lcap -lelf -lz -lrt -lpthread
>> --
>> 2.30.2
>>
next prev parent reply other threads:[~2021-04-11 17:41 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-10 16:49 [PATCH bpf-next 0/5] support build selftests/bpf with clang Yonghong Song
2021-04-10 16:49 ` [PATCH bpf-next 1/5] selftests: set CC to clang in lib.mk if LLVM is set Yonghong Song
2021-04-11 10:22 ` Sedat Dilek
2021-04-11 16:51 ` Yonghong Song
2021-04-11 17:10 ` Sedat Dilek
2021-04-10 16:49 ` [PATCH bpf-next 2/5] tools: allow proper CC/CXX/... override with LLVM=1 in Makefile.include Yonghong Song
2021-04-11 10:24 ` Sedat Dilek
2021-04-11 16:52 ` Yonghong Song
2021-04-10 16:49 ` [PATCH bpf-next 3/5] selftests/bpf: fix test_cpp compilation failure with clang Yonghong Song
2021-04-11 10:47 ` Sedat Dilek
2021-04-11 17:20 ` Yonghong Song
2021-04-11 17:31 ` Sedat Dilek
2021-04-11 19:08 ` Yonghong Song
2021-04-12 4:47 ` Sedat Dilek
2021-04-12 5:42 ` Yonghong Song
2021-04-12 6:06 ` Sedat Dilek
2021-04-12 14:15 ` Yonghong Song
2021-04-13 4:32 ` Andrii Nakryiko
2021-04-13 6:12 ` Yonghong Song
2021-04-13 17:50 ` Andrii Nakryiko
2021-04-10 16:49 ` [PATCH bpf-next 4/5] selftests/bpf: silence clang compilation warnings Yonghong Song
2021-04-11 11:12 ` Sedat Dilek
2021-04-11 17:40 ` Yonghong Song [this message]
2021-04-10 16:49 ` [PATCH bpf-next 5/5] bpftool: fix a clang compilation warning Yonghong Song
2021-04-11 11:05 ` Sedat Dilek
2021-04-11 17:24 ` Yonghong Song
2021-04-10 17:23 ` [PATCH bpf-next 0/5] support build selftests/bpf with clang Alexei Starovoitov
2021-04-10 17:38 ` Yonghong Song
2021-04-10 19:19 ` Sedat Dilek
2021-04-11 16:46 ` Yonghong Song
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