Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20200731061600.18344-1-Jianlin.Lv@arm.com> <20200806104224.95306-1-Jianlin.Lv@arm.com>
In-Reply-To: <20200806104224.95306-1-Jianlin.Lv@arm.com>
From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Thu, 6 Aug 2020 17:05:50 -0700
Message-ID: <CAADnVQLaxmftiSH6dk+NVv5FGvnB+C=rC978cCiL83d+M_zZ+Q@mail.gmail.com>
Subject: Re: [PATCH bpf-next v2] bpf: fix compilation warning of selftests
To:     Jianlin Lv <Jianlin.Lv@arm.com>
Cc:     bpf <bpf@vger.kernel.org>, "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Yonghong Song <yhs@fb.com>, Song.Zhu@arm.com,
        LKML <linux-kernel@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, Aug 6, 2020 at 3:46 AM Jianlin Lv <Jianlin.Lv@arm.com> wrote:
>
> Clang compiler version: 12.0.0
> The following warning appears during the selftests/bpf compilation:
>
> prog_tests/send_signal.c:51:3: warning: ignoring return value of =E2=80=
=98write=E2=80=99,
> declared with attribute warn_unused_result [-Wunused-result]
>    51 |   write(pipe_c2p[1], buf, 1);
>       |   ^~~~~~~~~~~~~~~~~~~~~~~~~~
> prog_tests/send_signal.c:54:3: warning: ignoring return value of =E2=80=
=98read=E2=80=99,
> declared with attribute warn_unused_result [-Wunused-result]
>    54 |   read(pipe_p2c[0], buf, 1);
>       |   ^~~~~~~~~~~~~~~~~~~~~~~~~
> ......
>
> prog_tests/stacktrace_build_id_nmi.c:13:2: warning: ignoring return value
> of =E2=80=98fscanf=E2=80=99,declared with attribute warn_unused_result [-=
Wunused-resul]
>    13 |  fscanf(f, "%llu", &sample_freq);
>       |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> test_tcpnotify_user.c:133:2: warning:ignoring return value of =E2=80=98sy=
stem=E2=80=99,
> declared with attribute warn_unused_result [-Wunused-result]
>   133 |  system(test_script);
>       |  ^~~~~~~~~~~~~~~~~~~
> test_tcpnotify_user.c:138:2: warning:ignoring return value of =E2=80=98sy=
stem=E2=80=99,
> declared with attribute warn_unused_result [-Wunused-result]
>   138 |  system(test_script);
>       |  ^~~~~~~~~~~~~~~~~~~
> test_tcpnotify_user.c:143:2: warning:ignoring return value of =E2=80=98sy=
stem=E2=80=99,
> declared with attribute warn_unused_result [-Wunused-result]
>   143 |  system(test_script);
>       |  ^~~~~~~~~~~~~~~~~~~
>
> Add code that fix compilation warning about ignoring return value and
> handles any errors; Check return value of library`s API make the code
> more secure.
>
> Signed-off-by: Jianlin Lv <Jianlin.Lv@arm.com>
> ---
> v2:
> - replease CHECK_FAIL by CHECK
> - fix test_tcpnotify_user failed issue

Applied. Thanks