Re: [PATCH bpf-next v2] bpf: fix compilation warning of selftests

[Alexei Starovoitov]

On Thu, Aug 6, 2020 at 3:46 AM Jianlin Lv <Jianlin.Lv@xxxxxxx> 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 ‘write’,
> 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 ‘read’,
> 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 ‘fscanf’,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 ‘system’,
> declared with attribute warn_unused_result [-Wunused-result]
>   133 |  system(test_script);
>       |  ^~~~~~~~~~~~~~~~~~~
> test_tcpnotify_user.c:138:2: warning:ignoring return value of ‘system’,
> declared with attribute warn_unused_result [-Wunused-result]
>   138 |  system(test_script);
>       |  ^~~~~~~~~~~~~~~~~~~
> test_tcpnotify_user.c:143:2: warning:ignoring return value of ‘system’,
> 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@xxxxxxx>
> ---
> v2:
> - replease CHECK_FAIL by CHECK
> - fix test_tcpnotify_user failed issue

Applied. Thanks