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Subject: Re: [PATCH] bpf/core.c - silence warning messages
To:     =?UTF-8?Q?Valdis_Kl=c4=93tnieks?= <valdis.kletnieks@vt.edu>,
        Alexei Starovoitov <ast@kernel.org>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        bpf@vger.kernel.org
References: <29466.1559875167@turing-police>
From:   Daniel Borkmann <daniel@iogearbox.net>
Message-ID: <d693c3bd-7491-588e-3648-59bbef3b88fa@iogearbox.net>
Date:   Wed, 12 Jun 2019 16:56:13 +0200
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On 06/07/2019 04:39 AM, Valdis Klētnieks wrote:
> Compiling kernel/bpf/core.c with W=1 causes a flood of warnings:
> 
> kernel/bpf/core.c:1198:65: warning: initialized field overwritten [-Woverride-init]
>  1198 | #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true
>       |                                                                 ^~~~
> kernel/bpf/core.c:1087:2: note: in expansion of macro 'BPF_INSN_3_TBL'
>  1087 |  INSN_3(ALU, ADD,  X),   \
>       |  ^~~~~~
> kernel/bpf/core.c:1202:3: note: in expansion of macro 'BPF_INSN_MAP'
>  1202 |   BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),
>       |   ^~~~~~~~~~~~
> kernel/bpf/core.c:1198:65: note: (near initialization for 'public_insntable[12]')
>  1198 | #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true
>       |                                                                 ^~~~
> kernel/bpf/core.c:1087:2: note: in expansion of macro 'BPF_INSN_3_TBL'
>  1087 |  INSN_3(ALU, ADD,  X),   \
>       |  ^~~~~~
> kernel/bpf/core.c:1202:3: note: in expansion of macro 'BPF_INSN_MAP'
>  1202 |   BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),
>       |   ^~~~~~~~~~~~
> 
> 98 copies of the above.
> 
> The attached patch silences the warnings, because we *know* we're overwriting
> the default initializer. That leaves bpf/core.c with only 6 other warnings,
> which become more visible in comparison.
> 
> Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>

Makes sense, applied!