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From:   Kees Cook <keescook@chromium.org>
Date:   Mon, 4 Mar 2019 12:47:31 -0800
Message-ID: <CAGXu5jLfAqwFBGH6VPLKrGXOdeEX4ngKdvsG729MbMOuBU7AcA@mail.gmail.com>
Subject: Re: [PATCH] bpf: fix sysctl.c warning
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     Luis Chamberlain <mcgrof@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Christian Brauner <christian@brauner.io>,
        LKML <linux-kernel@vger.kernel.org>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        bpf@vger.kernel.org
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On Mon, Mar 4, 2019 at 12:34 PM Arnd Bergmann <arnd@arndb.de> wrote:
>
> When CONFIG_BPF_SYSCALL or CONFIG_SYSCTL is disabled, we get
> a warning about an unused function:
>
> kernel/sysctl.c:3331:12: error: 'proc_dointvec_minmax_bpf_stats' defined but not used [-Werror=unused-function]
>  static int proc_dointvec_minmax_bpf_stats(struct ctl_table *table, int write,
>
> The CONFIG_BPF_SYSCALL check was already handled, but the SYSCTL check
> is needed on top.
>
> Fixes: 492ecee892c2 ("bpf: enable program stats")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

> ---
>  kernel/sysctl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index 46a0d0a14a66..b3df3ab7ac28 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -3330,7 +3330,7 @@ int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
>
>  #endif /* CONFIG_PROC_SYSCTL */
>
> -#ifdef CONFIG_BPF_SYSCALL
> +#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_SYSCTL)
>  static int proc_dointvec_minmax_bpf_stats(struct ctl_table *table, int write,
>                                           void __user *buffer, size_t *lenp,
>                                           loff_t *ppos)
> --
> 2.20.0
>


-- 
Kees Cook