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: <20210927121541.939745-1-arnd@kernel.org>
In-Reply-To: <20210927121541.939745-1-arnd@kernel.org>
From:   Sami Tolvanen <samitolvanen@google.com>
Date:   Mon, 27 Sep 2021 08:27:16 -0700
Message-ID: <CABCJKucOoov6aWzP3bcTwewNHFRbQn=nFvtkcZQ34hSm+K8+iw@mail.gmail.com>
Subject: Re: [PATCH] module: fix clang CFI with MODULE_UNLOAD=n
To:     Arnd Bergmann <arnd@kernel.org>
Cc:     Luis Chamberlain <mcgrof@kernel.org>, Jessica Yu <jeyu@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Miroslav Benes <mbenes@suse.cz>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Kees Cook <keescook@chromium.org>,
        Sergey Shtylyov <s.shtylyov@omprussia.ru>,
        Stephen Boyd <swboyd@chromium.org>,
        LKML <linux-kernel@vger.kernel.org>, llvm@lists.linux.dev
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hi Arnd,

On Mon, Sep 27, 2021 at 5:15 AM Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> When CONFIG_MODULE_UNLOAD is disabled, the module->exit member
> is not defined, causing a build failure:
>
> kernel/module.c:4493:8: error: no member named 'exit' in 'struct module'
>                 mod->exit = *exit;
>
> add an #ifdef block around this.
>
> Fixes: cf68fffb66d6 ("add support for Clang CFI")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  kernel/module.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/kernel/module.c b/kernel/module.c
> index 40ec9a030eec..5c26a76e800b 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -4489,8 +4489,10 @@ static void cfi_init(struct module *mod)
>         /* Fix init/exit functions to point to the CFI jump table */
>         if (init)
>                 mod->init = *init;
> +#ifdef CONFIG_MODULE_UNLOAD
>         if (exit)
>                 mod->exit = *exit;
> +#endif
>
>         cfi_module_add(mod, module_addr_min);
>  #endif

Thanks for the fix!

Reviewed-by: Sami Tolvanen <samitolvanen@google.com>

Sami