Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Wed, 1 Apr 2020 00:34:52 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Slava Bacherikov <slava@bacher09.org>
Cc:     andriin@fb.com, bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
        jannh@google.com, alexei.starovoitov@gmail.com,
        daniel@iogearbox.net, kernel-hardening@lists.openwall.com,
        Liu Yiding <liuyd.fnst@cn.fujitsu.com>
Subject: Re: [PATCH v2 bpf] kbuild: fix dependencies for DEBUG_INFO_BTF
Message-ID: <202004010033.A1523890@keescook>
References: <20200331215536.34162-1-slava@bacher09.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20200331215536.34162-1-slava@bacher09.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Apr 01, 2020 at 12:55:37AM +0300, Slava Bacherikov wrote:
> Currently turning on DEBUG_INFO_SPLIT when DEBUG_INFO_BTF is also
> enabled will produce invalid btf file, since gen_btf function in
> link-vmlinux.sh script doesn't handle *.dwo files.
> 
> Enabling DEBUG_INFO_REDUCED will also produce invalid btf file, and
> using GCC_PLUGIN_RANDSTRUCT with BTF makes no sense.
> 
> Signed-off-by: Slava Bacherikov <slava@bacher09.org>
> Reported-by: Jann Horn <jannh@google.com>
> Reported-by: Liu Yiding <liuyd.fnst@cn.fujitsu.com>
> Fixes: e83b9f55448a ("kbuild: add ability to generate BTF type info for vmlinux")
> ---
>  lib/Kconfig.debug | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index f61d834e02fe..9ae288e2a6c0 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -223,6 +223,7 @@ config DEBUG_INFO_DWARF4
>  config DEBUG_INFO_BTF
>  	bool "Generate BTF typeinfo"
>  	depends on DEBUG_INFO
> +	depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED && !GCC_PLUGIN_RANDSTRUCT
>  	help
>  	  Generate deduplicated BTF type information from DWARF debug info.
>  	  Turning this on expects presence of pahole tool, which will convert

Please make this:

depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
depends on COMPILE_TEST || !GCC_PLUGIN_RANDSTRUCT

-Kees

-- 
Kees Cook