Re: [PATCH v4 mips-next 4/7] MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time

From: Nathan Chancellor <natechancellor@gmail.com>
To: Alexander Lobakin <alobakin@pm.me>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	Arnd Bergmann <arnd@arndb.de>, Kees Cook <keescook@chromium.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Fangrui Song <maskray@google.com>,
	Huacai Chen <chenhuacai@kernel.org>,
	Pei Huang <huangpei@loongson.cn>,
	Jiaxun Yang <jiaxun.yang@flygoat.com>,
	Sami Tolvanen <samitolvanen@google.com>,
	Ingo Molnar <mingo@kernel.org>,
	Ralf Baechle <ralf@linux-mips.org>,
	Corey Minyard <cminyard@mvista.com>,
	linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arch@vger.kernel.org, stable@vger.kernel.org,
	clang-built-linux@googlegroups.com
Subject: Re: [PATCH v4 mips-next 4/7] MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time
Date: Fri, 8 Jan 2021 14:17:03 -0700	[thread overview]
Message-ID: <20210108211703.GD2547542@ubuntu-m3-large-x86> (raw)
In-Reply-To: <20210107132010.463129-1-alobakin@pm.me>

On Thu, Jan 07, 2021 at 01:20:33PM +0000, Alexander Lobakin wrote:
> Catch any symbols placed in .rel.dyn and check for these sections
> to be zero-sized at link time.
> Eliminates following ld warning:
> 
> mips-alpine-linux-musl-ld: warning: orphan section `.rel.dyn'
> from `init/main.o' being placed in section `.rel.dyn'
> 
> Adopted from x86/kernel/vmlinux.lds.S.
> 
> Suggested-by: Fangrui Song <maskray@google.com>
> Signed-off-by: Alexander Lobakin <alobakin@pm.me>

Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>

> ---
>  arch/mips/kernel/vmlinux.lds.S | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S
> index 0f4e46ea4458..0f736d60d43e 100644
> --- a/arch/mips/kernel/vmlinux.lds.S
> +++ b/arch/mips/kernel/vmlinux.lds.S
> @@ -226,4 +226,15 @@ SECTIONS
>  		*(.pdr)
>  		*(.reginfo)
>  	}
> +
> +	/*
> +	 * Sections that should stay zero sized, which is safer to
> +	 * explicitly check instead of blindly discarding.
> +	 */
> +
> +	.rel.dyn : {
> +		*(.rel.*)
> +		*(.rel_*)
> +	}
> +	ASSERT(SIZEOF(.rel.dyn) == 0, "Unexpected run-time relocations (.rel) detected!")
>  }
> -- 
> 2.30.0
> 
>