Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <6cd16364-f0cd-b3f3-248f-4b6d585d05ef@gmail.com>
Date:   Mon, 27 Jun 2022 10:03:07 -0700
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.9.1
Subject: Re: [PATCH 5.4 57/60] modpost: fix section mismatch check for
 exported init/exit sections
Content-Language: en-US
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org
Cc:     stable@vger.kernel.org, Masahiro Yamada <masahiroy@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>
References: <20220627111927.641837068@linuxfoundation.org>
 <20220627111929.368555413@linuxfoundation.org>
From:   Florian Fainelli <f.fainelli@gmail.com>
In-Reply-To: <20220627111929.368555413@linuxfoundation.org>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 6/27/22 04:22, Greg Kroah-Hartman wrote:
> From: Masahiro Yamada <masahiroy@kernel.org>
> 
> commit 28438794aba47a27e922857d27b31b74e8559143 upstream.
> 
> Since commit f02e8a6596b7 ("module: Sort exported symbols"),
> EXPORT_SYMBOL* is placed in the individual section ___ksymtab(_gpl)+<sym>
> (3 leading underscores instead of 2).
> 
> Since then, modpost cannot detect the bad combination of EXPORT_SYMBOL
> and __init/__exit.
> 
> Fix the .fromsec field.
> 
> Fixes: f02e8a6596b7 ("module: Sort exported symbols")
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This commit causes the following warning to show up on my kernel builds 
used for testing 5.4 stable candidates:

WARNING: vmlinux.o(___ksymtab+drm_fb_helper_modinit+0x0): Section 
mismatch in reference from the variable __ksymtab_drm_fb_helper_modinit 
to the function .init.text:drm_fb_helper_modinit()
The symbol drm_fb_helper_modinit is exported and annotated __init
Fix this by removing the __init annotation of drm_fb_helper_modinit or 
drop the export.

The kernel configuration to reproduce this is located here (this is 5.10 
but works in 5.4 as well):

https://gist.github.com/2c3e8edd5ceb089c8040db724073d941

Same applies to the 5.10, 5.15 and 5.18 stable queues FWIW.
-- 
Florian