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Date:   Mon, 14 Jun 2021 16:09:45 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Lecopzer Chen <lecopzer.chen@mediatek.com>
Cc:     masahiroy@kernel.org, michal.lkml@markovi.net, nathan@kernel.org,
        ndesaulniers@google.com, samitolvanen@google.com,
        linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com,
        linux-kernel@vger.kernel.org, yj.chiang@mediatek.com
Subject: Re: [PATCH] kbuild: lto: fix module versionings mismatch in
 incremental build
Message-ID: <202106141554.A2D26986A@keescook>
References: <20210614055109.28774-1-lecopzer.chen@mediatek.com>
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In-Reply-To: <20210614055109.28774-1-lecopzer.chen@mediatek.com>
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On Mon, Jun 14, 2021 at 01:51:09PM +0800, Lecopzer Chen wrote:
> When building modules(CONFIG_...=m), I found some of module versions
> are incorrect and set to 0.
> This can be found in build log for first clean build which shows
> 
> WARNING: EXPORT symbol "XXXX" [drivers/XXX/XXX.ko] version generation failed, symbol will not be versioned.

I'm doing this, and I don't see the problem:

$ make LLVM=1 LLVM_IAS=1 distclean
$ make LLVM=1 LLVM_IAS=1 menuconfig
	*enable LTO*
	*enable a module*
$ make LLVM=1 LLVM_IAS=1 -j...

What series of commands (and .config) shows this for you?

-- 
Kees Cook