linux-kernel - Re: [RFC PATCH 0/4] x86/build: Get rid of vmlinux postlink step

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Message-ID: <CAMj1kXHCia-gQy7fkVC5SgMyFqz6rRgpVbz6_W7e9jk7ENaQxA@mail.gmail.com>
Date: Sat, 8 Mar 2025 23:42:38 +0100
From: Ard Biesheuvel <ardb@...nel.org>
To: Masahiro Yamada <masahiroy@...nel.org>
Cc: linux-kernel@...r.kernel.org, x86@...nel.org, linux-kbuild@...r.kernel.org, 
	Ingo Molnar <mingo@...nel.org>
Subject: Re: [RFC PATCH 0/4] x86/build: Get rid of vmlinux postlink step

On Sat, 8 Mar 2025 at 17:17, Masahiro Yamada <masahiroy@...nel.org> wrote:
>
...
> I do not think it is broken.
> As I mentioned above, I regard vmlinux.relocs as a byproduct
> of the atomic build rule of vmlinux. This works.
>

There is no make rule for vmlinux.relocs, and so

- if it gets deleted, it cannot be rebuilt and even though the build
does not break, the relocation data is missing from the compressed
image, and this could potentially break the kaslr startup code,
- it vmlinux.relocs is older than vmlinux for some reason, make will
not notice and silently reuse the outdated version,
- when creating vmlinux.relocs from vmlinux and an error occurs,
vmlinux is deleted, making it difficult to diagnose the problem.

I think this is badly broken, but if you think this is all working as
it should, I am not going to debate this further, and you can consider
the patch series withdrawn.