linux-kernel - Re: [PATCH] objtool/klp: Fix bug table handling for __WARN

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Message-ID: <CAPhsuW6=+KCiOTeDT=AnR2tTF+ROnmCF5oZkBxxgTF8W1RyXwQ@mail.gmail.com>
Date: Mon, 26 Jan 2026 10:44:33 -0800
From: Song Liu <song@...nel.org>
To: Josh Poimboeuf <jpoimboe@...nel.org>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org, 
	live-patching@...r.kernel.org, Breno Leitao <leitao@...ian.org>, 
	Puranjay Mohan <puranjay@...nel.org>, Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH] objtool/klp: Fix bug table handling for __WARN_printf()

On Sun, Jan 25, 2026 at 9:56 PM Josh Poimboeuf <jpoimboe@...nel.org> wrote:
>
> Running objtool klp-diff on a changed function which uses WARN() can
> fail with:
>
>   vmlinux.o: error: objtool: md_run+0x866: failed to convert reloc sym '__bug_table' to its proper format
>
> The problem is that since commit 5b472b6e5bd9 ("x86_64/bug: Implement
> __WARN_printf()"), each __WARN_printf() call site now directly
> references its bug table entry.  klp-diff errors out when it can't
> convert such section-based references to object symbols (because bug
> table entries don't have symbols).
>
> Luckily, klp-diff already has code to create symbols for bug table
> entries.  Move that code earlier, before function diffing.
>
> Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files")
> Fixes: 5b472b6e5bd9 ("x86_64/bug: Implement __WARN_printf()")
> Reported-by: Song Liu <song@...nel.org>
> Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>

Tested-by: Song Liu <song@...nel.org>

Thanks for the fix!