linux-kernel - [tip: objtool/urgent] livepatch/klp-build: Require Clang assembler >= 20

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Message-ID: <177030804250.2495410.13722330109340992324.tip-bot2@tip-bot2>
Date: Thu, 05 Feb 2026 16:14:02 -0000
From: "tip-bot2 for Josh Poimboeuf" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Song Liu <song@...nel.org>, Josh Poimboeuf <jpoimboe@...nel.org>,
 x86@...nel.org, linux-kernel@...r.kernel.org
Subject:
 [tip: objtool/urgent] livepatch/klp-build: Require Clang assembler >= 20

The following commit has been merged into the objtool/urgent branch of tip:

Commit-ID:     a8ff29f0ca1d63a215ef445102662850a912d127
Gitweb:        https://git.kernel.org/tip/a8ff29f0ca1d63a215ef445102662850a912d127
Author:        Josh Poimboeuf <jpoimboe@...nel.org>
AuthorDate:    Tue, 27 Jan 2026 17:12:05 -08:00
Committer:     Josh Poimboeuf <jpoimboe@...nel.org>
CommitterDate: Thu, 29 Jan 2026 10:09:26 -08:00

livepatch/klp-build: Require Clang assembler >= 20

Some special sections specify their ELF section entsize, for example:

  .pushsection section, "M", @progbits, 8

The entsize (8 in this example) is needed by objtool klp-diff for
extracting individual entries.

Clang assembler versions older than 20 silently ignore the above
construct and set entsize to 0, resulting in the following error:

  .discard.annotate_data: missing special section entsize or annotations

Add a klp-build check to prevent the use of Clang assembler versions
prior to 20.

Fixes: 24ebfcd65a87 ("livepatch/klp-build: Introduce klp-build script for generating livepatch modules")
Reported-by: Song Liu <song@...nel.org>
Acked-by: Song Liu <song@...nel.org>
Link: https://patch.msgid.link/957fd52e375d0e2cfa3ac729160da995084a7f5e.1769562556.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
---
 scripts/livepatch/klp-build | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index a73515a..809e198 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -249,6 +249,10 @@ validate_config() {
 	[[ -v CONFIG_GCC_PLUGIN_RANDSTRUCT ]] &&	\
 		die "kernel option 'CONFIG_GCC_PLUGIN_RANDSTRUCT' not supported"
 
+	[[ -v CONFIG_AS_IS_LLVM ]] &&				\
+		[[ "$CONFIG_AS_VERSION" -lt 200000 ]] &&	\
+		die "Clang assembler version < 20 not supported"
+
 	return 0
 }