linux-kernel - [PATCH] tools/objtool: Copy the __cleanup unused variable fix for older clang

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Message-ID: <20251101124432.GBaQYAsK3mcvrB9cqm@fat_crate.local>
Date: Sat, 1 Nov 2025 13:44:32 +0100
From: Borislav Petkov <bp@...en8.de>
To: Nathan Chancellor <nathan@...nel.org>
Cc: Josh Poimboeuf <jpoimboe@...nel.org>, linux-kernel@...r.kernel.org,
	linux-tip-commits@...r.kernel.org, Petr Mladek <pmladek@...e.com>,
	Joe Lawrence <joe.lawrence@...hat.com>, x86@...nel.org
Subject: [PATCH] tools/objtool: Copy the __cleanup unused variable fix for
 older clang

From: "Borislav Petkov (AMD)" <bp@...en8.de>
Date: Sat, 1 Nov 2025 13:37:51 +0100

Copy from

  54da6a092431 ("locking: Introduce __cleanup() based infrastructure")

the bits which mark the variable with a cleanup attribute unused so that my
clang 15 can dispose of it properly instead of warning that it is unused which
then fails the build due to -Werror.

Suggested-by: Nathan Chancellor <nathan@...nel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Link: https://lore.kernel.org/r/20251031114919.GBaQSiPxZrziOs3RCW@fat_crate.local
---
 tools/objtool/include/objtool/warn.h | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/tools/objtool/include/objtool/warn.h b/tools/objtool/include/objtool/warn.h
index e88322d97573..a1e3927d8e7c 100644
--- a/tools/objtool/include/objtool/warn.h
+++ b/tools/objtool/include/objtool/warn.h
@@ -107,6 +107,15 @@ extern int indent;
 
 static inline void unindent(int *unused) { indent--; }
 
+/*
+ * Clang prior to 17 is being silly and considers many __cleanup() variables
+ * as unused (because they are, their sole purpose is to go out of scope).
+ *
+ * https://github.com/llvm/llvm-project/commit/877210faa447f4cc7db87812f8ed80e398fedd61
+ */
+#undef __cleanup
+#define __cleanup(func) __maybe_unused __attribute__((__cleanup__(func)))
+
 #define __dbg(format, ...)						\
 	fprintf(stderr,							\
 		"DEBUG: %s%s" format "\n",				\
@@ -127,7 +136,7 @@ static inline void unindent(int *unused) { indent--; }
 })
 
 #define dbg_indent(args...)						\
-	int __attribute__((cleanup(unindent))) __dummy_##__COUNTER__;	\
+	int __cleanup(unindent) __dummy_##__COUNTER__;			\
 	__dbg_indent(args);						\
 	indent++
 
-- 
2.51.0


-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette