linux-kernel - [PATCH v3 1/2] objtool: Fix the check for dead_end function with multiple sibling calls

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Message-ID: <20251119173243.1625930-1-xur@google.com>
Date: Wed, 19 Nov 2025 17:32:43 +0000
From: xur@...gle.com
To: Josh Poimboeuf <jpoimboe@...nel.org>, Peter Zijlstra <peterz@...radead.org>, Rong Xu <xur@...gle.com>
Cc: linux-kernel@...r.kernel.org, Sriraman Tallam <tmsriram@...gle.com>, 
	Han Shen <shenhan@...gle.com>, Krzysztof Pszeniczny <kpszeniczny@...gle.com>
Subject: [PATCH v3 1/2] objtool: Fix the check for dead_end function with
 multiple sibling calls

From: Rong Xu <xur@...gle.com>

If a function has multiple sibling calls, the dead_end check should
only return true if all sibling call targets are also dead_end
functions.

Signed-off-by: Rong Xu <xur@...gle.com>
Reviewed-by: Sriraman Tallam <tmsriram@...gle.com>
Reviewed-by: Han Shen <shenhan@...gle.com>
Reviewed-by: Krzysztof Pszeniczny <kpszeniczny@...gle.com>
Acked-by: Josh Poimboeuf <jpoimboe@...nel.org>

ChangedLog:
v3: Fix the typos in the commit message. (From Josh Poimboeuf).
    Drop the other patch (split funciton) as Josh has a better fix.
    Add Acked-by from Josh.
---
 tools/objtool/check.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 9004fbc067693..c2ee3c3a84a62 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -314,7 +314,13 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
 				return false;
 			}
 
-			return __dead_end_function(file, insn_func(dest), recursion+1);
+			/*
+			 * A function can have multiple sibling calls. All of
+			 * them need to be dead ends for the function to be a
+			 * dead end too.
+			 */
+			if (!__dead_end_function(file, insn_func(dest), recursion+1))
+				return false;
 		}
 	}
 

base-commit: 8b690556d8fe074b4f9835075050fba3fb180e93
-- 
2.52.0.rc1.455.g30608eb744-goog