[tip: objtool/core] objtool/klp: Improve local label check

[tip-bot2 for Josh Poimboeuf]

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

Commit-ID:     e872b3f13922ecd746f907e20261dfc11c9a9f28
Gitweb:        https://git.kernel.org/tip/e872b3f13922ecd746f907e20261dfc11c9a9f28
Author:        Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate:    Wed, 29 Apr 2026 16:02:38 -07:00
Committer:     Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
CommitterDate: Mon, 04 May 2026 21:16:00 -07:00

objtool/klp: Improve local label check

Clang emits various .L-prefixed local symbols beyond .Ltmp*, such as
.L__const.* for local constant data.  These are assembler-local labels
not present in kallsyms, so they can never be resolved at module load
time.

Broaden the check from .Ltmp* to all .L* symbols so they get cloned into
the patch module instead.

Acked-by: Song Liu <song@xxxxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
 tools/objtool/klp-diff.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
index ccb16a4..c5d4c9e 100644
--- a/tools/objtool/klp-diff.c
+++ b/tools/objtool/klp-diff.c
@@ -282,14 +282,14 @@ static bool is_uncorrelated_static_local(struct symbol *sym)
 }
 
 /*
- * Clang emits several useless .Ltmp_* code labels.
+ * .L symbols are assembler-local labels not present in kallsyms.  They must
+ * never become KLP relocations; instead their data is cloned into the patch
+ * module.  This covers .Ltmp* (Clang temp labels), .L__const.* (Clang local
+ * constants), and any other assembler-local pattern.
  */
-static bool is_clang_tmp_label(struct symbol *sym)
+static bool is_local_label(struct symbol *sym)
 {
-	return is_notype_sym(sym) &&
-	       is_text_sec(sym->sec) &&
-	       strstarts(sym->name, ".Ltmp") &&
-	       isdigit(sym->name[5]);
+	return strstarts(sym->name, ".L");
 }
 
 static bool is_special_section(struct section *sec)
@@ -388,7 +388,7 @@ static bool dont_correlate(struct symbol *sym)
 	       is_abs_sym(sym) ||
 	       is_prefix_func(sym) ||
 	       is_uncorrelated_static_local(sym) ||
-	       is_clang_tmp_label(sym) ||
+	       is_local_label(sym) ||
 	       is_string_sec(sym->sec) ||
 	       is_initcall_sym(sym) ||
 	       is_addressable_sym(sym) ||