From 86a697572c6271083694025eefa8de518eeef623 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Fri, 7 Aug 2026 14:37:51 -0700 Subject: [PATCH] objtool/klp: Don't match local symbols against exports While cloning a reloc, klp diff calls find_export() to determine whether the referenced symbol is exported. That decides whether the reference needs a klp reloc, which object the klp symbol belongs to, and whether the symbol's data needs to be copied into the patch module. But find_export() matches purely on symbol name, so a static function or variable which happens to share its name with an export is mistaken for a reference to that export: - klp_reloc_needed() creates a klp reloc pointing at the exporting module's symbol rather than the local one. For a vmlinux export it skips the klp reloc altogether, leaving a normal reloc which the module loader resolves to the vmlinux symbol. - clone_reloc() treats the symbol as external and clones it without its data, leaving a dangling reference. - validate_special_section_klp_reloc() attributes a static branch or call key to the wrong module, and for a vmlinux export skips the unsupported-key check entirely. Exports are always global, so ignore local symbols in find_export(). Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files") Acked-by: Song Liu Acked-by: Joe Lawrence Link: https://patch.msgid.link/dafc7c017d1f62e2190a20dc84a52fbfc4c70210.1786138493.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf --- tools/objtool/klp-diff.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c index e266a54b059d..a7cdba08b1de 100644 --- a/tools/objtool/klp-diff.c +++ b/tools/objtool/klp-diff.c @@ -1102,6 +1102,9 @@ static struct export *find_export(struct symbol *sym) { struct export *export; + if (is_local_sym(sym)) + return NULL; + hash_for_each_possible(exports, export, hash, str_hash(sym->name)) { if (!strcmp(export->sym, sym->name)) return export;