diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c index a7cdba08b1de..0211e5c87160 100644 --- a/tools/objtool/klp-diff.c +++ b/tools/objtool/klp-diff.c @@ -1295,6 +1295,28 @@ static int convert_reloc_sym(struct elf *elf, struct reloc *reloc) return convert_reloc_secsym_to_sym(elf, reloc); } +/* + * Check if the original module already has a dependency on dep_mod, i.e. it + * already references at least one export from that module. + */ +static bool has_module_dep(struct elfs *e, const char *dep_mod) +{ + struct symbol *sym; + + for_each_sym(e->orig, sym) { + struct export *exp; + + if (!is_undef_sym(sym) || is_weak_sym(sym)) + continue; + + exp = find_export(sym); + if (exp && !strcmp(exp->mod, dep_mod)) + return true; + } + + return false; +} + /* * Convert a regular relocation to a klp relocation (sort of). */ @@ -1314,8 +1336,17 @@ static int clone_reloc_klp(struct elfs *e, struct reloc *patched_reloc, unsigned long sympos; if (!patched_sym->twin) { - ERROR("unexpected klp reloc for new symbol %s", patched_sym->name); - return -1; + if (!export) { + ERROR("unexpected klp reloc for new symbol %s", patched_sym->name); + return -1; + } + + if (strcmp(export->mod, "vmlinux") && + !has_module_dep(e, export->mod)) { + ERROR("%s: new reference to %s (exported by %s) would create an undeclared module dependency", + patched_sym->name, export->sym, export->mod); + return -1; + } } /*