Greg Ungerer reported modpost produced false-positive "local symbol '...' was exported" errors when m68k-uclinux-gcc is used. I had assumed ELF_R_SYM(Elf_Rela::r_info) pointed to the exported symbol itself if it is in the global scope. This assumption worked for many toolchains, but as it turned out, it was not true for m68k-uclinux-gcc, at least. If the 'sym' argument passed to check_export_symbol() is not the exported symbol, look up the correct one in the symbol table. It incurs a search cost, but since we know its section index and address, we can exploit the binary search. Reported-by: Greg Ungerer <gerg@xxxxxxxxxx> Closes: https://lore.kernel.org/all/1fac9d12-2ec2-4ccb-bb81-34f3fc34789e@xxxxxxxxxxxxxx/ Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> --- scripts/mod/modpost.c | 31 ++++++++++++++++++++++--------- 1 file changed, 22 insertions(+), 9 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 896ecfa8483f..ee67bc6d71ee 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1021,6 +1021,18 @@ static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym) true, 20); } +static Elf_Sym *find_tosym_with_name(struct elf_info *elf, Elf_Addr addr, + Elf_Sym *sym, const char *name) +{ + /* If the supplied symbol has the expected name, return it. */ + if (!strcmp(sym_name(elf, sym), name)) + return sym; + + /* Look up a symbol with the given name. */ + return symsearch_find_with_name(elf, addr, get_secindex(elf, sym), + true, 20, name); +} + static bool is_executable_section(struct elf_info *elf, unsigned int secndx) { if (secndx >= elf->num_sections) @@ -1079,7 +1091,7 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, static void check_export_symbol(struct module *mod, struct elf_info *elf, Elf_Addr faddr, const char *secname, - Elf_Sym *sym) + Elf_Sym *sym, Elf_Addr taddr) { static const char *prefix = "__export_symbol_"; const char *label_name, *name, *data; @@ -1096,6 +1108,14 @@ static void check_export_symbol(struct module *mod, struct elf_info *elf, return; } + name = label_name + strlen(prefix); + sym = find_tosym_with_name(elf, taddr, sym, name); + if (!sym) { + error("%s: could not find the the export symbol '%s'\n", + mod->name, name); + return; + } + if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL && ELF_ST_BIND(sym->st_info) != STB_WEAK) { error("%s: local symbol '%s' was exported\n", mod->name, @@ -1103,13 +1123,6 @@ static void check_export_symbol(struct module *mod, struct elf_info *elf, return; } - name = sym_name(elf, sym); - if (strcmp(label_name + strlen(prefix), name)) { - error("%s: .export_symbol section references '%s', but it does not seem to be an export symbol\n", - mod->name, name); - return; - } - data = sym_get_data(elf, label); /* license */ if (!strcmp(data, "GPL")) { is_gpl = true; @@ -1156,7 +1169,7 @@ static void check_section_mismatch(struct module *mod, struct elf_info *elf, const struct sectioncheck *mismatch; if (module_enabled && elf->export_symbol_secndx == fsecndx) { - check_export_symbol(mod, elf, faddr, tosec, sym); + check_export_symbol(mod, elf, faddr, tosec, sym, taddr); return; } -- 2.40.1
