Commit 23beb44a authored by Masahiro Yamada's avatar Masahiro Yamada
Browse files

modpost: add a separate error for exported symbols without definition 

It took me a while to understand the intent of "exp->module == mod".

This code goes back to 2003. [1]

The commit is not in this git repository, and might be worth a little
explanation.

You can add EXPORT_SYMBOL() without having its definition in the same
file (but you need to put a declaration).

This is typical when EXPORT_SYMBOL() is added in a C file, but the
actual implementation is in a separate assembly file.

One example is arch/arm/kernel/armksyms.c

In the old days, EXPORT_SYMBOL() was only available in C files (but
this limitation does not exist any more). If you forget to add the
definition, this error occurs.

Add a separate, clearer message for this case. It should be an error
even if KBUILD_MODPOST_WARN is given.

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=2763b6bcb96e6a38a2fe31108fe5759ec5bcc80a



Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
Reviewed-by: default avatarNick Desaulniers <ndesaulniers@google.com>
parent 594ade3e

scripts/mod/modpost.c

+6 −1
Original line number Diff line number Diff line
@@ -2147,13 +2147,18 @@ static void check_exports(struct module *mod) 
	for (s = mod->unres; s; s = s->next) {

		const char *basename;

		exp = find_symbol(s->name);

		if (!exp || exp->module == mod) {

		if (!exp) {

			if (!s->weak && nr_unresolved++ < MAX_UNRESOLVED_REPORTS)

				modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR,

					    "\"%s\" [%s.ko] undefined!\n",

					    s->name, mod->name);

			continue;

		}

		if (exp->module == mod) {

			error("\"%s\" [%s.ko] was exported without definition\n",

			      s->name, mod->name);

			continue;

		}

		basename = strrchr(mod->name, '/');

		if (basename)

			basename++;