modpost: do not set ->preloaded for symbols from Module.symvers (e4b26c9f) · Commits · 戴 / test

Now that there is no overwrap between symbols from ELF files and ones from Module.symvers. So, the 'exported twice' warning should be reported irrespective of where the symbol in question came from. The exceptional case is external module; in some cases, we build an external module to provide a different version/variant of the corresponding in-kernel module, overriding the same set of exported symbols. You can see this use-case in upstream; tools/testing/nvdimm/libnvdimm.ko replaces drivers/nvdimm/libnvdimm.ko in order to link it against mocked version of core kernel symbols. So, let's relax the 'exported twice' warning when building external modules. The multiple export from external modules is warned only when the previous one is from vmlinux or itself. With this refactoring, the ugly preloading goes away. Signed-off-by:

Masahiro Yamada <yamada.masahiro@socionext.com>

scripts/mod/modpost.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -169,7 +169,6 @@ struct symbol {
		unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
		unsigned int kernel:1; /* 1 if symbol is from kernel
		* (only for external modules) **/
		unsigned int preloaded:1; /* 1 if symbol from Module.symvers */
		unsigned int is_static:1; /* 1 if symbol is not global */
		enum export export; /* Type of export */
		char name[0];
		@@ -394,7 +393,8 @@ static struct symbol sym_add_exported(const char name, struct module *mod,
		if (!s) {
		s = new_symbol(name, mod, export);
		} else {
		if (!s->preloaded) {
		if (!external_module \|\| is_vmlinux(s->module->name) \|\|
		s->module == mod) {
		warn("%s: '%s' exported twice. Previous export was in %s%s\n",
		mod->name, name, s->module->name,
		is_vmlinux(s->module->name) ? "" : ".ko");
		@@ -403,7 +403,6 @@ static struct symbol sym_add_exported(const char name, struct module *mod,
		s->module = mod;
		}
		}
		s->preloaded = 0;
		s->vmlinux = is_vmlinux(mod->name);
		s->kernel = 0;
		s->export = export;
		@@ -2481,7 +2480,6 @@ static void read_dump(const char *fname, unsigned int kernel)
		}
		s = sym_add_exported(symname, mod, export_no(export));
		s->kernel = kernel;
		s->preloaded = 1;
		s->is_static = 0;
		sym_set_crc(symname, crc);
		sym_update_namespace(symname, namespace);

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