diff mbox series

[v2,11/26] modpost: make multiple export error

Message ID	20220501084032.1025918-12-masahiroy@kernel.org (mailing list archive)
State	New
Headers	show Return-Path: <linux-kbuild-owner@kernel.org> From: Masahiro Yamada <masahiroy@kernel.org> To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Masahiro Yamada <masahiroy@kernel.org>, Nick Desaulniers <ndesaulniers@google.com>, Michal Marek <michal.lkml@markovi.net> Subject: [PATCH v2 11/26] modpost: make multiple export error Date: Sun, 1 May 2022 17:40:17 +0900 Message-Id: <20220501084032.1025918-12-masahiroy@kernel.org> In-Reply-To: <20220501084032.1025918-1-masahiroy@kernel.org> References: <20220501084032.1025918-1-masahiroy@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	kbuild: yet another series of cleanups (modpost and LTO) \| expand [v2,00/26] kbuild: yet another series of cleanups (modpost and LTO) [v2,01/26] modpost: use bool type where appropriate [v2,02/26] modpost: change mod->gpl_compatible to bool type [v2,03/26] modpost: import include/linux/list.h [v2,04/26] modpost: traverse modules in order [v2,05/26] modpost: add sym_add_unresolved() helper [v2,06/26] modpost: traverse unresolved symbols in order [v2,07/26] modpost: use doubly linked list for dump_lists [v2,08/26] modpost: traverse the namespace_list in order [v2,09/26] modpost: dump Module.symvers in the same order of modules.order [v2,10/26] modpost: move static EXPORT_SYMBOL check to check_exports() [v2,11/26] modpost: make multiple export error [v2,12/26] modpost: make sym_add_exported() always allocate a new symbol [v2,13/26] modpost: split new_symbol() to symbol allocation and hash table addition [v2,14/26] modpost: mitigate false-negatives for static EXPORT_SYMBOL checks [v2,15/26] kbuild: record symbol versions in .cmd files [v2,16/26] kbuild: generate a list of objects in vmlinux [v2,17/26] modpost: extract symbol versions from .cmd files [v2,18/26] modpost: generate linker script to collect symbol versions [v2,19/26] kbuild: embed symbol versions at final link of vmlinux or modules [v2,20/26] kbuild: stop merging .symversions [v2,21/26] genksyms: adjust the output format for .cmd files [v2,22/26] kbuild: do not create .prelink.o for Clang LTO or IBT [v2,23/26] kbuild: make built-in.a rule robust against too long argument error [v2,24/26] kbuild: make *.mod rule robust against too long argument error [v2,25/26] modpost: simplify the ->is_static initialization [v2,26/26] modpost: use hlist for hash table implementation

Commit Message

Masahiro Yamada May 1, 2022, 8:40 a.m. UTC

This is currently a warning, but I think modpost should stop building
in this case.

If the same symbol is exported multiple times and we let it keep going,
the sanity check becomes difficult.

Only the legitimate case is that an external module overrides the
corresponding in-tree module to provide a different implementation
with the same interface.

Also, there exists an upstream example that exploits this feature.

  $ make M=tools/testing/nvdimm

... builds tools/testing/nvdimm/libnvdimm.ko. This is a mocked module
that overrides the symbols from drivers/nvdimm/libnvdimm.ko.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
---

Changes in v2:
  - Add more commit description

 scripts/mod/modpost.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff mbox series

Patch

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 4ce8d164b8e0..1f01fc942f94 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -417,9 +417,9 @@  static struct symbol *sym_add_exported(const char *name, struct module *mod,
 		list_add_tail(&s->list, &mod->exported_symbols);
 	} else if (!external_module || s->module->is_vmlinux ||
 		   s->module == mod) {
-		warn("%s: '%s' exported twice. Previous export was in %s%s\n",
-		     mod->name, name, s->module->name,
-		     s->module->is_vmlinux ? "" : ".ko");
+		error("%s: '%s' exported twice. Previous export was in %s%s\n",
+		      mod->name, name, s->module->name,
+		      s->module->is_vmlinux ? "" : ".ko");
 		return s;
 	}