modpost: distinguish same module paths from different dump files

Since commit 13b25489b6f8 ("kbuild: change working directory to external
module directory with M="), module paths are always relative to the top
of the external module tree.

The module paths recorded in Module.symvers are no longer globally unique
when they are passed via KBUILD_EXTRA_SYMBOLS for building other external
modules, which may result in false-positive "exported twice" errors.
Such errors should not occur because external modules should be able to
override in-tree modules.

To address this, record the dump file path in struct module and check it
when searching for a module.

Fixes: 13b25489b6f8 ("kbuild: change working directory to external module directory with M=")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Closes: https://lore.kernel.org/all/eb21a546-a19c-40df-b821-bbba80f19a3d@nvidia.com/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Jon Hunter <jonathanh@nvidia.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 49848fcbe2a1..8b72c227ebf4 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -95,14 +95,15 @@ struct module_alias {
 /**
  * struct module - represent a module (vmlinux or *.ko)
  *
+ * @dump_file: path to the .symvers file if loaded from a file
  * @aliases: list head for module_aliases
  */
 struct module {
 	struct list_head list;
 	struct list_head exported_symbols;
 	struct list_head unresolved_symbols;
+	const char *dump_file;
 	bool is_gpl_compatible;
-	bool from_dump;		/* true if module was loaded from *.symvers */
 	bool is_vmlinux;
 	bool seen;
 	bool has_init;