tree ef5a3965b046be545e5a3b24101b08d978b0d847
parent f01ac2a15218f3282b0b09b7ef7f314cbd7dd2b3
author Masahiro Yamada <masahiroy@kernel.org> 1629334656 +0900
committer Masahiro Yamada <masahiroy@kernel.org> 1630624640 +0900

kbuild: remove stale *.symversions

cmd_update_lto_symversions merges all the existing *.symversions, but
some of them might be stale.

If the last EXPORT_SYMBOL is removed from a C file, the *.symversions
file is not deleted or updated. It contains stale CRCs, but still they
will be used for linking the vmlinux or modules.

It is not a big deal when the EXPORT_SYMBOL is really removed. However,
when the EXPORT_SYMBOL is moved to another file, the same __crc_<symbol>
will appear twice in the merged *.symversions, possibly with different
CRCs if the function argument is changed at the same time. It would
confuse module versioning.

If no EXPORT_SYMBOL is found, let's remove *.symversions explicitly.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>