From a8390ba9ddce15242a41ca04d097b75fd54fd63f Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 19 Aug 2021 09:57:36 +0900 Subject: [PATCH] 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_ 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 Reviewed-by: Kees Cook --- scripts/Makefile.build | 2 ++ 1 file changed, 2 insertions(+) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 6961b4acacf8..3efc984d4c69 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -177,6 +177,8 @@ cmd_modversions_c = \ if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \ $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ > $@.symversions; \ + else \ + rm -f $@.symversions; \ fi; else cmd_modversions_c = \