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, which 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 cause potential breakage of module versioning. If no EXPORT_SYMBOL is found, let's remove *.symversions explicitly. Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> --- scripts/Makefile.build | 2 ++ 1 file changed, 2 insertions(+) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 279363266455..585dae34746a 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 = \ -- 2.30.2
