diff --git a/Makefile b/Makefile
index 16e3fbb..f6703f1 100644
--- a/Makefile
+++ b/Makefile
@@ -437,7 +437,7 @@
 # KBUILD_DEFCONFIG may point out an alternative default configuration
 # used for 'make defconfig'
 include $(srctree)/arch/$(SRCARCH)/Makefile
-export KBUILD_DEFCONFIG
+export KBUILD_DEFCONFIG KBUILD_KCONFIG
 
 config %config: scripts_basic outputmakefile FORCE
 	$(Q)mkdir -p include/linux include/config