diff --git a/Makefile b/Makefile
index 523eead51a48..094f89883044 100644
--- a/Makefile
+++ b/Makefile
@@ -149,6 +149,10 @@ endif
 
 mixed-build-prefix = $(if $(KBUILD_MIXED_TREE),$(KBUILD_MIXED_TREE)/)
 export KBUILD_MIXED_TREE
+# This is a hack for kleaf to set mixed-build-prefix within the execution of a make rule, e.g.
+# within __modinst_pre.
+# TODO(b/205893923): Revert this hack once it is properly handled.
+export mixed-build-prefix
 
 # Kbuild will save output files in the current working directory.
 # This does not need to match to the root of the kernel source tree.