diff --git a/scripts/basic/docproc.c b/scripts/basic/docproc.c
index 4c9523e..99ca7a6 100644
--- a/scripts/basic/docproc.c
+++ b/scripts/basic/docproc.c
@@ -385,7 +385,7 @@
 	if (!srctree)
 		srctree = getcwd(NULL, 0);
 	kernsrctree = getenv("KBUILD_SRC");
-	if (!kernsrctree)
+	if (!kernsrctree || !*kernsrctree)
 		kernsrctree = srctree;
 	if (argc != 3) {
 		usage();