diff --git a/scripts/kernel-doc b/scripts/kernel-doc
index e4fa8d9568ba..8cf528b5e65a 100755
--- a/scripts/kernel-doc
+++ b/scripts/kernel-doc
@@ -334,7 +334,7 @@ while ($ARGV[0] =~ m/^-(.*)/) {
 
 # get kernel version from env
 sub get_kernel_version() {
-    my $version;
+    my $version = 'unknown kernel version';
 
     if (defined($ENV{'KERNELVERSION'})) {
 	$version = $ENV{'KERNELVERSION'};