diff --git a/src/libafs/make_kbuild_makefile.pl b/src/libafs/make_kbuild_makefile.pl
index ce046e1723..dd10db1e32 100755
--- a/src/libafs/make_kbuild_makefile.pl
+++ b/src/libafs/make_kbuild_makefile.pl
@@ -79,7 +79,7 @@ if (! -d $KDIR) {
 foreach (@objects) {
   die "No source known for $_\n" unless exists $deps{$_};
   if($deps{$_} =~ /\.s$/) {
-     ($src = $_) =~ s/\.o$/.s/;
+     ($src = $_) =~ s/\.o$/.S/;
   } else {
      ($src = $_) =~ s/\.o$/.c/;
   }