diff -ur /usr/src/sys/fs/nullfs/null_vnops.c src/sys/fs/nullfs/null_vnops.c
--- /usr/src/sys/fs/nullfs/null_vnops.c	Sat Apr 23 00:42:44 2005
+++ src/sys/fs/nullfs/null_vnops.c	Wed Aug 31 14:02:47 2005
@@ -636,7 +636,7 @@
 	VI_UNLOCK(vp);
 	if (lowervp) {
 		null_hashrem(xp);
-		vrele(lowervp);
+		vput(lowervp);
 	}
 
 	vp->v_object = NULL;