diff --git a/sys/fs/nullfs/null_vfsops.c b/sys/fs/nullfs/null_vfsops.c
index c3eec727aee..0ec4f9c8729 100644
--- a/sys/fs/nullfs/null_vfsops.c
+++ b/sys/fs/nullfs/null_vfsops.c
@@ -151,6 +151,14 @@ nullfs_mount(struct mount *mp)
 	 */
 	lowerrootvp = ndp->ni_vp;
 
+	/*
+	 * Do not allow to mount a vnode over itself.
+	 */
+	if (mp->mnt_vnodecovered == lowerrootvp) {
+		vput(lowerrootvp);
+		return (EDEADLK);
+	}
+
 	/*
 	 * Check multi null mount to avoid `lock against myself' panic.
 	 */