diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c
index 589a372fbea..8048ecbc725 100644
--- a/sys/kern/vfs_vnops.c
+++ b/sys/kern/vfs_vnops.c
@@ -265,6 +265,7 @@ restart:
 	if (fmode & FWRITE)
 		vp->v_writecount++;
 	*flagp = fmode;
+	ASSERT_VOP_LOCKED(vp, "vn_open_cred");
 	return (0);
 bad:
 	NDFREE(ndp, NDF_ONLY_PNBUF);