--- fs/nfsserver/nfs_nfsdstate.c.sav	2020-01-03 13:20:12.691769000 -0800
+++ fs/nfsserver/nfs_nfsdstate.c	2020-01-03 13:21:05.695731000 -0800
@@ -1554,7 +1554,8 @@ nfsrv_freeallnfslocks(struct nfsstate *stp, vnode_t vp
 				tvp = NULL;
 			else if (vp == NULL && cansleep != 0) {
 				tvp = nfsvno_getvp(&lfp->lf_fh);
-				NFSVOPUNLOCK(tvp, 0);
+				if (tvp != NULL)
+					NFSVOPUNLOCK(tvp, 0);
 			} else
 				tvp = vp;
 			gottvp = 1;