diff --git a/sys/kern/vfs_lookup.c b/sys/kern/vfs_lookup.c
--- a/sys/kern/vfs_lookup.c
+++ b/sys/kern/vfs_lookup.c
@@ -162,6 +162,7 @@
 	vfs_vector_op_register(&crossmp_vnodeops);
 	getnewvnode("crossmp", NULL, &crossmp_vnodeops, &vp_crossmp);
 	vp_crossmp->v_state = VSTATE_CONSTRUCTED;
+	vp_crossmp->v_irflag |= VIRF_CROSSMP;
 }
 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nameiinit, NULL);
 
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -5452,14 +5452,18 @@
 void
 assert_vop_locked(struct vnode *vp, const char *str)
 {
-	int locked;
-
 	if (KERNEL_PANICKED() || vp == NULL)
 		return;
 
-	locked = VOP_ISLOCKED(vp);
+#ifdef WITNESS
+	if ((vp->v_irflag & VIRF_CROSSMP) == 0)
+		witness_assert(&vp->v_vnlock->lock_object, LA_LOCKED,
+		    __FILE__, __LINE__);
+#else
+	int locked = VOP_ISLOCKED(vp);
 	if (locked == 0 || locked == LK_EXCLOTHER)
 		vfs_badlock("is not locked but should be", str, vp);
+#endif
 }
 
 void
@@ -5468,8 +5472,14 @@
 	if (KERNEL_PANICKED() || vp == NULL)
 		return;
 
+#ifdef WITNESS
+	if ((vp->v_irflag & VIRF_CROSSMP) == 0)
+		witness_assert(&vp->v_vnlock->lock_object, LA_UNLOCKED,
+		    __FILE__, __LINE__);
+#else
 	if (VOP_ISLOCKED(vp) == LK_EXCLUSIVE)
 		vfs_badlock("is locked but should not be", str, vp);
+#endif
 }
 
 void
diff --git a/sys/sys/vnode.h b/sys/sys/vnode.h
--- a/sys/sys/vnode.h
+++ b/sys/sys/vnode.h
@@ -228,6 +228,7 @@
 				   never cleared once set */
 #define	VIRF_MOUNTPOINT	0x0004	/* This vnode is mounted on */
 #define	VIRF_TEXT_REF	0x0008	/* Executable mappings ref the vnode */
+#define	VIRF_CROSSMP	0x0010	/* Cross-mp vnode, no locking */
 
 #define	VI_UNUSED0	0x0001	/* unused */
 #define	VI_MOUNT	0x0002	/* Mount in progress */