Index: sys/vm/vm_page.c
===================================================================
--- sys/vm/vm_page.c
+++ sys/vm/vm_page.c
@@ -1727,6 +1727,9 @@
 	mnew->pindex = pindex;
 	atomic_set_int(&mnew->ref_count, VPRC_OBJREF);
 	mold = vm_radix_replace(&object->rtree, mnew);
+	KASSERT((mold->oflags & VPO_UNMANAGED) ==
+	    (mnew->oflags & VPO_UNMANAGED),
+	    ("vm_page_replace: mismatched VPO_UNMANAGED"));
 
 	/* Keep the resident page list in sorted order. */
 	TAILQ_INSERT_AFTER(&object->memq, mold, mnew, listq);
@@ -2687,8 +2690,7 @@
 				KASSERT(pmap_page_get_memattr(m) ==
 				    VM_MEMATTR_DEFAULT,
 				    ("page %p has an unexpected memattr", m));
-				KASSERT((m->oflags & (VPO_SWAPINPROG |
-				    VPO_SWAPSLEEP | VPO_UNMANAGED)) == 0,
+				KASSERT(m->oflags == 0,
 				    ("page %p has unexpected oflags", m));
 				/* Don't care: PGA_NOSYNC. */
 				if (!vm_page_none_valid(m)) {
@@ -2756,6 +2758,7 @@
 					    ~PGA_QUEUE_STATE_MASK;
 					KASSERT(m_new->oflags == VPO_UNMANAGED,
 					    ("page %p is managed", m_new));
+					m_new->oflags &= ~VPO_UNMANAGED;
 					pmap_copy_page(m, m_new);
 					m_new->valid = m->valid;
 					m_new->dirty = m->dirty;
@@ -3669,9 +3672,13 @@
 		    ("vm_page_free_prep: freeing mapped page %p", m));
 		KASSERT((m->a.flags & (PGA_EXECUTABLE | PGA_WRITEABLE)) == 0,
 		    ("vm_page_free_prep: mapping flags set in page %p", m));
+		KASSERT((m->oflags & VPO_UNMANAGED) == 0,
+		    ("vm_page_free_prep: page %p is unmanaged", m));
 	} else {
 		KASSERT(m->a.queue == PQ_NONE,
 		    ("vm_page_free_prep: unmanaged page %p is queued", m));
+		KASSERT((m->oflags & VPO_UNMANAGED) != 0,
+		    ("vm_page_free_prep: page %p is managed", m));
 	}
 	VM_CNT_INC(v_tfree);