1 files changed, 6 insertions, 5 deletions

diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
index 8ea43b6d0403..38fe0e216fde 100644
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -363,15 +363,16 @@ vmspace_swap_count(struct vmspace *vmspace)
 		vm_object_t object;
 
 		if ((cur->eflags & MAP_ENTRY_IS_SUB_MAP) == 0 &&
-		    (object = cur->object.vm_object) != NULL &&
-		    object->type == OBJT_SWAP
-		) {
-			int n = (cur->end - cur->start) / PAGE_SIZE;
+		    (object = cur->object.vm_object) != NULL) {
+			VM_OBJECT_LOCK(object);
+			if (object->type == OBJT_SWAP &&
+			    object->un_pager.swp.swp_bcount != 0) {
+				int n = (cur->end - cur->start) / PAGE_SIZE;
 
-			if (object->un_pager.swp.swp_bcount) {
 				count += object->un_pager.swp.swp_bcount *
 				    SWAP_META_PAGES * n / object->size + 1;
 			}
+			VM_OBJECT_UNLOCK(object);
 		}
 	}
 	return (count);