diff --git a/sys/vm/vm_fault.c b/sys/vm/vm_fault.c
index 05dd8f7..21a5d08 100644
--- a/sys/vm/vm_fault.c
+++ b/sys/vm/vm_fault.c
@@ -1940,9 +1940,11 @@ vm_fault_copy_entry(vm_map_t dst_map, vm_map_t src_map,
 		 * Allocate a page in the destination object
 		 */
 		do {
+			vm_object_lock(dst_object);
 			dst_m = vm_page_alloc(dst_object,
 					      OFF_TO_IDX(dst_offset),
 					      VM_ALLOC_NORMAL);
+			vm_object_unlock(dst_object);
 			if (dst_m == NULL) {
 				vm_wait(0);
 			}
@@ -1953,8 +1955,11 @@ vm_fault_copy_entry(vm_map_t dst_map, vm_map_t src_map,
 		 * (Because the source is wired down, the page will be in
 		 * memory.)
 		 */
+		vm_object_lock(src_object);
 		src_m = vm_page_lookup(src_object,
 				       OFF_TO_IDX(dst_offset + src_offset));
+		vm_object_unlock(src_object);
+
 		if (src_m == NULL)
 			panic("vm_fault_copy_wired: page missing");