kernel - Fix deep recursion in vm_object_collapse() (2)

* Fix bug in previous deep recursion commit.  A chainlock was being
  released too late.

diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c
index ad0104d..99cabb9 100644 (file)
--- a/sys/vm/vm_object.c
+++ b/sys/vm/vm_object.c
@@ -2077,6 +2077,14 @@ vm_object_collapse(vm_object_t object, struct vm_object_dealloc_list **dlistp)
        }
 
        /*
+        * Clean up any left over backing_object
+        */
+       if (backing_object) {
+               vm_object_chain_release(backing_object);
+               vm_object_drop(backing_object);
+       }
+
+       /*
         * Clean up any auto-deallocation list.  This is a convenience
         * for top-level callers so they don't have to pass &dlist.
         * Do not clean up any caller-passed dlistp, the caller will
@@ -2085,15 +2093,6 @@ vm_object_collapse(vm_object_t object, struct vm_object_dealloc_list **dlistp)
        if (dlist)
                vm_object_deallocate_list(&dlist);
 
-       /*
-        * Clean up any left over backing_object
-        */
-       if (backing_object) {
-#if 1
-               vm_object_chain_release(backing_object);
-#endif
-               vm_object_drop(backing_object);
-       }
 }
 
 /*