diff --git a/openerp/osv/expression.py b/openerp/osv/expression.py
index f90e4a82944..f29fc8f7084 100644
--- a/openerp/osv/expression.py
+++ b/openerp/osv/expression.py
@@ -1000,7 +1000,7 @@ class expression(object):
                     call_null_m2m = True
                     if right is not False:
                         if isinstance(right, basestring):
-                            res_ids = [x[0] for x in comodel.name_search(cr, uid, right, [], operator, context=context)]
+                            res_ids = [x[0] for x in comodel.name_search(cr, uid, right, [], operator, context=context, limit=None)]
                             if res_ids:
                                 operator = 'in'
                         else: