Two change:

[model-checker.git] / model.cc

diff --git a/model.cc b/model.cc
index 9dc1d37c71bb6ac93844d057efd7928818d7e053..a22e0214a6c2a3fdabd01a5442b3cba6643c616d 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -658,7 +658,8 @@ Thread * ModelChecker::check_current_action(ModelAction *curr)
                        bool updated = false;
 
                        if (act->is_read()) {
-                               if (r_modification_order(act, act->get_reads_from()))
+                               const ModelAction *rf = act->get_reads_from();
+                               if (rf != NULL && r_modification_order(act, rf))
                                        updated = true;
                        }
                        if (act->is_write()) {