From b8545842296c9419371b92ba0e790098d54c33cd Mon Sep 17 00:00:00 2001
From: weiyu <weiyuluo1232@gmail.com>
Date: Wed, 11 Dec 2019 17:46:44 -0800
Subject: [PATCH] Fix segfault at the first lock action

---
 execution.cc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/execution.cc b/execution.cc
index 69b3b276..39abc039 100644
--- a/execution.cc
+++ b/execution.cc
@@ -1366,6 +1366,9 @@ ModelAction * ModelExecution::get_last_unlock(ModelAction *curr) const
 	void *location = curr->get_location();
 
 	action_list_t *list = obj_map.get(location);
+	if (list == NULL)
+		return NULL;
+
 	/* Find: max({i in dom(S) | isUnlock(t_i) && samevar(t_i, t)}) */
 	sllnode<ModelAction*>* rit;
 	for (rit = list->end();rit != NULL;rit=rit->getPrev())
-- 
2.34.1