From f7145d12ab23ce11e6d8ee4fb9f4da775ed12aed Mon Sep 17 00:00:00 2001
From: freewym <freewym@gmail.com>
Date: Thu, 3 Oct 2019 14:04:26 -0400
Subject: [PATCH] fix a bug in src/online/online-faster-decoder.cc that may
 cause SegFault

---
 src/online/online-faster-decoder.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/online/online-faster-decoder.cc b/src/online/online-faster-decoder.cc
index e00181e1fc4..007779293f8 100644
--- a/src/online/online-faster-decoder.cc
+++ b/src/online/online-faster-decoder.cc
@@ -88,7 +88,7 @@ void OnlineFasterDecoder::UpdateImmortalToken() {
   unordered_set<Token*> emitting;
   for (const Elem *e = toks_.GetList(); e != NULL; e = e->tail) {
     Token* tok = e->val;
-    while (tok->arc_.ilabel == 0) //deal with non-emitting ones ...
+    while (tok != NULL && tok->arc_.ilabel == 0) //deal with non-emitting ones ...
       tok = tok->prev_;
     if (tok != NULL)
       emitting.insert(tok);