From b7894f10ca631e5b66aeb0c5fd7db3a9d9d5b39c Mon Sep 17 00:00:00 2001
From: Renge <renge@renge.io>
Date: Fri, 6 May 2022 14:53:13 -0400
Subject: [PATCH] fix: double free when ref < 0

---
 hw5/src/tu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/hw5/src/tu.c b/hw5/src/tu.c
index 846ebc8..ccb7786 100644
--- a/hw5/src/tu.c
+++ b/hw5/src/tu.c
@@ -92,7 +92,7 @@ void tu_unref(TU *tu, char *reason) {
     pthread_mutex_lock(&tu->mutex);
     // debug(reason);
     tu->ref --;
-    if (tu->ref <= 0)
+    if (tu->ref == 0)
         tu_destroy(tu);
     else
         pthread_mutex_unlock(&tu->mutex);
@@ -419,7 +419,7 @@ int tu_hangup(TU *tu) {
             tu->chat_TU = NULL;
             tu->ref --;
             tu->chat_locked = 0;
-            if (tu->ref <= 0)
+            if (tu->ref == 0)
                 tu_destroy(tu);
             else
                 pthread_mutex_unlock(&tu->mutex);
@@ -456,7 +456,7 @@ int tu_hangup(TU *tu) {
             tu->chat_TU = NULL;
             tu->ref --;
             tu->chat_locked = 0;
-            if (tu->ref <= 0)
+            if (tu->ref == 0)
                 tu_destroy(tu);
             else
                 pthread_mutex_unlock(&tu->mutex);