diff --git a/binlog.c b/binlog.c
index 0414fa1..49dfee0 100644
--- a/binlog.c
+++ b/binlog.c
@@ -685,7 +685,7 @@ void replay_log_event (void) {
         assert (C->user_list[i].user_id != user);
       }
       C->user_list_size ++;
-      C->user_list = realloc (C->user_list, 12 * C->user_list_size);
+      C->user_list = trealloc (C->user_list, 12 * C->user_list_size);
       C->user_list[C->user_list_size - 1].user_id = user;
       C->user_list[C->user_list_size - 1].inviter_id = inviter;
       C->user_list[C->user_list_size - 1].date = date;
@@ -715,7 +715,7 @@ void replay_log_event (void) {
       }
       assert (C->user_list[C->user_list_size - 1].user_id == user);
       C->user_list_size --;
-      C->user_list = realloc (C->user_list, 12 * C->user_list_size);
+      C->user_list = trealloc (C->user_list, 12 * C->user_list_size);
       C->user_list_version = version;
     }
     break;
diff --git a/tools.c b/tools.c
index bcaa527..748edd5 100644
--- a/tools.c
+++ b/tools.c
@@ -31,6 +31,12 @@ static void out_of_memory (void) {
   assert (0 && "Out of memory");
 }
 
+void *trealloc (void *ptr, size_t size) {
+  void *p = realloc (ptr, size);
+  ensure_ptr (p);
+  return p;
+}
+
 void *talloc (size_t size) {
   void *p = malloc (size);
   ensure_ptr (p);
diff --git a/tools.h b/tools.h
index f3f7f88..9753b86 100644
--- a/tools.h
+++ b/tools.h
@@ -21,6 +21,7 @@
 #define __TOOLS_H__
 
 void *talloc (size_t size);
+void *trealloc (void *ptr, size_t size);
 void *talloc0 (size_t size);
 char *tstrdup (const char *s);
 void ensure (int r);