diff --git a/libtest/signal.cc b/libtest/signal.cc
index 2921f7143..48901b073 100644
--- a/libtest/signal.cc
+++ b/libtest/signal.cc
@@ -216,11 +216,11 @@ SignalThread::SignalThread() :
   sigaddset(&set, SIGUSR2);
 
   strcpy(lock_name, "/XXXXXXXX");
-  if (mkstemp(lock_name) == -1)
+  // random lock_name required
+  if (mkstemp(lock_name) != -1)
   {
-    // it doesn't matter
-    // mkstemp should get random lock_name
-    // Error << strerror(errno) << " mkstemp failed.";
+    // remove unnecessary file
+    remove(lock_name);
   }
 
   sigemptyset(&original_set);
diff --git a/util/signal.cc b/util/signal.cc
index 8371c1dc0..7723cc248 100644
--- a/util/signal.cc
+++ b/util/signal.cc
@@ -206,11 +206,11 @@ SignalThread::SignalThread(bool exit_on_signal_arg) :
   sigaddset(&set, SIGUSR2);
 
   strcpy(lock_name, "/XXXXXXXXX");
-  if (mkstemp(lock_name) == -1)
+  // random lock_name required
+  if (mkstemp(lock_name) != -1)
    {
-    // it doesn't matter
-    // mkstemp should get random lock_name
-    // std::cerr << strerror(errno) << " mkstemp failed.";
+    // remove unnecessary file
+    remove(lock_name);
   }
 }