diff --git a/include/util/command.hpp b/include/util/command.hpp
index ca10718..69b1fd4 100644
--- a/include/util/command.hpp
+++ b/include/util/command.hpp
@@ -33,7 +33,7 @@ inline int close(FILE* fp, pid_t pid) {
   fclose(fp);
   while (waitpid(pid, &stat, 0) == -1) {
     if (errno != EINTR) {
-      stat = -1;
+      stat = 0;
       break;
     }
   }
diff --git a/include/util/sleeper_thread.hpp b/include/util/sleeper_thread.hpp
index 90ef9d8..642d47d 100644
--- a/include/util/sleeper_thread.hpp
+++ b/include/util/sleeper_thread.hpp
@@ -14,7 +14,10 @@ class SleeperThread {
 
   SleeperThread(std::function<void()> func)
       : thread_{[this, func] {
-          while (do_run_) func();
+          while (do_run_) {
+            signal_ = false;
+            func();
+          }
         }} {}
 
   SleeperThread& operator=(std::function<void()> func) {
@@ -42,7 +45,10 @@ class SleeperThread {
   }
 
   auto wake_up() {
-    signal_ = true;
+    {
+      std::lock_guard<std::mutex> lck(mutex_);
+      signal_ = true;
+    }
     condvar_.notify_all();
   }