Index: lldb/tools/lldb-vscode/ProgressEvent.cpp
===================================================================
--- lldb/tools/lldb-vscode/ProgressEvent.cpp
+++ lldb/tools/lldb-vscode/ProgressEvent.cpp
@@ -179,15 +179,24 @@
     : m_report_callback(report_callback) {
   m_thread_should_exit = false;
   m_thread = std::thread([&] {
-    while (!m_thread_should_exit) {
-      std::this_thread::sleep_for(kUpdateProgressEventReportDelay);
-      ReportStartEvents();
+    while (true) {
+      m_mutex.lock();
+      bool thread_should_exit = m_thread_should_exit;
+      m_mutex.unlock();
+      if (!thread_should_exit) {
+        std::this_thread::sleep_for(kUpdateProgressEventReportDelay);
+        ReportStartEvents();
+      } else {
+        break;
+      }
     }
   });
 }
 
 ProgressEventReporter::~ProgressEventReporter() {
+  m_mutex.lock();
   m_thread_should_exit = true;
+  m_mutex.unlock();
   m_thread.join();
 }