diff --git a/webrtc/modules/utility/source/process_thread_impl.cc b/webrtc/modules/utility/source/process_thread_impl.cc
index 9028c445a5..bdbd5ca086 100644
--- a/webrtc/modules/utility/source/process_thread_impl.cc
+++ b/webrtc/modules/utility/source/process_thread_impl.cc
@@ -164,6 +164,7 @@ bool ProcessThreadImpl::Process()
         {
             return true;
         }
+        CriticalSectionScoped lock(_critSectModules);
         if(!_thread)
         {
             return false;