diff --git a/unsupported/Eigen/CXX11/src/ThreadPool/NonBlockingThreadPool.h b/unsupported/Eigen/CXX11/src/ThreadPool/NonBlockingThreadPool.h
index 1ac4de3b5..d710faa94 100644
--- a/unsupported/Eigen/CXX11/src/ThreadPool/NonBlockingThreadPool.h
+++ b/unsupported/Eigen/CXX11/src/ThreadPool/NonBlockingThreadPool.h
@@ -169,16 +169,16 @@ class ThreadPoolTempl : public Eigen::ThreadPoolInterface {
   EventCount ec_;
 #ifndef EIGEN_THREAD_LOCAL
   std::unique_ptr<Barrier> init_barrier_;
-  std::mutex mu;  // Protects per_thread_map_.
+  std::mutex per_thread_map_mutex_;  // Protects per_thread_map_.
   std::unordered_map<uint64_t, std::unique_ptr<PerThread>> per_thread_map_;
 #endif
 
   // Main worker thread loop.
   void WorkerLoop(int thread_id) {
 #ifndef EIGEN_THREAD_LOCAL
-    mu.lock();
+    per_thread_map_mutex_.lock();
     eigen_assert(per_thread_map_.emplace(GlobalThreadIdHash(), new PerThread()).second);
-    mu.unlock();
+    per_thread_map_mutex_.unlock();
     init_barrier_->Notify();
     init_barrier_->Wait();
 #endif