diff --git a/paddle/fluid/framework/details/op_handle_base.h b/paddle/fluid/framework/details/op_handle_base.h
index 9fbefabc841e3f6940860f60d959fee97495e4c9..d09b94a3fd32952985a37cf4246c7640d2db4f56 100644
--- a/paddle/fluid/framework/details/op_handle_base.h
+++ b/paddle/fluid/framework/details/op_handle_base.h
@@ -64,7 +64,8 @@ class OpHandleBase {
   virtual bool IsMultiDeviceTransfer() { return false; }
 
   const platform::DeviceContext *DeviceContext(platform::Place place) {
-    return dev_ctxes_[place];
+    auto it = dev_ctxes_.find(place);
+    return it != dev_ctxes_.end() ? it->second : nullptr;
   }
 
   void SetDeviceContext(platform::Place place, platform::DeviceContext *ctx_) {
diff --git a/paddle/fluid/framework/executor.cc b/paddle/fluid/framework/executor.cc
index 70ec6e90a4d0106b7f838e51b8357798daa4b10d..4576999c8ec756ee662ed91df198e1a96f9897fc 100644
--- a/paddle/fluid/framework/executor.cc
+++ b/paddle/fluid/framework/executor.cc
@@ -46,6 +46,41 @@ ExecutorPrepareContext::~ExecutorPrepareContext() {
   VLOG(5) << "destroy ExecutorPrepareContext";
 }
 
+template <typename RefCntMap>
+static void DeleteUnusedTensors(const Scope& scope, const OperatorBase* op,
+                                GarbageCollector<Tensor>* gc,
+                                RefCntMap* ref_cnts) {
+  std::unordered_set<Tensor*> erase_tensors;
+
+  auto handler = [&](const VariableNameMap& name_map) {
+    for (auto& name_pair : name_map) {
+      for (auto& name : name_pair.second) {
+        auto it = ref_cnts->find(name);
+        if (it == ref_cnts->end()) continue;
+        if ((it->second)-- == 1) {
+          auto* var = scope.FindVar(name);
+          if (var != nullptr) {
+            VLOG(10) << "Erase tensor \'" << name << "\'";
+            if (var->IsType<LoDTensor>()) {
+              erase_tensors.insert(var->GetMutable<LoDTensor>());
+            } else if (var->IsType<SelectedRows>()) {
+              erase_tensors.insert(
+                  var->GetMutable<SelectedRows>()->mutable_value());
+            }
+          }
+        }
+      }
+    }
+  };
+
+  handler(op->Inputs());
+  handler(op->Outputs());
+
+  if (!erase_tensors.empty()) {
+    gc->Add(erase_tensors);
+  }
+}
+
 Executor::Executor(const platform::Place& place) : place_(place) {}
 
 void Executor::Close() {
@@ -331,9 +366,13 @@ void Executor::RunPreparedContext(ExecutorPrepareContext* ctx, Scope* scope,
   }
 
   int64_t max_memory_size = GetEagerDeletionThreshold();
-
   std::unique_ptr<GarbageCollector<Tensor>> gc;
-  if (max_memory_size >= 0) {
+  // WhileOp would set keep_kids to false
+  // WhileGradOp would need the scopes created in WhileOp
+  // Perhaps, we should not perform eager deletion in WhileOp
+  // The scopes and variables created by WhileOp would be deleted
+  // in WhileGradOp.
+  if (max_memory_size >= 0 && !keep_kids) {
     ctx->ResetReferenceCount();
 #ifdef PADDLE_WITH_CUDA
     if (platform::is_gpu_place(place_)) {
@@ -352,45 +391,8 @@ void Executor::RunPreparedContext(ExecutorPrepareContext* ctx, Scope* scope,
     op->Run(*local_scope, place_);
 
     if (gc != nullptr) {
-      std::vector<std::string> erase_vars;
-      for (auto& input : op->Inputs()) {
-        for (auto& input_name : input.second) {
-          auto it = ctx->cur_ref_cnts_.find(input_name);
-          if (it == ctx->cur_ref_cnts_.end()) continue;
-          if (it->second == 1) {  // should delete it
-            erase_vars.emplace_back(input_name);
-            ctx->cur_ref_cnts_.erase(input_name);
-          } else {
-            --(it->second);
-          }
-        }
-      }
-
-      for (auto& output : op->Outputs()) {
-        for (auto& output_name : output.second) {
-          auto it = ctx->cur_ref_cnts_.find(output_name);
-          if (it == ctx->cur_ref_cnts_.end()) continue;
-          if (it->second == 1) {
-            erase_vars.emplace_back(output_name);
-            ctx->cur_ref_cnts_.erase(output_name);
-          } else {
-            --(it->second);
-          }
-        }
-      }
-
-      if (!erase_vars.empty()) {
-        std::vector<framework::LoDTensor*> erase_tensors;
-        for (auto& name : erase_vars) {
-          auto* var = local_scope->FindVar(name);
-          if (var == nullptr) continue;
-          if (var->IsType<framework::LoDTensor>()) {
-            auto* tensor = var->GetMutable<framework::LoDTensor>();
-            erase_tensors.push_back(tensor);
-          }
-        }
-        if (!erase_tensors.empty()) gc->Add(erase_tensors);
-      }
+      DeleteUnusedTensors(*local_scope, op.get(), gc.get(),
+                          &(ctx->cur_ref_cnts_));
     }
 
     if (FLAGS_benchmark) {
diff --git a/paddle/fluid/framework/executor.h b/paddle/fluid/framework/executor.h
index f0cc1338a8af50030a70a9797cbcd1b0567272b5..36b36d49c2728dbef93042158dffa26d8f56d529 100644
--- a/paddle/fluid/framework/executor.h
+++ b/paddle/fluid/framework/executor.h
@@ -32,38 +32,32 @@ template <typename T>
 std::unordered_map<std::string, T> GetNonPersistableReferenceCount(
     const ProgramDesc& prog, size_t block_id) {
   auto& block = prog.Block(block_id);
-  std::unordered_set<std::string> ignored_vars;
   std::unordered_map<std::string, T> ref_cnts;
 
-  for (auto var_desc : block.AllVars()) {
-    auto type = var_desc->Proto()->type().type();
-    if (type != proto::VarType::LOD_TENSOR || var_desc->Persistable()) {
-      ignored_vars.insert(var_desc->Name());  // ignore persistable vars
-    }
-  }
-
-  for (auto op_desc : block.AllOps()) {
-    for (auto& input : op_desc->Inputs()) {
-      for (auto& input_name : input.second) {
-        if (!ignored_vars.count(input_name)) {
-          if (ref_cnts.count(input_name))
-            ++ref_cnts[input_name];
-          else
-            ref_cnts[input_name] = 1;
+  auto update_ref_cnts = [&](OpDesc* op_desc, const VariableNameMap& name_map) {
+    for (auto& name_pair : name_map) {
+      for (auto& name : name_pair.second) {
+        auto* var_desc = block.FindVar(name);
+        if (var_desc == nullptr || var_desc->Persistable()) continue;
+        auto type = var_desc->Proto()->type().type();
+        if (type != proto::VarType::LOD_TENSOR &&
+            type != proto::VarType::SELECTED_ROWS) {
+          continue;
         }
-      }
-    }
 
-    for (auto& output : op_desc->Outputs()) {
-      for (auto output_name : output.second) {
-        if (!ignored_vars.count(output_name)) {
-          if (ref_cnts.count(output_name))
-            ++ref_cnts[output_name];
-          else
-            ref_cnts[output_name] = 1;
+        auto it = ref_cnts.find(name);
+        if (it != ref_cnts.end()) {
+          ++it->second;
+        } else {
+          ref_cnts[name] = 1;
         }
       }
     }
+  };
+
+  for (auto op_desc : block.AllOps()) {
+    update_ref_cnts(op_desc, op_desc->Inputs());
+    update_ref_cnts(op_desc, op_desc->Outputs());
   }
   return ref_cnts;
 }
diff --git a/paddle/fluid/framework/parallel_executor.cc b/paddle/fluid/framework/parallel_executor.cc
index f06bad6c78c05804e583f859906b88fb7b500372..8d2e66009c280426f795290fbbbf96a33c1aa637 100644
--- a/paddle/fluid/framework/parallel_executor.cc
+++ b/paddle/fluid/framework/parallel_executor.cc
@@ -64,6 +64,8 @@ ParallelExecutor::ParallelExecutor(
     const ExecutionStrategy &exec_strategy, const BuildStrategy &build_strategy,
     size_t num_trainers, size_t trainer_id)
     : member_(new ParallelExecutorPrivate(places)) {
+  is_alive_.test_and_set();
+
   member_->global_scope_ = scope;
   member_->use_cuda_ = exec_strategy.use_cuda_;
   member_->use_all_reduce_ =
@@ -246,6 +248,15 @@ void ParallelExecutor::BCastParamsToDevices(
 
 void ParallelExecutor::Run(const std::vector<std::string> &fetch_tensors,
                            const std::string &fetched_var_name) {
+  // If ParallelExecutor has been destructed
+  // just return
+  if (!is_alive_.test_and_set()) return;
+
+  // If ParallelExecutor is running
+  if (is_running_.test_and_set()) {
+    PADDLE_THROW("The previous ParallelExecutor::Run() has not stopped");
+  }
+
   platform::RecordBlock b(0);
 #ifdef PADDLE_WITH_CUDA
   if (!gcs_.empty()) {
@@ -259,9 +270,17 @@ void ParallelExecutor::Run(const std::vector<std::string> &fetch_tensors,
     }
   }
 #endif
-  auto fetch_data = member_->executor_->Run(fetch_tensors);
-  *member_->global_scope_->Var(fetched_var_name)->GetMutable<FeedFetchList>() =
-      fetch_data;
+  try {
+    auto fetch_data = member_->executor_->Run(fetch_tensors);
+    *member_->global_scope_->Var(fetched_var_name)
+         ->GetMutable<FeedFetchList>() = fetch_data;
+    is_running_.clear();
+  } catch (...) {
+    is_running_.clear();
+    if (is_alive_.test_and_set()) {
+      std::rethrow_exception(std::current_exception());
+    }
+  }
 }
 
 void ParallelExecutor::FeedTensorsIntoLocalScopes(
@@ -299,6 +318,7 @@ void ParallelExecutor::FeedAndSplitTensorIntoLocalScopes(
 }
 
 ParallelExecutor::~ParallelExecutor() {
+  is_alive_.clear();
   if (member_->own_local_scope_) {
     for (size_t i = 1; i < member_->local_scopes_.size(); ++i) {
       Scope *local_scope = member_->local_scopes_[i];
@@ -307,6 +327,12 @@ ParallelExecutor::~ParallelExecutor() {
       }
     }
   }
+
+  while (is_running_.test_and_set()) {
+    // wait unitl all threads have been stopped
+  }
+
+  member_.reset();
 }
 
 }  // namespace framework
diff --git a/paddle/fluid/framework/parallel_executor.h b/paddle/fluid/framework/parallel_executor.h
index fd386a5987f11ff64964e95eb7e9b83572dc790c..b78f7173752bd33e78c9d82080c72da7066facd6 100644
--- a/paddle/fluid/framework/parallel_executor.h
+++ b/paddle/fluid/framework/parallel_executor.h
@@ -75,7 +75,20 @@ class ParallelExecutor {
  private:
   void BCastParamsToDevices(const std::unordered_set<std::string> &vars) const;
 
-  ParallelExecutorPrivate *member_;
+  std::unique_ptr<ParallelExecutorPrivate> member_;
+
+  // FIXME(zjl): HOT-FIX
+  // A flag to indicate whether ParallelExecutor is destructed.
+  // In Python side, when users interrupt the process manually, such as
+  // keyboard interrupt, ParallelExecutor may be destructed before Run() ends.
+  // Thus, disturbing exception messages would occur when interrupted.
+  // If is_alive_ is false, we would discard the last exception thrown by Run().
+  // Since std::atomic_flag is always lock-free and faster than
+  // std::atomic<bool>, we choose std::atomic_flag to be the flag here.
+  std::atomic_flag is_alive_ = ATOMIC_FLAG_INIT;
+
+  // A flag to indicate whether ParallelExecutor is running.
+  std::atomic_flag is_running_ = ATOMIC_FLAG_INIT;
 
 #ifdef PADDLE_WITH_CUDA
   // ref_cnts_ is only initialized when ParallelExecutor constructs, and then
diff --git a/paddle/fluid/framework/scope.cc b/paddle/fluid/framework/scope.cc
index 1a727a2c8c759d010606d5b605823b7252b35c69..a4abd1b1283f08fb8431fbeea0cea17c8439fdd7 100644
--- a/paddle/fluid/framework/scope.cc
+++ b/paddle/fluid/framework/scope.cc
@@ -49,18 +49,18 @@ int64_t GetEagerDeletionThreshold() {
 Scope::~Scope() { DropKids(); }
 
 Scope& Scope::NewScope() const {
-  std::unique_lock<std::mutex> lock(mutex_);
+  std::lock_guard<std::mutex> lock(mutex_);
   kids_.push_back(new Scope(this));
   return *kids_.back();
 }
 
 Variable* Scope::Var(const std::string& name) {
-  std::unique_lock<std::mutex> lock(mutex_);
+  std::lock_guard<std::mutex> lock(mutex_);
   return VarInternal(name);
 }
 
 Variable* Scope::Var(std::string* name) {
-  std::unique_lock<std::mutex> lock(mutex_);
+  std::lock_guard<std::mutex> lock(mutex_);
   auto new_name = string::Sprintf("%p.%d", this, vars_.size());
   if (name != nullptr) {
     *name = new_name;
@@ -69,29 +69,34 @@ Variable* Scope::Var(std::string* name) {
 }
 
 Variable* Scope::FindVar(const std::string& name) const {
-  std::unique_lock<std::mutex> lock(mutex_);
+  std::lock_guard<std::mutex> lock(mutex_);
   return FindVarInternal(name);
 }
 
+Variable* Scope::FindLocalVar(const std::string& name) const {
+  std::lock_guard<std::mutex> lock(mutex_);
+  return FindVarLocally(name);
+}
+
 const Scope* Scope::FindScope(const Variable* var) const {
-  std::unique_lock<std::mutex> lock(mutex_);
+  std::lock_guard<std::mutex> lock(mutex_);
   return FindScopeInternal(var);
 }
 
 void Scope::DropKids() {
-  std::unique_lock<std::mutex> lock(mutex_);
+  std::lock_guard<std::mutex> lock(mutex_);
   for (Scope* s : kids_) delete s;
   kids_.clear();
 }
 
 bool Scope::HasKid(const Scope* scope) const {
-  std::unique_lock<std::mutex> lock(mutex_);
+  std::lock_guard<std::mutex> lock(mutex_);
   auto it = std::find(this->kids_.begin(), this->kids_.end(), scope);
   return it != this->kids_.end();
 }
 
 std::vector<std::string> Scope::LocalVarNames() const {
-  std::unique_lock<std::mutex> lock(mutex_);
+  std::lock_guard<std::mutex> lock(mutex_);
   std::vector<std::string> known_vars;
   known_vars.reserve(this->vars_.size());
   for (auto& p : vars_) {
@@ -101,7 +106,7 @@ std::vector<std::string> Scope::LocalVarNames() const {
 }
 
 void Scope::DeleteScope(Scope* scope) const {
-  std::unique_lock<std::mutex> lock(mutex_);
+  std::lock_guard<std::mutex> lock(mutex_);
   auto it = std::find(this->kids_.begin(), this->kids_.end(), scope);
   PADDLE_ENFORCE(it != this->kids_.end(), "Cannot find %p as kid scope", scope);
   this->kids_.erase(it);
@@ -114,7 +119,7 @@ void Scope::DeleteScope(Scope* scope) const {
 }
 
 void Scope::EraseVars(const std::vector<std::string>& var_names) {
-  std::unique_lock<std::mutex> lock(mutex_);
+  std::lock_guard<std::mutex> lock(mutex_);
   std::set<std::string> var_set(var_names.begin(), var_names.end());
   for (auto it = vars_.begin(); it != vars_.end();) {
     if (var_set.find(it->first) != var_set.end()) {
@@ -127,12 +132,12 @@ void Scope::EraseVars(const std::vector<std::string>& var_names) {
 
 void Scope::Rename(const std::string& origin_name,
                    const std::string& new_name) const {
-  std::unique_lock<std::mutex> lock(mutex_);
+  std::lock_guard<std::mutex> lock(mutex_);
   RenameInternal(origin_name, new_name);
 }
 
 std::string Scope::Rename(const std::string& origin_name) const {
-  std::unique_lock<std::mutex> lock(mutex_);
+  std::lock_guard<std::mutex> lock(mutex_);
   auto new_name = string::Sprintf("%p.%d", this, vars_.size());
   RenameInternal(origin_name, new_name);
   return new_name;
diff --git a/paddle/fluid/framework/scope.h b/paddle/fluid/framework/scope.h
index e42fff1d79d92fb7ed61768a614d8cd98f6775a0..14f9f36812d690fc4a7440f2e7e6a85e9993a535 100644
--- a/paddle/fluid/framework/scope.h
+++ b/paddle/fluid/framework/scope.h
@@ -63,6 +63,11 @@ class Scope {
   /// Caller doesn't own the returned Variable.
   Variable* FindVar(const std::string& name) const;
 
+  /// Find a variable in the current scope.
+  /// Return nullptr if cannot find.
+  /// Caller doesn't own the returned Variable.
+  Variable* FindLocalVar(const std::string& name) const;
+
   const Scope* parent() const { return parent_; }
 
   /// Find the scope or an ancestor scope that contains the given variable.