diff --git a/mindspore/ccsrc/fl/server/distributed_count_service.cc b/mindspore/ccsrc/fl/server/distributed_count_service.cc
index 766e5a4013f..e3ceb8ae7a9 100644
--- a/mindspore/ccsrc/fl/server/distributed_count_service.cc
+++ b/mindspore/ccsrc/fl/server/distributed_count_service.cc
@@ -121,7 +121,7 @@ bool DistributedCountService::CountReachThreshold(const std::string &name) {
   MS_LOG(INFO) << "Rank " << local_rank_ << " query whether count reaches threshold for " << name;
   if (local_rank_ == counting_server_rank_) {
     if (global_threshold_count_.count(name) == 0) {
-      MS_LOG(ERROR) << "Counter for " << name << " is not set.";
+      MS_LOG(ERROR) << "Counter for " << name << " is not registered.";
       return false;
     }
 
@@ -138,6 +138,7 @@ bool DistributedCountService::CountReachThreshold(const std::string &name) {
       return false;
     }
 
+    MS_ERROR_IF_NULL_W_RET_VAL(query_cnt_enough_rsp_msg, false);
     CountReachThresholdResponse count_reach_threshold_rsp;
     (void)count_reach_threshold_rsp.ParseFromArray(query_cnt_enough_rsp_msg->data(),
                                                    SizeToInt(query_cnt_enough_rsp_msg->size()));
@@ -173,11 +174,7 @@ bool DistributedCountService::ReInitForScaling() {
 }
 
 void DistributedCountService::HandleCountRequest(const std::shared_ptr<ps::core::MessageHandler> &message) {
-  if (message == nullptr) {
-    MS_LOG(ERROR) << "Message is nullptr.";
-    return;
-  }
-
+  MS_ERROR_IF_NULL_WO_RET_VAL(message);
   CountRequest report_count_req;
   (void)report_count_req.ParseFromArray(message->data(), SizeToInt(message->len()));
   const std::string &name = report_count_req.name();
@@ -235,11 +232,7 @@ void DistributedCountService::HandleCountRequest(const std::shared_ptr<ps::core:
 
 void DistributedCountService::HandleCountReachThresholdRequest(
   const std::shared_ptr<ps::core::MessageHandler> &message) {
-  if (message == nullptr) {
-    MS_LOG(ERROR) << "Message is nullptr.";
-    return;
-  }
-
+  MS_ERROR_IF_NULL_WO_RET_VAL(message);
   CountReachThresholdRequest count_reach_threshold_req;
   (void)count_reach_threshold_req.ParseFromArray(message->data(), SizeToInt(message->len()));
   const std::string &name = count_reach_threshold_req.name();
@@ -261,11 +254,7 @@ void DistributedCountService::HandleCountReachThresholdRequest(
 }
 
 void DistributedCountService::HandleCounterEvent(const std::shared_ptr<ps::core::MessageHandler> &message) {
-  if (message == nullptr) {
-    MS_LOG(ERROR) << "Message is nullptr.";
-    return;
-  }
-
+  MS_ERROR_IF_NULL_WO_RET_VAL(message);
   // Respond as soon as possible so the leader server won't wait for each follower servers to finish calling the
   // callbacks.
   std::string couter_event_rsp_msg = "success";
@@ -279,6 +268,10 @@ void DistributedCountService::HandleCounterEvent(const std::shared_ptr<ps::core:
   const auto &type = counter_event.type();
   const auto &name = counter_event.name();
 
+  if (counter_handlers_.count(name) == 0) {
+    MS_LOG(ERROR) << "The counter handler of " << name << " is not registered.";
+    return;
+  }
   MS_LOG(DEBUG) << "Rank " << local_rank_ << " do counter event " << type << " for " << name;
   if (type == CounterEventType::FIRST_CNT) {
     counter_handlers_[name].first_count_handler(message);
@@ -292,6 +285,11 @@ void DistributedCountService::HandleCounterEvent(const std::shared_ptr<ps::core:
 }
 
 bool DistributedCountService::TriggerCounterEvent(const std::string &name, std::string *reason) {
+  if (global_current_count_.count(name) == 0 || global_threshold_count_.count(name) == 0) {
+    MS_LOG(ERROR) << "The counter of " << name << " is not registered.";
+    return false;
+  }
+
   MS_LOG(INFO) << "Current count for " << name << " is " << global_current_count_[name].size()
                << ", threshold count is " << global_threshold_count_[name];
   // The threshold count may be 1 so the first and last count event should be both activated.
@@ -324,6 +322,11 @@ bool DistributedCountService::TriggerFirstCountEvent(const std::string &name, st
       return false;
     }
   }
+
+  if (counter_handlers_.count(name) == 0) {
+    MS_LOG(ERROR) << "The counter handler of " << name << " is not registered.";
+    return false;
+  }
   // Leader server directly calls the callback.
   counter_handlers_[name].first_count_handler(nullptr);
   return true;
@@ -345,6 +348,11 @@ bool DistributedCountService::TriggerLastCountEvent(const std::string &name, std
       return false;
     }
   }
+
+  if (counter_handlers_.count(name) == 0) {
+    MS_LOG(ERROR) << "The counter handler of " << name << " is not registered.";
+    return false;
+  }
   // Leader server directly calls the callback.
   counter_handlers_[name].last_count_handler(nullptr);
   return true;
diff --git a/mindspore/ccsrc/fl/server/distributed_metadata_store.cc b/mindspore/ccsrc/fl/server/distributed_metadata_store.cc
index e083475d25d..1b12143e9e2 100644
--- a/mindspore/ccsrc/fl/server/distributed_metadata_store.cc
+++ b/mindspore/ccsrc/fl/server/distributed_metadata_store.cc
@@ -181,11 +181,7 @@ void DistributedMetadataStore::InitHashRing() {
 }
 
 void DistributedMetadataStore::HandleUpdateMetadataRequest(const std::shared_ptr<ps::core::MessageHandler> &message) {
-  if (message == nullptr) {
-    MS_LOG(ERROR) << "Message is nullptr.";
-    return;
-  }
-
+  MS_ERROR_IF_NULL_WO_RET_VAL(message);
   PBMetadataWithName meta_with_name;
   (void)meta_with_name.ParseFromArray(message->data(), SizeToInt(message->len()));
   const std::string &name = meta_with_name.name();
@@ -206,17 +202,17 @@ void DistributedMetadataStore::HandleUpdateMetadataRequest(const std::shared_ptr
 }
 
 void DistributedMetadataStore::HandleGetMetadataRequest(const std::shared_ptr<ps::core::MessageHandler> &message) {
-  if (message == nullptr) {
-    MS_LOG(ERROR) << "Message is nullptr.";
-    return;
-  }
-
+  MS_ERROR_IF_NULL_WO_RET_VAL(message);
   GetMetadataRequest get_metadata_req;
   (void)get_metadata_req.ParseFromArray(message->data(), message->len());
   const std::string &name = get_metadata_req.name();
   MS_LOG(INFO) << "Getting metadata for " << name;
 
   std::unique_lock<std::mutex> lock(mutex_[name]);
+  if (metadata_.count(name) == 0) {
+    MS_LOG(ERROR) << "The metadata of " << name << " is not registered.";
+    return;
+  }
   PBMetadata stored_meta = metadata_[name];
   std::string getting_meta_rsp_msg = stored_meta.SerializeAsString();
   if (!communicator_->SendResponse(getting_meta_rsp_msg.data(), getting_meta_rsp_msg.size(), message)) {
@@ -228,6 +224,10 @@ void DistributedMetadataStore::HandleGetMetadataRequest(const std::shared_ptr<ps
 
 bool DistributedMetadataStore::DoUpdateMetadata(const std::string &name, const PBMetadata &meta) {
   std::unique_lock<std::mutex> lock(mutex_[name]);
+  if (metadata_.count(name) == 0) {
+    MS_LOG(ERROR) << "The metadata of " << name << " is not registered.";
+    return false;
+  }
   if (meta.has_device_meta()) {
     auto &fl_id_to_meta_map = *metadata_[name].mutable_device_metas()->mutable_fl_id_to_meta();
     auto &device_meta_fl_id = meta.device_meta().fl_id();
diff --git a/mindspore/ccsrc/fl/server/executor.cc b/mindspore/ccsrc/fl/server/executor.cc
index d5233a6e612..460b8dba502 100644
--- a/mindspore/ccsrc/fl/server/executor.cc
+++ b/mindspore/ccsrc/fl/server/executor.cc
@@ -158,17 +158,10 @@ bool Executor::HandlePushWeight(const std::map<std::string, Address> &feature_ma
     auto &param_aggr = param_aggrs_[param_name];
     MS_ERROR_IF_NULL_W_RET_VAL(param_aggr, false);
     AddressPtr old_weight = param_aggr->GetWeight();
-    if (old_weight == nullptr) {
-      MS_LOG(ERROR) << "Get weight of " << param_name << " failed: the AddressPtr is nullptr.";
-      return false;
-    }
-
     const Address &new_weight = trainable_param.second;
-    if (new_weight.addr == nullptr) {
-      MS_LOG(ERROR) << "The new weight is nullptr.";
-      return false;
-    }
-
+    MS_ERROR_IF_NULL_W_RET_VAL(old_weight, false);
+    MS_ERROR_IF_NULL_W_RET_VAL(old_weight->addr, false);
+    MS_ERROR_IF_NULL_W_RET_VAL(new_weight.addr, false);
     int ret = memcpy_s(old_weight->addr, old_weight->size, new_weight.addr, new_weight.size);
     if (ret != 0) {
       MS_LOG(ERROR) << "memcpy_s error, errorno(" << ret << ")";
@@ -295,6 +288,7 @@ std::string Executor::GetTrainableParamName(const CNodePtr &cnode) {
   MS_EXCEPTION_IF_NULL(weight_node);
   if (!weight_node->isa<Parameter>()) {
     MS_LOG(EXCEPTION) << weight_idx << " input of " << cnode_name << " is not a Parameter.";
+    return "";
   }
   return weight_node->fullname_with_scope();
 }
@@ -309,7 +303,7 @@ bool Executor::InitParamAggregator(const FuncGraphPtr &func_graph) {
       continue;
     }
     if (param_aggrs_.count(param_name) != 0) {
-      MS_LOG(WARNING) << param_name << " already has its control flow.";
+      MS_LOG(WARNING) << param_name << " already has parameter aggregator registered.";
       continue;
     }
 
diff --git a/mindspore/ccsrc/fl/server/iteration.cc b/mindspore/ccsrc/fl/server/iteration.cc
index 6d2b6fbb007..21e4ad014d6 100644
--- a/mindspore/ccsrc/fl/server/iteration.cc
+++ b/mindspore/ccsrc/fl/server/iteration.cc
@@ -66,9 +66,7 @@ void Iteration::InitRounds(const std::vector<std::shared_ptr<ps::core::Communica
   (void)std::for_each(communicators.begin(), communicators.end(),
                       [&](const std::shared_ptr<ps::core::CommunicatorBase> &communicator) {
                         for (auto &round : rounds_) {
-                          if (round == nullptr) {
-                            continue;
-                          }
+                          MS_EXCEPTION_IF_NULL(round);
                           round->Initialize(communicator, timeout_cb, finish_iteration_cb);
                         }
                       });
@@ -76,6 +74,7 @@ void Iteration::InitRounds(const std::vector<std::shared_ptr<ps::core::Communica
   // The time window for one iteration, which will be used in some round kernels.
   size_t iteration_time_window = std::accumulate(rounds_.begin(), rounds_.end(), IntToSize(0),
                                                  [](size_t total, const std::shared_ptr<Round> &round) {
+                                                   MS_EXCEPTION_IF_NULL(round);
                                                    return round->check_timeout() ? total + round->time_window() : total;
                                                  });
   LocalMetaStore::GetInstance().put_value(kCtxTotalTimeoutDuration, iteration_time_window);
@@ -172,11 +171,8 @@ bool Iteration::SyncIteration(uint32_t rank) {
     MS_LOG(ERROR) << "Sending synchronizing iteration message to leader server failed.";
     return false;
   }
-  if (sync_iter_rsp_msg == nullptr) {
-    MS_LOG(ERROR) << "Response from server 0 is empty.";
-    return false;
-  }
 
+  MS_ERROR_IF_NULL_W_RET_VAL(sync_iter_rsp_msg, false);
   SyncIterationResponse sync_iter_rsp;
   (void)sync_iter_rsp.ParseFromArray(sync_iter_rsp_msg->data(), SizeToInt(sync_iter_rsp_msg->size()));
   iteration_num_ = sync_iter_rsp.iteration();
@@ -372,16 +368,17 @@ void Iteration::Next(bool is_iteration_valid, const std::string &reason) {
   if (is_iteration_valid) {
     // Store the model which is successfully aggregated for this iteration.
     const auto &model = Executor::GetInstance().GetModel();
-    (void)ModelStore::GetInstance().StoreModelByIterNum(iteration_num_, model);
+    ModelStore::GetInstance().StoreModelByIterNum(iteration_num_, model);
     MS_LOG(INFO) << "Iteration " << iteration_num_ << " is successfully finished.";
   } else {
     // Store last iteration's model because this iteration is considered as invalid.
     const auto &model = ModelStore::GetInstance().GetModelByIterNum(iteration_num_ - 1);
-    (void)ModelStore::GetInstance().StoreModelByIterNum(iteration_num_, model);
+    ModelStore::GetInstance().StoreModelByIterNum(iteration_num_, model);
     MS_LOG(WARNING) << "Iteration " << iteration_num_ << " is invalid. Reason: " << reason;
   }
 
   for (auto &round : rounds_) {
+    MS_ERROR_IF_NULL_WO_RET_VAL(round);
     round->Reset();
   }
 }
diff --git a/mindspore/ccsrc/fl/server/iteration_timer.cc b/mindspore/ccsrc/fl/server/iteration_timer.cc
index f805aefafaf..27a98c4191a 100644
--- a/mindspore/ccsrc/fl/server/iteration_timer.cc
+++ b/mindspore/ccsrc/fl/server/iteration_timer.cc
@@ -36,10 +36,12 @@ void IterationTimer::Start(const std::chrono::milliseconds &duration) {
       std::this_thread::sleep_for(std::chrono::milliseconds(1));
     }
   });
-  monitor_thread_.detach();
 }
 
-void IterationTimer::Stop() { running_ = false; }
+void IterationTimer::Stop() {
+  running_ = false;
+  monitor_thread_.join();
+}
 
 void IterationTimer::SetTimeOutCallBack(const TimeOutCb &timeout_cb) {
   timeout_callback_ = timeout_cb;
diff --git a/mindspore/ccsrc/fl/server/kernel/fed_avg_kernel.h b/mindspore/ccsrc/fl/server/kernel/fed_avg_kernel.h
index 49fd0db563d..fa7b4abc172 100644
--- a/mindspore/ccsrc/fl/server/kernel/fed_avg_kernel.h
+++ b/mindspore/ccsrc/fl/server/kernel/fed_avg_kernel.h
@@ -82,6 +82,10 @@ class FedAvgKernel : public AggregationKernel {
       }
     };
     last_cnt_handler_ = [&](std::shared_ptr<ps::core::MessageHandler>) {
+      MS_ERROR_IF_NULL_WO_RET_VAL(weight_addr_);
+      MS_ERROR_IF_NULL_WO_RET_VAL(data_size_addr_);
+      MS_ERROR_IF_NULL_WO_RET_VAL(weight_addr_->addr);
+      MS_ERROR_IF_NULL_WO_RET_VAL(data_size_addr_->addr);
       T *weight_addr = reinterpret_cast<T *>(weight_addr_->addr);
       size_t weight_size = weight_addr_->size;
       S *data_size_addr = reinterpret_cast<S *>(data_size_addr_->addr);
diff --git a/mindspore/ccsrc/fl/server/model_store.cc b/mindspore/ccsrc/fl/server/model_store.cc
index 832468d9ddb..8cbab89a9cc 100644
--- a/mindspore/ccsrc/fl/server/model_store.cc
+++ b/mindspore/ccsrc/fl/server/model_store.cc
@@ -35,33 +35,27 @@ void ModelStore::Initialize(uint32_t max_count) {
   model_size_ = ComputeModelSize();
 }
 
-bool ModelStore::StoreModelByIterNum(size_t iteration, const std::map<std::string, AddressPtr> &new_model) {
+void ModelStore::StoreModelByIterNum(size_t iteration, const std::map<std::string, AddressPtr> &new_model) {
   std::unique_lock<std::mutex> lock(model_mtx_);
   if (iteration_to_model_.count(iteration) != 0) {
     MS_LOG(WARNING) << "Model for iteration " << iteration << " is already stored";
-    return false;
+    return;
   }
   if (new_model.empty()) {
     MS_LOG(ERROR) << "Model feature map is empty.";
-    return false;
+    return;
   }
 
   std::shared_ptr<MemoryRegister> memory_register = nullptr;
   if (iteration_to_model_.size() < max_model_count_) {
     // If iteration_to_model_.size() is not max_model_count_, need to assign new memory for the model.
     memory_register = AssignNewModelMemory();
-    if (memory_register == nullptr) {
-      MS_LOG(ERROR) << "Memory for the new model is nullptr.";
-      return false;
-    }
+    MS_ERROR_IF_NULL_WO_RET_VAL(memory_register);
     iteration_to_model_[iteration] = memory_register;
   } else {
     // If iteration_to_model_ size is already max_model_count_, we need to replace earliest model with the newest model.
     memory_register = iteration_to_model_.begin()->second;
-    if (memory_register == nullptr) {
-      MS_LOG(ERROR) << "Earliest model is nullptr.";
-      return false;
-    }
+    MS_ERROR_IF_NULL_WO_RET_VAL(memory_register);
     (void)iteration_to_model_.erase(iteration_to_model_.begin());
   }
 
@@ -74,6 +68,10 @@ bool ModelStore::StoreModelByIterNum(size_t iteration, const std::map<std::strin
       continue;
     }
 
+    MS_ERROR_IF_NULL_WO_RET_VAL(stored_model[weight_name]);
+    MS_ERROR_IF_NULL_WO_RET_VAL(stored_model[weight_name]->addr);
+    MS_ERROR_IF_NULL_WO_RET_VAL(weight.second);
+    MS_ERROR_IF_NULL_WO_RET_VAL(weight.second->addr);
     void *dst_addr = stored_model[weight_name]->addr;
     size_t dst_size = stored_model[weight_name]->size;
     void *src_addr = weight.second->addr;
@@ -81,11 +79,11 @@ bool ModelStore::StoreModelByIterNum(size_t iteration, const std::map<std::strin
     int ret = memcpy_s(dst_addr, dst_size, src_addr, src_size);
     if (ret != 0) {
       MS_LOG(ERROR) << "memcpy_s error, errorno(" << ret << ")";
-      return false;
+      return;
     }
   }
   iteration_to_model_[iteration] = memory_register;
-  return true;
+  return;
 }
 
 std::map<std::string, AddressPtr> ModelStore::GetModelByIterNum(size_t iteration) {
diff --git a/mindspore/ccsrc/fl/server/model_store.h b/mindspore/ccsrc/fl/server/model_store.h
index ea704bd3998..b8d38829ef8 100644
--- a/mindspore/ccsrc/fl/server/model_store.h
+++ b/mindspore/ccsrc/fl/server/model_store.h
@@ -47,7 +47,7 @@ class ModelStore {
 
   // Store the model of the given iteration. The model is acquired from Executor. If the current model count is already
   // max_model_count_, the earliest model will be replaced.
-  bool StoreModelByIterNum(size_t iteration, const std::map<std::string, AddressPtr> &model);
+  void StoreModelByIterNum(size_t iteration, const std::map<std::string, AddressPtr> &model);
 
   // Get model of the given iteration.
   std::map<std::string, AddressPtr> GetModelByIterNum(size_t iteration);
diff --git a/mindspore/ccsrc/fl/server/parameter_aggregator.cc b/mindspore/ccsrc/fl/server/parameter_aggregator.cc
index 2d73d24d797..cb93808ad24 100644
--- a/mindspore/ccsrc/fl/server/parameter_aggregator.cc
+++ b/mindspore/ccsrc/fl/server/parameter_aggregator.cc
@@ -49,7 +49,10 @@ bool ParameterAggregator::Init(const CNodePtr &cnode, size_t threshold_count) {
 
 bool ParameterAggregator::ReInitForScaling() {
   auto result = std::find_if(aggregation_kernel_parameters_.begin(), aggregation_kernel_parameters_.end(),
-                             [](auto aggregation_kernel) { return !aggregation_kernel.first->ReInitForScaling(); });
+                             [](auto aggregation_kernel) {
+                               MS_ERROR_IF_NULL_W_RET_VAL(aggregation_kernel.first, true);
+                               return !aggregation_kernel.first->ReInitForScaling();
+                             });
   if (result != aggregation_kernel_parameters_.end()) {
     MS_LOG(ERROR) << "Reinitializing aggregation kernel after scaling failed";
     return false;
@@ -65,6 +68,9 @@ bool ParameterAggregator::UpdateData(const std::map<std::string, Address> &new_d
       continue;
     }
 
+    MS_ERROR_IF_NULL_W_RET_VAL(name_to_addr[name], false);
+    MS_ERROR_IF_NULL_W_RET_VAL(name_to_addr[name]->addr, false);
+    MS_ERROR_IF_NULL_W_RET_VAL(data.second.addr, false);
     MS_LOG(DEBUG) << "Update data for " << name << ". Destination size: " << name_to_addr[name]->size
                   << ". Source size: " << data.second.size;
     int ret = memcpy_s(name_to_addr[name]->addr, name_to_addr[name]->size, data.second.addr, data.second.size);
@@ -228,9 +234,10 @@ bool ParameterAggregator::InitOptimizerKernels(const CNodePtr &cnode) {
 template <typename K>
 bool ParameterAggregator::AssignMemory(K server_kernel, const CNodePtr &cnode,
                                        const ReuseKernelNodeInfo &reuse_kernel_node_inputs_info,
-                                       std::shared_ptr<MemoryRegister> memory_register) {
+                                       const std::shared_ptr<MemoryRegister> &memory_register) {
   MS_EXCEPTION_IF_NULL(server_kernel);
   MS_EXCEPTION_IF_NULL(cnode);
+  MS_EXCEPTION_IF_NULL(memory_register);
 
   const std::vector<std::string> &input_names = server_kernel->input_names();
   const std::vector<size_t> &input_size_list = server_kernel->GetInputSizeList();
@@ -272,8 +279,8 @@ bool ParameterAggregator::AssignMemory(K server_kernel, const CNodePtr &cnode,
   return true;
 }
 
-bool ParameterAggregator::GenerateAggregationKernelParams(const std::shared_ptr<kernel::AggregationKernel> aggr_kernel,
-                                                          const std::shared_ptr<MemoryRegister> memory_register) {
+bool ParameterAggregator::GenerateAggregationKernelParams(const std::shared_ptr<kernel::AggregationKernel> &aggr_kernel,
+                                                          const std::shared_ptr<MemoryRegister> &memory_register) {
   MS_ERROR_IF_NULL_W_RET_VAL(aggr_kernel, false);
   MS_ERROR_IF_NULL_W_RET_VAL(memory_register, false);
   KernelParams aggr_params = {};
@@ -295,8 +302,9 @@ bool ParameterAggregator::GenerateAggregationKernelParams(const std::shared_ptr<
   return true;
 }
 
-bool ParameterAggregator::GenerateOptimizerKernelParams(const std::shared_ptr<kernel::OptimizerKernel> optimizer_kernel,
-                                                        const std::shared_ptr<MemoryRegister> memory_register) {
+bool ParameterAggregator::GenerateOptimizerKernelParams(
+  const std::shared_ptr<kernel::OptimizerKernel> &optimizer_kernel,
+  const std::shared_ptr<MemoryRegister> &memory_register) {
   MS_ERROR_IF_NULL_W_RET_VAL(optimizer_kernel, false);
   MS_ERROR_IF_NULL_W_RET_VAL(memory_register, false);
   KernelParams optimizer_params = {};
@@ -335,12 +343,12 @@ std::vector<std::string> ParameterAggregator::SelectAggregationAlgorithm(const C
 template bool ParameterAggregator::AssignMemory(std::shared_ptr<kernel::OptimizerKernel> server_kernel,
                                                 const CNodePtr &cnode,
                                                 const ReuseKernelNodeInfo &reuse_kernel_node_inputs_info,
-                                                std::shared_ptr<MemoryRegister> memory_register);
+                                                const std::shared_ptr<MemoryRegister> &memory_register);
 
 template bool ParameterAggregator::AssignMemory(std::shared_ptr<kernel::AggregationKernel> server_kernel,
                                                 const CNodePtr &cnode,
                                                 const ReuseKernelNodeInfo &reuse_kernel_node_inputs_info,
-                                                std::shared_ptr<MemoryRegister> memory_register);
+                                                const std::shared_ptr<MemoryRegister> &memory_register);
 }  // namespace server
 }  // namespace fl
 }  // namespace mindspore
diff --git a/mindspore/ccsrc/fl/server/parameter_aggregator.h b/mindspore/ccsrc/fl/server/parameter_aggregator.h
index 0121f0d97bc..f7f02f7ea07 100644
--- a/mindspore/ccsrc/fl/server/parameter_aggregator.h
+++ b/mindspore/ccsrc/fl/server/parameter_aggregator.h
@@ -105,14 +105,14 @@ class ParameterAggregator {
   // momentum, etc.
   template <typename K>
   bool AssignMemory(K server_kernel, const CNodePtr &cnode, const ReuseKernelNodeInfo &reuse_kernel_node_inputs_info,
-                    std::shared_ptr<MemoryRegister> memory_register);
+                    const std::shared_ptr<MemoryRegister> &memory_register);
 
   // Generate kernel parameters for aggregation/optimizer kernels. All the parameters is registered and stored in
   // memory_register.
-  bool GenerateAggregationKernelParams(const std::shared_ptr<kernel::AggregationKernel> aggr_kernel,
-                                       const std::shared_ptr<MemoryRegister> memory_register);
-  bool GenerateOptimizerKernelParams(const std::shared_ptr<kernel::OptimizerKernel> optim_kernel,
-                                     const std::shared_ptr<MemoryRegister> memory_register);
+  bool GenerateAggregationKernelParams(const std::shared_ptr<kernel::AggregationKernel> &aggr_kernel,
+                                       const std::shared_ptr<MemoryRegister> &memory_register);
+  bool GenerateOptimizerKernelParams(const std::shared_ptr<kernel::OptimizerKernel> &optim_kernel,
+                                     const std::shared_ptr<MemoryRegister> &memory_register);
 
   // The selection of the aggregation algorithm depends on multiple factors. For example, server mode, user
   // configuration, etc.
diff --git a/mindspore/ccsrc/fl/server/round.cc b/mindspore/ccsrc/fl/server/round.cc
index 3ece5ed728d..2805d27a880 100644
--- a/mindspore/ccsrc/fl/server/round.cc
+++ b/mindspore/ccsrc/fl/server/round.cc
@@ -40,8 +40,10 @@ void Round::Initialize(const std::shared_ptr<ps::core::CommunicatorBase> &commun
   communicator_ = communicator;
 
   // Register callback for round kernel.
-  communicator_->RegisterMsgCallBack(
-    name_, [&](std::shared_ptr<ps::core::MessageHandler> message) { LaunchRoundKernel(message); });
+  communicator_->RegisterMsgCallBack(name_, [&](std::shared_ptr<ps::core::MessageHandler> message) {
+    MS_ERROR_IF_NULL_WO_RET_VAL(message);
+    LaunchRoundKernel(message);
+  });
 
   // Callback when the iteration is finished.
   finish_iteration_cb_ = [this, finish_iteration_cb](bool is_iteration_valid, const std::string &) -> void {
@@ -50,10 +52,14 @@ void Round::Initialize(const std::shared_ptr<ps::core::CommunicatorBase> &commun
   };
 
   // Callback for finalizing the server. This can only be called once.
-  finalize_cb_ = [&](void) -> void { (void)communicator_->Stop(); };
+  finalize_cb_ = [&](void) -> void {
+    MS_ERROR_IF_NULL_WO_RET_VAL(communicator_);
+    (void)communicator_->Stop();
+  };
 
   if (check_timeout_) {
     iter_timer_ = std::make_shared<IterationTimer>();
+    MS_EXCEPTION_IF_NULL(iter_timer_);
 
     // 1.Set the timeout callback for the timer.
     iter_timer_->SetTimeOutCallBack([this, timeout_cb](bool is_iteration_valid, const std::string &) -> void {
@@ -63,6 +69,7 @@ void Round::Initialize(const std::shared_ptr<ps::core::CommunicatorBase> &commun
 
     // 2.Stopping timer callback which will be set to the round kernel.
     stop_timer_cb_ = [&](void) -> void {
+      MS_ERROR_IF_NULL_WO_RET_VAL(iter_timer_);
       MS_LOG(INFO) << "Round " << name_ << " kernel stops its timer.";
       iter_timer_->Stop();
     };
@@ -90,10 +97,7 @@ bool Round::ReInitForScaling(uint32_t server_num) {
                                                            {first_count_handler, last_count_handler});
   }
 
-  if (kernel_ == nullptr) {
-    MS_LOG(WARNING) << "Reinitializing for round " << name_ << " failed: round kernel is nullptr.";
-    return false;
-  }
+  MS_ERROR_IF_NULL_W_RET_VAL(kernel_, false);
   kernel_->InitKernel(threshold_count_);
   return true;
 }
@@ -108,6 +112,8 @@ void Round::BindRoundKernel(const std::shared_ptr<kernel::RoundKernel> &kernel)
 
 void Round::LaunchRoundKernel(const std::shared_ptr<ps::core::MessageHandler> &message) {
   MS_ERROR_IF_NULL_WO_RET_VAL(message);
+  MS_ERROR_IF_NULL_WO_RET_VAL(kernel_);
+  MS_ERROR_IF_NULL_WO_RET_VAL(communicator_);
   // If the server is still in the process of scaling, refuse the request.
   if (Server::GetInstance().IsSafeMode()) {
     MS_LOG(WARNING) << "The cluster is still in process of scaling, please retry " << name_ << " later.";
@@ -149,7 +155,10 @@ void Round::LaunchRoundKernel(const std::shared_ptr<ps::core::MessageHandler> &m
   return;
 }
 
-void Round::Reset() { (void)kernel_->Reset(); }
+void Round::Reset() {
+  MS_ERROR_IF_NULL_WO_RET_VAL(kernel_);
+  (void)kernel_->Reset();
+}
 
 const std::string &Round::name() const { return name_; }
 
@@ -160,6 +169,9 @@ bool Round::check_timeout() const { return check_timeout_; }
 size_t Round::time_window() const { return time_window_; }
 
 void Round::OnFirstCountEvent(const std::shared_ptr<ps::core::MessageHandler> &message) {
+  MS_ERROR_IF_NULL_WO_RET_VAL(message);
+  MS_ERROR_IF_NULL_WO_RET_VAL(kernel_);
+  MS_ERROR_IF_NULL_WO_RET_VAL(iter_timer_);
   MS_LOG(INFO) << "Round " << name_ << " first count event is triggered.";
   // The timer starts only after the first count event is triggered by DistributedCountService.
   if (check_timeout_) {
@@ -172,6 +184,9 @@ void Round::OnFirstCountEvent(const std::shared_ptr<ps::core::MessageHandler> &m
 }
 
 void Round::OnLastCountEvent(const std::shared_ptr<ps::core::MessageHandler> &message) {
+  MS_ERROR_IF_NULL_WO_RET_VAL(message);
+  MS_ERROR_IF_NULL_WO_RET_VAL(kernel_);
+  MS_ERROR_IF_NULL_WO_RET_VAL(iter_timer_);
   MS_LOG(INFO) << "Round " << name_ << " last count event is triggered.";
   // Same as the first count event, the timer must be stopped by DistributedCountService.
   if (check_timeout_) {
diff --git a/mindspore/ccsrc/fl/server/server.cc b/mindspore/ccsrc/fl/server/server.cc
index 4d5511ef780..69ad3fe52f1 100644
--- a/mindspore/ccsrc/fl/server/server.cc
+++ b/mindspore/ccsrc/fl/server/server.cc
@@ -86,7 +86,11 @@ void Server::Run() {
 
   // Wait communicators to stop so the main thread is blocked.
   (void)std::for_each(communicators_with_worker_.begin(), communicators_with_worker_.end(),
-                      [](const std::shared_ptr<ps::core::CommunicatorBase> &communicator) { communicator->Join(); });
+                      [](const std::shared_ptr<ps::core::CommunicatorBase> &communicator) {
+                        MS_EXCEPTION_IF_NULL(communicator);
+                        communicator->Join();
+                      });
+  MS_EXCEPTION_IF_NULL(communicator_with_server_);
   communicator_with_server_->Join();
   MsException::Instance().CheckException();
   return;
@@ -151,6 +155,7 @@ bool Server::InitCommunicatorWithWorker() {
     return false;
   }
   if (use_tcp_) {
+    MS_EXCEPTION_IF_NULL(communicator_with_server_);
     auto tcp_comm = communicator_with_server_;
     MS_EXCEPTION_IF_NULL(tcp_comm);
     communicators_with_worker_.push_back(tcp_comm);
@@ -201,21 +206,32 @@ void Server::InitIteration() {
 
     std::shared_ptr<Round> exchange_keys_round =
       std::make_shared<Round>("exchangeKeys", true, cipher_time_window_, true, cipher_exchange_secrets_cnt_);
+    MS_EXCEPTION_IF_NULL(exchange_keys_round);
     iteration_->AddRound(exchange_keys_round);
+
     std::shared_ptr<Round> get_keys_round =
       std::make_shared<Round>("getKeys", true, cipher_time_window_, true, cipher_exchange_secrets_cnt_);
+    MS_EXCEPTION_IF_NULL(get_keys_round);
     iteration_->AddRound(get_keys_round);
+
     std::shared_ptr<Round> share_secrets_round =
       std::make_shared<Round>("shareSecrets", true, cipher_time_window_, true, cipher_share_secrets_cnt_);
+    MS_EXCEPTION_IF_NULL(share_secrets_round);
     iteration_->AddRound(share_secrets_round);
+
     std::shared_ptr<Round> get_secrets_round =
       std::make_shared<Round>("getSecrets", true, cipher_time_window_, true, cipher_share_secrets_cnt_);
+    MS_EXCEPTION_IF_NULL(get_secrets_round);
     iteration_->AddRound(get_secrets_round);
+
     std::shared_ptr<Round> get_clientlist_round =
       std::make_shared<Round>("getClientList", true, cipher_time_window_, true, cipher_get_clientlist_cnt_);
+    MS_EXCEPTION_IF_NULL(get_clientlist_round);
     iteration_->AddRound(get_clientlist_round);
+
     std::shared_ptr<Round> reconstruct_secrets_round = std::make_shared<Round>(
       "reconstructSecrets", true, cipher_time_window_, true, cipher_reconstruct_secrets_up_cnt_);
+    MS_EXCEPTION_IF_NULL(reconstruct_secrets_round);
     iteration_->AddRound(reconstruct_secrets_round);
     MS_LOG(INFO) << "Cipher rounds has been added.";
   }
@@ -253,8 +269,16 @@ void Server::InitCipher() {
   mindspore::armour::CipherPublicPara param;
   param.g = cipher_g;
   param.t = cipher_t;
-  memcpy_s(param.p, SECRET_MAX_LEN, cipher_p, SECRET_MAX_LEN);
-  memcpy_s(param.prime, PRIME_MAX_LEN, cipher_prime, PRIME_MAX_LEN);
+  int ret = memcpy_s(param.p, SECRET_MAX_LEN, cipher_p, SECRET_MAX_LEN);
+  if (ret != 0) {
+    MS_LOG(EXCEPTION) << "memcpy_s error, errorno(" << ret << ")";
+    return;
+  }
+  ret = memcpy_s(param.prime, PRIME_MAX_LEN, cipher_prime, PRIME_MAX_LEN);
+  if (ret != 0) {
+    MS_LOG(EXCEPTION) << "memcpy_s error, errorno(" << ret << ")";
+    return;
+  }
   param.dp_delta = dp_delta;
   param.dp_eps = dp_eps;
   param.dp_norm_clip = dp_norm_clip;
@@ -268,6 +292,8 @@ void Server::InitCipher() {
 void Server::RegisterCommCallbacks() {
   // The message callbacks of round kernels are already set in method InitIteration, so here we don't need to register
   // rounds' callbacks.
+  MS_EXCEPTION_IF_NULL(server_node_);
+  MS_EXCEPTION_IF_NULL(iteration_);
 
   auto tcp_comm = std::dynamic_pointer_cast<ps::core::TcpCommunicator>(communicator_with_server_);
   MS_EXCEPTION_IF_NULL(tcp_comm);
@@ -302,9 +328,13 @@ void Server::RegisterExceptionEventCallback(const std::shared_ptr<ps::core::TcpC
   communicator->RegisterEventCallback(ps::core::ClusterEvent::SCHEDULER_TIMEOUT, [&]() {
     MS_LOG(ERROR) << "Event SCHEDULER_TIMEOUT is captured. This is because scheduler node is finalized or crashed.";
     safemode_ = true;
-    (void)std::for_each(
-      communicators_with_worker_.begin(), communicators_with_worker_.end(),
-      [](const std::shared_ptr<ps::core::CommunicatorBase> &communicator) { (void)communicator->Stop(); });
+    (void)std::for_each(communicators_with_worker_.begin(), communicators_with_worker_.end(),
+                        [](const std::shared_ptr<ps::core::CommunicatorBase> &communicator) {
+                          MS_ERROR_IF_NULL_WO_RET_VAL(communicator);
+                          (void)communicator->Stop();
+                        });
+
+    MS_ERROR_IF_NULL_WO_RET_VAL(communicator_with_server_);
     (void)communicator_with_server_->Stop();
   });
 
@@ -313,14 +343,19 @@ void Server::RegisterExceptionEventCallback(const std::shared_ptr<ps::core::TcpC
       << "Event NODE_TIMEOUT is captured. This is because some server nodes are finalized or crashed after the "
          "network building phase.";
     safemode_ = true;
-    (void)std::for_each(
-      communicators_with_worker_.begin(), communicators_with_worker_.end(),
-      [](const std::shared_ptr<ps::core::CommunicatorBase> &communicator) { (void)communicator->Stop(); });
+    (void)std::for_each(communicators_with_worker_.begin(), communicators_with_worker_.end(),
+                        [](const std::shared_ptr<ps::core::CommunicatorBase> &communicator) {
+                          MS_ERROR_IF_NULL_WO_RET_VAL(communicator);
+                          (void)communicator->Stop();
+                        });
+
+    MS_ERROR_IF_NULL_WO_RET_VAL(communicator_with_server_);
     (void)communicator_with_server_->Stop();
   });
 }
 
 void Server::InitExecutor() {
+  MS_EXCEPTION_IF_NULL(func_graph_);
   if (executor_threshold_ == 0) {
     MS_LOG(EXCEPTION) << "The executor's threshold should greater than 0.";
     return;
@@ -342,6 +377,7 @@ void Server::RegisterRoundKernel() {
   }
 
   for (auto &round : rounds) {
+    MS_EXCEPTION_IF_NULL(round);
     const std::string &name = round->name();
     std::shared_ptr<kernel::RoundKernel> round_kernel = kernel::RoundKernelFactory::GetInstance().Create(name);
     if (round_kernel == nullptr) {
@@ -357,12 +393,13 @@ void Server::RegisterRoundKernel() {
 }
 
 void Server::StartCommunicator() {
-  MS_EXCEPTION_IF_NULL(communicator_with_server_);
   if (communicators_with_worker_.empty()) {
     MS_LOG(EXCEPTION) << "Communicators for communication with worker is empty.";
     return;
   }
 
+  MS_EXCEPTION_IF_NULL(server_node_);
+  MS_EXCEPTION_IF_NULL(communicator_with_server_);
   MS_LOG(INFO) << "Start communicator with server.";
   if (!communicator_with_server_->Start()) {
     MS_LOG(EXCEPTION) << "Starting communicator with server failed.";
@@ -376,6 +413,7 @@ void Server::StartCommunicator() {
   MS_LOG(INFO) << "Start communicator with worker.";
   (void)std::for_each(communicators_with_worker_.begin(), communicators_with_worker_.end(),
                       [](const std::shared_ptr<ps::core::CommunicatorBase> &communicator) {
+                        MS_ERROR_IF_NULL_WO_RET_VAL(communicator);
                         if (!communicator->Start()) {
                           MS_LOG(EXCEPTION) << "Starting communicator with worker failed.";
                         }
@@ -383,11 +421,13 @@ void Server::StartCommunicator() {
 }
 
 void Server::ProcessBeforeScalingOut() {
+  MS_ERROR_IF_NULL_WO_RET_VAL(iteration_);
   iteration_->ScalingBarrier();
   safemode_ = true;
 }
 
 void Server::ProcessBeforeScalingIn() {
+  MS_ERROR_IF_NULL_WO_RET_VAL(iteration_);
   iteration_->ScalingBarrier();
   safemode_ = true;
 }
@@ -419,9 +459,13 @@ void Server::ProcessAfterScalingIn() {
   MS_ERROR_IF_NULL_WO_RET_VAL(server_node_);
   if (server_node_->rank_id() == UINT32_MAX) {
     MS_LOG(WARNING) << "This server the one to be scaled in. Server exiting.";
-    (void)std::for_each(
-      communicators_with_worker_.begin(), communicators_with_worker_.end(),
-      [](const std::shared_ptr<ps::core::CommunicatorBase> &communicator) { (void)communicator->Stop(); });
+    (void)std::for_each(communicators_with_worker_.begin(), communicators_with_worker_.end(),
+                        [](const std::shared_ptr<ps::core::CommunicatorBase> &communicator) {
+                          MS_ERROR_IF_NULL_WO_RET_VAL(communicator);
+                          (void)communicator->Stop();
+                        });
+
+    MS_ERROR_IF_NULL_WO_RET_VAL(communicator_with_server_);
     (void)communicator_with_server_->Stop();
     return;
   }
diff --git a/mindspore/ccsrc/fl/worker/fl_worker.cc b/mindspore/ccsrc/fl/worker/fl_worker.cc
index 77da81ed564..a004ba74042 100644
--- a/mindspore/ccsrc/fl/worker/fl_worker.cc
+++ b/mindspore/ccsrc/fl/worker/fl_worker.cc
@@ -91,6 +91,7 @@ void FLWorker::Finalize() {
 
 bool FLWorker::SendToServer(uint32_t server_rank, const void *data, size_t size, ps::core::TcpUserCommand command,
                             std::shared_ptr<std::vector<unsigned char>> *output) {
+  MS_EXCEPTION_IF_NULL(data);
   // If the worker is in safemode, do not communicate with server.
   while (safemode_.load()) {
     std::this_thread::yield();
@@ -169,6 +170,7 @@ std::string FLWorker::fl_name() const { return ps::kServerModeFL; }
 std::string FLWorker::fl_id() const { return std::to_string(rank_id_); }
 
 void FLWorker::InitializeFollowerScaler() {
+  MS_EXCEPTION_IF_NULL(worker_node_);
   if (!worker_node_->InitFollowerScaler()) {
     MS_LOG(EXCEPTION) << "Initializing follower elastic scaler failed.";
     return;
@@ -225,10 +227,7 @@ void FLWorker::ProcessBeforeScalingIn() {
 }
 
 void FLWorker::ProcessAfterScalingOut() {
-  if (worker_node_ == nullptr) {
-    return;
-  }
-
+  MS_ERROR_IF_NULL_WO_RET_VAL(worker_node_);
   MS_LOG(INFO) << "Cluster scaling out completed. Reinitialize for worker.";
   server_num_ = IntToUint(worker_node_->server_num());
   worker_num_ = IntToUint(worker_node_->worker_num());
@@ -239,10 +238,7 @@ void FLWorker::ProcessAfterScalingOut() {
 }
 
 void FLWorker::ProcessAfterScalingIn() {
-  if (worker_node_ == nullptr) {
-    return;
-  }
-
+  MS_ERROR_IF_NULL_WO_RET_VAL(worker_node_);
   MS_LOG(INFO) << "Cluster scaling in completed. Reinitialize for worker.";
   server_num_ = IntToUint(worker_node_->server_num());
   worker_num_ = IntToUint(worker_node_->worker_num());