diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index 547f2d4c2..f6f56b086 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -2869,6 +2869,8 @@ void Blockchain::return_tx_to_pool(const std::vector<transaction> &txs)
 //------------------------------------------------------------------
 bool Blockchain::flush_txes_from_pool(const std::list<crypto::hash> &txids)
 {
+  CRITICAL_REGION_LOCAL(m_tx_pool);
+
   bool res = true;
   for (const auto &txid: txids)
   {
@@ -2877,7 +2879,7 @@ bool Blockchain::flush_txes_from_pool(const std::list<crypto::hash> &txids)
     uint64_t fee;
     bool relayed;
     LOG_PRINT_L1("Removing txid " << txid << " from the pool");
-    if(!m_tx_pool.take_tx(txid, tx, blob_size, fee, relayed))
+    if(m_tx_pool.have_tx(txid) && !m_tx_pool.take_tx(txid, tx, blob_size, fee, relayed))
     {
       LOG_PRINT_L0("Failed to remove txid " << txid << " from the pool");
       res = false;
diff --git a/src/cryptonote_core/tx_pool.cpp b/src/cryptonote_core/tx_pool.cpp
index e7d3908e5..dcbb7cc04 100644
--- a/src/cryptonote_core/tx_pool.cpp
+++ b/src/cryptonote_core/tx_pool.cpp
@@ -662,6 +662,7 @@ namespace cryptonote
   //---------------------------------------------------------------------------------
   size_t tx_memory_pool::validate(uint8_t version)
   {
+    CRITICAL_REGION_LOCAL(m_transactions_lock);
     size_t n_removed = 0;
     size_t tx_size_limit = (version < 2 ? TRANSACTION_SIZE_LIMIT_V1 : TRANSACTION_SIZE_LIMIT_V2);
     for (auto it = m_transactions.begin(); it != m_transactions.end(); ) {