Merge pull request #7873

d4c7549 node_server: fix race condition (anon)
2909bd1 node_server: add race condition demo (anon)

6 files changed, 389 insertions, 52 deletions

diff --git a/src/cryptonote_protocol/levin_notify.cpp b/src/cryptonote_protocol/levin_notify.cpp
index ab4eeeb82..8b36ca58c 100644
--- a/src/cryptonote_protocol/levin_notify.cpp
+++ b/src/cryptonote_protocol/levin_notify.cpp
@@ -298,6 +298,12 @@ namespace levin
       boost::asio::steady_timer next_epoch;
       boost::asio::steady_timer flush_txs;
       boost::asio::io_service::strand strand;
+      struct context_t {
+        std::vector<cryptonote::blobdata> fluff_txs;
+        std::chrono::steady_clock::time_point flush_time;
+        bool m_is_income;
+      };
+      boost::unordered_map<boost::uuids::uuid, context_t> contexts;
       net::dandelionpp::connection_map map;//!< Tracks outgoing uuid's for noise channels or Dandelion++ stems
       std::deque<noise_channel> channels;  //!< Never touch after init; only update elements on `noise_channel.strand`
       std::atomic<std::size_t> connection_count; //!< Only update in strand, can be read at any time
@@ -374,14 +380,16 @@ namespace levin
         const auto now = std::chrono::steady_clock::now();
         auto next_flush = std::chrono::steady_clock::time_point::max();
         std::vector<std::pair<std::vector<blobdata>, boost::uuids::uuid>> connections{};
-        zone_->p2p->foreach_connection([timer_error, now, &next_flush, &connections] (detail::p2p_context& context)
+        for (auto &e: zone_->contexts)
         {
+          auto &id = e.first;
+          auto &context = e.second;
           if (!context.fluff_txs.empty())
           {
             if (context.flush_time <= now || timer_error) // flush on canceled timer
             {
               context.flush_time = std::chrono::steady_clock::time_point::max();
-              connections.emplace_back(std::move(context.fluff_txs), context.m_connection_id);
+              connections.emplace_back(std::move(context.fluff_txs), id);
               context.fluff_txs.clear();
             }
             else // not flushing yet
@@ -389,8 +397,7 @@ namespace levin
           }
           else // nothing to flush
             context.flush_time = std::chrono::steady_clock::time_point::max();
-          return true;
-        });
+        }
 
         /* Always send with `fluff` flag, even over i2p/tor. The hidden service
 	   will disable the forwarding delay and immediately fluff. The i2p/tor
@@ -438,22 +445,21 @@ namespace levin
 
 
         MDEBUG("Queueing " << txs.size() << " transaction(s) for Dandelion++ fluffing");
-
-        zone->p2p->foreach_connection([txs, now, &zone, &source, &in_duration, &out_duration, &next_flush] (detail::p2p_context& context)
+        for (auto &e: zone->contexts)
         {
+          auto &id = e.first;
+          auto &context = e.second;
           // When i2p/tor, only fluff to outbound connections
-          if (context.handshake_complete() && source != context.m_connection_id && (zone->nzone == epee::net_utils::zone::public_ || !context.m_is_income))
+          if (source != id && (zone->nzone == epee::net_utils::zone::public_ || !context.m_is_income))
           {
             if (context.fluff_txs.empty())
               context.flush_time = now + (context.m_is_income ? in_duration() : out_duration());
 
             next_flush = std::min(next_flush, context.flush_time);
             context.fluff_txs.reserve(context.fluff_txs.size() + txs.size());
-            for (const blobdata& tx : txs)
-              context.fluff_txs.push_back(tx); // must copy instead of move (multiple conns)
+            context.fluff_txs.insert(context.fluff_txs.end(), txs.begin(), txs.end());
           }
-          return true;
-        });
+        }
 
         if (next_flush == std::chrono::steady_clock::time_point::max())
           MWARNING("Unable to send transaction(s), no available connections");
@@ -764,6 +770,32 @@ namespace levin
     );
   }
 
+  void notify::on_handshake_complete(const boost::uuids::uuid &id, bool is_income)
+  {
+    if (!zone_)
+      return;
+
+    auto& zone = zone_;
+    zone_->strand.dispatch([zone, id, is_income]{
+      zone->contexts[id] = {
+        .fluff_txs = {},
+        .flush_time = std::chrono::steady_clock::time_point::max(),
+        .m_is_income = is_income,
+      };
+    });
+  }
+
+  void notify::on_connection_close(const boost::uuids::uuid &id)
+  {
+    if (!zone_)
+      return;
+
+    auto& zone = zone_;
+    zone_->strand.dispatch([zone, id]{
+      zone->contexts.erase(id);
+    });
+  }
+
   void notify::run_epoch()
   {
     if (!zone_)
diff --git a/src/cryptonote_protocol/levin_notify.h b/src/cryptonote_protocol/levin_notify.h
index abbf9d461..12704746a 100644
--- a/src/cryptonote_protocol/levin_notify.h
+++ b/src/cryptonote_protocol/levin_notify.h
@@ -101,6 +101,9 @@ namespace levin
     //! Probe for new outbound connection - skips if not needed.
     void new_out_connection();
 
+    void on_handshake_complete(const boost::uuids::uuid &id, bool is_income);
+    void on_connection_close(const boost::uuids::uuid &id);
+
     //! Run the logic for the next epoch immediately. Only use in testing.
     void run_epoch();
 
diff --git a/src/p2p/net_node.h b/src/p2p/net_node.h
index 59a6e5091..3660d2edb 100644
--- a/src/p2p/net_node.h
+++ b/src/p2p/net_node.h
@@ -111,15 +111,11 @@ namespace nodetool
   struct p2p_connection_context_t: base_type //t_payload_net_handler::connection_context //public net_utils::connection_context_base
   {
     p2p_connection_context_t()
-      : fluff_txs(),
-        flush_time(std::chrono::steady_clock::time_point::max()),
-        peer_id(0),
+      : peer_id(0),
         support_flags(0),
         m_in_timedsync(false)
     {}
 
-    std::vector<cryptonote::blobdata> fluff_txs;
-    std::chrono::steady_clock::time_point flush_time;
     peerid_type peer_id;
     uint32_t support_flags;
     bool m_in_timedsync;
diff --git a/src/p2p/net_node.inl b/src/p2p/net_node.inl
index b8cf2d124..438b8ca11 100644
--- a/src/p2p/net_node.inl
+++ b/src/p2p/net_node.inl
@@ -1432,6 +1432,7 @@ namespace nodetool
     ape.first_seen = first_seen_stamp ? first_seen_stamp : time(nullptr);
 
     zone.m_peerlist.append_with_peer_anchor(ape);
+    zone.m_notifier.on_handshake_complete(con->m_connection_id, con->m_is_income);
     zone.m_notifier.new_out_connection();
 
     LOG_DEBUG_CC(*con, "CONNECTION HANDSHAKED OK.");
@@ -2559,6 +2560,8 @@ namespace nodetool
       return 1;
     }
 
+    zone.m_notifier.on_handshake_complete(context.m_connection_id, context.m_is_income);
+
     if(has_too_many_connections(context.m_remote_address))
     {
       LOG_PRINT_CCONTEXT_L1("CONNECTION FROM " << context.m_remote_address.host_str() << " REFUSED, too many connections from the same address");
@@ -2683,6 +2686,9 @@ namespace nodetool
       zone.m_peerlist.remove_from_peer_anchor(na);
     }
 
+    if (!zone.m_net_server.is_stop_signal_sent()) {
+      zone.m_notifier.on_connection_close(context.m_connection_id);
+    }
     m_payload_handler.on_connection_close(context);
 
     MINFO("["<< epee::net_utils::print_connection_context(context) << "] CLOSE CONNECTION");
diff --git a/tests/unit_tests/levin.cpp b/tests/unit_tests/levin.cpp
index 4d8c5225e..3e7a32557 100644
--- a/tests/unit_tests/levin.cpp
+++ b/tests/unit_tests/levin.cpp
@@ -265,11 +265,17 @@ namespace
         virtual void callback(cryptonote::levin::detail::p2p_context& context) override final
         {}
 
-        virtual void on_connection_new(cryptonote::levin::detail::p2p_context&) override final
-        {}
+        virtual void on_connection_new(cryptonote::levin::detail::p2p_context& context) override final
+        {
+            if (notifier)
+                notifier->on_handshake_complete(context.m_connection_id, context.m_is_income);
+        }
 
-        virtual void on_connection_close(cryptonote::levin::detail::p2p_context&) override final
-        {}
+        virtual void on_connection_close(cryptonote::levin::detail::p2p_context& context) override final
+        {
+            if (notifier)
+                notifier->on_connection_close(context.m_connection_id);
+        }
 
     public:
         test_receiver()
@@ -306,6 +312,8 @@ namespace
         {
             return get_raw_message(notified_);
         }
+
+        std::shared_ptr<cryptonote::levin::notify> notifier{};
     };
 
     class levin_notify : public ::testing::Test
@@ -343,13 +351,16 @@ namespace
             EXPECT_EQ(connection_ids_.size(), connections_->get_connections_count());
         }
 
-        cryptonote::levin::notify make_notifier(const std::size_t noise_size, bool is_public, bool pad_txs)
+        std::shared_ptr<cryptonote::levin::notify> make_notifier(const std::size_t noise_size, bool is_public, bool pad_txs)
         {
             epee::byte_slice noise = nullptr;
             if (noise_size)
                 noise = epee::levin::make_noise_notify(noise_size);
             epee::net_utils::zone zone = is_public ? epee::net_utils::zone::public_ : epee::net_utils::zone::i2p;
-            return cryptonote::levin::notify{io_service_, connections_, std::move(noise), zone, pad_txs, events_};
+            receiver_.notifier.reset(
+              new cryptonote::levin::notify{io_service_, connections_, std::move(noise), zone, pad_txs, events_}
+            );
+            return receiver_.notifier;
         }
 
         boost::uuids::random_generator random_generator_;
@@ -517,7 +528,8 @@ TEST_F(levin_notify, defaulted)
 
 TEST_F(levin_notify, fluff_without_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, true, false);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, true, false);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -563,7 +575,8 @@ TEST_F(levin_notify, fluff_without_padding)
 
 TEST_F(levin_notify, stem_without_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, true, false);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, true, false);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -635,7 +648,8 @@ TEST_F(levin_notify, stem_without_padding)
 
 TEST_F(levin_notify, stem_no_outs_without_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, true, false);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, true, false);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(true);
@@ -690,7 +704,8 @@ TEST_F(levin_notify, stem_no_outs_without_padding)
 
 TEST_F(levin_notify, local_without_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, true, false);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, true, false);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -762,7 +777,8 @@ TEST_F(levin_notify, local_without_padding)
 
 TEST_F(levin_notify, forward_without_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, true, false);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, true, false);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -834,7 +850,8 @@ TEST_F(levin_notify, forward_without_padding)
 
 TEST_F(levin_notify, block_without_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, true, false);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, true, false);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -863,7 +880,8 @@ TEST_F(levin_notify, block_without_padding)
 
 TEST_F(levin_notify, none_without_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, true, false);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, true, false);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -892,7 +910,8 @@ TEST_F(levin_notify, none_without_padding)
 
 TEST_F(levin_notify, fluff_with_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, true, true);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, true, true);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -938,7 +957,8 @@ TEST_F(levin_notify, fluff_with_padding)
 
 TEST_F(levin_notify, stem_with_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, true, true);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, true, true);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1005,7 +1025,8 @@ TEST_F(levin_notify, stem_with_padding)
 
 TEST_F(levin_notify, stem_no_outs_with_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, true, true);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, true, true);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(true);
@@ -1059,7 +1080,8 @@ TEST_F(levin_notify, stem_no_outs_with_padding)
 
 TEST_F(levin_notify, local_with_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, true, true);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, true, true);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1126,7 +1148,8 @@ TEST_F(levin_notify, local_with_padding)
 
 TEST_F(levin_notify, forward_with_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, true, true);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, true, true);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1193,7 +1216,8 @@ TEST_F(levin_notify, forward_with_padding)
 
 TEST_F(levin_notify, block_with_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, true, true);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, true, true);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1222,7 +1246,8 @@ TEST_F(levin_notify, block_with_padding)
 
 TEST_F(levin_notify, none_with_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, true, true);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, true, true);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1251,7 +1276,8 @@ TEST_F(levin_notify, none_with_padding)
 
 TEST_F(levin_notify, private_fluff_without_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, false, false);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, false, false);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1302,7 +1328,8 @@ TEST_F(levin_notify, private_fluff_without_padding)
 TEST_F(levin_notify, private_stem_without_padding)
 {
     // private mode always uses fluff but marked as stem
-    cryptonote::levin::notify notifier = make_notifier(0, false, false);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, false, false);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1353,7 +1380,8 @@ TEST_F(levin_notify, private_stem_without_padding)
 TEST_F(levin_notify, private_local_without_padding)
 {
     // private mode always uses fluff but marked as stem
-    cryptonote::levin::notify notifier = make_notifier(0, false, false);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, false, false);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1404,7 +1432,8 @@ TEST_F(levin_notify, private_local_without_padding)
 TEST_F(levin_notify, private_forward_without_padding)
 {
     // private mode always uses fluff but marked as stem
-    cryptonote::levin::notify notifier = make_notifier(0, false, false);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, false, false);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1455,7 +1484,8 @@ TEST_F(levin_notify, private_forward_without_padding)
 TEST_F(levin_notify, private_block_without_padding)
 {
     // private mode always uses fluff but marked as stem
-    cryptonote::levin::notify notifier = make_notifier(0, false, false);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, false, false);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1485,7 +1515,8 @@ TEST_F(levin_notify, private_block_without_padding)
 TEST_F(levin_notify, private_none_without_padding)
 {
     // private mode always uses fluff but marked as stem
-    cryptonote::levin::notify notifier = make_notifier(0, false, false);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, false, false);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1514,7 +1545,8 @@ TEST_F(levin_notify, private_none_without_padding)
 
 TEST_F(levin_notify, private_fluff_with_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, false, true);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, false, true);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1564,7 +1596,8 @@ TEST_F(levin_notify, private_fluff_with_padding)
 
 TEST_F(levin_notify, private_stem_with_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, false, true);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, false, true);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1614,7 +1647,8 @@ TEST_F(levin_notify, private_stem_with_padding)
 
 TEST_F(levin_notify, private_local_with_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, false, true);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, false, true);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1664,7 +1698,8 @@ TEST_F(levin_notify, private_local_with_padding)
 
 TEST_F(levin_notify, private_forward_with_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, false, true);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, false, true);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1714,7 +1749,8 @@ TEST_F(levin_notify, private_forward_with_padding)
 
 TEST_F(levin_notify, private_block_with_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, false, true);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, false, true);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1743,7 +1779,8 @@ TEST_F(levin_notify, private_block_with_padding)
 
 TEST_F(levin_notify, private_none_with_padding)
 {
-    cryptonote::levin::notify notifier = make_notifier(0, false, true);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, false, true);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < 10; ++count)
         add_connection(count % 2 == 0);
@@ -1774,7 +1811,8 @@ TEST_F(levin_notify, stem_mappings)
 {
     static constexpr const unsigned test_connections_count = (CRYPTONOTE_DANDELIONPP_STEMS + 1) * 2;
 
-    cryptonote::levin::notify notifier = make_notifier(0, true, false);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, true, false);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < test_connections_count; ++count)
         add_connection(count % 2 == 0);
@@ -1897,7 +1935,8 @@ TEST_F(levin_notify, fluff_multiple)
 {
     static constexpr const unsigned test_connections_count = (CRYPTONOTE_DANDELIONPP_STEMS + 1) * 2;
 
-    cryptonote::levin::notify notifier = make_notifier(0, true, false);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(0, true, false);
+    auto &notifier = *notifier_ptr;
 
     for (unsigned count = 0; count < test_connections_count; ++count)
         add_connection(count % 2 == 0);
@@ -2015,7 +2054,8 @@ TEST_F(levin_notify, noise)
     txs[0].resize(1900, 'h');
 
     const boost::uuids::uuid incoming_id = random_generator_();
-    cryptonote::levin::notify notifier = make_notifier(2048, false, true);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(2048, false, true);
+    auto &notifier = *notifier_ptr;
 
     {
         const auto status = notifier.get_status();
@@ -2106,7 +2146,8 @@ TEST_F(levin_notify, noise_stem)
     txs[0].resize(1900, 'h');
 
     const boost::uuids::uuid incoming_id = random_generator_();
-    cryptonote::levin::notify notifier = make_notifier(2048, false, true);
+    std::shared_ptr<cryptonote::levin::notify> notifier_ptr = make_notifier(2048, false, true);
+    auto &notifier = *notifier_ptr;
 
     {
         const auto status = notifier.get_status();
diff --git a/tests/unit_tests/node_server.cpp b/tests/unit_tests/node_server.cpp
index f91e2e78b..b2da2eb60 100644
--- a/tests/unit_tests/node_server.cpp
+++ b/tests/unit_tests/node_server.cpp
@@ -35,6 +35,7 @@
 #include "cryptonote_core/i_core_events.h"
 #include "cryptonote_protocol/cryptonote_protocol_handler.h"
 #include "cryptonote_protocol/cryptonote_protocol_handler.inl"
+#include <condition_variable>
 
 #define MAKE_IPV4_ADDRESS(a,b,c,d) epee::net_utils::ipv4_network_address{MAKE_IP(a,b,c,d),0}
 #define MAKE_IPV4_ADDRESS_PORT(a,b,c,d,e) epee::net_utils::ipv4_network_address{MAKE_IP(a,b,c,d),e}
@@ -914,5 +915,263 @@ TEST(cryptonote_protocol_handler, race_condition)
   remove_tree(dir);
 }
 
+TEST(node_server, race_condition)
+{
+  struct contexts {
+    using cryptonote = cryptonote::cryptonote_connection_context;
+    using p2p = nodetool::p2p_connection_context_t<cryptonote>;
+  };
+  using context_t = contexts::cryptonote;
+  using options_t = boost::program_options::variables_map;
+  using options_description_t = boost::program_options::options_description;
+  using worker_t = std::thread;
+  struct protocol_t {
+  private:
+    using p2p_endpoint_t = nodetool::i_p2p_endpoint<context_t>;
+    using lock_t = std::mutex;
+    using condition_t = std::condition_variable_any;
+    using unique_lock_t = std::unique_lock<lock_t>;
+    p2p_endpoint_t *p2p_endpoint;
+    lock_t lock;
+    condition_t condition;
+    bool started{};
+    size_t counter{};
+  public:
+    using payload_t = cryptonote::CORE_SYNC_DATA;
+    using blob_t = cryptonote::blobdata;
+    using connection_context = context_t;
+    using payload_type = payload_t;
+    using relay_t = cryptonote::relay_method;
+    using string_t = std::string;
+    using span_t = epee::span<const uint8_t>;
+    using blobs_t = epee::span<const cryptonote::blobdata>;
+    using connections_t = std::list<cryptonote::connection_info>;
+    using block_queue_t = cryptonote::block_queue;
+    using stripes_t = std::pair<uint32_t, uint32_t>;
+    struct core_events_t: cryptonote::i_core_events {
+      uint64_t get_current_blockchain_height() const override { return {}; }
+      bool is_synchronized() const override { return {}; }
+      void on_transactions_relayed(blobs_t blobs, relay_t relay) override {}
+    };
+    int handle_invoke_map(bool is_notify, int command, const span_t in, string_t &out, context_t &context, bool &handled) {
+      return {};
+    }
+    bool on_idle() {
+      if (not p2p_endpoint)
+        return {};
+      {
+        unique_lock_t guard(lock);
+        if (not started)
+          started = true;
+        else
+          return {};
+      }
+      std::vector<blob_t> txs(128 / 64 * 1024 * 1024, blob_t(1, 'x'));
+      worker_t worker([this]{
+        p2p_endpoint->for_each_connection(
+          [this](context_t &, uint64_t, uint32_t){
+            {
+              unique_lock_t guard(lock);
+              ++counter;
+              condition.notify_all();
+              condition.wait(guard, [this]{ return counter >= 3; });
+            }
+            std::this_thread::sleep_for(std::chrono::milliseconds(8));
+            return false;
+          }
+        );
+      });
+      {
+        unique_lock_t guard(lock);
+        ++counter;
+        condition.notify_all();
+        condition.wait(guard, [this]{ return counter >= 3; });
+        ++counter;
+        condition.notify_all();
+        condition.wait(guard, [this]{ return counter >= 5; });
+      }
+      p2p_endpoint->send_txs(
+        std::move(txs),
+        epee::net_utils::zone::public_,
+        {},
+        relay_t::fluff
+      );
+      worker.join();
+      return {};
+    }
+    bool init(const options_t &options) { return {}; }
+    bool deinit() { return {}; }
+    void set_p2p_endpoint(p2p_endpoint_t *p2p_endpoint) {
+      this->p2p_endpoint = p2p_endpoint;
+    }
+    bool process_payload_sync_data(const payload_t &payload, contexts::p2p &context, bool is_inital) {
+      context.m_state = context_t::state_normal;
+      context.m_needed_objects.resize(512 * 1024);
+      {
+        unique_lock_t guard(lock);
+        ++counter;
+        condition.notify_all();
+        condition.wait(guard, [this]{ return counter >= 3; });
+        ++counter;
+        condition.notify_all();
+        condition.wait(guard, [this]{ return counter >= 5; });
+      }
+      return true;
+    }
+    bool get_payload_sync_data(blob_t &blob) { return {}; }
+    bool get_payload_sync_data(payload_t &payload) { return {}; }
+    bool on_callback(context_t &context) { return {}; }
+    core_events_t &get_core(){ static core_events_t core_events; return core_events;}
+    void log_connections() {}
+    connections_t get_connections() { return {}; }
+    const block_queue_t &get_block_queue() const {
+      static block_queue_t block_queue;
+      return block_queue;
+    }
+    void stop() {}
+    void on_connection_close(context_t &context) {}
+    void set_max_out_peers(unsigned int max) {}
+    bool no_sync() const { return {}; }
+    void set_no_sync(bool value) {}
+    string_t get_peers_overview() const { return {}; }
+    stripes_t get_next_needed_pruning_stripe() const { return {}; }
+    bool needs_new_sync_connections() const { return {}; }
+    bool is_busy_syncing() { return {}; }
+  };
+  using node_server_t = nodetool::node_server<protocol_t>;
+  auto conduct_test = [](protocol_t &protocol){
+    struct messages {
+      struct core {
+        using sync = cryptonote::CORE_SYNC_DATA;
+      };
+      using handshake = nodetool::COMMAND_HANDSHAKE_T<core::sync>;
+    };
+    using handler_t = epee::levin::async_protocol_handler<context_t>;
+    using connection_t = epee::net_utils::connection<handler_t>;
+    using connection_ptr = boost::shared_ptr<connection_t>;
+    using shared_state_t = typename connection_t::shared_state;
+    using shared_state_ptr = std::shared_ptr<shared_state_t>;
+    using io_context_t = boost::asio::io_service;
+    using work_t = boost::asio::io_service::work;
+    using work_ptr = std::shared_ptr<work_t>;
+    using workers_t = std::vector<std::thread>;
+    using endpoint_t = boost::asio::ip::tcp::endpoint;
+    using event_t = epee::simple_event;
+    struct command_handler_t: epee::levin::levin_commands_handler<context_t> {
+      using span_t = epee::span<const uint8_t>;
+      using string_t = std::string;
+      int invoke(int, const span_t, string_t &, context_t &) override { return {}; }
+      int notify(int, const span_t, context_t &) override { return {}; }
+      void callback(context_t &) override {}
+      void on_connection_new(context_t &) override {}
+      void on_connection_close(context_t &) override {}
+      ~command_handler_t() override {}
+      static void destroy(epee::levin::levin_commands_handler<context_t>* ptr) { delete ptr; }
+    };
+    io_context_t io_context;
+    work_ptr work = std::make_shared<work_t>(io_context);
+    workers_t workers;
+    while (workers.size() < 4) {
+      workers.emplace_back([&io_context]{
+        io_context.run();
+      });
+    }
+    io_context.post([&]{
+      protocol.on_idle();
+    });
+    io_context.post([&]{
+      protocol.on_idle();
+    });
+    shared_state_ptr shared_state = std::make_shared<shared_state_t>();
+    shared_state->set_handler(new command_handler_t, &command_handler_t::destroy);
+    connection_ptr conn{new connection_t(io_context, shared_state, {}, {})};
+    endpoint_t endpoint(boost::asio::ip::address::from_string("127.0.0.1"), 48080);
+    conn->socket().connect(endpoint);
+    conn->socket().set_option(boost::asio::ip::tcp::socket::reuse_address(true));
+    conn->start({}, {});
+    context_t context;
+    conn->get_context(context);
+    event_t handshaked;
+    typename messages::handshake::request_t msg{{
+      ::config::NETWORK_ID,
+      58080,
+    }};
+    epee::net_utils::async_invoke_remote_command2<typename messages::handshake::response>(
+      context,
+      messages::handshake::ID,
+      msg,
+      *shared_state,
+      [conn, &handshaked](int code, const typename messages::handshake::response &msg, context_t &context){
+        EXPECT_TRUE(code >= 0);
+        handshaked.raise();
+      },
+      P2P_DEFAULT_HANDSHAKE_INVOKE_TIMEOUT
+    );
+    handshaked.wait();
+    conn->strand_.post([conn]{
+      conn->cancel();
+    });
+    conn.reset();
+    work.reset();
+    for (auto& w: workers) {
+      w.join();
+    }
+  };
+  using path_t = boost::filesystem::path;
+  using ec_t = boost::system::error_code;
+  auto create_dir = []{
+    ec_t ec;
+    path_t path = boost::filesystem::temp_directory_path() / boost::filesystem::unique_path("daemon-%%%%%%%%%%%%%%%%", ec);
+    if (ec)
+      return path_t{};
+    auto success = boost::filesystem::create_directory(path, ec);
+    if (not ec && success)
+      return path;
+    return path_t{};
+  };
+  auto remove_tree = [](const path_t &path){
+    ec_t ec;
+    boost::filesystem::remove_all(path, ec);
+  };
+  const auto dir = create_dir();
+  ASSERT_TRUE(not dir.empty());
+  protocol_t protocol{};
+  node_server_t node_server(protocol);
+  protocol.set_p2p_endpoint(&node_server);
+  node_server.init(
+    [&dir]{
+      options_t options;
+      boost::program_options::store(
+        boost::program_options::command_line_parser({
+          "--p2p-bind-ip=127.0.0.1",
+          "--p2p-bind-port=48080",
+          "--out-peers=0",
+          "--data-dir",
+          dir.string(),
+          "--no-igd",
+          "--add-exclusive-node=127.0.0.1:48080",
+          "--check-updates=disabled",
+          "--disable-dns-checkpoints",
+        }).options([]{
+          options_description_t options_description{};
+          cryptonote::core::init_options(options_description);
+          node_server_t::init_options(options_description);
+          return options_description;
+        }()).run(),
+        options
+      );
+      return options;
+    }()
+  );
+  worker_t worker([&]{
+    node_server.run();
+  });
+  conduct_test(protocol);
+  node_server.send_stop_signal();
+  worker.join();
+  node_server.deinit();
+  remove_tree(dir);
+}
+
 namespace nodetool { template class node_server<cryptonote::t_cryptonote_protocol_handler<test_core>>; }
 namespace cryptonote { template class t_cryptonote_protocol_handler<test_core>; }