[HICN-60] Solved concurrent memory access which was leading to seg-fault

Change-Id: I7b9fcf79bb97650346f7d92af8cbb419f0a5cb95
Signed-off-by: Alberto Compagno <acompagn+fdio@cisco.com>

5 files changed, 15 insertions, 22 deletions

diff --git a/libtransport/src/hicn/transport/core/memif_connector.cc b/libtransport/src/hicn/transport/core/memif_connector.cc
index a650c3681..38b2a2a98 100644
--- a/libtransport/src/hicn/transport/core/memif_connector.cc
+++ b/libtransport/src/hicn/transport/core/memif_connector.cc
@@ -298,17 +298,11 @@ int MemifConnector::txBurst(uint16_t qid) {
 }
 
 void MemifConnector::sendCallback(const std::error_code &ec) {
+  timer_set_ = false;
+
   if (TRANSPORT_EXPECT_TRUE(!ec && !is_connecting_)) {
     doSend();
   }
-
-  if (output_buffer_.size() > 0) {
-    send_timer_->expiresFromNow(std::chrono::microseconds(50));
-    send_timer_->asyncWait(
-        std::bind(&MemifConnector::sendCallback, this, std::placeholders::_1));
-  } else {
-    timer_set_ = false;
-  }
 }
 
 void MemifConnector::processInputBuffer() {
@@ -378,6 +372,7 @@ int MemifConnector::onInterrupt(memif_conn_handle_t conn, void *private_ctx,
       packet->append(packet_length);
 
       if (!connector->input_buffer_.push(std::move(packet))) {
+
         TRANSPORT_LOGI("Error pushing packet. Ring buffer full.");
 
         // TODO Here we should consider the possibility to signal the congestion
@@ -442,7 +437,11 @@ void MemifConnector::close() {
 void MemifConnector::enableBurst() { enable_burst_ = true; }
 
 void MemifConnector::send(const Packet::MemBufPtr &packet) {
-#ifdef CANCEL_TIMER
+  {
+    utils::SpinLock::Acquire locked(write_msgs_lock_);
+    output_buffer_.push_back(packet);
+  }
+#if CANCEL_TIMER
   if (!timer_set_) {
     timer_set_ = true;
     send_timer_->expiresFromNow(std::chrono::microseconds(50));
@@ -450,11 +449,6 @@ void MemifConnector::send(const Packet::MemBufPtr &packet) {
         std::bind(&MemifConnector::sendCallback, this, std::placeholders::_1));
   }
 #endif
-
-  {
-    utils::SpinLock::Acquire locked(write_msgs_lock_);
-    output_buffer_.push_back(packet);
-  }
 }
 
 int MemifConnector::doSend() {
diff --git a/libtransport/src/hicn/transport/core/memif_connector.h b/libtransport/src/hicn/transport/core/memif_connector.h
index 6e76b78da..3d2e8411d 100644
--- a/libtransport/src/hicn/transport/core/memif_connector.h
+++ b/libtransport/src/hicn/transport/core/memif_connector.h
@@ -110,7 +110,7 @@ class MemifConnector : public Connector {
   int epfd;
   std::unique_ptr<std::thread> memif_worker_;
   utils::EpollEventReactor event_reactor_;
-  volatile bool timer_set_;
+  std::atomic_bool timer_set_;
   std::unique_ptr<utils::FdDeadlineTimer> send_timer_;
   asio::io_service &io_service_;
   std::unique_ptr<asio::io_service::work> work_;
diff --git a/libtransport/src/hicn/transport/utils/epoll_event_reactor.cc b/libtransport/src/hicn/transport/utils/epoll_event_reactor.cc
index 81b471857..6df9e5656 100644
--- a/libtransport/src/hicn/transport/utils/epoll_event_reactor.cc
+++ b/libtransport/src/hicn/transport/utils/epoll_event_reactor.cc
@@ -51,10 +51,9 @@ int EpollEventReactor::addFileDescriptor(int fd, uint32_t events) {
 int EpollEventReactor::addFileDescriptor(int fd, uint32_t events,
                                          EventCallback &callback) {
   auto it = event_callback_map_.find(fd);
-  event_callback_map_[fd] = callback;
-  if (it != event_callback_map_.end()) {
+
+  if (it == event_callback_map_.end()) {
     event_callback_map_[fd] = callback;
-  } else {
     return addFileDescriptor(fd, events);
   }
 
@@ -64,10 +63,9 @@ int EpollEventReactor::addFileDescriptor(int fd, uint32_t events,
 int EpollEventReactor::addFileDescriptor(int fd, uint32_t events,
                                          EventCallback &&callback) {
   auto it = event_callback_map_.find(fd);
-  event_callback_map_[fd] = callback;
-  if (it != event_callback_map_.end()) {
+
+  if (it == event_callback_map_.end()) {
     event_callback_map_[fd] = callback;
-  } else {
     return addFileDescriptor(fd, events);
   }
 
diff --git a/libtransport/src/hicn/transport/utils/object_pool.h b/libtransport/src/hicn/transport/utils/object_pool.h
index 9fda214cd..e34730e81 100644
--- a/libtransport/src/hicn/transport/utils/object_pool.h
+++ b/libtransport/src/hicn/transport/utils/object_pool.h
@@ -62,6 +62,7 @@ class ObjectPool {
 
   void add(T *object) {
     utils::SpinLock::Acquire locked(object_pool_lock_);
+
     if (TRANSPORT_EXPECT_TRUE(!destructor_)) {
       object_pool_.emplace_back(makePtr(object));
     }
diff --git a/libtransport/src/hicn/transport/utils/ring_buffer.h b/libtransport/src/hicn/transport/utils/ring_buffer.h
index 52bcd81c4..9babe56bd 100644
--- a/libtransport/src/hicn/transport/utils/ring_buffer.h
+++ b/libtransport/src/hicn/transport/utils/ring_buffer.h
@@ -86,7 +86,7 @@ bool CircularFifo<Element, Size>::push(Element&& item) {
 // the tail must be accessed with at least acquire
 template <typename Element, std::size_t Size>
 bool CircularFifo<Element, Size>::pop(Element& item) {
-  const auto current_head = head_.load(std::memory_order_relaxed);
+  const size_t current_head = head_.load(std::memory_order_relaxed);
   if (current_head == tail_.load(std::memory_order_acquire)) {
     return false;  // empty queue
   }