Fix data race in ul_harq.

srsue/hdr/stack/mac/ul_harq.h

@@ -100,7 +100,7 @@ private:
 
   srsran::ul_harq_cfg_t harq_cfg = {};
 
-  float    average_retx = 0.0;
+  std::atomic<float> average_retx{0};
   uint64_t           nof_pkts     = 0;
   ra_proc*           ra_procedure = nullptr;
 

srsue/src/stack/mac/ul_harq.cc

@@ -103,7 +103,7 @@ int ul_harq_entity::get_current_tbs(uint32_t pid)
 
 float ul_harq_entity::get_average_retx()
 {
-  return average_retx;
+  return average_retx.load(std::memory_order_relaxed);
 }
 
 ul_harq_entity::ul_harq_process::ul_harq_process() : logger(srslog::fetch_basic_logger("MAC"))
@@ -348,7 +348,10 @@ void ul_harq_entity::ul_harq_process::generate_new_tx(mac_interface_phy_lte::mac
                                                       mac_interface_phy_lte::tb_action_ul_t* action)
 {
   // Compute average number of retransmissions per packet considering previous packet
-  harq_entity->average_retx = SRSRAN_VEC_CMA((float)current_tx_nb, harq_entity->average_retx, harq_entity->nof_pkts++);
+  harq_entity->average_retx.store(SRSRAN_VEC_CMA((float)current_tx_nb,
+                                                 harq_entity->average_retx.load(std::memory_order_relaxed),
+                                                 harq_entity->nof_pkts++),
+                                  std::memory_order_relaxed);
   cur_grant           = grant;
   harq_feedback       = false;
   is_grant_configured = true;