ue,mac: adding missing mutex when updating metrics

srsue/src/stack/mac/mac.cc

@@ -493,6 +493,9 @@ void mac::new_grant_ul(uint32_t                               cc_idx,
   }
 
   ul_harq.at(cc_idx)->new_grant_ul(grant, action);
+
+  {
+    std::lock_guard<std::mutex> lock(metrics_mutex);
     metrics[cc_idx].tx_pkts++;
 
     if (grant.phich_available) {
@@ -502,6 +505,7 @@ void mac::new_grant_ul(uint32_t                               cc_idx,
         metrics[cc_idx].tx_brate += ul_harq.at(cc_idx)->get_current_tbs(grant.pid) * 8;
       }
     }
+  } // end of holding metrics mutex
 }
 
 void mac::new_mch_dl(const srsran_pdsch_grant_t& phy_grant, tb_action_dl_t* action)
@@ -623,6 +627,8 @@ void mac::mch_start_rx(uint32_t lcid)
 
 void mac::get_metrics(mac_metrics_t m[SRSRAN_MAX_CARRIERS])
 {
+  std::lock_guard<std::mutex> lock(metrics_mutex);
+
   int   tx_pkts          = 0;
   int   tx_errors        = 0;
   int   tx_brate         = 0;