Fix deadlock caused by update_measurements calling in_sync (#1760)

srsue/src/phy/phy_common.cc

@@ -620,6 +620,8 @@ void phy_common::update_measurements(uint32_t
                                      std::vector<rrc_interface_phy_lte::phy_meas_t>& serving_cells,
                                      cf_t*                                           rssi_power_buffer)
 {
+  bool insync = true;
+  {
     std::unique_lock<std::mutex> lock(meas_mutex);
 
     float snr_ema_coeff = args->snr_ema_coeff;
@@ -635,8 +637,9 @@ void phy_common::update_measurements(uint32_t
 
       if (!rssi_read_cnt) {
         // Average RSSI over all symbols in antenna port 0 (make sure SF length is non-zero)
-      float rssi_dbm = SRSLTE_SF_LEN_PRB(cell.nof_prb) > 0 ? (srslte_convert_power_to_dB(srslte_vec_avg_power_cf(
-                                                                  rssi_power_buffer, SRSLTE_SF_LEN_PRB(cell.nof_prb))) +
+        float rssi_dbm = SRSLTE_SF_LEN_PRB(cell.nof_prb) > 0
+                             ? (srslte_convert_power_to_dB(
+                                    srslte_vec_avg_power_cf(rssi_power_buffer, SRSLTE_SF_LEN_PRB(cell.nof_prb))) +
                                 30)
                              : 0;
         if (std::isnormal(rssi_dbm)) {
@@ -736,16 +739,22 @@ void phy_common::update_measurements(uint32_t
     if (avg_rsrp_dbm[0] > args->in_sync_rsrp_dbm_th && avg_snr_db_cqi[0] > args->in_sync_snr_db_th) {
       log_h->debug(
           "SNR=%.1f dB, RSRP=%.1f dBm sync=in-sync from channel estimator\n", avg_snr_db_cqi[0], avg_rsrp_dbm[0]);
-    if (insync_itf) {
-      insync_itf->in_sync();
-    }
     } else {
       log_h->warning(
           "SNR=%.1f dB RSRP=%.1f dBm, sync=out-of-sync from channel estimator\n", avg_snr_db_cqi[0], avg_rsrp_dbm[0]);
+      insync = false;
+    }
+  }
+
+  // Report in-sync status to the stack outside the mutex lock
   if (insync_itf) {
+    if (insync) {
+      insync_itf->in_sync();
+    } else {
       insync_itf->out_of_sync();
     }
   }
+
   // Call feedback loop for chest
   if (cc_idx == 0) {
     if (insync_itf && ((1U << (sf_cfg_dl.tti % 10U)) & args->cfo_ref_mask)) {