diff --git a/lib/include/srsran/interfaces/rlc_interface_types.h b/lib/include/srsran/interfaces/rlc_interface_types.h
index 308bfa3cc..11c124ca5 100644
--- a/lib/include/srsran/interfaces/rlc_interface_types.h
+++ b/lib/include/srsran/interfaces/rlc_interface_types.h
@@ -22,7 +22,7 @@
 namespace srsran {
 
 enum class rlc_mode_t { tm, um, am, nulltype };
-inline std::string to_string(const rlc_mode_t& mode, bool long_txt = true)
+inline const char* to_string(const rlc_mode_t& mode, bool long_txt = true)
 {
   constexpr static const char* long_options[]  = {"Transparent Mode", "Unacknowledged Mode", "Acknowledged Mode"};
   constexpr static const char* short_options[] = {"TM", "UM", "AM"};
diff --git a/lib/src/upper/rlc.cc b/lib/src/upper/rlc.cc
index 030c28137..76836800e 100644
--- a/lib/src/upper/rlc.cc
+++ b/lib/src/upper/rlc.cc
@@ -462,8 +462,7 @@ void rlc::add_bearer(uint32_t lcid, const rlc_config_t& cnfg)
       goto delete_and_exit;
     }
 
-    logger.info(
-        "Added %s radio bearer with LCID %d in %s", to_string(cnfg.rat), lcid, to_string(cnfg.rlc_mode).c_str());
+    logger.info("Added %s radio bearer with LCID %d in %s", to_string(cnfg.rat), lcid, to_string(cnfg.rlc_mode));
     rlc_entity = NULL;
   }
 
@@ -475,8 +474,7 @@ void rlc::add_bearer(uint32_t lcid, const rlc_config_t& cnfg)
     }
   }
 
-  logger.info(
-      "Configured %s radio bearer with LCID %d in %s", to_string(cnfg.rat), lcid, to_string(cnfg.rlc_mode).c_str());
+  logger.info("Configured %s radio bearer with LCID %d in %s", to_string(cnfg.rat), lcid, to_string(cnfg.rlc_mode));
 
 delete_and_exit:
   if (rlc_entity) {
diff --git a/lib/src/upper/rlc_tm.cc b/lib/src/upper/rlc_tm.cc
index 08478a6bc..e1da8b802 100644
--- a/lib/src/upper/rlc_tm.cc
+++ b/lib/src/upper/rlc_tm.cc
@@ -152,7 +152,7 @@ int rlc_tm::read_pdu(uint8_t* payload, uint32_t nof_bytes)
                 pdu_size,
                 "%s Tx %s PDU, queue size=%d, bytes=%d",
                 rrc->get_rb_name(lcid),
-                srsran::to_string(rlc_mode_t::tm).c_str(),
+                srsran::to_string(rlc_mode_t::tm),
                 ul_queue.size(),
                 ul_queue.size_bytes());
 
diff --git a/lib/src/upper/rlc_um_lte.cc b/lib/src/upper/rlc_um_lte.cc
index f90ffd387..004787c12 100644
--- a/lib/src/upper/rlc_um_lte.cc
+++ b/lib/src/upper/rlc_um_lte.cc
@@ -52,7 +52,7 @@ bool rlc_um_lte::configure(const rlc_config_t& cnfg_)
 
   logger.info("%s configured in %s: t_reordering=%d ms, rx_sn_field_length=%u bits, tx_sn_field_length=%u bits",
               rb_name.c_str(),
-              srsran::to_string(cnfg_.rlc_mode).c_str(),
+              srsran::to_string(cnfg_.rlc_mode),
               cfg.um.t_reordering,
               srsran::to_number(cfg.um.rx_sn_field_length),
               srsran::to_number(cfg.um.tx_sn_field_length));
diff --git a/lib/src/upper/rlc_um_nr.cc b/lib/src/upper/rlc_um_nr.cc
index b02060334..1c88f3aaa 100644
--- a/lib/src/upper/rlc_um_nr.cc
+++ b/lib/src/upper/rlc_um_nr.cc
@@ -51,7 +51,7 @@ bool rlc_um_nr::configure(const rlc_config_t& cnfg_)
 
   logger.info("%s configured in %s: sn_field_length=%u bits",
               rb_name.c_str(),
-              srsran::to_string(cnfg_.rlc_mode).c_str(),
+              srsran::to_string(cnfg_.rlc_mode),
               srsran::to_number(cfg.um_nr.sn_field_length));
 
   rx_enabled = true;