diff --git a/arch/renesas/src/m16c/m16c_serial.c b/arch/renesas/src/m16c/m16c_serial.c
index 37543fa0ce..ff2a3fe2a2 100644
--- a/arch/renesas/src/m16c/m16c_serial.c
+++ b/arch/renesas/src/m16c/m16c_serial.c
@@ -843,6 +843,7 @@ static void m16c_rxint(struct up_dev_s *dev, bool enable)
 #endif
     {
       _err("ERROR: Invalid UART #\n");
+      leave_critical_section(flags);
       return;
     }
 
@@ -975,6 +976,7 @@ static void m16c_txint(struct up_dev_s *dev, bool enable)
 #endif
     {
       _err("ERROR: Invalid UART #\n");
+      leave_critical_section(flags);
       return;
     }
 
diff --git a/arch/renesas/src/rx65n/rx65n_dtc.c b/arch/renesas/src/rx65n/rx65n_dtc.c
index 81dbc8d85a..3565b8ee3d 100644
--- a/arch/renesas/src/rx65n/rx65n_dtc.c
+++ b/arch/renesas/src/rx65n/rx65n_dtc.c
@@ -1326,6 +1326,7 @@ dtc_err_t rx65n_dtc_setup_seq_dynamic_transferdata(DTC_HANDLE handle,
   ret = rx65n_dtc_validate_dynamic_params(p_dtransfer_cfg, p_transfer_data);
   if (DTC_SUCCESS != ret)
     {
+      leave_critical_section(flags);
       return ret;
     }
 
@@ -1345,6 +1346,7 @@ dtc_err_t rx65n_dtc_setup_seq_dynamic_transferdata(DTC_HANDLE handle,
           if (rx65n_dtc_set_dynamic_transfer_data(p_dtransfer_cfg,
                                   p_transfer_data) != DTC_SUCCESS)
             {
+              leave_critical_section(flags);
               return DTC_ERR_INVALID_ARG;
             }
 
@@ -1536,6 +1538,7 @@ dtc_err_t rx65n_dtc_setup_dynamic_transferdata(DTC_HANDLE handle,
   ret = rx65n_dtc_validate_dynamic_params(p_dtransfer_cfg, p_transfer_data);
   if (DTC_SUCCESS != ret)
     {
+      leave_critical_section(flags);
       return ret;
     }
 
@@ -1546,6 +1549,7 @@ dtc_err_t rx65n_dtc_setup_dynamic_transferdata(DTC_HANDLE handle,
       if (rx65n_dtc_set_dynamic_transfer_data(p_dtransfer_cfg,
                                   p_transfer_data) != DTC_SUCCESS)
         {
+          leave_critical_section(flags);
           return DTC_ERR_INVALID_ARG;
         }
 
diff --git a/arch/renesas/src/rx65n/rx65n_rspi.c b/arch/renesas/src/rx65n/rx65n_rspi.c
index df7ff615e3..35086c2f00 100644
--- a/arch/renesas/src/rx65n/rx65n_rspi.c
+++ b/arch/renesas/src/rx65n/rx65n_rspi.c
@@ -2547,7 +2547,6 @@ FAR struct spi_dev_s *rx65n_rspibus_initialize(int bus)
 #endif
     {
       spierr("ERROR: Unsupported RSPI bus: %d\n", bus);
-      return NULL;
     }
 
   leave_critical_section(flags);
diff --git a/arch/renesas/src/rx65n/rx65n_rspi_sw.c b/arch/renesas/src/rx65n/rx65n_rspi_sw.c
index 2a66d21674..13546d44a9 100644
--- a/arch/renesas/src/rx65n/rx65n_rspi_sw.c
+++ b/arch/renesas/src/rx65n/rx65n_rspi_sw.c
@@ -2144,7 +2144,6 @@ FAR struct spi_dev_s *rx65n_rspibus_initialize(int bus)
 #endif
     {
       spierr("ERROR: Unsupported RSPI bus: %d\n", bus);
-      return NULL;
     }
 
   leave_critical_section(flags);
diff --git a/arch/renesas/src/rx65n/rx65n_rtc.c b/arch/renesas/src/rx65n/rx65n_rtc.c
index 9a675b7710..1196df16ab 100644
--- a/arch/renesas/src/rx65n/rx65n_rtc.c
+++ b/arch/renesas/src/rx65n/rx65n_rtc.c
@@ -912,7 +912,6 @@ int rx65n_rtc_setalarm(FAR struct alm_setalarm_s *alminfo)
   uint8_t dummy_byte;
   uint8_t dummy_word;
   uint8_t i;
-  int ret = -EBUSY;
 
   /* Is there already something waiting on the ALARM? */
 
@@ -1068,11 +1067,10 @@ int rx65n_rtc_setalarm(FAR struct alm_setalarm_s *alminfo)
   /* Set Priority of ALM interrupt */
 
   IPR(RTC, ALM) = _0F_RTC_PRIORITY_LEVEL15;
-  ret = OK;
   leave_critical_section(flags);
   UNUSED(dummy_byte);
   UNUSED(dummy_word);
-  return ret;
+  return OK;
 }
 #endif
 
@@ -1117,8 +1115,8 @@ int rx65n_rtc_setperiodic(FAR const struct timespec *period,
   /* Set PRD priority level */
 
   IPR(RTC, PRD) = _0F_RTC_PRIORITY_LEVEL15;
-  return OK;
   leave_critical_section(flags);
+  return OK;
 }
 #endif
 
diff --git a/arch/renesas/src/rx65n/rx65n_usbdev.c b/arch/renesas/src/rx65n/rx65n_usbdev.c
index 5f5570b884..66bfff9013 100644
--- a/arch/renesas/src/rx65n/rx65n_usbdev.c
+++ b/arch/renesas/src/rx65n/rx65n_usbdev.c
@@ -3138,6 +3138,7 @@ static int rx65n_epsubmit(FAR struct usbdev_ep_s *ep, FAR struct
         {
           privreq->req.len = CDC_CLASS_DATA_LENGTH;
           rx65n_rdrequest(epno, priv, privep);
+          leave_critical_section(flags);
           return OK;
         }
 
@@ -3146,6 +3147,7 @@ static int rx65n_epsubmit(FAR struct usbdev_ep_s *ep, FAR struct
       if (!privep->txbusy)
         {
           ret = rx65n_wrrequest(epno, priv, privep);
+          leave_critical_section(flags);
           return OK;
         }
     }
@@ -3159,6 +3161,7 @@ static int rx65n_epsubmit(FAR struct usbdev_ep_s *ep, FAR struct
       if (priv->ep0state == EP0STATE_RDREQUEST)
         {
           rx65n_rdrequest(epno, priv, privep);
+          leave_critical_section(flags);
           return OK;
         }