sched: handle failure to schedule RAR

srsenb/src/stack/mac/mac.cc

@@ -598,7 +598,10 @@ void mac::rach_detected(uint32_t tti, uint32_t enb_cc_idx, uint32_t preamble_idx
     }
 
     // Trigger scheduler RACH
-    scheduler.dl_rach_info(enb_cc_idx, rar_info);
+    if (scheduler.dl_rach_info(enb_cc_idx, rar_info) != SRSRAN_SUCCESS) {
+      ue_rem(rnti);
+      return;
+    }
 
     auto get_pci = [this, enb_cc_idx]() {
       srsran::rwlock_read_guard lock(rwlock);

srsenb/src/stack/mac/sched_carrier.cc

@@ -298,6 +298,7 @@ int ra_sched::dl_rach_info(dl_sched_rar_info_t rar_info)
   if (not pending_rars.try_push(p)) {
     logger.warning("SCHED: Unable to handle RAR ra-rnti=0x%x, as the maximum number of pending RARs has been reached",
                    ra_rnti);
+    return SRSRAN_ERROR;
   }
 
   return SRSRAN_SUCCESS;