sched: fix possible use of pointer from deleted cfg

Signed-off-by: Carlo Galiotto <[email protected]>

Author: carlo-gal

lib/scheduler/pucch_scheduling/pucch_allocator_impl.cpp

@@ -1305,7 +1305,24 @@ pucch_allocator_impl::get_pucch_res_pre_multiplexing(slot_point
     // There is already a PUCCH resource for HARQ-ACK; if so, we use the info and configuration from this resource.
     if (ue_current_grants.pucch_grants.harq_resource.has_value() and
         ue_current_grants.pucch_grants.harq_resource.value().harq_id.pucch_set_idx == pucch_set_idx) {
-      harq_candidate_grant = ue_current_grants.pucch_grants.harq_resource.value();
+      const pucch_resource* pucch_res =
+          pucch_set_idx == pucch_res_set_idx::set_0
+              ? resource_manager.reserve_f1_res_by_res_indicator(
+                    sl_tx,
+                    ue_current_grants.rnti,
+                    ue_current_grants.pucch_grants.harq_resource.value().harq_id.pucch_res_ind,
+                    pucch_cfg)
+              : resource_manager.reserve_f2_res_by_res_indicator(
+                    sl_tx,
+                    ue_current_grants.rnti,
+                    ue_current_grants.pucch_grants.harq_resource.value().harq_id.pucch_res_ind,
+                    pucch_cfg);
+      if (pucch_res == nullptr) {
+        srsran_assertion_failure("rnti={}: PUCCH HARQ-ACK resource previously reserved not available anymore",
+                                 ue_current_grants.rnti);
+        return std::nullopt;
+      }
+      harq_candidate_grant.pucch_res_cfg = pucch_res;
     }
     // Get a new PUCCH resource for HARQ-ACK from the correct PUCCH resource set.
     else {
@@ -1338,22 +1355,19 @@ pucch_allocator_impl::get_pucch_res_pre_multiplexing(slot_point
     candidate_resources.sr_resource.emplace(pucch_grant{.type = pucch_grant_type::sr});
     pucch_grant& sr_candidate_grant = candidate_resources.sr_resource.value();
 
-    // There is already a PUCCH resource for SR; if so, we use the info and configuration from this resource.
-    if (ue_current_grants.pucch_grants.sr_resource.has_value()) {
-      sr_candidate_grant = ue_current_grants.pucch_grants.sr_resource.value();
-    }
-    // Get the new resource from the resource manager; the UCI bits will be added later.
-    else {
-      // TODO: handle case in which the resource is already used by the same UE.
-      const pucch_resource* sr_resource =
-          resource_manager.reserve_sr_res_available(sl_tx, ue_current_grants.rnti, pucch_cfg);
-      // Save the resources that have been generated; if at some point the allocation fails, we need to release them.
-      resource_manager.set_new_resource_allocation(ue_current_grants.rnti, pucch_resource_usage::SR);
-      if (sr_resource == nullptr) {
-        return std::nullopt;
-      }
-      sr_candidate_grant.pucch_res_cfg = sr_resource;
+    // Get the resource from the resource manager; the UCI bits will be added later.
+    // NOTE: if the SR resource was already assigned to this UE, the resource manager will only return the PUCCH config
+    // that was reserved previously.
+    const pucch_resource* sr_resource =
+        resource_manager.reserve_sr_res_available(sl_tx, ue_current_grants.rnti, pucch_cfg);
+    // Save the resources that have been generated; if at some point the allocation fails, we need to release them.
+    resource_manager.set_new_resource_allocation(ue_current_grants.rnti, pucch_resource_usage::SR);
+    if (sr_resource == nullptr) {
+      srsran_assertion_failure("rnti={}: PUCCH SR resource previously reserved not available anymore",
+                               ue_current_grants.rnti);
+      return std::nullopt;
     }
+    sr_candidate_grant.pucch_res_cfg = sr_resource;
     // Only copy the SR bits, as at this stage we only need to consider the UCI bits assuming the resources still
     // need to be multiplexed.
     sr_candidate_grant.bits.harq_ack_nof_bits  = 0U;
@@ -1365,22 +1379,19 @@ pucch_allocator_impl::get_pucch_res_pre_multiplexing(slot_point
     candidate_resources.csi_resource.emplace(pucch_grant{.type = pucch_grant_type::csi});
     pucch_grant& csi_candidate_grant = candidate_resources.csi_resource.value();
 
-    // There is already a PUCCH resource for SR; if so, we use the info and configuration from this resource.
-    if (ue_current_grants.pucch_grants.csi_resource.has_value()) {
-      csi_candidate_grant = ue_current_grants.pucch_grants.csi_resource.value();
-    }
-    // Get the new resource from the resource manager; the UCI bits will be added later.
-    else {
-      // TODO: handle case in which the resource is already used by the same UE.
-      const pucch_resource* csi_resource =
-          resource_manager.reserve_csi_resource(sl_tx, ue_current_grants.rnti, ue_cell_cfg);
-      // Save the resources that have been generated; if at some point the allocation fails, we need to release them.
-      resource_manager.set_new_resource_allocation(ue_current_grants.rnti, pucch_resource_usage::CSI);
-      if (csi_resource == nullptr) {
-        return std::nullopt;
-      }
-      csi_candidate_grant.pucch_res_cfg = csi_resource;
+    // Get the resource from the resource manager; the UCI bits will be added later.
+    // NOTE: if the CSI resource was already assigned to this UE, the resource manager will only return the PUCCH config
+    // that was reserved previously.
+    const pucch_resource* csi_resource =
+        resource_manager.reserve_csi_resource(sl_tx, ue_current_grants.rnti, ue_cell_cfg);
+    // Save the resources that have been generated; if at some point the allocation fails, we need to release them.
+    resource_manager.set_new_resource_allocation(ue_current_grants.rnti, pucch_resource_usage::CSI);
+    if (csi_resource == nullptr) {
+      srsran_assertion_failure("rnti={}: PUCCH CSI resource previously reserved not available anymore",
+                               ue_current_grants.rnti);
+      return std::nullopt;
     }
+    csi_candidate_grant.pucch_res_cfg = csi_resource;
     // Only copy the HARQ-ACK bits, as at this stage we only need to consider the UCI bits assuming the resources still
     // need to be multiplexed.
     csi_candidate_grant.bits.harq_ack_nof_bits  = 0U;

lib/scheduler/pucch_scheduling/pucch_allocator_impl.h

@@ -108,8 +108,10 @@ class pucch_allocator_impl final : public pucch_allocator
   public:
     pucch_grant_type type;
     // Only relevant for HARQ-ACK resources.
-    harq_res_id           harq_id;
-    pucch_uci_bits        bits;
+    harq_res_id    harq_id;
+    pucch_uci_bits bits;
+    // NOTE: The pointer to the PUCCH resource configuration can only be used within the same slot; this is to prevent
+    // the possibility that the re-configurations can null the pointer before an allocation and the next.
     const pucch_resource* pucch_res_cfg = nullptr;
 
     [[nodiscard]] pucch_format get_format() const
@@ -237,12 +239,12 @@ class pucch_allocator_impl final : public pucch_allocator
   // \brief Ring of PUCCH allocations indexed by slot.
   circular_array<slot_pucch_grants, cell_resource_allocator::RING_ALLOCATOR_SIZE> pucch_grants_alloc_grid;
 
-  constexpr static unsigned     PUCCH_FORMAT_1_NOF_PRBS{1};
-  const cell_configuration&     cell_cfg;
-  const unsigned                max_pucch_grants_per_slot;
-  const unsigned                max_ul_grants_per_slot;
-  slot_point                    last_sl_ind;
-  pucch_resource_manager        resource_manager;
+  constexpr static unsigned PUCCH_FORMAT_1_NOF_PRBS{1};
+  const cell_configuration& cell_cfg;
+  const unsigned            max_pucch_grants_per_slot;
+  const unsigned            max_ul_grants_per_slot;
+  slot_point                last_sl_ind;
+  pucch_resource_manager    resource_manager;
 
   srslog::basic_logger& logger;
 };