changes as per new analysis

Author: sabollim-silabs

src/inet/UDPEndPoint.cpp

@@ -124,7 +124,15 @@ CHIP_ERROR UDPEndPoint::SendMsg(const IPPacketInfo * pktInfo, System::PacketBuff
 void UDPEndPoint::Free()
 {
     Close();
-    Delete();
+
+    // CloseImpl() may have called Ref() to keep endpoint alive for pending operations
+    // (when mDelayReleaseCount != 0). Only delete if ref count is still 0.
+    // If ref count > 0, the deferred Unref() scheduled by CloseImpl() will eventually
+    // call Free() again when all pending operations complete.
+    if (GetReferenceCount() == 0)
+    {
+        Delete();
+    }
 }
 
 void UDPEndPoint::Close()

src/inet/UDPEndPointImplLwIP.cpp

@@ -221,19 +221,7 @@ void UDPEndPointImplLwIP::CloseImpl()
     if (mDelayReleaseCount != 0)
     {
         Ref();
-        // Capture the instance ID to validate this is still the same endpoint instance
-        uint32_t expectedInstanceId = mInstanceId.load();
-        CHIP_ERROR err              = GetSystemLayer().ScheduleLambda([this, expectedInstanceId] {
-            // Verify this is still the same endpoint instance by checking the instance ID
-            if (mInstanceId.load() != expectedInstanceId)
-            {
-                // This endpoint memory was reused for a new endpoint with different instance ID.
-                // The original endpoint this Unref was intended for is already gone.
-                return;
-            }
-
-            Unref();
-        });
+        CHIP_ERROR err = GetSystemLayer().ScheduleLambda([this] { Unref(); });
         if (err != CHIP_NO_ERROR)
         {
             ChipLogError(Inet, "Unable to schedule lambda: %" CHIP_ERROR_FORMAT, err.Format());
@@ -390,24 +378,8 @@ void UDPEndPointImplLwIP::LwIPReceiveUDPMessage(void * arg, struct udp_pcb * pcb
     // pending on it.
     ep->mDelayReleaseCount++;
 
-    // Capture the instance ID to validate this is still the same endpoint instance
-    uint32_t expectedInstanceId = ep->mInstanceId.load();
-    CHIP_ERROR err              = ep->GetSystemLayer().ScheduleLambda(
-        [ep, expectedInstanceId, p = System::LwIPPacketBufferView::UnsafeGetLwIPpbuf(buf), pktInfo = pktInfo.get()] {
-            // Critical check: Verify this lambda is for the correct endpoint instance
-            // by comparing the instance ID. If they don't match, the endpoint was
-            // deleted and new endpoint wascreated at the same memory address.
-            if (ep->mInstanceId.load() != expectedInstanceId)
-            {
-                // This is a stale lambda for a previously deleted endpoint.
-                // The memory was reused for a new endpoint with different instance ID.
-                // Note: We don't decrement mDelayReleaseCount here because:
-                // - The original endpoint's count is gone with the deleted endpoint
-                // - The new endpoint's count should not be decremented (it never had this packet)
-                pbuf_free(p);
-                return;
-            }
-
+    CHIP_ERROR err = ep->GetSystemLayer().ScheduleLambda(
+        [ep, p = System::LwIPPacketBufferView::UnsafeGetLwIPpbuf(buf), pktInfo = pktInfo.get()] {
             ep->mDelayReleaseCount--;
 
             auto handle = System::PacketBufferHandle::Adopt(p);
@@ -430,6 +402,7 @@ void UDPEndPointImplLwIP::LwIPReceiveUDPMessage(void * arg, struct udp_pcb * pcb
             (void) sQueueFilter->FilterAfterDequeue(ep, *(pktInfo.get()), buf);
             ChipLogError(Inet, "Dequeue ERROR err = %" CHIP_ERROR_FORMAT, err.Format());
         }
+
         ep->mDelayReleaseCount--;
     }
 }

src/inet/UDPEndPointImplLwIP.h

@@ -33,12 +33,7 @@ namespace Inet {
 class UDPEndPointImplLwIP : public UDPEndPoint, public EndPointStateLwIP
 {
 public:
-    UDPEndPointImplLwIP(EndPointManager<UDPEndPoint> & endPointManager) : UDPEndPoint(endPointManager), mUDP(nullptr)
-    {
-        // Generate a unique instance ID to detect endpoint reuse
-        static std::atomic<uint32_t> sNextInstanceId{ 1 };
-        mInstanceId.store(sNextInstanceId.fetch_add(1));
-    }
+    UDPEndPointImplLwIP(EndPointManager<UDPEndPoint> & endPointManager) : UDPEndPoint(endPointManager), mUDP(nullptr) {}
 
     // UDPEndPoint overrides.
     CHIP_ERROR SetMulticastLoopback(IPVersion aIPVersion, bool aLoopback) override;
@@ -81,7 +76,6 @@ class UDPEndPointImplLwIP : public UDPEndPoint, public EndPointStateLwIP
 
     udp_pcb * mUDP; // LwIP User datagram protocol (UDP) control block.
     std::atomic_int mDelayReleaseCount{ 0 };
-    std::atomic<uint32_t> mInstanceId{ 0 }; // Unique endpoint ID
 
     static EndpointQueueFilter * sQueueFilter;
 };