[SYCL] Fix memory leak for interop events created from native handle

sycl/plugins/level_zero/pi_level_zero.cpp

@@ -5664,6 +5664,13 @@ pi_result piextEventCreateWithNativeHandle(pi_native_handle NativeHandle,
   // need to create a host-visible proxy for it.
   (*Event)->HostVisibleEvent = *Event;
 
+  // Unlike regular events managed by SYCL RT we don't have to wait for interop
+  // events completion, and not need to do the their `cleanup()`. This in
+  // particular guarantees that the extra `piEventRelease` is not called on
+  // them. That release is needed to match the `piEventRetain` of regular events
+  // made for waiting for event completion, but not this interop event.
+  (*Event)->CleanedUp = true;
+
   return PI_SUCCESS;
 }
 

sycl/source/backend.cpp

@@ -130,8 +130,12 @@ __SYCL_EXPORT event make_event(pi_native_handle NativeHandle,
   Plugin.call<PiApiKind::piextEventCreateWithNativeHandle>(
       NativeHandle, ContextImpl->getHandleRef(), !KeepOwnership, &PiEvent);
 
-  return detail::createSyclObjFromImpl<event>(
+  event Event = detail::createSyclObjFromImpl<event>(
       std::make_shared<event_impl>(PiEvent, Context));
+
+  if (Backend == backend::opencl)
+    Plugin.call<PiApiKind::piEventRetain>(PiEvent);
+  return Event;
 }
 
 std::shared_ptr<detail::kernel_bundle_impl>

sycl/source/detail/event_impl.cpp

@@ -123,8 +123,6 @@ event_impl::event_impl(RT::PiEvent Event, const context &SyclContext)
         "clEvent.",
         PI_INVALID_CONTEXT);
   }
-
-  getPlugin().call<PiApiKind::piEventRetain>(MEvent);
 }
 
 event_impl::event_impl(const QueueImplPtr &Queue)