[UR][L0] Fix Barrier Event Cleanup (#17989)

- Fix barrier wait cleanup of events given an out event such that an
additional refcnt release is done and with multi command lists and in
order, the active barrier is properly cleared before reassignment.

Signed-off-by: Neil R. Spruit <[email protected]>

Author: nrspruit

unified-runtime/source/adapters/level_zero/event.cpp

@@ -318,6 +318,9 @@ ur_result_t urEnqueueEventsWaitWithBarrierExt(
     // need to keep track of any active barriers if we have in-order queue.
     if (UseMultipleCmdlistBarriers && !Queue->isInOrderQueue()) {
       auto UREvent = reinterpret_cast<ur_event_handle_t>(ResultEvent);
+      // We must release the Active Barrier before we start the next one
+      // otherwise we will leak an event that won't be released.
+      UR_CALL(Queue->ActiveBarriers.clear());
       Queue->ActiveBarriers.add(UREvent);
     }
 
@@ -900,12 +903,21 @@ ur_result_t
 urEventRelease(/** [in] handle of the event object */ ur_event_handle_t Event) {
   Event->RefCountExternal--;
   bool isEventsWaitCompleted =
-      Event->CommandType == UR_COMMAND_EVENTS_WAIT && Event->Completed;
+      (Event->CommandType == UR_COMMAND_EVENTS_WAIT ||
+       Event->CommandType == UR_COMMAND_EVENTS_WAIT_WITH_BARRIER) &&
+      Event->Completed;
   UR_CALL(urEventReleaseInternal(Event));
   // If this is a Completed Event Wait Out Event, then we need to cleanup the
   // event at user release and not at the time of completion.
+  // If the event is labelled as completed and no additional references are
+  // removed, then we still need to decrement the event, but not mark as
+  // completed.
   if (isEventsWaitCompleted) {
-    UR_CALL(CleanupCompletedEvent((Event), false, false));
+    if (Event->CleanedUp) {
+      UR_CALL(urEventReleaseInternal(Event));
+    } else {
+      UR_CALL(CleanupCompletedEvent((Event), false, false));
+    }
   }
 
   return UR_RESULT_SUCCESS;

unified-runtime/source/adapters/level_zero/queue.cpp

@@ -2356,10 +2356,11 @@ ur_queue_handle_t_::insertActiveBarriers(ur_command_list_ptr_t &CmdList,
   Event->WaitList = ActiveBarriersWaitList;
   Event->OwnNativeHandle = true;
 
-  // If there are more active barriers, insert a barrier on the command-list. We
-  // do not need an event for finishing so we pass nullptr.
+  // If there are more active barriers, insert a barrier on the command-list.
+  // We need to signal the current active barrier event otherwise we will leak
+  // the Event object when we replace the active barrier.
   ZE2UR_CALL(zeCommandListAppendBarrier,
-             (CmdList->first, nullptr, ActiveBarriersWaitList.Length,
+             (CmdList->first, Event->ZeEvent, ActiveBarriersWaitList.Length,
               ActiveBarriersWaitList.ZeEventList));
   return UR_RESULT_SUCCESS;
 }