SWDEV-568847 - prevent UAF when registering callbacks on completed events (#2066)

* SWDEV-568847 - prevent UAF when registering callbacks on completed events

* cache the status() of event earlier

* Update command.cpp

* revert cl_event.cpp

* Update cl_event.cpp

---------

Co-authored-by: cadolphe-amd <chris.adolphe@amd.com>

projects/clr/opencl/amdocl/cl_event.cpp

@@ -377,11 +377,17 @@ RUNTIME_ENTRY(cl_int, clSetEventCallback,
     return CL_INVALID_VALUE;
   }
 
-  if (!as_amd(event)->setCallback(command_exec_callback_type, pfn_notify, user_data)) {
+  amd::Event* ev = as_amd(event);
+  ev->retain();
+
+  if (!ev->setCallback(command_exec_callback_type, pfn_notify, user_data)) {
+    ev->release();
     return CL_OUT_OF_HOST_MEMORY;
   }
-
-  as_amd(event)->notifyCmdQueue();
+  if (ev->status() > CL_COMPLETE) {
+    ev->notifyCmdQueue();
+  }
+  ev->release();
 
   return CL_SUCCESS;
 }