mtapi_opencl_c: fixed race condition in opencl plugin

mtapi_plugins_c/mtapi_opencl_c/src/embb_mtapi_opencl.c

@@ -174,34 +174,43 @@ static void opencl_task_start(
 
         err = clSetKernelArg(opencl_action->kernel, 0, sizeof(cl_mem),
           (const void*)&opencl_task->arguments);
-        err = clSetKernelArg(opencl_action->kernel, 1, sizeof(cl_int),
+        err |= clSetKernelArg(opencl_action->kernel, 1, sizeof(cl_int),
           (const void*)&opencl_task->arguments_size);
 
-        err = clSetKernelArg(opencl_action->kernel, 2, sizeof(cl_mem),
+        err |= clSetKernelArg(opencl_action->kernel, 2, sizeof(cl_mem),
           (const void*)&opencl_task->result_buffer);
-        err = clSetKernelArg(opencl_action->kernel, 3, sizeof(cl_int),
+        err |= clSetKernelArg(opencl_action->kernel, 3, sizeof(cl_int),
           (const void*)&opencl_task->result_buffer_size);
 
-        err = clEnqueueWriteBuffer(plugin->command_queue,
+        err |= clEnqueueWriteBuffer(plugin->command_queue,
           opencl_task->arguments, CL_FALSE, 0,
           (size_t)opencl_task->arguments_size, local_task->arguments,
           0, NULL, NULL);
-        err = clEnqueueNDRangeKernel(plugin->command_queue,
+
+        if (CL_SUCCESS == err) {
+          err |= clEnqueueNDRangeKernel(plugin->command_queue,
             opencl_action->kernel, 1, NULL,
             &global_work_size, &opencl_action->local_work_size, 0, NULL, NULL);
-        err = clEnqueueReadBuffer(plugin->command_queue,
+          err |= clEnqueueReadBuffer(plugin->command_queue,
             opencl_task->result_buffer, CL_FALSE, 0,
             (size_t)opencl_task->result_buffer_size, local_task->result_buffer,
             0, NULL, &opencl_task->kernel_finish_event);
-        err = clSetEventCallback(opencl_task->kernel_finish_event,
+          err |= clSetEventCallback(opencl_task->kernel_finish_event,
             CL_COMPLETE, opencl_task_complete, opencl_task);
-        err = clFlush(plugin->command_queue);
 
           embb_mtapi_task_set_state(local_task, MTAPI_TASK_RUNNING);
+        }
+
+        err |= clFlush(plugin->command_queue);
+        if (CL_SUCCESS != err) {
+          embb_mtapi_task_set_state(local_task, MTAPI_TASK_ERROR);
+          local_status = MTAPI_ERR_ACTION_FAILED;
+        } else {
           local_status = MTAPI_SUCCESS;
         }
       }
     }
+  }
 
   mtapi_status_set(status, local_status);
 }