diff --git a/artiq/coredevice/comm_kernel.py b/artiq/coredevice/comm_kernel.py
index e44327887..9e5711bf6 100644
--- a/artiq/coredevice/comm_kernel.py
+++ b/artiq/coredevice/comm_kernel.py
@@ -758,7 +758,7 @@ class CommKernel:
         self._process_async_error()
 
         traceback = list(symbolizer(backtrace))
-        core_exn = exceptions.CoreException(nested_exceptions, exception_info,
+        core_exn = CoreException(nested_exceptions, exception_info,
                                             traceback, stack_pointers)
 
         if core_exn.id == 0: