[BugFix] Handle case where async utility call is cancelled (#22996)

Signed-off-by: Nick Hill <nhill@redhat.com>
Co-authored-by: Yinghai Lu <yinghai@thinkingmachines.ai>

vllm/v1/engine/core_client.py

@@ -574,13 +574,22 @@ class MPClient(EngineCoreClient):
 
 def _process_utility_output(output: UtilityOutput,
                             utility_results: dict[int, AnyFuture]):
-    """Set the result from a utility method in the waiting future"""
+    """Set the result from a utility method in the waiting future."""
     future = utility_results.pop(output.call_id)
-    if output.failure_message is not None:
-        future.set_exception(Exception(output.failure_message))
-    else:
-        assert output.result is not None
-        future.set_result(output.result.result)
+    failure_message = output.failure_message
+    try:
+        if failure_message is not None:
+            future.set_exception(Exception(failure_message))
+        else:
+            assert output.result is not None
+            future.set_result(output.result.result)
+    except asyncio.InvalidStateError:
+        # This can happen if the future is cancelled due to the
+        # original calling task being cancelled.
+        if failure_message is not None:
+            logger.error(
+                "Cancelled call to utility method failed "
+                "with error: %s", failure_message)
 
 
 class SyncMPClient(MPClient):