From 09ad3b76b320fffcb6b0214bd90851c3328581ea Mon Sep 17 00:00:00 2001 From: Michael Goin Date: Fri, 12 Dec 2025 10:40:50 -0500 Subject: [PATCH] [Bug] Fix attention_backend arg string parsing (#30534) Signed-off-by: mgoin --- vllm/engine/arg_utils.py | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/vllm/engine/arg_utils.py b/vllm/engine/arg_utils.py index 757023e12d439..2867532756450 100644 --- a/vllm/engine/arg_utils.py +++ b/vllm/engine/arg_utils.py @@ -1649,7 +1649,13 @@ class EngineArgs: "attention_backend and attention_config.backend " "are mutually exclusive" ) - attention_config.backend = self.attention_backend + # Convert string to enum if needed (CLI parsing returns a string) + if isinstance(self.attention_backend, str): + attention_config.backend = AttentionBackendEnum[ + self.attention_backend.upper() + ] + else: + attention_config.backend = self.attention_backend load_config = self.create_load_config()