From b2c8573b2b075e0edd7480b76c6f87a595d2f232 Mon Sep 17 00:00:00 2001
From: taking-lying-flat <1615405@qq.com>
Date: Sun, 23 Aug 2026 16:33:11 +0800
Subject: [PATCH] Reject negative gradient clipping max norm

---
 torchtitan/config/configs.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/torchtitan/config/configs.py b/torchtitan/config/configs.py
index 90c38afeaa..3f338fe217 100644
--- a/torchtitan/config/configs.py
+++ b/torchtitan/config/configs.py
@@ -60,6 +60,8 @@ def __post_init__(self) -> None:
             raise ValueError("num_tokens_per_train_step must be -1 or greater than 0.")
         if self.max_context_length <= 0:
             raise ValueError("max_context_length must be greater than 0.")
+        if self.max_norm < 0:
+            raise ValueError("max_norm must be greater than or equal to 0.")
 
     max_norm: float | int = 1.0
     """Max norm for gradient clipping"""