From 1bc0cf375a0028ef8c12de94e72f784f52c4bbaf Mon Sep 17 00:00:00 2001 From: Cursor Agent Date: Wed, 20 May 2026 20:53:44 +0000 Subject: [PATCH] fix(vertex): serialize credentials.refresh() across threads via _sync_refresh_lock refresh_auth is invoked from three call sites that can run on different threads (sync get_access_token, async slow path via asyncify, and the background proactive refresh task). Only the sync path was protected by _sync_refresh_lock, so a concurrent sync + async/background call could invoke google-auth's Credentials.refresh() on the same object from two threads simultaneously, mutating internal credential state. Move the lock acquisition into refresh_auth itself; the lock is an RLock so reentrant acquisition from the sync path remains safe. Co-authored-by: Yassin Kortam --- litellm/llms/vertex_ai/vertex_llm_base.py | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/litellm/llms/vertex_ai/vertex_llm_base.py b/litellm/llms/vertex_ai/vertex_llm_base.py index f21ad6ac071..5a3695a3536 100644 --- a/litellm/llms/vertex_ai/vertex_llm_base.py +++ b/litellm/llms/vertex_ai/vertex_llm_base.py @@ -366,7 +366,17 @@ class VertexBase: except ImportError: raise ImportError(GOOGLE_IMPORT_ERROR_MESSAGE) - credentials.refresh(Request()) + # Serialize all refreshes on this VertexBase across threads. + # ``credentials.refresh()`` is not safe to call concurrently on the + # same credentials object, and this method is invoked from three + # places that can run on different threads: + # - sync ``get_access_token`` (already holds ``_sync_refresh_lock``) + # - the async slow path (via ``asyncify`` in a worker thread) + # - the background proactive refresh task (via ``asyncify``) + # ``_sync_refresh_lock`` is an ``RLock`` so reentrant acquisition + # from the sync path is safe. + with self._sync_refresh_lock: + credentials.refresh(Request()) def _acquire_async_refresh_lock(self, credential_cache_key: tuple) -> asyncio.Lock: """Increment the refcount and return the lock for ``credential_cache_key``.