---
id: pr-vllm-27884
repo: vllm-project/vllm
pr: 27884
title: '[Bug] Batch invariant: Fix flash attn MLA `RuntimeError: scheduler_metadata must have shape (metadata_size)`'
author: yewentao256
date: '2025-11-04'
url: https://github.com/vllm-project/vllm/pull/27884
source_category: upstream-code
architectures:
- sm100
tags:
- attention
- mla
techniques: []
hardware_features: []
kernel_types:
- attention
- mla
languages:
- python
captured_at: '2026-04-27'
status: merged
merge_sha: 7e4be741044bfead91afc418100ff9a4d804bf7f
inclusion_reason: kernel file changes
changed_paths:
- vllm/model_executor/layers/batch_invariant.py
- vllm/v1/attention/backends/mla/flashattn_mla.py
head_ref_oid: 9820d9a61c336985e63eada647b1c39da22f253e
artifact_dir: evidence/pull-bundles/vllm/gh-27884
---
# [Bug] Batch invariant: Fix flash attn MLA `RuntimeError: scheduler_metadata must have shape (metadata_size)`

- Repository: `vllm-project/vllm`
- PR: [27884](https://github.com/vllm-project/vllm/pull/27884)
- Decision: `kernel file changes`
- Reason: kernel file changes

## Changed Paths

- `vllm/model_executor/layers/batch_invariant.py`
- `vllm/v1/attention/backends/mla/flashattn_mla.py`

## Evidence Bundle

`evidence/pull-bundles/vllm/gh-27884`
