---
id: pr-flash-attention-2137
repo: Dao-AILab/flash-attention
pr: 2137
title: score-mod backward SM90
author: drisspg
date: '2026-01-10'
url: https://github.com/Dao-AILab/flash-attention/pull/2137
source_category: upstream-code
architectures:
- sm90
tags:
- sm90
techniques: []
hardware_features:
- hopper
kernel_types:
- attention
languages: []
captured_at: '2026-05-16'
status: merged
merge_sha: 844b10fe36880ce070a6f16338fde09ad8e6c138
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- flash_attn/cute/block_sparsity.py
- flash_attn/cute/flash_bwd_sm90.py
- flash_attn/cute/interface.py
- flash_attn/cute/mask.py
- tests/cute/test_mask_mod.py
- tests/cute/test_score_mod.py
artifact_dir: evidence/pull-bundles/flash-attention/gh-2137
head_ref_oid: c8aa2cbf6f0a6de2a519c8ca9a8e25f407cad37a
---
# score-mod backward SM90

- Repository: `Dao-AILab/flash-attention`
- PR: [2137](https://github.com/Dao-AILab/flash-attention/pull/2137)
- Decision: `Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.`
- Reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.

## Changed Paths

- `flash_attn/cute/block_sparsity.py`
- `flash_attn/cute/flash_bwd_sm90.py`
- `flash_attn/cute/interface.py`
- `flash_attn/cute/mask.py`
- `tests/cute/test_mask_mod.py`
- `tests/cute/test_score_mod.py`

## Evidence Bundle

`evidence/pull-bundles/flash-attention/gh-2137`
