---
id: pr-vllm-35219
repo: vllm-project/vllm
pr: 35219
title: '[BUGFIX][Mamba][Qwen3.5] Zero freed SSM cache blocks on GPU'
author: vadiklyutiy
date: '2026-03-10'
url: https://github.com/vllm-project/vllm/pull/35219
source_category: upstream-code
architectures:
- sm100
tags:
- attention
techniques: []
hardware_features: []
kernel_types:
- attention
languages:
- python
captured_at: '2026-04-27'
status: merged
merge_sha: 4ff8c3c8f9ece010a1d0e376f5cc1b468b95f366
inclusion_reason: kernel file changes
changed_paths:
- vllm/utils/math_utils.py
- vllm/v1/attention/backend.py
- vllm/v1/core/kv_cache_manager.py
- vllm/v1/core/sched/output.py
- vllm/v1/core/sched/scheduler.py
- vllm/v1/core/single_type_kv_cache_manager.py
- vllm/v1/kv_cache_interface.py
- vllm/v1/worker/gpu_model_runner.py
- vllm/v1/worker/gpu_worker.py
- vllm/v1/worker/utils.py
head_ref_oid: 67fcd34b00f8e70a86ce20e780261c17fa8150c0
artifact_dir: evidence/pull-bundles/vllm/gh-35219
---
# [BUGFIX][Mamba][Qwen3.5] Zero freed SSM cache blocks on GPU

- Repository: `vllm-project/vllm`
- PR: [35219](https://github.com/vllm-project/vllm/pull/35219)
- Decision: `kernel file changes`
- Reason: kernel file changes

## Changed Paths

- `vllm/utils/math_utils.py`
- `vllm/v1/attention/backend.py`
- `vllm/v1/core/kv_cache_manager.py`
- `vllm/v1/core/sched/output.py`
- `vllm/v1/core/sched/scheduler.py`
- `vllm/v1/core/single_type_kv_cache_manager.py`
- `vllm/v1/kv_cache_interface.py`
- `vllm/v1/worker/gpu_model_runner.py`
- `vllm/v1/worker/gpu_worker.py`
- `vllm/v1/worker/utils.py`

## Evidence Bundle

`evidence/pull-bundles/vllm/gh-35219`
