[Bugfix][ROCm] Add record_logical_topk_ready to ROCMAiterMLASparseImpl (GLM-5.3-Flash boot crash)

[mustafayildirim]

Why this is not duplicating #56604

#56604 (open since 2026-09-12) fixes the same crash class by adding a default no-op record_logical_topk_ready on the MLAAttentionImpl base class in vllm/v1/attention/backend.py, so every backend silently inherits it.

This PR instead adds the method on ROCMAiterMLASparseImpl itself, mirroring the existing SparseMLACommonImpl contract (vllm/model_executor/layers/attention/sparse_mla_attention.py:717): impls that participate in sparse-MLA index groups implement the hook with real semantics; impls that don't declare an explicit no-op at their own site.

Trade-off: the base-class default in #56604 is broader (also covers any other backend that skips SparseMLACommonImpl) but weakens the interface — a new sparse backend that should implement index-group notification would silently no-op instead of failing loudly. This PR keeps that failure loud and fixes the one backend that currently crashes (ROCm AITER sparse MLA, GLM-5.3-Flash on MI350X). Either fix resolves the boot regression in #57248; happy to withdraw this in favor of #56604 if maintainers prefer the base-class default.

Description

MLAAttention.forward calls impl.record_logical_topk_ready() on every sparse layer (vllm/model_executor/layers/mla.py:235). ROCMAiterMLASparseImpl inherits SharedTopkIndicesBuffer directly (not SparseMLACommonImpl) and never gained the method, so serving GLM-5.3-Flash on ROCm (gfx950, ROCM_AITER_MLA_SPARSE) crashes at the first forward with AttributeError: 'ROCMAiterMLASparseImpl' object has no attribute 'record_logical_topk_ready'.

This impl shares the top-k indices buffer via SharedTopkIndicesBuffer but does not participate in SparseMLAIndexGroup host-side prefetching, so the correct implementation is a no-op.

Fixes the first boot regression in #57248.

Test commands run and results

• Reproduced on the cluster before the fix: nightly af1c01499 on 8×MI350X TP8, engine dies at first forward with the AttributeError above.
• With the equivalent no-op method patched in-pod (same 5-line change), the model boots and serves; combined with VLLM_USE_BREAKABLE_CUDAGRAPH=0 it passes the full chunked-prefill repro suite with zero faults (details in [Bug][ROCm/gfx950] GLM-5.3-Flash 16K-chunk prefill: GPU memory-access fault when indexer triton kernels JIT during lazy CUDA-graph capture — clean under --enforce-eager #57227).
• python3 -c "import ast; ast.parse(...)" — syntax OK; AST check confirms the method is now on the class.
• No GPU/ROCm environment is available in CI for the full path, so no new automated test is added here; [Bugfix][ROCm][Attention] Add missing record_logical_topk_ready to sparse MLA impls #56604 already adds an interface-level test (tests/v1/attention/test_sparse_mla_topk_ready_hook.py) that covers this method's presence on backends.

AI assistance

This PR was prepared with AI assistance (Hermes Agent). The change was reviewed and validated end-to-end on the affected hardware by the submitter: the same no-op patch was applied in-pod on the MI350X cluster and confirmed to resolve the crash.

[claude]

Claude Code Review

This pull request is from a fork — automated review is disabled. A repository maintainer can comment @claude review to run a one-time review.

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[mustafayildirim]

Unit tests + end-to-end validation of the fix on the affected hardware

Added unit tests for the fix (run on the actual ROCm nightly image, MI350X):

test_rocm_mla_topk_ready.py::test_method_exists PASSED
test_rocm_mla_topk_ready.py::test_method_is_no_arg_noop PASSED
test_rocm_mla_topk_ready.py::test_method_semantics_match_base_contract PASSED
test_rocm_mla_topk_ready.py::test_module_imports_without_aiter_gpu_errors PASSED
4 passed in 6.55s

test_method_semantics_match_base_contract asserts the no-op is semantically equivalent to SparseMLACommonImpl.record_logical_topk_ready for this impl: the base implementation only acts when an index group is registered (if self.index_group is not None), and ROCMAiterMLASparseImpl never registers one (it has no set_logical_topk_ready / index-group machinery — it shares the top-k buffer via SharedTopkIndicesBuffer only).

End-to-end on 8×MI350X (nightly af1c014 + this patch)

With this exact patch applied in-place, the engine boots (previously died at first forward with the AttributeError) and passes the full chunked-prefill repro twice, combined with VLLM_USE_BREAKABLE_CUDAGRAPH=0 and --kernel-config '{"enable_jit_warmup": false}':

• Ready with 57 FULL cudagraphs captured (FULL_AND_PIECEWISE active)
• prefill-cold OK 10.3s (20K-token prompt, 16K chunks)
• Mixed-phase + cached-decode phases OK
• Memory access faults: 0

[simondanielsson]

Thanks @mustafayildirim! I think this is the same fix as @Rohan138 suggested in a comment on that other PR: #56604 (comment)

[mergify]

Hi @mustafayildirim, the pre-commit checks have failed. Please run:

uv pip install pre-commit>=4.5.1
pre-commit install
pre-commit run --all-files

Then, commit the changes and push to your branch.

For future commits, pre-commit will run automatically on changed files before each commit.

[github-actions]

✅ @mustafayildirim, CI is now available for this PR.

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[Rohan138]

Hi @mustafayildirim thanks for the PR! Can you fix pre-commit, merge main and comment /ci run? Otherwise LGTM

[dllehr-amd]

Thanks @mustafayildirim for fixing this!

[AndreasKaratzas]

/ci run

[github-actions]

✅ Triggered Buildkite CI #89716 for commit af4782de7fc7.