Fix for Issue 52413: causal_conv1d Alignment Specialization Race Condition - #52611
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…ition Problem The causal_conv1d Triton kernels (_causal_conv1d_fwd_kernel and _causal_conv1d_update_kernel) were allowing Triton to specialize on pointer alignment for dynamic metadata pointers that change on every inference request: batch_ptr, token_chunk_offset_ptr cache_indices_ptr, query_start_loc_ptr block_idx_first_scheduled_token, block_idx_last_scheduled_token initial_state_idx, num_computed_tokens, etc. Since batch sizes, sequence lengths, and memory layouts differ per request, pointer alignment changes frequently, causing Triton to: Trigger inference-time JIT recompiles for each new alignment → latency spikes Create write races in the shared Triton JIT cache when multiple requests compile simultaneously → corrupted kernel binaries Produce silent all-NaN outputs from corrupted kernels → data corruption (HIGH IMPACT) Solution Added all dynamic metadata pointers to the do_not_specialize_on_alignment list in both kernel decorators: This ensures: One stable kernel variant used for all pointer alignments (no recompiles) No JIT cache races (no concurrent writes) No silent all-NaN data corruption Lower inference latency (no compilation overhead) Testing Added regression test in test_causal_conv1d_jit_metadata.py that statically validates both kernels keep metadata pointers in the alignment exemption list. This prevents accidental regression if someone removes these pointers in the future. Test command: Impact Scope: Mamba and Mamba2 model inference (all variants using causal_conv1d) Severity: HIGH (silent data corruption risk eliminated) Performance: Inference latency reduced (no JIT compiles at runtime) Backwards Compatibility: Fully compatible (kernel math unchanged, only specialization metadata)
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Purpose
Fixes issue #52413: Alignment specialization on causal_conv1d metadata pointers forces inference-time JIT compiles; raced shared-cache writes produced silent all-NaN outputs.
Problem:
Solution:
Added dynamic metadata pointers to
do_not_specialize_on_alignmentin both_causal_conv1d_fwd_kerneland_causal_conv1d_update_kerneldecorators to prevent alignment-based specialization.Test Plan
test_causal_conv1d_metadata_ptrs_not_alignment_specialized()that validates kernel decorators keep metadata pointers in alignment exemption list.venv/bin/python -m pytest -v --noconftest tests/kernels/mamba/test_causal_conv1d_jit_metadata.py.venv/bin/python -m pytest -v tests/kernels/mamba/test_causal_conv1d.py)Test Results
test_causal_conv1d_metadata_ptrs_not_alignment_specializedEssential Elements of an Effective PR Description Checklist
supported_models.mdandexamplesfor a new model.