What's Changed

• [CuTe, Fwd, SM100] Prevent NaN contamination from unused V cache entries by @fusheng-ji in #2983
• [CuTe] Format config.py with ruff so the Lint workflow passes again by @WeiYedi in #3067
• [CuTe, Bwd, SM100] Bound the K/V TMA loads by seqlen_k so unused rows cannot poison dQ (packed varlen and dense seqused_k) by @yunweili3 in #3012
• [CuTe, SM90] Bound the K/V TMA loads by seqlen_k (fwd + bwd, packed varlen and dense seqused_k) by @yunweili3 in #3013
• [CuTe] Bound ragged K/V TMA loads with per-CTA descriptor updates instead of a wrap-around descriptor by @yunweili3 in #3071
• [CuTe, SM100] Unify hd256 backward (4/7): pack the query heads of a KV head into the Q tile (GQA) by @Johnsonms in #2967
• [CuTe, SM100] Fix 2CTA CLC tile coords and make forward work-tile coordinates logical by @drisspg in #3034

New Contributors

• @fusheng-ji made their first contribution in #2983
• @WeiYedi made their first contribution in #3067

Full Changelog: fa4-v4.0.0.beta36...fa4-v4.0.0.beta37

What's Changed

• Fix paged KV-cache CUDA graph capture by @pkuwangh in #2984
• [CuTe, SM100] Unify hd256 backward (2/5): 64-row KV tile per CTA (M=64 TMEM layout) with GQA, varlen and deterministic support by @Johnsonms in #2965
• [Tests] CUDA graph capture/replay coverage for FA4 (CuTe) and FA2 entry points by @yunweili3 in #3007
• [CuTe, SM100] Unify hd256 backward (3/5): hdim 256 on FlashAttentionBackwardSm100 (opt-in) by @Johnsonms in #2966
• [CuTe] Add typed forward configurations by @drisspg in #2732

New Contributors

• @pkuwangh made their first contribution in #2984

Full Changelog: fa4-v4.0.0.beta35...fa4-v4.0.0.beta36

Maintenance release of FlashAttention 2 on top of v2.8.3.post1. No kernel feature changes.

• Backport #2622: torch.load(..., weights_only=True) in flash_attn/utils/distributed.py and flash_attn/models (CVE-2026-31253 / GHSA-7g5w-pq96-8c5w). #2974
• Backport #2702: safe tarfile extraction in hopper/setup.py (CVE-2026-62239 / GHSA-w9r7-4gwr-j959). #2974
• Backport #2260: fix int32 overflow in the FA2 backward dq_accum offsets, which caused an illegal memory access or NaN gradients when batch * round128(seqlen_q) * nheads * headdim exceeded 2^31 (#2987). #2994
• setup.py: request cu13 prebuilt wheels for CUDA 13 torch.

What's Changed

• bump version to 3.0.1 by @liangel-02 in #2992
• [CuTe, SM120] Support automatic num_splits by @bvolpato in #2758

New Contributors

• @bvolpato made their first contribution in #2758

Full Changelog: fa4-v4.0.0.beta34...fa4-v4.0.0.beta35

What's Changed

• Fix Windows builds with CUDA 13 and PyTorch 2.15 by @tuananhlfc in #2872
• [CuTe] Allow apache-tvm-ffi 0.1.11 by @felipemello1 in #2948
• [CuTe, SM100] S/P ping-pong to overlap QK with softmax in decode by @drisspg in #2928
• [CuTe, SM100] Unify hd256 forward and recover the remaining stack by @drisspg in #2962
• [CuTe, SM100] Fix hd128 decode crash on SM103: cap other-WG registers at the launch count by @felipemello1 in #2950
• [Cute,Fwd,Sm100] hd256: S ping-pong on SM103, 2CTA for varlen Q and decode by @felipemello1 in #2951
• [CuTe, SM100] Allow deterministic=True in the hd256 backward by @felipemello1 in #2952
• [Cute, Sm100] bwd postprocess: load 2-CTA dQaccum directly into registers by @pchen7e2 in #2960
• [CuTe, SM100] Unify hd256 backward (1/5): tests first, named 2CTA schedules and TMEM widths by @Johnsonms in #2964
• [CuTe, SM100] Key MLA forward compilation on the KV head count by @drisspg in #2978

New Contributors

• @tuananhlfc made their first contribution in #2872
• @felipemello1 made their first contribution in #2948
• @pchen7e2 made their first contribution in #2960

Full Changelog: fa4-v4.0.0.beta33...fa4-v4.0.0.beta34

What's Changed

• [CuTe, SM100] Sparse MLA bwd: keep P normalization and dS product in fp32 by @abcdabcd987 in #2893
• [CuTe, SM100] Sparse MLA training fwd: exact running softmax max by @abcdabcd987 in #2907
• [CuTe, SM100] Sparse MLA training: dpsum from an O residual by @abcdabcd987 in #2908
• [CuTe, SM100] Sparse MLA recompute-P: allow 64 Q heads by @abcdabcd987 in #2911
• [CuTe, SM100] Sparse MLA bwd preprocess: stop the lse_log2 store at the sequence's rows by @abcdabcd987 in #2912
• [CuTe, SM100] Write real zeros for block-sparse empty tiles by @pashu-cohere in #2906
• [CuTe, SM90] Fit forward tile to the block-sparse block size by @LiRunGuo in #2903
• [CuTe, SM90] Skip the causal/local mask on unmasked KV blocks in forward by @LiRunGuo in #2904
• [ROCm/CK] Fix num_splits heuristic, which could never return more than 1 by @Johnsonms in #2901
• Support seqused_q/seqused_k in SM100 HD256 backward by @Mellonta in #2891
• [CuTe, SM100] hd256 fwd: derive lengths and KV ranges from BlockInfo/SeqlenInfoQK by @drisspg in #2917
• [Cute, Sm100] 1CTA MLA forward (dense + sparse top-k), MLA dispatch heuristic, sparse MLA backward at any head count by @jayhshah in #2938
• Fix lint failure by @jayhshah in #2940

New Contributors

• @LiRunGuo made their first contribution in #2903
• @Mellonta made their first contribution in #2891

Full Changelog: fa4-v4.0.0.beta32...fa4-v4.0.0.beta33

What's Changed

• [CuTe, SM100] Sparse MLA bwd: in-kernel recompute-P + token-chunked backward by @abcdabcd987 in #2816
• Build CUDA extension with C++20 on PyTorch 2.13+ by @zhang-keliang in #2879
• ci: add PyTorch 2.14 to the wheel build matrix by @Johnsonms in #2892
• ci: registry-free GPU job (runner-local SIF) + verify the provisioned overlay from a fresh session by @Johnsonms in #2894
• Compile with c++20 for pytorch 2.13+ by @cih9088 in #2899
• [ROCM] add FLASH_ATTENTION_USE_SYSTEM_AITER flag and commit bump by @micmelesse in #2900
• [CuTe, SM100] Support 1..128 Q heads in sparse MLA via in-kernel TMA padding by @drisspg in #2883

New Contributors

• @zhang-keliang made their first contribution in #2879
• @cih9088 made their first contribution in #2899

Full Changelog: fa4-v4.0.0.beta31...fa4-v4.0.0.beta32

What's Changed

• Add an Attention Sink to Flash MLA for SM100 by @floatingtrees in #2768
• [CuTe, SM100] Stop the non-causal hdim 128 softmax warps spilling by @dawnop in #2869
• [CuTe, SM100] hd256 2-CTA: support seqused_q/seqused_k and the decoder paged-KV shape by @kzos in #2810
• [CuTe, SM100] Preserve hd256 output alignment for vectorized stores by @drisspg in #2880
• One more deprecation; by @drisspg in #2867
• [CuTe, SM100, HD256] optimize SM100 HD256 varlen scheduling and epilogues by @catwinee in #2807
• [CuTe, SM90] Fix swapped backward MMA layout and use 2-stage hdim256 config by @SuperGoodGame in #2888
• [CuTe, Bwd] Return zero gradients for empty Q/K workloads by @guoriyue in #2776
• [CuTe, Fwd] Fix PackGQA predication for padded head dimensions by @guoriyue in #2775

New Contributors

• @floatingtrees made their first contribution in #2768
• @dawnop made their first contribution in #2869
• @kzos made their first contribution in #2810
• @catwinee made their first contribution in #2807
• @SuperGoodGame made their first contribution in #2888

Full Changelog: fa4-v4.0.0.beta30...fa4-v4.0.0.beta31

What's Changed

• [CuTe, SM80/SM120] Guard invalid varlen forward tiles by @eamonn-zh in #2763
• [CuTe] Include callable defaults in JIT cache hashes by @guoriyue in #2773
• [CuTe,Bwd,Sm100] Support head_dim not a multiple of 32 in backward by @KaijingOfficial in #2698
• [CuTe] Speed up SM100 hdim-64 bwd: dedicated P/dS TMEM slots + per-warp signaling by @jack-carlisle-2025 in #2804
• cute: don't widen intentionally-empty offset windows to full attention by @cora-codes in #2490
• Fix seqlen_k_loaded treating a window bound of 0 as unbounded (sliding window) by @lollinng in #2624
• Fix SM90 bwd crash for head_dim in (128, 192] by @cora-codes in #2482

New Contributors

• @guoriyue made their first contribution in #2773
• @KaijingOfficial made their first contribution in #2698
• @jack-carlisle-2025 made their first contribution in #2804
• @cora-codes made their first contribution in #2490
• @lollinng made their first contribution in #2624

Full Changelog: fa4-v4.0.0.beta29...fa4-v4.0.0.beta30

What's Changed

• [CuTe] Speed up scalar SM100 mask compilation by @drisspg in #2819

Full Changelog: fa4-v4.0.0.beta27...fa4-v4.0.0.beta29