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A high-throughput and memory-efficient inference and serving engine for LLMs

Mirrored from https://github.com/tduncan-lum/Nvidia-Optimization-Stack---VLLM.git

Synced Nov 14, 05:30 UTC

[AMD][Kernel][Bugfix] Cast offsets tensor bn to tl.int64 to avoid GPU segfault (#23692)

Signed-off-by: Randall Smith <Randall.Smith@amd.com>

rasmith committed Sep 2, 2025 at 17:13 UTC 457e4719710e44014fb8b2eaf668d0c5cfa145c1
1 file changed +3 -3
vllm/attention/ops/prefix_prefill.py
+3 -3
@@ -146,7 +146,7 @@ def _fwd_kernel(Q,
146 start_n = tl.multiple_of(start_n, BLOCK_SIZE)
147 # -- compute qk ----
148 bn = tl.load(B_Loc + cur_batch * stride_b_loc_b +
149 - (start_n // BLOCK_SIZE) * stride_b_loc_s)
149 + (start_n // BLOCK_SIZE) * stride_b_loc_s).to(tl.int64)
150 # [D,BLOCK_SIZE]
151 off_k = (
152 bn[None, :] * stride_k_cache_bs + cur_kv_head * stride_k_cache_h +
@@ -367,7 +367,7 @@ def _fwd_kernel_flash_attn_v2(
367 bn = tl.load(B_Loc + cur_batch * stride_b_loc_b +
368 ((start_n + offs_n) // block_size) * stride_b_loc_s,
369 mask=(start_n + offs_n) < cur_batch_ctx_len,
370 - other=0)
370 + other=0).to(tl.int64)
371 off_k = (
372 bn[None, :] * stride_k_cache_bs + cur_kv_head * stride_k_cache_h +
373 (offs_d[:, None] // x) * stride_k_cache_d +
@@ -575,7 +575,7 @@ def _fwd_kernel_alibi(
575 bn = tl.load(B_Loc + cur_batch * stride_b_loc_b +
576 ((start_n + offs_n) // block_size) * stride_b_loc_s,
577 mask=(start_n + offs_n) < cur_batch_ctx_len,
578 - other=0)
578 + other=0).to(tl.int64)
579 off_k = (
580 bn[None, :] * stride_k_cache_bs + cur_kv_head * stride_k_cache_h +
581 (offs_d[:, None] // x) * stride_k_cache_d +