[BugFix][FlashInfer] Fix potential race condition for paged_kv_indptr_cpu #23737
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Signed-off-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>
WoosukKwon
requested review from
alexm-redhat,
comaniac,
njhill,
robertgshaw2-redhat and
ywang96
as code owners
WoosukKwon
changed the title
![gemini-code-assist[bot]](https://avatars.githubusercontent.com/in/956858?s=60&v=4){kind=small}
Contributor
There was a problem hiding this comment.
Code Review
This pull request correctly identifies and fixes a potential race condition in the FlashInfer backend related to paged_kv_indptr_cpu. The race condition could occur during asynchronous data transfers to the GPU, especially when CUDA graphs are enabled. The implemented solution, which involves using an intermediate buffer (paged_kv_indptr_buffer) for the asynchronous copy, is a standard and effective way to resolve this kind of issue. The changes also include a minor optimization for calculating the number of actual pages. Overall, the fix is well-implemented and enhances the robustness of the attention mechanism.
eicherseiji
pushed a commit
to eicherseiji/vllm
that referenced
this pull request
Sep 9, 2025
…_cpu (vllm-project#23737) Signed-off-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>
FeiDaLI
pushed a commit
to FeiDaLI/vllm
that referenced
this pull request
Sep 25, 2025
…_cpu (vllm-project#23737) Signed-off-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
No description provided.