Checklist

• 1. I have searched related issues but cannot get the expected help.
• 2. The bug has not been fixed in the latest version.
• 3. Please note that if the bug-related issue you submitted lacks corresponding environment info and a minimal reproducible demo, it will be challenging for us to reproduce and resolve the issue, reducing the likelihood of receiving feedback.
• 4. If the issue you raised is not a bug but a question, please raise a discussion at https://github.com/sgl-project/sglang/discussions/new/choose Otherwise, it will be closed.
• 5. Please use English, otherwise it will be closed.

Describe the bug

When I conducted a stability stress test with 400 concurrent requests of varying lengths, the unbootstrap queue in the prefill stage kept piling up. Additionally, the token_usage on the decode side approached 1. Due to the timeout mechanism in our link (e.g., automatically disconnecting when TTFT exceeds 60s), the business layer actively terminates the connection with the sglang HTTP server. However, it appears that the decode side fails to release resources properly, leading to the accumulation of unbootstrap tasks in the prefill stage and eventually causing the decode side to hang.

Decode

Prefill

Reproduction

Look Above

Environment

H20
Prefill 2-node
Decode 4-node