[Bugfix] Reject negative values for max_logprobs and long_prefill_token_threshold#44002
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jwzheng96 wants to merge 6 commits into
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[Bugfix] Reject negative values for max_logprobs and long_prefill_token_threshold#44002jwzheng96 wants to merge 6 commits into
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…en_threshold `ModelConfig.max_logprobs` and `SchedulerConfig.long_prefill_token_threshold` are CLI-settable ints with no Pydantic constraint, so negative values are stored verbatim. Downstream code only special-cases specific sentinels, so the malformed flag is either silently ineffective or surfaces a confusing "max allowed: <negative>" message — same admission shape that vllm-project#43794 tightened for other config fields. Add `Field(default=20, ge=-1)` to `max_logprobs` (-1 is the existing "no cap, use vocab size" sentinel) and `Field(default=0, ge=0)` to `long_prefill_token_threshold` (0 is the existing "disabled" sentinel). Fixes vllm-project#43985 Signed-off-by: jwzheng96 <jianweizheng@pku.edu.cn> Co-authored-by: Claude <noreply@anthropic.com>
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yewentao256
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May 29, 2026
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both constraints are right and the sentinels are preserved correctly — tests cover sentinel-accept + negative-reject for both. lgtm from my read. |
…config.py Co-authored-by: Wentao Ye <44945378+yewentao256@users.noreply.github.com> Signed-off-by: JianweiZheng <32029023+jwzheng96@users.noreply.github.com>
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LGTM, thanks for the work!
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May 30, 2026
…l_token_threshold Both fields were declared as bare `int` with no Field constraint, and the downstream validation chain only handled specific values: - `max_logprobs`: only `-1` is rewritten to vocab_size; other negatives flow through and either land in a confusing "max allowed: -5" error or silently no-op on the cap check. - `long_prefill_token_threshold`: the clamp is guarded by `0 < threshold < num_new_tokens` and the cap by `> max_model_len`, so a negative value matches neither and silently passes through unvalidated. Add field_validators (mode="after"), matching the pattern landed in vllm-project#43794 and the recent vllm-project#44002 / vllm-project#44042 / vllm-project#44057. `max_logprobs` keeps the `-1` sentinel for auto-derive; `long_prefill_token_threshold` requires `>= 0` (0 = off, > 0 = clamp). Fixes vllm-project#43985. Signed-off-by: Chenglun Hu <chenglunhu@gmail.com>
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…vents configs Add @field_validator decorators to reject invalid configuration values at construction time, preventing silent failures and confusing errors. - flash_attn_max_num_splits_for_cuda_graph: reject non-positive values - tq_max_kv_splits_for_cuda_graph: reject non-positive values - flex_attn_block_m, flex_attn_block_n: validate >= 16 and power of 2 - flex_attn_q_block_size, flex_attn_kv_block_size: validate power of 2 - buffer_steps: reject non-positive values - hwm: reject non-positive values - max_queue_size: reject non-positive values - kv_buffer_size: reject non-positive values - kv_rank: reject negative values when set - kv_parallel_size: reject non-positive values - kv_port: validate port range [1, 65535] - ec_buffer_size: reject non-positive values - ec_rank: reject negative values when set - ec_parallel_size: reject non-positive values - ec_port: validate port range [1, 65535] These fields currently accept invalid values that downstream code doesn't expect, leading to: - Silent no-ops (negative values ignored by conditionals) - Runtime errors with confusing messages - Undefined behavior Pattern follows recent PRs: vllm-project#43794, vllm-project#44002, vllm-project#44070, vllm-project#44093, vllm-project#44125 All validators use mode='after' with clear error messages following project conventions. Signed-off-by: Joinal Ahmed <jahmed@redhat.com>
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Purpose
Two CLI-settable integer config fields silently accept negative values that no
validator rejects:
ModelConfig.max_logprobs(vllm/config/model.py:234) — declaredint = 20with no constraint.
_validate_logprobsonly rewrites the== -1sentinel;every other negative survives. For logprob-requesting traffic the error
message reflects the malformed cap back at the user
(
"max allowed: -5"); for logprob-free traffic the validator is skippedentirely and the flag is a pure no-op.
SchedulerConfig.long_prefill_token_threshold(vllm/config/scheduler.py:80)— declared
int = 0with no constraint. The scheduler clamp is guarded by0 < threshold, so any negative makes the conjunctFalseand the user-setcap has zero effect on scheduling. The existing sanity check only rejects
the too-large case.
Same admission shape that #43794 tightened for other config fields.
Fixes #43985
Test Plan
For this small update, do not need specific unit tests
Test Result
None
Duplicate-work check:
gh pr list --search "43985 in:body",--search "long_prefill_token_threshold validate",--search "max_logprobs Field ge"— no open PR addresses this issue.Reference: same
Field(default=..., ge=N)admission-tightening pattern asthe recently merged #43794 (fixes #43496, #43521, #43532).
AI assistance: drafted with help of Claude (Anthropic) under human review;
the submitter has read every changed line. Attribution recorded as
Co-authored-by: Claude <noreply@anthropic.com>.