[Bugfix][VoxCPM2]: Fix vectorized_gather OOB under concurrent prefill+decode batches (#2903)

Signed-off-by: Sy03 <1370724210@qq.com>

vllm_omni/model_executor/models/voxcpm2/voxcpm2_talker.py

@@ -41,6 +41,11 @@ logger = init_logger(__name__)
 
 _ENABLE_PROFILING = os.environ.get("VOXCPM2_PROFILE", "0") == "1"
 
+# Lower bound for the _active_states leak-warn threshold.  The effective
+# threshold is max(_ACTIVE_STATE_LEAK_WARN_MIN, 4 * max_batch_size) so small
+# deployments still get a usable floor instead of a tiny noisy one.
+_ACTIVE_STATE_LEAK_WARN_MIN = 512
+
 
 def is_cjk_char(c: str) -> bool:
     """Check if a character is a CJK ideograph."""
@@ -440,6 +445,9 @@ class VoxCPM2TalkerForConditionalGeneration(nn.Module):
         self._results_queue: list[tuple[str, torch.Tensor | None]] = []
         self._audio_queue: list[tuple[str, Any]] = []
         self._deferred_cleanup_ids: set[str] = set()
+        self._active_state_warn_threshold = max(_ACTIVE_STATE_LEAK_WARN_MIN, 4 * self._max_batch_size)
+        # one-shot by design: fires at most once per process to avoid log spam.
+        self._active_state_warned = False
 
     @property
     def tts(self) -> nn.Module:
@@ -449,9 +457,20 @@ class VoxCPM2TalkerForConditionalGeneration(nn.Module):
     # -------------------- request state management --------------------
 
     def _get_or_create_state(self, request_id: str) -> _RequestState:
-        if request_id not in self._active_states:
-            self._active_states[request_id] = _RequestState(request_id=request_id)
-        return self._active_states[request_id]
+        state = self._active_states.get(request_id)
+        if state is None:
+            state = _RequestState(request_id=request_id)
+            self._active_states[request_id] = state
+            if len(self._active_states) > self._active_state_warn_threshold and not self._active_state_warned:
+                logger.warning(
+                    "VoxCPM2: _active_states size=%d exceeds threshold %d "
+                    "(max_batch_size=%d); possible cleanup path leak",
+                    len(self._active_states),
+                    self._active_state_warn_threshold,
+                    self._max_batch_size,
+                )
+                self._active_state_warned = True
+        return state
 
     def _switch_to_request(self, request_id: str) -> _RequestState:
         if request_id != self._current_request_id:
@@ -1087,14 +1106,10 @@ class VoxCPM2TalkerForConditionalGeneration(nn.Module):
         is_prefill = span_len > 1
 
         if is_prefill:
-            # Evict stale states
-            pending_ids = {rid for rid, *_ in self._pending_requests}
-            pending_ids.add(req_id)
-            if self._current_request_id:
-                pending_ids.add(self._current_request_id)
-            for rid in [r for r, s in self._active_states.items() if r not in pending_ids and s.prefill_completed]:
-                self._cleanup_request(rid)
-
+            # Do not evict state here: _pending_requests is a per-step prefix,
+            # not the full batch. Cleanup is driven by on_requests_finished ->
+            # _flush_deferred_cleanup (fed by vLLM scheduler._free_request via
+            # gpu_ar_model_runner.py).
             real = info_dict.get("text_token_ids")
             token_ids = input_ids.tolist() if real is None else real[0]
             # Fail-fast: unsplit multichar Chinese IDs in input_ids means the