[Bugfix][Hardware][CPU] Fix CPU `input_positions` creation for text-only inputs with mrope (#11434)

Signed-off-by: Isotr0py <2037008807@qq.com>

vllm/worker/cpu_model_runner.py

@@ -114,8 +114,7 @@ class ModelInputForCPUBuilder(ModelRunnerInputBuilderBase[ModelInputForCPU]):
         def __init__(self, use_mrope: bool):
             self.use_mrope = use_mrope
             self.input_tokens: List[int] = []
-            self.input_positions: Optional[
-                List[int]] = [] if not self.use_mrope else None
+            self.input_positions: List[int] = []
             self.token_type_ids: Optional[List[int]] = []
             self.seq_lens: List[int] = []
             self.query_lens: List[int] = []
@@ -130,9 +129,8 @@ class ModelInputForCPUBuilder(ModelRunnerInputBuilderBase[ModelInputForCPU]):
             self.multi_modal_placeholder_maps: Dict[
                 str, MultiModalPlaceholderMap] = defaultdict(
                     MultiModalPlaceholderMap)
-            self.input_mrope_positions: Optional[List[List[int]]] = [
-                [] for _ in range(3)
-            ] if self.use_mrope else None
+            self.input_mrope_positions: List[List[int]] = [[]
+                                                           for _ in range(3)]
 
     def __init__(self,
                  runner: "CPUModelRunner",
@@ -167,7 +165,8 @@ class ModelInputForCPUBuilder(ModelRunnerInputBuilderBase[ModelInputForCPU]):
                                     device="cpu")
         input_positions = torch.tensor(
             input_data.input_positions
-            if not input_data.use_mrope else input_data.input_mrope_positions,
+            if not any(input_data.input_mrope_positions) else
+            input_data.input_mrope_positions,
             dtype=torch.long,
             device="cpu")
         token_type_ids = torch.tensor(input_data.token_type_ids,
@@ -236,7 +235,7 @@ class ModelInputForCPUBuilder(ModelRunnerInputBuilderBase[ModelInputForCPU]):
             block_table = block_table[start_block:]
 
         # For MRotaryEmbedding
-        if data.input_positions is None:
+        if seq_data.mrope_position_delta is not None:
             next_pos = MRotaryEmbedding.get_next_input_positions(
                 seq_data.mrope_position_delta,
                 context_len,
@@ -309,7 +308,6 @@ class ModelInputForCPUBuilder(ModelRunnerInputBuilderBase[ModelInputForCPU]):
             data.slot_mapping.extend(slot_mapping)
 
         # The MROPE positions are prepared in _compute_multi_modal_input
-        if data.input_positions is not None:
         data.input_positions.extend(token_positions)
 
         if data.token_type_ids is not None: