[Bugfix] Check that number of images matches number of <|image|> tokens with mllama (#11939)

Signed-off-by: Travis Johnson <tsjohnso@us.ibm.com>

vllm/model_executor/models/mllama.py

@@ -123,6 +123,13 @@ def input_processor_for_mllama(
 
     assert is_list_of(image_data, Image.Image)
 
+    num_image_tokens = dec_inputs['prompt_token_ids'].count(
+        MLLAMA_IMAGE_TOKEN_ID)
+    if num_image_tokens != len(image_data):
+        raise ValueError(
+            f"The number of image tokens ({num_image_tokens}) must be"
+            f" the same as the number of images ({len(image_data)})")
+
     # Since only the last group of consecutive images
     # are attended by the decoded tokens, we only need to
     # get the number of tiles for those images.
@@ -1493,6 +1500,8 @@ def convert_sparse_cross_attention_mask_to_dense(
             dense_mask[seq_start + start:seq_start + end,
                        tile_start:tile_start + tile] = 1
             tile_start += tile
+        assert ts != -1
+        assert td != 0
         tile_range_for_decode.append((ts, ts + td))
         seq_start += length