fix: add safeguards to _convert_to_json_serializable_dict to prevent infinite recursion

- Add max_depth parameter (default 20) to prevent infinite recursion
- Add circular reference protection using visited set
- Add function to recursive_detector ignore list with proper safeguards
- Fixes CPU usage spikes caused by unguarded recursive function

litellm/proxy/spend_tracking/spend_tracking_utils.py

@@ -641,7 +641,9 @@ def _sanitize_request_body_for_spend_logs_payload(
     return {k: _sanitize_value(v) for k, v in request_body.items()}
 
 
-def _convert_to_json_serializable_dict(obj: Any) -> Any:
+def _convert_to_json_serializable_dict(
+    obj: Any, visited: Optional[set] = None, max_depth: int = 20
+) -> Any:
     """
     Convert object to JSON-serializable dict, handling Pydantic models safely.
 
@@ -650,23 +652,55 @@ def _convert_to_json_serializable_dict(obj: Any) -> Any:
 
     Args:
         obj: Object to convert (dict, list, Pydantic model, or primitive)
+        visited: Set of object IDs to track circular references
+        max_depth: Maximum recursion depth to prevent infinite recursion
 
     Returns:
         JSON-serializable version of the object
     """
-    if isinstance(obj, BaseModel):
-        # Use Pydantic's model_dump() instead of pickle
-        return obj.model_dump()
-    elif isinstance(obj, dict):
-        return {k: _convert_to_json_serializable_dict(v) for k, v in obj.items()}
-    elif isinstance(obj, list):
-        return [_convert_to_json_serializable_dict(item) for item in obj]
-    elif hasattr(obj, "__dict__"):
-        # Handle objects with __dict__ attribute
-        return _convert_to_json_serializable_dict(obj.__dict__)
-    else:
-        # Primitives (str, int, float, bool, None) pass through
-        return obj
+    if max_depth <= 0:
+        # Return a placeholder if max depth is exceeded
+        return "<max_depth_exceeded>"
+    
+    if visited is None:
+        visited = set()
+    
+    # Get the object's memory address to track visited objects
+    obj_id = id(obj)
+    if obj_id in visited:
+        # Circular reference detected, return placeholder
+        return "<circular_reference>"
+    
+    # Only track mutable objects (dict, list, objects with __dict__)
+    if isinstance(obj, (dict, list)) or hasattr(obj, "__dict__"):
+        visited.add(obj_id)
+    
+    try:
+        if isinstance(obj, BaseModel):
+            # Use Pydantic's model_dump() instead of pickle
+            result = obj.model_dump()
+            # Recursively process the dumped dict
+            return _convert_to_json_serializable_dict(result, visited, max_depth - 1)
+        elif isinstance(obj, dict):
+            return {
+                k: _convert_to_json_serializable_dict(v, visited, max_depth - 1)
+                for k, v in obj.items()
+            }
+        elif isinstance(obj, list):
+            return [
+                _convert_to_json_serializable_dict(item, visited, max_depth - 1)
+                for item in obj
+            ]
+        elif hasattr(obj, "__dict__"):
+            # Handle objects with __dict__ attribute
+            return _convert_to_json_serializable_dict(obj.__dict__, visited, max_depth - 1)
+        else:
+            # Primitives (str, int, float, bool, None) pass through
+            return obj
+    finally:
+        # Remove from visited set when done processing this object
+        if obj_id in visited:
+            visited.remove(obj_id)
 
 
 def _get_proxy_server_request_for_spend_logs_payload(

tests/code_coverage_tests/recursive_detector.py

@@ -42,6 +42,7 @@ IGNORE_FUNCTIONS = [
     "_validate_inheritance_chain",  # max depth set (default 100) to prevent infinite recursion in policy inheritance validation.
     "_basic_json_schema_validate",  # max depth set.
     "extract_text_from_a2a_message",  # max depth set (default 10) to prevent infinite recursion in A2A message parsing.
+    "_convert_to_json_serializable_dict",  # max depth set (default 20) and circular reference protection to prevent infinite recursion.
 ]