ST_AsText on a deeply nested GeometryCollection crashes mariadbd

The following SQL reproduced the failure on MariaDB 12.3.3 (12.3.3-MariaDB-ubu2404) on Linux/amd64:

DROP DATABASE IF EXISTS nested_geometry;

CREATE DATABASE nested_geometry;

USE nested_geometry;

DELIMITER $$

CREATE PROCEDURE render_nested_collection()

BEGIN

  DECLARE text_length BIGINT;

  SELECT LENGTH(

           ST_AsText(

             CONCAT(

               x'00000000',

               REPEAT(x'010700000001000000', 100000),

               x'010100000000000000000000000000000000000000'

             )

           )

         )

    INTO text_length;

  SELECT text_length;

END$$

DELIMITER ;

CALL render_nested_collection();

The CALL terminated mariadbd with exit code 139. The server was no longer running immediately afterward and required recovery. The process was not terminated by an out-of-memory condition. The server log ended before the fatal event and contained no stack trace.

ST_AsText should return a value or reject the excessively nested geometry with a controlled SQL error. Processing the input must not terminate the database server.

Source inspection indicates that Gis_geometry_collection::get_data_as_wkt() recursively calls geom->as_wkt() without a stack-overrun check. This is an inference from the inspected source because no crash backtrace was recorded.

This occurs when ST_AsText deparses a GeometryCollection containing 100,000 nested collections inside a stored procedure.