Tvm.build build with Target("c")(target.build.c) built moduler failed to run

If i want to set target = tvm.Target(“c”) when build with tvm.build() (call target.build.c),the rt_mod which is a CSourceModuleNode will be successfully built. However it fails to run, it turns out that GetFunction did’n implement the function that returns the function handle we builit, what i should to do to CSourceModuleNode to make Target(“c”) built moduler runable?