epoll_reactor::deregister_descriptor() release descriptor_data

[ljl <404140036@…>]

epoll_reactor::deregister_descriptor() function puts descriptor_state object in its object_pool, so it can be reused by epoll_reactor::register_descriptor() immediately, but the descriptor_state object may be yet referenced somewhere, for example, epoll_reactor::run() puts it in op_queue<operation>, and be about to execute operation::complete() in task_io_service::do_run_one() function. it will make logic problems when the descriptor_state object is reused indeed in a third thread by calling epoll_reactor::allocate_descriptor_state().

[anonymous]

descriptor_state::do_complete() running this time seems for other associated socket, is this condition in your consideration?