nbd: defer config put in recv_work
In the Linux kernel, the following vulnerability has been resolved: nbd: defer config put in recv_work There is one uaf issue in recv_work when running NBD_CLEAR_SOCK and NBD_CMD_RECONFIGURE: nbd_genl_connect // conf_ref=2 (connect and recv_work A) nbd_open // conf_ref=3 recv_work A done // conf_ref=2 NBD_CLEAR_SOCK // conf_ref=1 nbd_genl_reconfigure // conf_ref=2 (trigger recv_work B) close nbd // conf_ref=1 recv_work B config_put // conf_ref=0 atomic_dec(&config->recv_threads); -> UAF Or only running NBD_CLEAR_SOCK: nbd_genl_connect // conf_ref=2 nbd_open // conf_ref=3