root@fledgling:/usr/src # dtrace -n 'fbt::usb_probe_and_attach:entry{print(*args[0]); exit(0);}'
dtrace: description 'fbt::usb_probe_and_attach:entry' matched 1 probe
CPU     ID                    FUNCTION:NAME
 59   6149       usb_probe_and_attach:entry struct device {
    kobj_ops_t ops = 0
    struct link = {
        struct device *tqe_next = 0
        struct device **tqe_prev = 0xc000000002b1bb9c
    }
    struct devlink = {
        struct device *tqe_next = 0
        struct device **tqe_prev = 0xc000000032504000
    }
    device_t parent = 0
    device_list_t children = {
        struct device *tqh_first = 0
        struct device **tqh_last = 0xc000000002b1bb9c
    }
    driver_t *driver = 0
    devclass_t devclass = 0xc000000032504000
    int unit = 0xc0000000
    char *nameunit = 0x273000000000000
    char *desc = 0
    int busy = 0
    device_state_t state = 1
    uint32_t devflags = 0xc0000000
    u_int flags = 0x346c84a
    u_int order = 0x2310000
    void *ivars = 0
    void *softc = 0x1
    struct sysctl_ctx_list sysctl_ctx = {
        struct sysctl_ctx_entry *tqh_first = 0xc0000000034c6a61
        struct sysctl_ctx_entry **tqh_last = 0x273000000000000
    }
    struct sysctl_oid *sysctl_tree = 0
}