# fix kernel #2 (occupied-slot rejection):
DF2970: linesw[6] (NETGRAPHDISC) live l_open=0xffffffff8279ba70
DF2970: ldisc_register(6, fake) -> slot=-1 ... linesw[6].l_open unchanged (0xffffffff8279ba70)
# slot=-1 = REJECTED; linesw[6] NOT overwritten (stock: slot=6 silently accepted + overwrite)