From: daniel.starke@siemens.com daniel.starke@siemens.com
commit e3b7468f082d106459e86e8dc6fb9bdd65553433 upstream.
Trying to open a DLCI by sending a SABM frame may fail with a timeout. The link is closed on the initiator side without informing the responder about this event. The responder assumes the link is open after sending a UA frame to answer the SABM frame. The link gets stuck in a half open state.
This patch fixes this by initiating the proper link termination procedure after link setup timeout instead of silently closing it down.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Cc: stable@vger.kernel.org Signed-off-by: Daniel Starke daniel.starke@siemens.com Link: https://lore.kernel.org/r/20220218073123.2121-3-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/n_gsm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1506,7 +1506,7 @@ static void gsm_dlci_t1(unsigned long da dlci->mode = DLCI_MODE_ADM; gsm_dlci_open(dlci); } else { - gsm_dlci_close(dlci); + gsm_dlci_begin_close(dlci); /* prevent half open link */ }
break;