From 519d0b389c10b3a59a63670a83b094fec92b4f6e Mon Sep 17 00:00:00 2001 From: "daniel.starke@siemens.com" Date: Thu, 17 Feb 2022 23:31:19 -0800 Subject: [PATCH] tty: n_gsm: fix proper link termination after failed open 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 Link: https://lore.kernel.org/r/20220218073123.2121-3-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_gsm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index c2b661eb0ff2d..3a11600389b44 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1488,7 +1488,7 @@ static void gsm_dlci_t1(struct timer_list *t) dlci->mode = DLCI_MODE_ADM; gsm_dlci_open(dlci); } else { - gsm_dlci_close(dlci); + gsm_dlci_begin_close(dlci); /* prevent half open link */ } break;