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Message-Id: <20220217080555.5387-3-daniel.starke@siemens.com>
Date: Thu, 17 Feb 2022 00:05:51 -0800
From: daniel.starke@...mens.com
To: linux-serial@...r.kernel.org, gregkh@...uxfoundation.org,
jirislaby@...nel.org
Cc: linux-kernel@...r.kernel.org,
Daniel Starke <daniel.starke@...mens.com>
Subject: [PATCH 1/1] tty: n_gsm: fix proper link termination after failed open
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@...r.kernel.org
Signed-off-by: Daniel Starke <daniel.starke@...mens.com>
---
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 0b1808e3a912..52224a3494a0 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -1514,7 +1514,7 @@ 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;
--
2.25.1
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