This is a note to let you know that I've just added the patch titled
tty: n_gsm: fix packet re-transmission without open control channel
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tty-n_gsm-fix-packet-re-transmission-without-open-co.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1503c79d18b419c40fedd0123f45200b2a5c1bd1
Author: Daniel Starke <daniel.starke@xxxxxxxxxxx>
Date: Fri Jul 1 08:16:50 2022 +0200
tty: n_gsm: fix packet re-transmission without open control channel
[ Upstream commit 4fae831b3a71fc5a44cc5c7d0b8c1267ee7659f5 ]
In the current implementation control packets are re-transmitted even if
the control channel closed down during T2. This is wrong.
Check whether the control channel is open before re-transmitting any
packets. Note that control channel open/close is handled by T1 and not T2
and remains unaffected by this.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
Signed-off-by: Daniel Starke <daniel.starke@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220701061652.39604-7-daniel.starke@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index e7fd4ed08bd5..01ff3f1b2350 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -1398,7 +1398,7 @@ static void gsm_control_retransmit(unsigned long data)
spin_lock_irqsave(&gsm->control_lock, flags);
ctrl = gsm->pending_cmd;
if (ctrl) {
- if (gsm->cretries == 0) {
+ if (gsm->cretries == 0 || !gsm->dlci[0] || gsm->dlci[0]->dead) {
gsm->pending_cmd = NULL;
ctrl->error = -ETIMEDOUT;
ctrl->done = 1;
