[PATCH v2 7/9] tty: n_gsm: fix packet re-transmission without open control channel

D. Starke
2022-05-19T07:10:10Z

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")
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
---
drivers/tty/n_gsm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

See patch 6 regarding changes since to v1.

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 6d68aaf1dae8..dfc537eb2b49 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -1624,7 +1624,7 @@ static void gsm_control_retransmit(struct timer_list *t)
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;
--
2.34.1