From a2baa907c2818131cd05cca3c33cff955993f2b4 Mon Sep 17 00:00:00 2001 From: Daniel Starke Date: Thu, 14 Apr 2022 02:42:14 -0700 Subject: [PATCH] tty: n_gsm: fix wrong DLCI release order commit deefc58bafb4841df7f0a0d85d89a1c819db9743 upstream. The current DLCI release order starts with the control channel followed by the user channels. Reverse this order to keep the control channel open until all user channels have been released. Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Cc: stable@vger.kernel.org Signed-off-by: Daniel Starke Link: https://lore.kernel.org/r/20220414094225.4527-9-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_gsm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index ea7283b6037d..77bb93262c65 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -2073,8 +2073,8 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc) /* Finish outstanding timers, making sure they are done */ del_timer_sync(&gsm->t2_timer); - /* Free up any link layer users */ - for (i = 0; i < NUM_DLCI; i++) + /* Free up any link layer users and finally the control channel */ + for (i = NUM_DLCI - 1; i >= 0; i--) if (gsm->dlci[i]) gsm_dlci_release(gsm->dlci[i]); mutex_unlock(&gsm->mutex);