From: Daniel Starke daniel.starke@siemens.com
commit 17eac652028501df7ea296b1d9b9c134db262b7d upstream.
In gsm_cleanup_mux() the muxer is closed down and all queues are removed. However, removing the queues is done without explicit control of the underlying buffers. Flush those before freeing up our queues to ensure that all outgoing queues are cleared consistently. Otherwise, a new mux connection establishment attempt may time out while the underlying tty is still busy sending out the remaining data from the previous connection.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Cc: stable@vger.kernel.org Signed-off-by: Daniel Starke daniel.starke@siemens.com Link: https://lore.kernel.org/r/20220414094225.4527-10-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/n_gsm.c | 1 + 1 file changed, 1 insertion(+)
--- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -2087,6 +2087,7 @@ static void gsm_cleanup_mux(struct gsm_m gsm_dlci_release(gsm->dlci[i]); mutex_unlock(&gsm->mutex); /* Now wipe the queues */ + tty_ldisc_flush(gsm->tty); list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list) kfree(txq); INIT_LIST_HEAD(&gsm->tx_list);