tty: n_gsm: fix missing explicit ldisc flush

commit 17eac65202 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: e1eaea46bb ("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>
This commit is contained in:
Daniel Starke
2022-04-14 02:42:15 -07:00
committed by Greg Kroah-Hartman
parent 2484787cde
commit 73defa00a7

View File

@@ -2087,6 +2087,7 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc)
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);