From: Daniel Starke daniel.starke@siemens.com
commit 284260f278b706364fb4c88a7b56ba5298d5973c upstream.
Internally, we manage the alive state of the mux channels and mux itself with the field member 'dead'. This makes it possible to notify the user if the accessed underlying link is already gone. On the other hand, however, removing the virtual ttys before terminating the channels may result in peer messages being received without any internal target. Move the mux cleanup procedure from gsmld_detach_gsm() to gsmld_close() to fix this by keeping the virtual ttys open until the mux has been cleaned up.
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/20220414094225.4527-4-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/n_gsm.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
--- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -2418,7 +2418,6 @@ static void gsmld_detach_gsm(struct tty_ WARN_ON(tty != gsm->tty); for (i = 1; i < NUM_DLCI; i++) tty_unregister_device(gsm_tty_driver, base + i); - gsm_cleanup_mux(gsm, false); tty_kref_put(gsm->tty); gsm->tty = NULL; } @@ -2483,6 +2482,12 @@ static void gsmld_close(struct tty_struc { struct gsm_mux *gsm = tty->disc_data;
+ /* The ldisc locks and closes the port before calling our close. This + * means we have no way to do a proper disconnect. We will not bother + * to do one. + */ + gsm_cleanup_mux(gsm, false); + gsmld_detach_gsm(tty, gsm);
gsmld_flush_buffer(tty);