ipack: ipoctal: fix tty registration race

commit 65c001df517a7bf9be8621b53d43c89f426ce8d6 upstream.

Make sure to set the tty class-device driver data before registering the
tty to avoid having a racing open() dereference a NULL pointer.

Fixes: 9c1d784afc6f ("Staging: ipack/devices/ipoctal: Get rid of ipoctal_list.")
Cc: stable@vger.kernel.org      # 3.7
Acked-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210917114622.5412-3-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/ipack/devices/ipoctal.c b/drivers/ipack/devices/ipoctal.c
index ced928a..84488dc 100644 (file)
--- a/drivers/ipack/devices/ipoctal.c
+++ b/drivers/ipack/devices/ipoctal.c
@@ -395,13 +395,13 @@ static int ipoctal_inst_slot(struct ipoctal *ipoctal, unsigned int bus_nr,
                spin_lock_init(&channel->lock);
                channel->pointer_read = 0;
                channel->pointer_write = 0;
-               tty_dev = tty_port_register_device(&channel->tty_port, tty, i, NULL);
+               tty_dev = tty_port_register_device_attr(&channel->tty_port, tty,
+                                                       i, NULL, channel, NULL);
                if (IS_ERR(tty_dev)) {
                        dev_err(&ipoctal->dev->dev, "Failed to register tty device.\n");
                        tty_port_destroy(&channel->tty_port);
                        continue;
                }
-               dev_set_drvdata(tty_dev, channel);
        }
 
        /*