ipack: ipoctal: fix module reference leak

commit bb8a4fcb2136508224c596a7e665bdba1d7c3c27 upstream.

A reference to the carrier module was taken on every open but was only
released once when the final reference to the tty struct was dropped.

Fix this by taking the module reference and initialising the tty driver
data when installing the tty.

Fixes: 82a82340bab6 ("ipoctal: get carrier driver to avoid rmmod")
Cc: stable@vger.kernel.org      # 3.18
Cc: Federico Vaga <federico.vaga@cern.ch>
Acked-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210917114622.5412-6-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 2765ab54b582966ee37511f200f8a928368e07d5..f558aeb8f88843c28ad0743e5a87d6ee1ec498f3 100644 (file)
--- a/drivers/ipack/devices/ipoctal.c
+++ b/drivers/ipack/devices/ipoctal.c
@@ -87,22 +87,34 @@ static int ipoctal_port_activate(struct tty_port *port, struct tty_struct *tty)
        return 0;
 }
 
-static int ipoctal_open(struct tty_struct *tty, struct file *file)
+static int ipoctal_install(struct tty_driver *driver, struct tty_struct *tty)
 {
        struct ipoctal_channel *channel = dev_get_drvdata(tty->dev);
        struct ipoctal *ipoctal = chan_to_ipoctal(channel, tty->index);
-       int err;
-
-       tty->driver_data = channel;
+       int res;
 
        if (!ipack_get_carrier(ipoctal->dev))
                return -EBUSY;
 
-       err = tty_port_open(&channel->tty_port, tty, file);
-       if (err)
-               ipack_put_carrier(ipoctal->dev);
+       res = tty_standard_install(driver, tty);
+       if (res)
+               goto err_put_carrier;
+
+       tty->driver_data = channel;
+
+       return 0;
+
+err_put_carrier:
+       ipack_put_carrier(ipoctal->dev);
+
+       return res;
+}
+
+static int ipoctal_open(struct tty_struct *tty, struct file *file)
+{
+       struct ipoctal_channel *channel = tty->driver_data;
 
-       return err;
+       return tty_port_open(&channel->tty_port, tty, file);
 }
 
 static void ipoctal_reset_stats(struct ipoctal_stats *stats)
@@ -668,6 +680,7 @@ static void ipoctal_cleanup(struct tty_struct *tty)
 
 static const struct tty_operations ipoctal_fops = {
        .ioctl =                NULL,
+       .install =              ipoctal_install,
        .open =                 ipoctal_open,
        .close =                ipoctal_close,
        .write =                ipoctal_write_tty,