--- /dev/null
+From e8f69b16ee776da88589b5271e3f46020efc8f6c Mon Sep 17 00:00:00 2001
+From: Johan Hovold <johan@kernel.org>
+Date: Fri, 17 Sep 2021 12:12:04 +0200
+Subject: net: hso: fix muxed tty registration
+
+From: Johan Hovold <johan@kernel.org>
+
+commit e8f69b16ee776da88589b5271e3f46020efc8f6c upstream.
+
+If resource allocation and registration fail for a muxed tty device
+(e.g. if there are no more minor numbers) the driver should not try to
+deregister the never-registered (or already-deregistered) tty.
+
+Fix up the error handling to avoid dereferencing a NULL pointer when
+attempting to remove the character device.
+
+Fixes: 72dc1c096c70 ("HSO: add option hso driver")
+Cc: stable@vger.kernel.org # 2.6.27
+Signed-off-by: Johan Hovold <johan@kernel.org>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/net/usb/hso.c | 12 +++++-------
+ 1 file changed, 5 insertions(+), 7 deletions(-)
+
+--- a/drivers/net/usb/hso.c
++++ b/drivers/net/usb/hso.c
+@@ -2729,14 +2729,14 @@ struct hso_device *hso_create_mux_serial
+
+ serial = kzalloc(sizeof(*serial), GFP_KERNEL);
+ if (!serial)
+- goto exit;
++ goto err_free_dev;
+
+ hso_dev->port_data.dev_serial = serial;
+ serial->parent = hso_dev;
+
+ if (hso_serial_common_create
+ (serial, 1, CTRL_URB_RX_SIZE, CTRL_URB_TX_SIZE))
+- goto exit;
++ goto err_free_serial;
+
+ serial->tx_data_length--;
+ serial->write_data = hso_mux_serial_write_data;
+@@ -2752,11 +2752,9 @@ struct hso_device *hso_create_mux_serial
+ /* done, return it */
+ return hso_dev;
+
+-exit:
+- if (serial) {
+- tty_unregister_device(tty_drv, serial->minor);
+- kfree(serial);
+- }
++err_free_serial:
++ kfree(serial);
++err_free_dev:
+ kfree(hso_dev);
+ return NULL;
+