serial: 8250_dw: unregister 8250 port if clk_notifier_register() fails

dw8250_probe() registers the 8250 port via serial8250_register_8250_port()
and then, if the device has a clock, registers a clock notifier. If
clk_notifier_register() fails, probe returns the error but leaves the
8250 port registered. The matching serial8250_unregister_port() lives
in dw8250_remove(), which is not called when probe fails, so the port
slot stays occupied until the device is rebound or the system is
rebooted. The devm-allocated driver data is freed while the port still
references it (via the saved private_data and serial_in/serial_out
callbacks), so any access to that port slot before a rebind is a
use-after-free hazard.

Unregister the port on the clk_notifier_register() error path.

Fixes: cc816969d7b5 ("serial: 8250_dw: Fix common clocks usage race condition")
Cc: stable@vger.kernel.org
Signed-off-by: Stepan Ionichev <sozdayvek@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20260514143746.23671-2-sozdayvek@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 55e40c10f46a295e6f36ba825397de9768629a38..2d30a164eeae0aaba644fafa247161a6a8fd8146 100644 (file)
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -839,8 +839,10 @@ static int dw8250_probe(struct platform_device *pdev)
         */
        if (data->clk) {
                err = clk_notifier_register(data->clk, &data->clk_notifier);
-               if (err)
+               if (err) {
+                       serial8250_unregister_port(data->data.line);
                        return dev_err_probe(dev, err, "Failed to set the clock notifier\n");
+               }
                queue_work(system_dfl_wq, &data->clk_work);
        }