Re: [PATCH] serial: 8250-dw: unregister 8250 port if clk_notifier_register() fails

[Andy Shevchenko]

On Wed, May 13, 2026 at 08:05:03PM +0500, Stepan Ionichev wrote:
> dw8250_probe() registers the 8250 port via serial8250_register_8250_port()
> and then, if the device has a clock, registers a clock notifier:
> 
> 	data->data.line = serial8250_register_8250_port(up);
> 	if (data->data.line < 0)
> 		return data->data.line;
> 	...
> 	if (data->clk) {
> 		err = clk_notifier_register(data->clk, &data->clk_notifier);
> 		if (err)
> 			return dev_err_probe(dev, err,
> 					     "Failed to set the clock notifier\n");
> 		...
> 	}
> 
> 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 in the serial8250 array 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 would be a use-after-free.
> 
> Unregister the port on the clk_notifier_register() error path.

Maybe as a fix for backporting. For the current cycle can you remove that
notifier and all that crap that was brought by Baikal upstreaming which won't
ever be finished (as we actually dropped Baikal code in the kernel)?

Or maybe series of two: this one as backport and the other one as fix / remove
Baikal support entirely from this driver.

-- 
With Best Regards,
Andy Shevchenko