[PATCH] watchdog: ixp4xx: fix reference leak on platform_device_register() failure

[Linus Walleij]

On Sun, Apr 19, 2026 at 11:08 PM Guenter Roeck <linux at roeck-us.net> wrote:
> On 4/19/26 13:22, Linus Walleij wrote:

> > Hi Guangshuo,
> >
> > thanks for your patch!
> >
> > On Mon, Apr 13, 2026 at 5:47 PM Guangshuo Li <lgs201920130244 at gmail.com> wrote:
> >
> >> ixp4xx_timer_probe() directly returns the result of
> >> platform_device_register(&ixp4xx_watchdog_device). When registration
> >> fails, the embedded struct device in ixp4xx_watchdog_device has already
> >> been initialized by device_initialize(), but the failure path does not
> >> drop the device reference, leading to a reference leak.
> > (...)
> >
> >> -       return platform_device_register(&ixp4xx_watchdog_device);
> >> +       ret = platform_device_register(&ixp4xx_watchdog_device);
> >> +       if (ret)
> >> +               platform_device_put(&ixp4xx_watchdog_device);
> >
> > If the problem in the description is indeed there, it seems the bug
> > is inside platform_device_register(), surely a function returning an
> > error code is supposed to clean up any resources it takes before
> > returning an error. It seems wrong to try to fix this in all the
> > consumers.
> >
>
>  From platform_device_register():
>
> /**
>   * platform_device_register - add a platform-level device
>   * @pdev: platform device we're adding
>   *
>   * NOTE: _Never_ directly free @pdev after calling this function, even if it
>   * returned an error! Always use platform_device_put() to give up the
>   * reference initialised in this function instead.
>   */
>
> Not that any code actually does that as far as I can see, but isn't
> the above doing exactly what the comment suggests ?

Yeah and Johan Hovold wrote that comment and he usually knows
what he's doing so let's go with this then, I'm convinced!

Reviewed-by: Linus Walleij <linusw at kernel.org>

Yours,
Linus Walleij