Re: [PATCH] serial: 8250_accent: fix reference leak on failed device registration

[Guangshuo Li]

Hi Jiri,

Please disregard this patch.

On Thu, 16 Apr 2026 at 14:14, Jiri Slaby <jirislaby@xxxxxxxxxx> wrote:
>
> Hi,
>
> On 15. 04. 26, 20:34, Guangshuo Li wrote:
> > When platform_device_register() fails in accent_init(), the embedded
> > struct device in accent_device has already been initialized by
> > device_initialize(), but the failure path returns the error without
> > dropping the device reference for the current platform device:
> >
> >    accent_init()
> >      -> platform_device_register(&accent_device)
> >         -> device_initialize(&accent_device.dev)
> >         -> setup_pdev_dma_masks(&accent_device)
> >         -> platform_device_add(&accent_device)
> >
> > This leads to a reference leak when platform_device_register() fails.
>
> What reference exactly?
>
> > Fix this by calling platform_device_put() before returning the error.
> >
> > The issue was identified by a static analysis tool I developed and
> > confirmed by manual review.
>
> How did you verify you did the right change?
>
> > Fixes: ec9f47cd6a14c ("[PATCH] Serial: Split 8250 port table")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Guangshuo Li <lgs201920130244@xxxxxxxxx>
> > ---
> >   drivers/tty/serial/8250/8250_accent.c | 8 +++++++-
> >   1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/tty/serial/8250/8250_accent.c b/drivers/tty/serial/8250/8250_accent.c
> > index 1691f1a57f89..e9cf40268c0e 100644
> > --- a/drivers/tty/serial/8250/8250_accent.c
> > +++ b/drivers/tty/serial/8250/8250_accent.c
> > @@ -25,7 +25,13 @@ static struct platform_device accent_device = {
> >
> >   static int __init accent_init(void)
> >   {
> > -     return platform_device_register(&accent_device);
> > +     int ret;
> > +
> > +     ret = platform_device_register(&accent_device);
> > +     if (ret)
> > +             platform_device_put(&accent_device);
>
> In particular, what does put_device() do on a static device, even
> initialized, ie. with no device::release? Try it...
>
> IMO, all the patches are bogus.
>
> thanks,
> --
> js
> suse labs

After re-checking it, accent_device is a static platform_device and it
does not provide a dev.release callback, so calling platform_device_put()
on the platform_device_register() failure path is not appropriate and can
trigger the missing release callback warning.

This falls into the same static platform_device pattern as the other
patches, so I will drop it.

Sorry for the noise.

Best regards,
Guangshuo Li