Re: [PATCH] media: rtl28xxu: fix SDR platform device leak

[Guangshuo Li]

Hi Hans,

On Wed, 23 Sept 2026 at 16:49, Hans Verkuil <hverkuil+cisco@xxxxxxxxxx> wrote:
>
> On 21/09/2026 10:15, Guangshuo Li wrote:
> > rtl2832u_tuner_attach() registers an rtl2832_sdr platform device, but
> > if registration succeeds without a bound driver, it breaks out without
> > unregistering the device.
> >
> > dev->platform_device_sdr is assigned only after a driver is bound, so
> > rtl28xxu_tuner_detach() cannot unregister the unbound device later.
> > This leaves the registered platform device and its associated resources
> > allocated.
> >
> > Split the registration failure and driver binding checks. Unregister
> > the successfully registered platform device when no driver is bound
> > before leaving the switch.
> >
> > The issue was identified by a static analysis tool I developed and
> > confirmed by manual review.
> >
> > Fixes: a2f7f220df5e ("[media] rtl28xxu: switch SDR module to platform driver")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Guangshuo Li <lgs201920130244@xxxxxxxxx>
> > ---
> >  drivers/media/usb/dvb-usb-v2/rtl28xxu.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/usb/dvb-usb-v2/rtl28xxu.c b/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
> > index 487c6ab784ab..3603d0cf638b 100644
> > --- a/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
> > +++ b/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
> > @@ -1391,8 +1391,12 @@ static int rtl2832u_tuner_attach(struct dvb_usb_adapter *adap)
> >                                                    "rtl2832_sdr",
> >                                                    PLATFORM_DEVID_AUTO,
> >                                                    &pdata, sizeof(pdata));
> > -             if (IS_ERR(pdev) || pdev->dev.driver == NULL)
> > +             if (IS_ERR(pdev))
> >                       break;
> > +             if (!pdev->dev.driver) {
> > +                     platform_device_unregister(pdev);
> > +                     break;
> > +             }
>
> Looking at other drivers, I think this is incomplete.
>
> drivers/media/usb/dvb-usb-v2/zd1301.c, line 142, does it correct. Note the
> try_module_get() call that is missing in rtl28xxu.c.
>
> Regards,
>
>         Hans
>
> >               dev->platform_device_sdr = pdev;
> >               break;
> >       default:
>

Thanks for pointing that out. I'll follow the zd1301.c pattern, add the
missing try_module_get()/module_put() pair, and include it in v2.

Thanks,
Guangshuo