Re: [PATCH] parisc: led: fix reference leak on failed device registration

[Guangshuo Li]

Hi Jiri, Helge,

Thanks for pointing this out, and thanks Helge for taking care of the
revert.

On Thu, 23 Apr 2026 at 15:09, Helge Deller <deller@xxxxxx> wrote:
>
> Hi Jiri,
>
> On 4/23/26 07:24, Jiri Slaby wrote:
> > On 17. 04. 26, 11:39, Helge Deller wrote:
> >> On 4/15/26 19:05, Guangshuo Li wrote:
> >>> When platform_device_register() fails in startup_leds(), the embedded
> >>> struct device in platform_leds has already been initialized by
> >>> device_initialize(), but the failure path only reports the error and
> >>> does not drop the device reference for the current platform device:
> >>>
> >>>    startup_leds()
> >>>      -> platform_device_register(&platform_leds)
> >>>         -> device_initialize(&platform_leds.dev)
> >>>         -> setup_pdev_dma_masks(&platform_leds)
> >>>         -> platform_device_add(&platform_leds)
> >>>
> >>> This leads to a reference leak when platform_device_register() fails.
> >>> Fix this by calling platform_device_put() after reporting the error.
> >>>
> >>> The issue was identified by a static analysis tool I developed and
> >>> confirmed by manual review.
> >>>
> >>> Fixes: 789e527adfc33 ("parisc: led: Rewrite LED/LCD driver to utilizize Linux LED subsystem")
> >>> Cc: stable@xxxxxxxxxxxxxxx
> >>> Signed-off-by: Guangshuo Li <lgs201920130244@xxxxxxxxx>
> >>> ---
> >>>   drivers/parisc/led.c | 6 ++++--
> >>>   1 file changed, 4 insertions(+), 2 deletions(-)
> >>
> >> applied.
> >> Thanks!
> >> Helge
> >
> > Unless the static pcmtst_pdev has ->type->release or ->release set, the patch triggers a warning upon put().
> >
> > platform_device_register() should be fixed instead.
>
> Thanks for the notice! I'm going to revert that patch.
>
> Just yesterday I refused to apply the other patches for fbdev and suggested
> to fix platform_device_register() instead. See:
> https://marc.info/?l=linux-fbdev&m=177687117206684&w=2
>
> > See also:
> > https://patchew.org/linux/20260415174159.3625777-1-lgs201920130244@xxxxxxxxx/
> Thanks!
> Helge

I agree that this patch is not appropriate. platform_leds 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 can
trigger the missing release callback warning.

Please disregard this patch. I will drop it, and I am also going through
the other patches I sent for the same pattern and following up where they
should be ignored or reverted.

Sorry for the noise.

Best regards,
Guangshuo Li