Re: [PATCH v1] drm/sysfb: ofdrm: fix PCI device reference leaks

[최유호]

Dear Thomas,

This issue was identified during our ongoing static-analysis research
while reviewing
kernel code. Specifically, an experimental static analysis tool found
that we are currently
developing. The tool is not public yet, so I prefer not to disclose
further project details
at this stage. AI was used only for cross-review, not as the primary
means of finding or
fixing the bug. I manually reviewed the code and verified the issue
before sending
the patch.

Best regards,
Yuho Choi


On Mon, 20 Apr 2026 at 02:21, Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:
>
> Hi,
>
> thanks for the patch.
>
> Am 20.04.26 um 02:25 schrieb Yuho Choi:
> > display_get_pci_dev_of() gets a referenced PCI device via
> > pci_get_device(). Drop that reference when pci_enable_device() fails and
> > release it during the managed teardown path after pci_disable_device().
> >
> > Without that, ofdrm leaks the pci_dev reference on both the error path
> > and the normal cleanup path.
>
> Did you use an AI to find or fix this bug?
>
> https://docs.kernel.org/process/coding-assistants.html
>
> Best regards
> Thomas
>
> >
> > Fixes: c8a17756c425 ("drm/ofdrm: Add ofdrm for Open Firmware framebuffers")
> > Co-developed-by: Myeonghun Pak <mhun512@xxxxxxxxx>
> > Signed-off-by: Myeonghun Pak <mhun512@xxxxxxxxx>
> > Co-developed-by: Ijae Kim <ae878000@xxxxxxxxx>
> > Signed-off-by: Ijae Kim <ae878000@xxxxxxxxx>
> > Co-developed-by: Taegyu Kim <tmk5904@xxxxxxx>
> > Signed-off-by: Taegyu Kim <tmk5904@xxxxxxx>
> > Signed-off-by: Yuho Choi <dbgh9129@xxxxxxxxx>
> > ---
> >   drivers/gpu/drm/sysfb/ofdrm.c | 2 ++
> >   1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/sysfb/ofdrm.c b/drivers/gpu/drm/sysfb/ofdrm.c
> > index d38ba70f4e0d3..247cf13c80a05 100644
> > --- a/drivers/gpu/drm/sysfb/ofdrm.c
> > +++ b/drivers/gpu/drm/sysfb/ofdrm.c
> > @@ -350,6 +350,7 @@ static void ofdrm_pci_release(void *data)
> >       struct pci_dev *pcidev = data;
> >
> >       pci_disable_device(pcidev);
> > +     pci_dev_put(pcidev);
> >   }
> >
> >   static int ofdrm_device_init_pci(struct ofdrm_device *odev)
> > @@ -375,6 +376,7 @@ static int ofdrm_device_init_pci(struct ofdrm_device *odev)
> >       if (ret) {
> >               drm_err(dev, "pci_enable_device(%s) failed: %d\n",
> >                       dev_name(&pcidev->dev), ret);
> > +             pci_dev_put(pcidev);
> >               return ret;
> >       }
> >       ret = devm_add_action_or_reset(&pdev->dev, ofdrm_pci_release, pcidev);
>
> --
> --
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
> GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)
>
>