Re: [PATCH] platform/x86: Fix NULL deref in amd_isp_probe

[Ilpo Järvinen]

On Tue, 11 Aug 2026, Mario Limonciello wrote:

> 
> 
> On 8/10/26 16:52, Nirujogi, Pratap wrote:
> > 
> > 
> > On 8/9/2026 11:24 PM, Xueqin Luo wrote:
> > > [You don't often get email from luoxueqin@xxxxxxxxxx. Learn why this is
> > > important at https://aka.ms/LearnAboutSenderIdentification ]
> > > 
> > > Caution: This message originated from an External Source. Use proper
> > > caution when opening attachments, clicking links, or responding.
> > > 
> > > 
> > > amd_isp_probe() uses ACPI_COMPANION() without NULL check. Add it to
> > > prevent crash when driver_override matches a device without ACPI
> > > companion.
> > > 
> > > Fixes: e1af6f0146d6 ("platform/x86: Update swnode graph for amd isp4")
> > > Signed-off-by: Xueqin Luo <luoxueqin@xxxxxxxxxx>
> > > ---
> > >   drivers/platform/x86/amd/amd_isp4.c | 7 +++++++
> > >   1 file changed, 7 insertions(+)
> > > 
> > > diff --git a/drivers/platform/x86/amd/amd_isp4.c b/drivers/platform/
> > > x86/amd/amd_isp4.c
> > > index 0d494899502c..0026d6663c5c 100644
> > > --- a/drivers/platform/x86/amd/amd_isp4.c
> > > +++ b/drivers/platform/x86/amd/amd_isp4.c
> > > @@ -379,6 +379,11 @@ static int amd_isp_probe(struct platform_device
> > > *pdev)
> > >                  goto error_unregister_sw_node;
> > > 
> > >          adev = ACPI_COMPANION(&pdev->dev);
> > > +       if (!adev) {
> > > +               ret = -ENODEV;
> > > +               goto error_unregister_notifier;
> > > +       }
> > > +
> > >          /* initialize root amd_camera_node */
> > >          adev->driver_data = (void *)pinfo->swnodes[0];
> > > 
> > > @@ -388,6 +393,8 @@ static int amd_isp_probe(struct platform_device *pdev)
> > >          platform_set_drvdata(pdev, isp4_platform);
> > >          return 0;
> > > 
> > > +error_unregister_notifier:
> > > +       bus_unregister_notifier(&i2c_bus_type, &isp4_platform->i2c_nb);
> > >   error_unregister_sw_node:
> > >          software_node_unregister_node_group(isp4_platform->pinfo-
> > > >swnodes);
> > >          return ret;
> > LGTM. I agree that adding the NULL check is good practice. That said, I
> > believe it's not strictly needed as the device_get_match_data() in line#366
> > is expected to fail if there is no ACPI companion.
> 
> It sounds like it's essentially dead code then.

Yeah, lets not add dead-code NULL checks.

> > https://github.com/torvalds/linux/blob/master/drivers/platform/x86/amd/
> > amd_isp4.c#L366
> > 
> > Reviewed-by: Pratap Nirujogi <pratap.nirujogi@xxxxxxx>
> > 
> > > -- 
> > > 2.43.0
> > > 
> > 
> 

-- 
 i.