Re: [PATCH] drm/i915: Guard against NULL driver_data in i915_pci_probe()

[Krzysztof Karas]

Hi Deepanshu,

On 2026-08-09 at 14:34:30 +0530, Deepanshu Kartikey wrote:
> pci_match_device() can return the dummy pci_device_id_any entry
> when a device is force-bound via sysfs driver_override, in which
> case ->driver_data is unset (NULL). i915_pci_probe() casts it to
> struct intel_device_info * unconditionally and dereferences
> intel_info->require_force_probe, causing a NULL-ptr-deref.
> 
> Reported-by: syzbot+db96c5ff032f4292a8dc@xxxxxxxxxxxxxxxxxxxxxxxxx
> Closes: https://syzkaller.appspot.com/bug?extid=db96c5ff032f4292a8dc
> Tested-by: syzbot+db96c5ff032f4292a8dc@xxxxxxxxxxxxxxxxxxxxxxxxx
> Fixes: 42f5551d2769 ("drm/i915: Split out the PCI driver interface to i915_pci.c")
This "Fixes" tag should point to the commit that breaks stuff,
I believe, so what you are looking for is
7ef5ef5cdead ("drm/i915: add force_probe module parameter to replace alpha_support")
since this patch introduced that unconditional dereference.

> Signed-off-by: Deepanshu Kartikey <kartikey406@xxxxxxxxx>
> ---
>  drivers/gpu/drm/i915/i915_pci.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
> index 82415af47d54..2f03f95945f1 100644
> --- a/drivers/gpu/drm/i915/i915_pci.c
> +++ b/drivers/gpu/drm/i915/i915_pci.c
> @@ -958,6 +958,9 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>  		(struct intel_device_info *) ent->driver_data;
>  	int err;
>  
> +	if (!intel_info)
> +		return -ENODEV;
> +
>  	if (intel_info->require_force_probe && !id_forced(pdev->device)) {
>  		dev_info(&pdev->dev,
>  			 "Your graphics device %04x is not properly supported by i915 in this\n"
> -- 
> 2.43.0
> 

-- 
Best Regards,
Krzysztof