Re: [PATCH] iommu/vt-d: Fix 'Null pointer dereferences' issue

[Ethan Zhao <haifeng.zhao@linux.intel.com>]

On 9/3/2024 10:46 PM, Qianqiang Liu wrote:
> Passing null pointer "pdev" to "pci_enable_pasid", which dereferences it.
> Check the "pdev" is null or not before passing to "pci_enable_pasid".
>
> Signed-off-by: Qianqiang Liu <qianqiang.liu@163.com>
> ---
>   drivers/iommu/intel/iommu.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 9f6b0780f2ef..a1e54f334330 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -3935,7 +3935,7 @@ static struct iommu_device *intel_iommu_probe_device(struct device *dev)
>   	 * So always enable PASID support on devices which have it, even if
>   	 * we can't yet know if we're ever going to use it.
>   	 */
> -	if (info->pasid_supported &&
> +	if (info->pasid_supported && pdev &&
>   	    !pci_enable_pasid(pdev, info->pasid_supported & ~1))

You hit any issue with specific ver kernel ? seems impossible to hit
such NULL pointer issue with the latest kernel for which you sent
this patch.

Thanks,
Ethan

>   		info->pasid_enabled = 1;
>