[PATCH v8 13/15] iommu/amd: Use the generic iommu page table

[Alejandro Jimenez]

On 12/5/25 2:46 PM, Jason Gunthorpe wrote:
> On Fri, Dec 05, 2025 at 10:40:49AM +0800, Lai, Yi wrote:
>> Hi Alejandro Jimenez,
>>
>> Greetings!
>>
>> I used Syzkaller and found that there is WARNING in iommufd_fops_release in linux-next next-20251203.
>>
>> After bisection and the first bad commit is:
>> "
>> 789a5913b29c iommu/amd: Use the generic iommu page table
>> "
> 
> This bisect didn't work out, it is close, but the commit is
> 

Thank you Jason for debugging this. I was wondering what could be the 
possible relation with the AMD changes, since the commit doesn't touch 
iommufd/main.c, and the syskaller logs show Intel HW so the AMD driver 
code is not involved.

Thank you,
Alejandro

> e93d5945ed5b ("iommufd: Change the selftest to use iommupt instead of xarray")
> 
> It is a refcount leak:
> 
> @@ -1215,8 +1215,10 @@ static int iommufd_test_md_check_pa(struct iommufd_ucmd *ucmd,
>          page_size = 1 << __ffs(mock->domain.pgsize_bitmap);
>          if (iova % page_size || length % page_size ||
>              (uintptr_t)uptr % page_size ||
> -           check_add_overflow((uintptr_t)uptr, (uintptr_t)length, &end))
> -               return -EINVAL;
> +           check_add_overflow((uintptr_t)uptr, (uintptr_t)length, &end)) {
> +               rc = -EINVAL;
> +               goto out_put;
> +       }
> 
> I'll send a patch, thanks
> 
> Jason