Re: [PATCH 1/1] iommu/vt-d: Fix incorrect pci_for_each_dma_alias() for non-PCI devices

[Bjorn Helgaas <helgaas@kernel.org>]

[+cc Marcin, Thorsten]

On Sat, Oct 12, 2024 at 11:07:20AM +0800, Lu Baolu wrote:
> Previously, the domain_context_clear() function incorrectly called
> pci_for_each_dma_alias() to set up context entries for non-PCI devices.
> This could lead to kernel hangs or other unexpected behavior.
> 
> Add a check to only call pci_for_each_dma_alias() for PCI devices. For
> non-PCI devices, domain_context_clear_one() is called directly.
> 
> Reported-by: Todd Brandt <todd.e.brandt@intel.com>
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219363

Likely the same problem reported earlier by Marcin at
https://bugzilla.kernel.org/show_bug.cgi?id=219349

Thanks to Thorsten for pointing this out.

> Fixes: 9a16ab9d6402 ("iommu/vt-d: Make context clearing consistent with context mapping")
> Cc: stable@vger.kernel.org
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
>  drivers/iommu/intel/iommu.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 9f6b0780f2ef..e860bc9439a2 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -3340,8 +3340,10 @@ static int domain_context_clear_one_cb(struct pci_dev *pdev, u16 alias, void *op
>   */
>  static void domain_context_clear(struct device_domain_info *info)
>  {
> -	if (!dev_is_pci(info->dev))
> +	if (!dev_is_pci(info->dev)) {
>  		domain_context_clear_one(info, info->bus, info->devfn);
> +		return;
> +	}
>  
>  	pci_for_each_dma_alias(to_pci_dev(info->dev),
>  			       &domain_context_clear_one_cb, info);
> -- 
> 2.43.0
>