Re: [PATCH v4] iommu/s390: Implement blocking domain

[Joerg Roedel]

On Tue, Sep 10, 2024 at 05:15:16PM -0400, Matthew Rosato wrote:
> This fixes a crash when surprise hot-unplugging a PCI device. This crash
> happens because during hot-unplug __iommu_group_set_domain_nofail()
> attaching the default domain fails when the platform no longer
> recognizes the device as it has already been removed and we end up with
> a NULL domain pointer and UAF. This is exactly the case referred to in
> the second comment in __iommu_device_set_domain() and just as stated
> there if we can instead attach the blocking domain the UAF is prevented
> as this can handle the already removed device. Implement the blocking
> domain to use this handling.  With this change, the crash is fixed but
> we still hit a warning attempting to change DMA ownership on a blocked
> device.

Applied, thanks.